Niagara Power Project FERC No. 2216

 

ASSESSMENT OF THE POTENTIAL EFFECTS OF WATER LEVEL AND FLOW FLUCTUATIONS

AND LAND MANAGEMENT PRACTICES ON RARE, THREATENED, AND ENDANGERED SPECIES

AND SIGNIFICANT OCCURRENCES OF NATURAL COMMUNITIES AT THE NIAGARA POWER PROJECT

 

HTML Format.  Text only

 

Prepared for: New York Power Authority 

Prepared by:  Riveredge Associates, LLC

 

August 2005

 

___________________________________________________

 

Copyright © 2005 New York Power Authority

 

 

1.0                   EXECUTIVE SUMMARY

Purpose of Study

The Niagara Power Project in Lewiston, Niagara County, New York, is one of the largest non-federal hydroelectric facilities in North America.  In 1957, a 50-year license for operation of the Project was issued by the Federal Power Commission (now the Federal Energy Regulatory Commission, or FERC) to the Power Authority of the State of New York (now the New York Power Authority, or NYPA).  The Project first produced electricity in 1961.  The operating license for the Project expires in August 2007 and NYPA has begun the relicensing process.  As part of the relicensing process, NYPA is required to investigate the potential effects of water level and flow fluctuations and land management practices on species listed as threatened (T) or endangered (E) by the United States Fish and Wildlife Service (USFWS) or the New York State Department of Environmental Conservation (NYSDEC). 

Study Parameters

NYPA, through URS Corporation, contracted Riveredge Associates to conduct this investigation to determine the potential effects of water level and flow fluctuations and land management practices on species listed as threatened of endangered.  Riveredge Associates updated records of federal and state rare, threatened, and endangered (RTE) species and significant occurrences of natural communities on lands and waters associated with the Niagara Power Project, and performed a literature-based assessment of the potential effects of water level and flow fluctuations and land management practices on these species and communities.  All species known to occur in or near the investigation area that are currently designated T or E by NYSDEC or USFWS were included in this analysis.  In addition, those species designated as special concern (SC) or rare (R) by NYSDEC are also included in this analysis.  Some unprotected (U) species and significant occurrences of natural communities were included in this analysis because they are unusually rare, declining, or exceptionally important or unique to the local ecology.  Unprotected species and natural communities found in the investigation area considered in this analysis include five significant natural communities, one plant, and all extant occurrences of freshwater mussels.

Factors related to water that could affect RTE species and significant occurrences of natural communities include fluctuations in water level and flow; entrainment; sedimentation; and erosion.  Water level and flow fluctuations in both the upper and lower Niagara River are caused by a number of factors in addition to the operation of the Niagara Power Project.  These include water withdrawals for the production of electricity by NYPA and Ontario Power Generation (OPG), flow variations from Lake Erie, regional and long-term precipitation patterns that affect lake levels, control of Niagara Falls flow for scenic purposes, the backwater effect from Lake Ontario, wind effects, boat wakes, and other natural and anthropogenic factors.  Analysis of water level gauge data from 1991 to 2001 revealed that it is not possible to accurately determine the extent of water level and flow fluctuation attributable to each factor.  For this study, the analysis of potential effects was conducted by considering all causal factors of water level and flow fluctuations combined in the investigation area.  Water level fluctuations in the upper Niagara River from all causes are normally less than 1.5 feet per day.  Water level fluctuations in the lower river near the Falls may be as much as 12 feet per day.  Near Lewiston, 1.4 miles downstream of the Project, average daily water level fluctuations are 1.5 feet per day.

Land management and maintenance activities include day-to-day Project operations that are performed by NYPA and occur on NYPA-owned lands and are directly related to the production or distribution of electricity, as well as other activities that are not performed by NYPA but nevertheless occur on NYPA-owned lands, such as public recreation or land management activities conducted by other agencies in public parks or along public roadways.  Most NYPA-owned lands where day-to-day Project operations linked to electricity generation occur are in the area of the Project structures and buildings, including the forebay, the switchyard, and the Lewiston Reservoir.  In these areas, land management and maintenance activities include building and grounds maintenance; road and parking lot maintenance; switchyard, reservoir and forebay maintenance; and the maintenance of power-line right-of-ways.  Land management and maintenance activities related to recreation and other public uses of Project lands include the building and maintenance of recreational trails, landscaping public park areas, and the effects of the public’s use of these trails and parks.  Maintenance activities on NYPA-owned lands are conducted by NYPA, as well as by Niagara Mohawk (NIMO), the New York State Office of Parks, Recreation and Historic Preservation (NYSOPRHP), the City of Niagara Falls, and others.

In general, factors that may significantly affect RTE species in the investigation area that are not related to Project operations are not specifically discussed in this report   For example, the effects of contaminants or botulism poisoning may be significant factors in the decline of native mussels, lake sturgeon and some birds, but these factors are not directly related to water level and flow fluctuations or NYPA land management practices and are not considered in detail in this report.

Findings

Forty-nine extant RTE species and significant natural communities are found in the investigation area.  These include 23 species currently listed as threatened and endangered, eight species listed as special concern, and 18 species or significant natural communities that are unprotected but inventoried by the New York Natural Heritage Program (NYNHP).  Taxonomically, these 49 species and communities include five significant natural communities, 14 plants, three native mussels, one crayfish, seven fish, one amphibian and 18 birds.

A geographic information system (GIS) analysis was used to compare the occurrence records of these RTE species and significant occurrences of natural communities to the portions of the investigation area influenced by water level and flow fluctuations and NYPA land management practices.  To determine where areas of potential Project effects might occur, documented occurrences of RTE species and significant occurrences of natural communities were compared with GIS coverages of NYPA-owned lands and land management and maintenance activities and with water level and flow data from permanent and temporary gauges established in the upper and lower river.  A literature search was conducted to determine the potential effects of water level and flow fluctuations or land management practices on the natural history or habitat requirements of each RTE species or community in the investigation area.

Of the 23 extant threatened and endangered (T&E) species, twelve occur in areas subject to water level and flow fluctuations or land management activities on NYPA lands and could be affected by them.  These T&E species include seven plants (Aster oolentangiensis, Carex garberi, Gentianopsis procera, Iris virginica var shrevei, Liatris cylindracea, Pellaea glabella, and Solidago ohioensis), one fish (lake sturgeon) and four birds (bald eagle, common tern, least bittern, and pied-billed grebe).  Three of these species are plants that occur on NYPA-owned lands, while the other species occur in areas not owned by NYPA but could be affected by water level and flow fluctuations or land management practices.  One additional threatened plant species, Solidago ohioensis, occurs along the shoreline of the Niagara River, but the extent of its occurrence has not been fully determined and the degree to which it could be affected by water level and flow fluctuations is unknown.

Of the unprotected species and communities examined in this assessment, portions of three significant occurrences of natural communities (deep emergent marsh, calcareous cliff, and calcareous talus slope woodland) and three species of extant native mussels (fragile papershell, round pigtoe, pink heelsplitter) occur in areas subject to water level and flow fluctuations or land management activities on NYPA lands.

T&E species that are known to occur in the investigation area but not in areas subject to water level and flow fluctuations or NYPA land management practices include six species of plants (Agastache nepetoides, Asimina triloba, Carya laciniosa, Lysimachia quadriflora, Solidago rigida, Zigadenus elegans ssp glaucus) and five species of birds (short-eared owl, upland sandpiper, northern harrier, sedge wren, peregrine falcon).  No species listed as SC or R occur in areas potentially affected by water level and flow fluctuations or NYPA land management practices.  SC or R species include one amphibian (Jefferson/blue-spotted salamander) and seven birds (Cooper’s hawk, sharp-shinned hawk, grasshopper sparrow, common nighthawk, horned lark, red-headed woodpecker, golden-winged warbler).

Two species of birds, bald eagle and common tern, forage along the upper Niagara River in areas of water level fluctuations but do not nest in areas that could be affected by these fluctuations.  In addition, peregrine falcons forage in the lower river gorge.  Eagles are only present on the Niagara River in winter and do not nest in the investigation area.  Terns nest on cement and steel structures, and peregrine falcons nest on the cliffs near the falls; areas that are well above the influence of water level fluctuations and away from land management practices on NYPA lands.  Since water level fluctuations and land management practices on NYPA lands are not known to affect the foraging and/or nesting of these species, they were not considered further in this analysis.

Two wetland breeding birds, pied-billed grebe and least bittern, nest in or near Buckhorn marsh where water level fluctuations occur.  NYSDEC field surveys confirmed successful breeding of least bittern, and this study confirmed successful breeding by pied-billed grebe.  Least bitterns build their nests in cattails above the influence of water level fluctuations, but grebes build floating nests on the waters surface where water level fluctuations could lower their breeding productivity.  Rapid, steep, and frequent water level fluctuations such as those created by wind-generated waves and boat wakes likely have the greatest effect on nesting grebes.

In small rivers, sturgeon are known to move during spring and fall when river flows change by a factor of two or more.  This behavior has not been recorded in a few hydrosonically tagged sturgeon on the Niagara River, where overall flows are approximately 250 times greater than in smaller rivers and changes in flow much smaller.  Sturgeon spawning sites are not well documented in the Niagara River, but suspected lower river locations are at water depths well below the influence of water level fluctuations.  No spawning locations are known in the upper river, and historic sites are upstream of the Peace Bridge, outside the area influenced by project operations.  Because little is known about where sturgeon spawn in the Niagara River, the possibility remains that sturgeon could spawn in shallow areas or in areas where productivity might be affected by fluctuations in water level or flow, although this is unlikely.  Lake sturgeon are probably not affected by entrainment at the NYPA water intakes.  Fishery surveys involving netting, electrofishing and angler interviews have never recorded lake sturgeon in the Lewiston Reservoir.

Water level and flow fluctuations could affect the plants Gentianopsis procera (lesser fringed gentian), Carex garberi (elk sedge), and Solidago ohioensis (Ohio goldenrod) where they occur along the Niagara River shoreline, but probably do not affect the wetland plant Iris virginica var. shrevei (southern blueflag).  The gentian, sedge, and goldenrod occur in areas where exceptionally high water levels could wash them away.  The gentian and sedge occur in the upper river at Niagara Reservation State Park.  The gentian occurs near the brink of the Falls, and it also could be affected by changes in water availability from seeps or from Falls generated mist.  Both plants also occur in Whirlpool State Park, but not in areas close to the river.  The goldenrod occurs along steep slopes of the lower river where waves or boat wakes undercut the unstable bank.  The iris has been documented in Niagara River wetlands for over 100 years.  It is well adapted to diverse conditions and may be found in areas that range from damp soil to areas that are completely saturated or inundated.  Recent surveys suggest this plant is more common in the lower Great Lakes than previously recognized.  Other, more common plants associated with wetlands are less tolerant of changes in water levels, and the vegetative structure of wetlands commonly changes dynamically, especially at the interface of the wetland with the adjacent forest.  Changes such as these may be occurring in the deep emergent marsh natural community at Buckhorn Island State Park.

Field surveys for native mussels indicate the mainstem Niagara River is almost completely devoid of living native mussels, primarily due to the invasion of exotic zebra mussels.  However, native mussels still occur in good numbers in Grand Island tributaries, and these areas experience water level fluctuations of less than seven inches during the spring to fall (tourist season) period when mussels are active.  In contrast to zebra mussels, native mussels generally move or burrow in response to changes in water level, temperature, or dissolved oxygen, and tourist season water level fluctuations probably never strand native mussels in Grand Island tributaries.  In addition, these tributaries are not blocked to mussel host fish and the creek substrates probably never dry out or freeze during the winter.  If, however, mussels were stranded and exposed to high or low temperatures or even moderate temperatures for periods greater than 24 hours, they would likely be killed.  Mussels are sensitive to sedimentation, and sediment can smother native mussel beds.  On Grand Island, live native mussels were most commonly found in creeks with a coarse gravel bottom where ground water inflow was apparent.

Land management and maintenance activities that could affect RTE species and significant occurrences of natural communities include uncontrolled public recreation, landscaping and mowing, and the application of salt and sand on roads during winter.  Most of the areas where these land management activities have the potential to affect RTE species are on lands that are not owned by NYPA and where these land management activities are conducted by agencies other than NYPA.  However, the winter sanding and salting of the Project access road could introduce surface water, sand and salt to the portion of the calcareous talus slope woodland natural community adjacent to the Niagara Power Project.  On NYPA-owned lands, uncontrolled recreation could affect the plants Aster oolentangiensis (sky-blue aster), Liatris cylindracea (slender blazing-star), and Pellaea glabella (smooth cliff brake), as well as portions of the calcareous cliff and calcareous talus slope woodland natural communities.  The impacts of uncontrolled recreation include the picking, collecting, or trampling of plants, and soil compaction and erosion.  The greatest threats to native plants in the Niagara region are uncontrolled recreation, particularly in and near the Niagara Gorge, and the establishment and rapid growth of alien invasive species such as Lythrum salicaria (purple loosestrife), Phragmites australis (common reed), Rhamnus cathartica (common buckthorn), Lonicera tartarica (Tartarian honeysuckle), Alliaria petiolata (garlic mustard), and Acer platanoides (Norway maple).  In some cases, alien invasive species have been planted for landscaping purposes in parks on both sides of the gorge.

Conclusions

Of the forty-nine extant RTE species and significant occurrences of natural communities addressed in this study, 12 T&E species (seven plants, one fish, and four birds), three unprotected species of native mussels, and three significant occurrences of natural communities occur in areas influenced by water level and flow fluctuations or NYPA land management activities.  Of these, water level and flow fluctuations could affect the productivity of pied-billed grebe, the behavior and productivity of lake sturgeon, the sites of occurrence of two plant species, and the vegetative structure of the deep emergent marsh natural community at Buckhorn marsh.  Land management activities such as uncontrolled public recreation on NYPA-owned lands could affect three additional plant species and the calcareous cliff and calcareous talus slope woodland natural communities, and the winter sanding and salting of the Project access road could introduce surface water, sand and salt to portion of the calcareous talus slope woodland natural community adjacent to the road.

Most RTE species and significant occurrences of natural communities in the Niagara Falls area are concentrated in parks and public lands that are managed for public access and recreation by agencies other than NYPA.  The primary threats to these species and communities are related to the maintenance and use of these lands for public recreation, the growing number of alien invasive species found in the area, and the overall loss of suitable habitat due to development and the urban and industrial character of the investigation area.

 

2.0     INTRODUCTION

The Niagara Power Project in Lewiston, Niagara County, New York, is one of the largest non-federal hydroelectric facilities in North America.  It is constructed on the Niagara River, a 37-mile strait connecting Lakes Erie and Ontario, and which forms the boundary in this region between the United States and Canada.  In 1957, a 50-year license for operation of the Project was issued by the Federal Power Commission (now the Federal Energy Regulatory Commission, or FERC) to the Power Authority of the State of New York (now the New York Power Authority, or NYPA).  The Project first produced electricity in 1961.  The operating license for the Project expires in August 2007 and NYPA has begun the relicensing process.  As part of this process, NYPA is conducting a number of ecological, engineering, and other investigations in the Project vicinity.

In 2001, Riveredge Associates, LLC (Riveredge) contracted with NYPA to conduct literature reviews and field surveys for rare (including species of special concern (SC)), threatened, and endangered (RTE) species and significant occurrences of natural communities in the investigation area (Riveredge 2005a).  RTE species and significant occurrences of natural communities in the investigation area were determined through the review of New York Natural Heritage Program (NYNHP) inventory records (NYNHP 2001), original NYNHP field survey forms, published museum records, discussions with selected knowledgeable individuals in the region, and field surveys.  As part of that study, field surveys were conducted to confirm existing NYNHP records.  Field surveys for native mussels were conducted for a separate study (Riveredge 2005b).

These studies documented species listed as RTE by the New York State Department of Environmental Conservation (NYSDEC) in the investigation area.  One of these species, the bald eagle (Haliaeetus leucocephalus), is also listed as threatened by the United States Fish and Wildlife Service (USFWS).  These studies also documented a number of species and significant occurrences of natural communities on the New York Natural Heritage Program’s (NYNHP) active inventory list (NYNHP 2002).  Although these species and significant occurrences of natural communities are considered unprotected under New York law, they may be protected under other legislation such as the federal Migratory Bird Treaty Act.

Riveredge (2005a) noted that most RTE species and significant occurrences of natural communities known to occur in the investigation area are plants of the Niagara River gorge and Niagara escarpment, wetland birds found in Buckhorn Island State Park, grassland birds found at and near the Niagara Falls Air Reserve Station (NFARS), or species associated with the Niagara River and its tributaries.

In 2002, Riveredge was contracted to conduct a literature-based analysis of the potential effects of water level and flow fluctuations and land management practices on RTE species and significant occurrences of natural communities.  Where data were lacking, limited field surveys were conducted to gather new information on the distribution of some species and the potential effects of Niagara Power Project operations.  In particular, this analysis included field surveys for grassland birds and the monitoring of nests of the threatened pied-billed grebe (Podilymbus podiceps).

This report includes a description of the Niagara Power Project and water level and flow fluctuations (Section 2), methods (Section 3), results from a review of records on the occurrence of RTE species and significant occurrences of natural communities in the investigation area (Section 4.1), descriptions of these significant occurrences of natural communities (Section 4.2), natural history and habitat requirements of RTE species (Section 4.3), an overview of Project operations, and an assessment of the potential effects of water level and flow fluctuations and land management practices on these species and significant occurrences of natural communities in the investigation area (Section 5).

 

3.0     PROJECT DESCRIPTION AND OVERVIEW OF WATER LEVEL FLUCTUATIONS

The 1,880-MW (firm power output) Niagara Power Project is one of the largest non-federal hydroelectric facilities in North America.  The Project was licensed to the Power Authority of the State of New York (now the New York Power Authority) in 1957.  Construction of the Project began in 1958, and electricity was first produced in 1961.

The Project has several components, including water intakes, conduits, a forebay, a reservoir and two generating plants.  Twin water intakes on the Niagara River are located approximately 2.6 miles above Niagara Falls.  Water entering these intakes is routed around the Falls via two large underground conduits to a forebay, lying on an east-west axis about four miles downstream of the Falls.  The forebay is located on the east bank of the Niagara River.  At the west end of the forebay, between the forebay itself and the river, is the Robert Moses Niagara Power Plant, NYPA’s main generating plant at Niagara.  This plant has 13 turbines that generate electricity from water stored in the forebay.  Head is approximately 300 feet.  At the east end of the forebay is the Lewiston Pump Generating Plant.  Under non-peak-usage conditions (i.e., at night and on weekends), water is pumped from the forebay via the plant’s 12 pumps/generators into the Lewiston Reservoir, which lies east of the plant.  During peak usage conditions (i.e., daytime, Monday through Friday), the pumps are reversed for use as generators, and water is allowed to flow back through the plant, producing electricity.  The forebay, therefore, serves as headwater for the Robert Moses plant and tailwater from the Lewiston Plant.  South of the forebay is a switchyard, which serves as the electrical interface between the Project and its service area.

For purposes of generating electricity from the Niagara River, two seasons are recognized:  tourist season and non-tourist season.  By international treaty, at least 100,000 cubic feet per second (cfs) must be allowed to flow over Niagara Falls during tourist season (April 1-October 31) daytime hours, and at least 50,000 cfs at all other times.  Canada and the United States are entitled by treaty to produce hydroelectric power with the remainder.

According to a 1993 Directive of the International Niagara Board of Control (INBC), water level fluctuations in the Chippawa-Grass Island Pool (in the upper Niagara River, i.e., above Niagara Falls) are limited to 1.5 feet per day within a three foot range for normal conditions.  For extreme conditions (i.e. high flow, low flow, ice, etc.), the allowable range of Chippawa-Grass Island Pool water levels is extended to four feet.

NYPA has conducted a comprehensive study of water level and flow fluctuations at the Project (URS et al. 2005).  This investigation examined water level data from gauges in the upper and lower Niagara River for the past 12 years as well as data from a number of temporary gauges established in the upper and lower river during 2001 and 2002.

Water level fluctuations in both the upper and lower Niagara River are caused by a number of factors in addition to the operation of the Niagara Power Project.  These include wind, natural flow and ice conditions, regional and long-term precipitation patterns that affect lake levels, control of Niagara Falls flow for scenic purposes, operation of power plants on the Canadian side of the river, and the backwater effect from Lake Ontario.  Water level fluctuations in the upper Niagara River from all causes are normally less than 1.5 feet per day.

Daily water level fluctuations in the lower Niagara from all causes can be as great as 12 feet per day at the Ashland Avenue gauge, downstream of Niagara Falls.  Water level fluctuations downstream of the Niagara Power Project are much less.  The average daily water level fluctuation during the 2002 tourist season at the gauge SG-01A, located 1.4 miles downstream of the Robert Moses tailrace, is approximately 1.5 feet.  The daily fluctuations decrease progressively at the temporary gauges located further downstream.  At the most downstream temporary gauge, SG-04A, the average daily fluctuation during the tourist season was 0.6 feet.  From the data collected, it appears that manmade regulation for Treaty flows and Canadian and U.S. hydroelectric generation have an effect on water levels and flows in the lower Niagara River to its mouth at Lake Ontario.

Operation of the Niagara Power Project can result in water level fluctuations in the Lewiston Reservoir of 3 to 18 feet per day, and approximately 11 to 36 feet per week depending on the season and river flows.  Weekly drawdowns are typically greater (21 to 36 feet per week) during the tourist season, when NYPA’s allocated share of water for power generation is reduced during daytime hours to provide higher Falls flow for scenic purposes.  During the non-tourist season, weekly drawdowns range from 11 to 30 feet.  Storage in the Lewiston Reservoir is used to generate power to meet daily peak energy demands.

 

4.0     METHODS

4.1         Investigation Area

The investigation area for this study includes lands within New York State adjacent to the Niagara River, the Niagara River proper, and tributaries of the river (within New York State) from just upstream of the southern tip of Grand Island downstream to the river mouth at Lake Ontario, as well as all NYPA-owned lands near the Project facilities, forebay, and reservoir.  The extent of this investigation area was determined through engineering analysis that revealed the upstream and downstream limits of hydroelectric project (both U.S. and Canadian) contribution to water level and flow fluctuations in the upper and lower Niagara River.  In addition, this investigation area encompasses land management activities on NYPA lands.  At the time this study was conducted, this defined investigation area was thought to fully encompass the area of hydroelectric project influence and contribution to water level and flow fluctuations.   However, subsequent analysis by URS Corporation and others has revealed that the backwater effect caused by U.S. and Canadian power generation influences water levels between Frenchman’s Creek and the Peace Bridge in the mainstem, and further upstream in several creeks than originally thought.  Therefore, additional work similar to this study may need to be conducted to determine the potential presence of RTE species and significant occurrences of natural communities in these areas, and whether they are affected by water level and flow fluctuations and land management practices.

4.2         Occurrence Records for the Investigation Area

4.2.1        Sources

The occurrences of RTE species and natural communities in the investigation area during 2001 and 2002 were documented through a literature review and limited field surveys (Riveredge 2005a, Riveredge 2005b).  The species and significant occurrences of natural communities present in the investigation area were determined through a review of NYNHP inventory records (NYNHP 2001), original NYNHP field survey forms, NYNHP reports (Evans et al. 2001a, 2001b, 2001c) published museum records, discussions with selected knowledgeable individuals in the region, Christmas bird counts (BirdSource 2003), and field surveys.  In addition, field surveys were conducted for RTE grassland birds, native mussels (Riveredge 2005b), and to confirm successful breeding by the pied-billed grebe.

In addition to the 2001 data provided by NYNHP (2001), an updated data set provided by NYNHP (2003a) was reviewed for the preparation of this report.

4.2.2        Changes

Because of changes in the NYNHP Rare Plant Status List (NYNHP 2003b) and changes in species identifications made by NYSDEC, the species included in this report differ from the previous report (Riveredge 2005a).  Records of four plants (Poa sylvestris, Physocarpus opulifolius, Cornus drummondii, and Lithospermum caroliniense var croceum) and one fish (black redhorse, Moxostoma duquensnei) are no longer considered valid due to the misidentifications of the specimens or to changes in the taxonomic classification of the species (NYNHP 2003a).  Additional changes include the update of existing records or the addition of new records that were either already known to Riveredge Associates (2005a), were historical in nature, or that do not occur in the investigation area.

Records of three plant species, Poa sylvestris, Cornus drummondii, and Lithospermum caroliniense var croceum, were apparently based on misidentifications of the original specimens.  These species are not known to occur in the investigation area.  The plant Physocarpus opulifolius var intermedius was considered a state-listed endangered species in 2001.  In 2002, NYNHP removed this species from the list based on new taxonomic information.  The plant is now considered a synonym of the common Physocarpus opulifolius.  Another change in the NYNHP Rare Plant Status List (NYNHP 2003b) is the addition of the oak Quercus shumardii.  This addition was anticipated however, and this plant was included in Riveredge Associates (2005a).  Finally, the record of the fish, black redhorse, reported to occur in the Niagara River in the previous report, was reexamined by NYSDEC and the specimen was identified as a different species of redhorse.  The black redhorse is not known to occur in the Niagara River.

4.2.3        Extant RTE Species and Significant Occurrences of Natural Communities

Of the species currently documented in the investigation area, 23 are extant and are listed as threatened or endangered by NYSDEC (Table 3.2.3-1).  One of these species, the bald eagle is also listed as threatened by the United States Fish and Wildlife Service.  These 23 species include 13 plant, one fish, and nine bird species.  In addition, eight species of special concern and 18 unprotected species inventoried by NYNHP currently occur in the investigation area.  The special concern species include one amphibian and seven birds.  The unprotected species include one plant, three mussel species, one crayfish, six fish, and two bird species.  In addition to RTE species, the NYNHP database includes five significant occurrences of natural communities for the investigation area.

Riveredge (2005a) noted that most RTE species known to occur in the vicinity of the Niagara Power Project are plants of the Niagara River gorge and Niagara escarpment, wetland birds found in Buckhorn Island State Park, and grassland birds found at or near the Niagara Falls Air Reserve Station.  In addition, fish and some waterbirds are found in the Niagara River, and native mussels are found in its tributaries.

Because existing information on the occurrences of grassland birds and native mussels in the investigation area was lacking, field surveys were conducted for them during 2002 as part of this investigation.  Mussel surveys produced live specimens of three species, and these species are included in this report.  Complete information on the mussel surveys can be found in Riveredge Associates (2005b). The field surveys for grassland birds did not reveal the presence of any additional RTE bird species on or near NYPA-owned grassland habitats.  Four surveys were conducted at eight sites in May, June, and July, but no northern harriers (Circus cyaneus), upland sandpipers (Bartramia longicauda), or grasshopper sparrows (Ammodramus savannarum) were observed.

4.2.4        Location Information

Location information and details about RTE species occurrences are considered sensitive.  In accordance with the policies of NYNHP and the Endangered Species Unit of NYSDEC, this report contains no specific location information or details about the occurrence of RTE species in the investigation area.

4.3         Nomenclature

Species in this report are referred to by their scientific names, their common names, or both.  The use of scientific names and common names follows accepted usage.  Some taxa, especially among birds, fish, and amphibians, are primarily referred to by their common names.  Plants are primarily referred to by their scientific names.  For all species, both scientific and common names may be found in the tables contained in this report.

4.4         Literature Review of Natural History and Habitat Requirements

Literature searches were conducted to establish the natural history characteristics and habitat requirements of species known to occur in areas of Project operations.  Breeding bird atlases were consulted for New York and Ontario, as well as species dossiers from NYSDEC.  General references such as Scott and Crossman (1973) and DeGraaf and Rudis (1986) were consulted, as were specific references on the conservation of endangered species, such as Schneider and Pence (1992).  Detailed, technical literature was also reviewed, such as the species accounts of The Birds of North America volume produced by the Academy of Natural Sciences and The American Ornithologists Union (several references in this report are to articles in this 1996 volume).  In addition, sources with information specific to the Niagara region were reviewed.  Sections 4.2 and 4.3 present summaries of the natural history and habitat requirements for each of the species and natural communities that are known to occur in the investigation area as breeding summer residents, as winter residents, or as permanent components of the landscape, such as significant occurrences of natural communities.

4.5         Determination and Description of Legal Status

In New York, all plant and animal species that are federally listed are automatically included on NYSDEC’s lists of threatened and endangered species.  The RTE species laws in New York State consider plant and animal species according to different criteria and laws.  NYSDEC’s species lists are passed into law by the state legislature after a period of public comment.

For animals, endangered (E), threatened (T) and special concern (SC) species are defined and designated in Title 6 of the New York Code of Rules and Regulations (6 NYCRR) Part 182.  Threatened and endangered animal species are protected by Environmental Conservation Law of New York, Section 11-0535.  Special Concern animal species do not receive legal protection under this law.

Plant species are defined as endangered (E), threatened (T), rare (R) or exploitably vulnerable (V) in 6 NYCRR Part 193 and are protected under Environmental Conservation Law Section 9-1503.  Plants included on the New York State list of “Protected Native Plants” are protected under New York State Environmental Conservation Law Section 9-1503.  It is a violation of this law to knowingly pick, pluck, sever, remove, damage by the application of herbicides or defoliants, or carry away, any protected plant without the prior consent of the landowner.

In New York, significant occurrences of natural communities are designated by NYNHP but have no formal protected legal status under the New York Code of Rules and Regulations or under the Environmental Conservation Law of New York.

It is important to note that species or natural communities listed as unprotected in this report only means they are unprotected under the specific laws and legislation pertaining to RTE species as described above.  Natural communities and species listed as unprotected may be protected by other laws.  For example, migratory birds are protected by the Federal Migratory Bird Treaty Act.  Mussels are shellfish and are protected by specific laws governing shellfish harvest.  Fish are protected by laws governing seasons and harvest limits, and each of the natural communities discussed here are located in protected State Parks.

The legal status of each species was determined by consulting the current list of designated RTE species (NYSDEC 2001).

4.6         Effects Analysis

This qualitative analysis of the potential effects of water level and flow fluctuations or land management practices on RTE species and significant occurrences of natural communities began by assessing (1) which species and significant occurrences of natural communities occur in the investigation area, (2) the extent of water level and flow fluctuations (from all causes) and the locations and types of land management practices, (3) where RTE species or significant occurrences of natural communities occur relative to water level and flow fluctuations and land management practices, and (4) the potential effects of these water level and flow fluctuations and land management practices on the natural history or habitat of these species and communities.

4.6.1        Species and Natural Communities Included in the Analysis

NYPA is required to investigate the potential effects of water level and flow fluctuations and land management practices on threatened and endangered species as part of FERC relicensing.  All species known to occur in or near the investigation area that are currently designated threatened or endangered by NYSDEC or USFWS were included in this analysis.  In addition, those species designated as special concern or rare by NYSDEC are also included in this analysis.  Some unprotected species and all significant occurrences of natural communities were included in this analysis because they are unusually rare, declining, or exceptionally important or unique to the local ecology.  Unprotected species considered in this analysis include one plant and all extant occurrences of freshwater mussels (Table 3.2.3-1).

The species and significant occurrences of natural communities considered in this analysis include those that occur on lands owned and managed by NYPA (e.g., lands around the reservoir, forebay and power dam), lands that are NYPA-owned but managed by other agencies or entities (e.g. Devil’s Hole State Park, Earl W. Brydges Artpark), and lands that are neither NYPA-owned nor NYPA-managed (e.g., Niagara Reservation State Park, Buckhorn Island State Park, Beaver Island State Park).

4.6.2        Potential Effects Included in this Analysis

Potential effects were grouped into two basic categories: (1) the potential effects of land management activities, and (2) the potential effects of water level and flow fluctuations from all causal factors.

Factors that cause water level fluctuation in the Niagara River include water withdrawals for electrical production by the Niagara Power Project and Ontario Power Generation, flow variations from Lake Erie, wind, boat wakes, and other anthropogenic and natural factors.  Because it is not possible to determine the exact extent to which each factor influences water levels in the Niagara River, all contributing factors were considered in the analysis of the potential effects of water level fluctuations on RTE species and their habitats.

4.6.2.1                                                                                                                                                    Land Management and Maintenance Activities

Land management and maintenance activities fall into two basic categories: (1) those activities directly related to day-to-day Project operations that are performed by NYPA and that occur on NYPA-owned lands and are linked to the production or distribution of electricity, and (2) those activities not related to power production and not performed by NYPA but that do occur on NYPA-owned lands, such as land management or maintenance activities conducted by other agencies or entities in areas of public parks or along public roadways.

Most NYPA-owned lands where day-to-day Project operations linked to electricity generation occur are in the area of the Project structures and buildings, including the forebay, the switchyard, and the Lewiston Reservoir.  In these areas, land management and maintenance activities include: building maintenance; road and parking lot maintenance; switchyard, reservoir and forebay maintenance; and the maintenance of power-line right-of-ways (these right-of-ways are maintained by Niagara Mohawk (NIMO)).  More specifically, this includes: repaving or resealing parking lot surfaces; painting of parking space lines; maintenance of curbing, signs, and guide rails; seasonal snow plowing; salting or sanding of roadways and parking areas; and seasonal mowing and maintenance of lawn areas.

Land management and maintenance activities related to recreation and other public uses of Project lands include the building and maintenance of recreational trails, landscaping public park areas, and the effects of the public’s use of these trails and parks.  During the warmer months, these activities include the periodic upkeep and maintenance of playgrounds, parks, and beaches; lawn mowing; building and pavilion repair and maintenance; trash collection; landscaping; road and trail maintenance; maintenance of signs and security; possible lake or river shore maintenance; and parking lot maintenance.

Maintenance activities on NYPA-owned lands are conducted by NYPA, as well as by Niagara Mohawk (NIMO), the New York State Office of Parks, Recreation and Historic Preservation (NYSOPRHP), the City of Niagara Falls, and others.

This analysis includes all land management and maintenance activities conducted on NYPA-owned lands and their potential impact on RTE species and natural communities, regardless of what entity conducts these activities.

4.6.2.2                                                                                                                                                    Water Level and Flow Fluctuations

Several factors have been identified related to water level and flow fluctuations that could affect RTE species and significant occurrences of natural communities.  These factors include but are not limited to: fluctuations in water level, temperature, and flow; entrainment; sedimentation; and erosion.  Water level and flow fluctuations in the upper and lower Niagara River are caused by water withdrawals for electrical production by the Niagara Power Project and Ontario Power Generation, flow variations from Lake Erie, wind, boat wakes, and other anthropogenic and natural factors.

The extent and causes of water level and flow fluctuations in the Niagara River were examined in detail in the report, Niagara River Water Level and Flow Fluctuations Study (URS et al. 2005).  This study estimated the relative effects of regulation and natural conditions on water level fluctuation over the length of the Niagara River using water level and flow data from 1991 to 2002.  The large database (over 5 million entries) included hourly data for 15 permanent and temporary water level gauges and three flow gauges in the upper and lower Niagara River.  Hourly water levels and daily water level fluctuation (difference between maximum and minimum water levels over a 24-hour period) were the parameters studied.  The data were sorted between the tourist season (April 1–October 31), when Falls flow is subjected to regulated changes over a 24-hour period, and the non-tourist season (November 1–March 31), when Falls flow is not regulated for tourism and is held relatively constant.

In addition to the 18 water level and flow gauges discussed above, temporary water level gauges were installed and monitored in the vicinity of wetland bird nesting areas at Buckhorn Island State Park in 2002.  These gauges collected water level data at intervals from every five seconds to every five minutes, and these data were also examined for this report.

The potential for entrainment of RTE fish species was qualitatively assessed based on the known occurrences of RTE fish in the vicinity of the intake structures, on the known natural history and habitat requirements of these species, and on the results of fisheries surveys conducted in the reservoir.  The potential effects of erosion and sedimentation were qualitatively assessed, although the contribution of each individual causal factor of water level and flow fluctuations to these processes is currently not known.

4.7         Interactions of Species or Natural Communities and Project Operations

A geographic information system (GIS) analysis was used to compare the occurrence records of RTE species and significant occurrences of natural communities to the portions of the investigation area influenced by operation of the Niagara Power Project and land management activities.

4.7.1        Land Management and Maintenance Activities

To determine where areas of potential Project effects might occur, documented occurrences of RTE species and significant occurrences of natural communities from NYNHP (2001) and from Riveredge (2005a) were compared with GIS coverages of NYPA-owned lands and land management and maintenance activities developed by URS Corporation.  URS used existing NYPA data, field observations, and maps from NYPA's real estate and maintenance departments to develop GIS coverage of NYPA land management and maintenance activities.

In addition, a GIS coverage depicting the agency or entity responsible for land management was examined to determine the type of land management or maintenance activity taking place in the vicinity of known occurrences of RTE species and of significant occurrences of natural communities, and to determine whether the activity was related to power generation, to recreation, or to other activities in the area.  Finally, a literature search was conducted to determine the potential effects of land use activities on the natural history and habitat requirements of RTE species in the area.

4.7.2        Water Level and Flow Fluctuations

GIS coverages of the occurrences of RTE species and significant occurrences of natural communities from NYNHP (2001) and from Riveredge (2005a) were reviewed and compared to water level and flow data from permanent and temporary gauges established in the upper and lower river (URS et al. 2005).  The period of record for gauge data was 1991 to 2002.  These gauges recorded water level fluctuations that occurred in the river from all causal factors; the relative contributions of natural and anthropogenic factors cannot be determined.

Occurrence records of RTE species were also compared to the physical location of Project structures (intakes, conduit, forebay, reservoir, tailrace) and relative to water level and flow fluctuations in the investigation area to determine the potential effect on these species and significant occurrences of natural communities.  RTE species that are widely distributed in the investigation area, such as lake sturgeon, were assumed to be present in all suitable habitats of the river.

 

Table 3.2.3-1

Extant RTE Species and Natural Communities of the Investigation Area

 

RTE Species or Significant Occurrence of a Natural Community

USFWS

NYSDEC and NYNHP

Total

T&E

T&E

SC

U

Natural Communities

 

 

 

5

5

Plants

 

13

 

1

14

Bivalve Mollusks

 

 

 

3

3

Crayfish

 

 

 

1

1

Fishes

 

1

 

6

7

Reptiles and Amphibians

 

 

1

 

1

Birds

1 1

9

7

2

18

Total

1 1

23

8

18

49

 

Notes:  These data from NYNHP (2001, 2003a) and Riveredge Associates (2005a, 2005b).  Most of these investigation area records are not in areas of Project operations.

1 = Bald Eagle, listed at State (NYSDEC) and Federal (USFWS) level and appears in both columns of table but counted only once in the columns of totals

 

Legal Status Codes: E=Endangered, T=Threatened, SC=Special Concern, R=Rare, U=Unprotected under NYS T&E or SC legislation but may be protected by other laws such as Migratory Bird Treaty Act

 

5.0     RESULTS

5.1         RTE Species and Significant Occurrences of Natural Communities in Areas Influenced by Water Level and Flow Fluctuations and NYPA Land Management Practices

Most RTE species identified in the investigation area by Riveredge Associates (2005a) do not occur in areas potentially influenced by water level and flow fluctuations and NYPA land management practices.  However, 12 T&E species (seven species of plants, one fish, and four birds) occur in areas potentially affected by water level and flow fluctuations and land management practices.  In addition, the three species of unprotected native mussels and three significant occurrences of natural communities occur in areas potentially affected by water level and flow fluctuations and NYPA land management practices.  The potential effects of these factors on these species and communities are discussed below.  For information on the effects of water level and flow fluctuations on common species and their habitats, please refer to the report “Effects of Water Level and Flow Fluctuations on Aquatic and Terrestrial Habitat” (Stantec et al. 2005).

5.1.1        Threatened and Endangered Species

Threatened and endangered species that occur in areas potentially affected by water level and flow fluctuations and land management practices include the plants Aster oolentangiensis (sky-blue aster), Carex garberi (elk sedge), Gentianopsis procera (lesser fringed gentian), Iris virginica var shrevei (southern blueflag), Liatris cylindracea (slender blazing-star), Pellaea glabella (smooth cliff brake) and Solidago ohioensis (Ohio goldenrod) (Table 4.1.1-1), one fish, the lake sturgeon (Acipenser fulvescens), and four birds, least bittern (Ixobrychus exilis), pied-billed grebe (Podilymbus podiceps), bald eagle (Haliaeetus leucocephalus) and common tern (Sterna hirundo) (Table 4.1.1-2).

Two of these species, bald eagle and common tern, forage along the Niagara River but do not nest in areas that could be affected by water level or flow fluctuations or NYPA land management activities.  Eagles occur along the upper Niagara River and water level fluctuations are unlikely to affect their foraging behavior.  In New York, hydroelectric projects may provide suitable wintering habitat for eagles (NYSDEC 2003). Common terns nest on cribs and potable water intakes in the Niagara River investigation area (Riveredge 2005a).  All of these structures are built of concrete and steel and are high enough off the water so that tern nesting is not influenced by fluctuations in water levels.  Because common tern and bald eagle do not nest in habitats that are directly affected by water level or flow fluctuations or NYPA land management practices, they will not be addressed further in this report.  Although NPP operations do not affect common tern productivity, terns are habitat limited and have low breeding productivity in and near the investigation area.  Terns are one of the threatened species proposed for consideration of habitat improvement projects (Kleinschmidt and Riveredge 2005).

5.1.2        Species of Special Concern

None of the species of special concern identified in the investigation area by Riveredge Associates (2002a) occur in areas potentially affected by water level and flow fluctuations and land management practices (Table 4.1.2-1).  The special concern fish species black redhorse (Moxostoma duquesnei) was reportedly captured in 2000 in the Niagara River north of Spicer Creek (Riveredge 2005a), but a more recent examination of the specimen by a redhorse expert determined that the fish was a different species (D. Carlson, NYSDEC, personal communication July 3, 2003).  There are no records of the black redhorse for the Niagara River, although they are well documented in the Buffalo River.  Six black redhorse were captured in the Buffalo River in July 2003 as part of NYSDEC’s ongoing efforts to learn more about the occurrence and distribution of this fish (D. Carlson, NYSDEC, personal communication July 3, 2003).  A second SC fish species, redfin shiner (Lythrurus umbratilis), once occurred in the upper Niagara River but has not been recorded in over 25 years.  The redfin shiner is considered historical for the investigation area.

5.1.3        Unprotected Species and Natural Communities

Native mussels and significant occurrences of natural communities were included in this study because they are unusually rare, declining, or exceptionally important to the ecology of the investigation area.  Although the native mussels and natural communities are considered unprotected under the conservation laws governing T&E and SC species in New York, they are protected under other laws as described in Section 3.5.  The three unprotected species of mussels include the fragile papershell (Leptodea fragilis), round pigtoe (Pleurobema sintoxia), and pink heelsplitter (Potamilus alatus) (Table 4.1.3-1).  The three natural communities with significant occurrences (NYNHP 2001) in areas potentially affected by water level and flow fluctuations and land management practices are the calcareous cliff community, calcareous talus slope woodland community, and deep emergent marsh community (Table 4.1.3-2).

5.2         Significant Occurrences of Natural Communities

Three significant occurrences of natural communities occur in areas potentially affected by water level and flow fluctuations and land management practices: the calcareous cliff, calcareous talus slope woodland, and deep emergent marsh communities (Table 4.1.3-2).  The calcareous cliff and talus slope woodland natural communities occur in the Niagara gorge.  The deep emergent marsh occurs at Buckhorn Island State Park.

Nearly all RTE plants found in the investigation area occur within the calcareous cliff community and the calcareous talus slope woodland community of the Niagara gorge.  The gorge is a unique geological formation that contains one of the greatest assemblages of rare plants in the state (Evans et al. 2001c).  The two natural communities are found in the gorge from Goat Island north to the Robert Moses Power Plant.

The portions of these two communities of the Niagara gorge that contain the majority of RTE plants are located in Niagara Reservation State Park, Whirlpool State Park, and Devil’s Hole State Park.  These lands are not owned or managed by NYPA.  Much of the cliff community and talus slope woodland community between the Rainbow Bridge and Whirlpool State Park is owned and managed by NYPA.  No portions of the cliff community from Whirlpool State Park to Devil’s Hole State Park are owned or managed by NYPA.  The entire lower portion of the talus slope woodland community (i.e., near the river) in this area is owned and managed by NYPA.

The community descriptions below come from Reschke (1990) and Edinger et al. (2002).

5.2.1        Calcareous Cliff

The calcareous cliff community is characterized by Reschke (1990) and Edinger et al. (2002) as occurring on vertical exposures of erosion resistant, calcareous bedrock such as limestone or dolomite.  The cliffs often include ledges and small areas of talus.  Very little soil is present and vegetation is sparse.  Reschke (1990) describes characteristic species as Pellaea atropurpurea (purple cliff brake), Cystopteris bulbifera (bulblet fern), Saxifraga virginiensis (early saxifrage), Juniperus virginiana (eastern red cedar), and Thuja occidentalis (northern white cedar).

The calcareous cliff community of the Niagara gorge includes a number of stunted, mature northern white cedar trees.  These cedars are an important and unique component of this community.  Stunted cedars from the Ontario portion of the Niagara gorge were included in a global study of ancient trees and cliff ecosystems.  Core samples of trees growing on cliffs in Europe, Great Britain, New Zealand, and North America revealed that cliffs generally support slow-growing trees up to and exceeding 1,000 years old.  In the Niagara gorge, tree core data indicate that some white cedars are over 1,500 years old, and are likely among the oldest trees on the continent (Larson et al. 2000).

Recognition of the unique plants, natural communities, watersheds and geological formations found along the Niagara gorge in Ontario resulted in Canada’s first large-scale environmental land-use plan in the 1985 Niagara Escarpment Act (McKibbon et al. 1987, Tovell 1992).  In 1990, the United Nations named Canada’s portion of the Niagara escarpment a World Biosphere Reserve.  Although the area specifically designated a World Biosphere Reserve is located in Ontario, the New York portion of the escarpment is equally important in terms of its contribution to the biodiversity of the region (Evans et al. 2001c).

5.2.2        Calcareous Talus Slope Woodland

The calcareous talus slope woodland occurs downslope of the cliffs of the calcareous cliff community.  Reschke (1990) describes these woodlands as having either a closed or open canopy and occurring on talus slopes of calcareous rock such as limestone or dolomite.  The slopes may contain numerous outcrops of exposed bedrock.  Soils are usually moist and loamy.  Characteristic trees include Acer saccharum (sugar maple), Fraxinus americana (white ash), Ostrya virginiana (eastern hop hornbeam), Quercus alba (white oak), Juniperus virginiana (eastern red cedar), and Thuja occidentalis (northern white cedar).  Shrubs may be abundant if the canopy is open and may include Cornus rugosa (round-leaf dogwood), Viburnum rafinesquianum (downy arrowwood), Zanthoxylum americanum (prickly-ash), and Staphylea trifolia (bladdernut).  Herbaceous vegetation may be quite diverse, including such characteristic species as Cystopteris bulbifera (bulblet fern), Athyrium filix-femina (=A. asplenioides, lady fern), Elymus hystrix (bottlebrush grass), Polygonatum pubescens (Solomon’s-seal), Asarum canadense (wild ginger), Actaea pachypoda (white baneberry), Thalictrum dioicum (early meadow-rue), Sanguinaria canadensis (bloodroot), Solidago caesia (blue-stem goldenrod), and Aster divaricatus (white wood aster).  Rock outcrops may have ferns such as Asplenium rhizophyllus (=Camptosorus rhizophyllus, walking fern) and Asplenium trichomanes (maidenhair spleenwort) (Reschke 1990).

5.2.3        Deep Emergent Marsh

This marsh community is characterized by Reschke (1990) as occurring on mineral soils or fine-grained organic soils such as muck or well decomposed peat.  The substrate is flooded by waters that are not subject to high energy wave action.  Water depths can range from a few inches to approximately six feet.  Water levels may fluctuate seasonally, although the substrate is rarely dry.  Deep emergent marshes usually contain standing water, even at the driest times of the year.

Characteristic vegetation of these marshes includes emergent aquatics such as Nuphar spp (yellow pond-lily), Nymphaea odorata (white water-lily), Typha spp (cattails), Scirpus acutus and S. tabernaemontani (hard-stem and soft-stem bulrushes), Sparganium eurycarpum (bur-reed), Peltandra virginica (arrowleaf), and Zizania aquatica (wild rice) (Reschke 1990).

A significant occurrence of the deep emergent marsh community is found at Buckhorn Island State Park.

5.3         Natural History and Habitat Requirements of RTE Species

5.3.1        Plants

The following individual species accounts contain notes on the general natural history and habitat requirements for the four extant RTE plant species that occur in the investigation area.  Three plants occur in or near the Niagara gorge, and one in the marsh at Buckhorn Island State Park and other wetland and shoreline areas.  Text was taken from Cody and Britton (1989), Fernald (1970), Gleason and Cronquist (1991), Mitchell (1988), Voss (1996) and NYNHP (2002).

5.3.1.1                                                                                                                                                    Aster oolentangiensis

Aster oolentangiensis Ridd.  Sky-blue aster; Syn.: Aster azureus Lindl. ex Hooker.

This showy perennial herb (NYSDEC Endangered, USFWS Unlisted) ranges from one to three feet tall.  It is characterized by much reduced leaves on stem branches, and by its azure blue flowers.  In New York these flowers have been observed from mid-August through September.  This aster is found in usually dry prairies, meadows, and open woods.  It ranges from western New York and southern Ontario west to Minnesota and South Dakota, and south to northwestern Mississippi and East Texas.

5.3.1.2                                                                                                                                                    Carex garberi

Carex garberi Fern.  Garber's sedge, elk sedge; Syn.: Carex  aurea Nutt. in part.

Elk sedge (NYSDEC Endangered, USFWS Unlisted) is a grass-like perennial herb that usually grows in tufts.  Its culms (stems), eight to eighteen inches tall, bear three to seven flower clusters.  This species is characterized by obscurely nerved perigynia that have white papillae on their golden surfaces.  Its fruits have been found in New York from mid-June through August.  This sedge grows on calcareous sands, gravels, and ledges, especially in the Great Lakes region.  It also occurs on riverbanks, in swamps, on pond margins, marly shores, interdunal flats, rock crevices, and at the edges of northern white-cedar (Thuja occidentalis) thickets.   Its range extends from Quebec west to British Columbia, north to Alaska, and south to Indiana and California.

5.3.1.3                                                                                                                                                    Gentianopsis procera

Gentianopsis procera (Holm) Ma.  Smaller fringed gentian, lesser fringed gentian.

The lesser fringed gentian (NYSDEC Endangered, USFWS Unlisted) is a showy taprooted annual or biennial ranging from a few inches to about three feet tall.  Its leaves are distinctive and are sessile and linear or very narrowly lance-shaped.  Its blue flowers, with four fringed petal lobes (corolla) are solitary on very small plants but numerous at the branch tips of larger plants.  In New York the flowers bloom from mid-July well into October.  This gentian occurs in bogs and boggy prairies, meadows, sandy swamps, and on wet rocky shores, especially in calcareous areas.  Its range extends from northern New York and southern Ontario west to southern Manitoba and Iowa.

5.3.1.4                                                                                                                                                    Iris virginica var shrevei

Iris virginica var. shrevei (Small) Anders.  Southern blue flag; Syn.: Iris shrevei Small. 

This showy perennial herb (NYSDEC Endangered, USFWS Unlisted) is widely distributed and can grow up to six feet tall.  It often forms extensive colonies by means of rhizomes.  The inland shrevei variety is characterized by greater branching and also by longer (to four inches) seed capsules.  Its usually purple flowers are two to three inches across.  In New York these flowers have been observed from mid-May to mid-June, and its capsules through July.  This iris grows in full sun in wet areas such as shorelines, wetlands, marshes, ditches, and shallow water.  It ranges from southwestern Quebec to Minnesota, south to the Carolina uplands and west to Texas.

The first records for western New York are recent but it is common in the investigation area.  Recent records for this plant include Niagara Reservation State Park, Beaver Island State Park, Jayne Park on Cayuga Island, Buckhorn Island State Park, and Strawberry Island.

5.3.1.5                                                                                                                                                    Liatris cylindracea

Liatris cylindracea Michx.  Slender blazing star.

This showy unbranched perennial (NYSDEC Endangered, USFWS Unlisted) of the Aster family grows eight to 24 inches tall.  It typically has only a few, rose-purple flowering heads that are alternately arranged on the stems.  Each head is composed of many small flowers, none of them being rays.  In New York it has been observed in bloom from mid-July through August.  This blazing star is usually found in dry, open places such as rocky or sandy prairies and also on bluffs containing sandstone or dolomite near the surface.  It ranges from western New York and southern Ontario to southern Ohio, west to Missouri, and irregularly to Alabama and Tennessee.

5.3.1.6                                                                                                                                                    Pellaea glabella

Pellaea glabella Mett. ex Kuhn.  Smooth cliff-brake; Syn.: Pellaea atropurpurea (L.) Link var. bushii Mackz.

Pellaea glabella (NYSDEC Threatened, USFWS Unlisted) is a small evergreen fern with wiry rachis and stipe.  Its fronds reach four to eight inches in length.  It is characterized also by sporangia that are mostly hidden beneath the reflexed margins of the fertile frond segments.  In New York, fronds have been observed from mid-June to mid-October.  This rare fern grows on usually calcareous, sometimes partly shaded, cliffs and bluffs, often in crevices.  It is found from Ontario and Vermont south to Virginia and Tennessee and west to British Columbia and Arizona.

5.3.1.7                                                                                                                                                    Solidago ohioensis

Solidago ohioensis Riddell.  Ohio Goldenrod

This erect perennial forb (NYSDEC Threatened, USFWS Unlisted) reaches heights of three to four feet and has a branching, open, flat- or dome-topped inflorescence.  It is one of the largest and showiest goldenrods, and most often is found in open habitats with full sun.  It is often an indicator of wet alkaline meadows underlain with calcareous substrate.  This species was last seen in the Niagara Falls area in 1873.  In New York, this plant flowers from mid-July to mid-September, and fruits from mid-September to mid-October.  Solidago ohioensis is restricted to glaciated habitats from northern Illinois to Minnesota, Wisconsin, Ohio, southwest Ontario and New York.

5.3.2        Bivalve Mollusks (Native Mussels)

Freshwater mussels live on the bottoms of lakes, streams, and rivers.  Those that belong to the family Unionidae are sometimes called pearly mussels because of the lustrous nacre or mother of pearl that is found inside their shells.  Before plastics became widely available, people collected shells to make buttons.  In some parts of their range mussels are still collected commercially but for a different purpose.  Today their shells are exported to Japan where they are used to make nuclei that seed pearl oysters for the manufacture of cultured pearls.

Mussels are filter feeders that spend most of their lives partially or completely buried in the bottom sediments of rivers, streams, and lakes.  Unionids extract the materials they need to sustain life from their surrounding aquatic environment.  They pump water into their bodies through the incurrent siphon.  Once inside the shell, the water bathes the body tissues and the gills extract both oxygen and organic nutrients.  Water is pumped out through the excurrent siphon.

When mussels are ready to reproduce, at an age that varies from one to ten years, males release sperm into the water where the gametes enter the female through a siphon.  The eggs are fertilized in the gills where they develop into an immature stage called a glochidium.  The glochidia are released into the water where they attach to the gills or fins of a host species, which is usually, but not always, a fish.  One mussel, the salamander mussel (Simpsonaias ambigua), is known to use a salamander as a host.  Some unionids are host-specific; they can complete their development only on one species, but other mussel species can mature and metamorphose on a variety of fish.  A growing body of evidence shows that a number of mussels have evolved elaborate displays and adaptations for attracting appropriate hosts (Barnhart and Roberts 1996, Hartfield and Hartfield 1996).  The hosts of some unionids are poorly documented or in some cases completely unknown.  The glochidia complete their development attached to the host over a period of time that varies from a few days to several months but they eventually drop off onto the stream or river bottom as young mussels.

Freshwater mussels exhibit two basic seasonal breeding patterns.  In tachytictic species mating occurs in the spring and the glochidia mature and fall off the hosts as juvenile mussels in late summer.  In the alternative pattern found among bradytictic species, the mussels produce gametes and breed in late summer but the glochidia overwinter on the hosts and young unionids are not released until the next spring.

The modern distribution of pearly mussels in New York strongly reflects the state’s geologic history of glaciers and drainage connections.  The last glacier covered most of the state, and those areas that were not covered with ice were probably too cold to support mussels.  Thus, today’s distribution of species depends greatly on the dispersal of these animals and their host fish species along the waterways that existed after the last glacier began its retreat approximately 18,000 years ago.  New York’s mussels came from two refugia south of the glacial boundary:  parts of the Ohio and Mississippi River basins (interior basin) and the Atlantic slope.  Most, but not all, of the mussels found in the investigation area came to New York from refugia in the interior basin.

Besides opportunities for post-glacial dispersal into a region, mussel distributions may also be affected by the presence of fish hosts, competition for resources, and environmental factors both natural and anthropogenic.  Much of the existing literature on the habitat requirements of freshwater mussels is based on habitat characteristics at collection sites (Strayer and Jirka 1997).  These types of data are probably biased toward the conditions at sites that are selected by and accessible to malacologists.  However, Strayer and Jirka (1997) state that mussels need permanent waters and that running waters, such as streams and rivers, usually support greater mollusk diversity than lakes and ponds.   There is also a relationship between the size of the stream and the number of species present with large rivers supporting the most diverse mussel assemblages.  Even in streams where mussels are present, we do not have a clear understanding of the factors that govern their distribution.  Current velocity, the size of particles that make up the streambed, substrate stability, and water chemistry are probably important under some conditions but most of these factors have not been carefully investigated.

Freshwater mussels are one of the most imperiled groups of animals in North America (Wilcove et al. 1998).  Strayer and Jirka (1997) present data that show that several species have been eliminated from New York, and that human activities have reduced the ranges of some species, eliminated the mussel community from many sites, and reduced the diversity of certain streams.

Pollution in many forms can kill mussels.  Industrial wastes, organic pollutants, agricultural runoff, toxic metals, and even chlorine from wastewater treatment plants have all played a role in eliminating mussels from some habitats (Goudreau et al. 1993).  Some pollutants poison mussels directly but others simply create eutrophic conditions where mussels are starved for oxygen.  Mussels need clean water, although the level of contaminants they can tolerate and still maintain healthy, viable populations is unknown.

Mussel populations typically decrease when streams are physically altered by the construction of dams, channelization, or clearing of the stream banks.  Impoundments convert streams to lakes, and these habitats are typically less diverse.  Impoundments, especially those with excessive amounts of silt, are detrimental to mussels.  On some rivers, dams have caused the extirpation of 30-60% of native mussels (Williams and Neves 1995).  Below dams, streams are usually regulated and seasonal changes in flow are muted.  The bottom sediments above and below dams are altered over time and fish hosts cannot move freely (Donnelly 1993).  In developed areas streams are often rerouted and straightened through ditches and culverts.  This practice ignores the fact that streams are naturally dynamic systems that move around in the floodplain.  These movements create riffles, pools, and midchannel bars, microhabitats that may be essential to mussel survival.

In many areas, especially in agricultural settings and places where roads parallel waterways, the natural vegetation that borders streams is reduced to a narrow strip of trees.  Where streams pass through residential sites the floodplains are sometimes cleared and mowed.  Under these circumstances the link between the floodplain forest and the aquatic system is damaged or broken.  The cleared areas cannot absorb nutrients or protect the stream from excessive runoff.  Fewer leaves fall into the water to provide organic nutrients for the organisms below, and water temperatures rise because of a lack of shade.

Finally, the zebra mussel (Dreissena polymorpha) has recently emerged as a new and pervasive threat to freshwater unionid mussels.  This invasive European bivalve arrived in the Great Lakes about 1985 (Hebert et al. 1989).  Habitat analyses have shown that we can expect this animal to occupy most New York waters except for small streams, calcium-poor sites and areas with soft sediments (Mellina and Rasmussen 1994, Ramcharan et al. 1992, Strayer 1991).  A growing body of evidence has shown that native mussels can be smothered or starved by zebra mussels, leading to dramatic population declines (Schloesser et al. 1996, Strayer and Smith 1996, Strayer and Jirka 1997).  Zebra mussels are already present in Lake Erie, the Niagara River, and many of its tributaries.  Zebra mussels can quickly smother and kill native mussels (Schloesser et al. 1996) and probably represent the single greatest threat to them in these areas (Strayer and Jirka 1997).  In wetland areas of the Great Lakes, native mussels may be able to persist where they can bury themselves is soft sediments that zebra mussels cannot tolerate (Nichols and Wilcox 1997).

The following sections describe the three unprotected, native freshwater mussel species that were found represented by living specimens within the investigation area during field surveys conducted in 2001 and 2002.

5.3.2.1                                                                                                                                                    Fragile Papershell

Leptodea fragilis, Fragile Papershell

Typically the fragile papershell (NYSDEC Unprotected, USFWS Unlisted) has a thin, light colored shell and a well-developed dorsal wing, but the shell is variable depending on environmental conditions.  This species is widely distributed and common throughout the Mississippi and Great Lakes watershed.  In New York it is found in Lake Champlain, the Erie-Niagara basin, tributaries of Lake Ontario, and the Mohawk River.  While it is not documented from the St. Lawrence, its presence in Lake Champlain suggests it might be present in this watershed.  This species tolerates slack water and is especially characteristic of the quiet waters of canals and lakes.  The freshwater drum is a possible host (Hoggarth 1992).

5.3.2.2                                                                                                                                                    Round Pigtoe

Pleurobema sintoxia, Round Pigtoe

Easily confused with other pigtoes, this species (NYSDEC Unprotected, USFWS Unlisted) is plagued with taxonomic uncertainties based on variable morphology that may or may not have a genetic basis.  It is uncommon in New York, being found only in the Erie-Niagara and Allegheny watersheds, where it seems to occur in fairly large streams and rivers.  Hosts include bluegill and an assortment of other small fish (Hoggarth 1992).

5.3.2.3                                                                                                                                                    Pink Heelsplitter

Potamilus alatus, Pink Heelsplitter

This beautiful heelsplitter (NYSDEC Unprotected, USFWS Unlisted) usually has a large dorsal wing and brilliant pinkish-purple nacre, from which it derives its common name.  To the west of New York, it is common and widespread but in this state it has a limited distribution in the Lake Champlain and Erie-Niagara watersheds eastward along the Barge Canal.  Based on this distribution, it might also be expected in tributaries of the St. Lawrence.  This species is especially common in quiet waters and is often found in lakes and canals (Strayer and Jirka 1997).  Hoggarth (1992) reported freshwater drum as a probable host.

5.3.3        Fish

One threatened fish species, the lake sturgeon, is known to occur in the Niagara River within the investigation area.  No other species of threatened, endangered or special concern fish are known to be extant in the investigation area (NYNHP 2003a).

5.3.3.1                                                                                                                                                    Lake Sturgeon

Acipenser fulvescens, Lake Sturgeon

The lake sturgeon (NYSDEC Threatened, USFWS Unlisted) is New York’s largest freshwater fish.  Mature adults average from three to five feet in length and 10 to 80 pounds in weight, but can occasionally grow to seven or more feet, and over 300 pounds (NYSDEC 1999).  In New York, lake sturgeon have been collected in Lake Ontario, Lake Erie, the St. Lawrence River, Niagara River, Oneida and Cayuga Lakes, Lake Champlain, the Oswegatchie River, Grasse River, and Black Lake.  Since 1995, sturgeon populations in five northern New York waters have been supplemented through the stocking of hatchery-raised fish.  Outside New York, the lake sturgeon is found in the midwestern and northeastern United States and inhabits the Mississippi River and Great Lakes drainages (Carlson 1998).

Lake sturgeon primarily occur in large bodies of water, where they generally stay close to the bottom (Werner 1980).  Lake sturgeon use a wide variety of habitats, but are most often associated with deep runs and pools that lack aquatic vegetation.  Adult fish are most often found only in deep water.  Females may live 80 years or more and males may live 55 years or more.  Not only are lake sturgeon long-lived, but they have delayed maturity.  Age at first spawning for females may be 14 to 33 years and for males from 12 to 22 years old.  Sturgeon feed primarily on invertebrates such as leeches, snails, and bivalves, as well as on small fish and algae (Houston 1986, Bouton 1994, Hay-Chmielewski and Whelan 1997).

The lake sturgeon spawns from early May to late June in swift water, rapids, the tailraces of hydroelectric projects or the bases of small falls in water ranging from two to 39 feet deep (Scott and Crossman 1973, Hayes 2000, Knights et al. 2002, Manny and Kennedy 2002).  In major connecting rivers of the Great Lakes such as the Detroit River and the St. Clair Rivers between Lake Erie and Lake Huron, sturgeon have been recorded spawning at depths between 29 and 39 feet (9 to 12 meters) (Manny and Kennedy 2002).  Prior to spawning, adults may form pre-spawning congregations.  Clean rock, gravel, and stone bottom substrates are used for spawning  (Houston 1986, Bouton 1994, Auer 1996, Hay-Chmielewski and Whelan 1997, Borkholder et al. 2002, Knights et al. 2002, Hughes 2002).  Where suitable spawning streams are unavailable, lake sturgeon may spawn in wave action over ledges or around rocky islands (Scott and Crossman 1973).  The sticky eggs adhere to stones and vegetation.  Young hatch in five to eight days and grow rapidly (Bouton 1994).  In general, females spawn every three to seven years and males may spawn every other year (Hay-Chmielewski and Whelan 1997).

Throughout their range declining numbers of lake sturgeon have been attributed to overexploitation (due to high demand for caviar and smoked flesh), construction of dams that cut off spawning and nursery areas, pollution, and degradation and fragmentation of habitat.  In New York, lake sturgeon numbers have declined due to a combination of overexploitation, pollution, and degradation and fragmentation of habitat (Bouton 1994, Carlson 1998, NYSDEC 1999).

In the Niagara River, lake sturgeon have been studied by Chris Lowie and Thomas Hughes as part of a Great Lakes native fish restoration project (Hughes 2002, USFWS 1999, USFWS 2002).  Much of this work is available on the Web (http://midwest.fws.gov/alpena/rpt-stnib00.html#niagara) in a series of annual reports.

To determine movement patterns and habitat preferences in the lower Niagara River, adult sturgeon were captured and fitted with ultrasonic tags (Hughes 2002, USFWS 2002).  Tagged sturgeon showed some preference for a back eddy area known as Peggy’s Eddy below Joseph Davis State Park and the Queenston Long Drift near Lewiston with bottom velocities between 0.62 and 1.2 feet per second (fps) and depths between 30 and 35 feet.  Juvenile lake sturgeon seemed to prefer nearshore, slow-water currents (mean bottom velocity 0.62 fps) in Peggy’s Eddy and the Queenston Long Drift.  Subadults preferred areas with currents of approximately 0.88 fps, and adults seemed to prefer the faster currents (mean bottom velocity 1.2 fps) of the river and the area of the river’s confluence with the lake.  Juveniles, subadults, and adults all occupied similar depths between 30 and 35 feet (Hughes 2002).

In addition to tracking tagged fish, observational records were collected from divers, anglers, guides, and others in both the upper and lower Niagara River.  These observations appear to indicate that sturgeon frequent areas in Whirlpool State Park in the lower river and near Grass Island in the upper river (USFWS 1999).  Particularly interesting was the presence of young-of-year fish at Grass Island.  The lower river has a year-round resident population of juvenile and subadult fish.  Although no spawning areas have been documented, there are several suspected spawning locations in the lower river.

5.3.4        Birds

RTE birds that occur in or near the investigation area are found primarily in the grasslands of the Niagara Falls Air Reserve Station (NFARS) and the wetlands of Buckhorn Island State Park (Riveredge 2005a).  The least bittern and pied-billed grebe nest or forage along the Niagara River and could potentially be affected by water level and flow fluctuations.

Three other species, bald eagle, common tern, and peregrine falcon also occur on the Niagara River.  Bald eagle and common tern forage along the upper Niagara River and peregrine falcons have been observed foraging in the gorge.  None of these species nest in areas affected by water level and flow fluctuations and land management practices on NYPA lands.  Wintering bald eagles have been recorded along the Niagara River in recent years.  The annual midwinter eagle survey conducted by NYSDEC on the upper and lower Niagara River reported the occurrence of five bald eagles in January 2001 and four in January 2002.  There is no evidence that fluctuating water levels or flows in the investigation area negatively affect the foraging efficiency of bald eagles.  Buehler (2000) reports that hydroelectric facilities in the U.S. have increased food and habitat availability for bald eagles.

Peregrine falcons forage primarily on other birds and typically take their prey while in flight (Sibley 2001) and there is no evidence that water level and flow fluctuations affect the foraging efficiency of this species.  In the investigation area they nest on the cliffs near the falls well above the influence of water level fluctuations and away from land management practices on NYPA lands.      

            Common terns nest on concrete and steel structures in the upper river that are well above the influence of water level fluctuations, but forage for small fish along the shorelines and beds of submerged aquatic vegetation.  In the upper river, water level fluctuations affect the 0- to 2-foot water depth zone and have limited influence on the distribution and abundance of submerged aquatic vegetation (Stantec et al. 2005).  Common terns are widespread in areas of water level fluctuations and such fluctuations are not known to affect their foraging behavior (Nisbet 2002).  Such fluctuations could, however, affect their foraging habitat in ways similar to the habitat of least bittern and pied-billed grebe (below) and discussed further in the habitat report (Stantec et al. 2005).  No other T&E or SC birds occur in the investigation area. (Table 4.1.1-2, Table 4.1.2-1).

5.3.4.1                                                                                                                                                    Least Bittern

Ixobrychus exilis, Least Bittern

Least bitterns (NYSDEC Threatened, USFWS Unlisted) are the smallest members of the heron family found in North America.  Only about 13 inches long, this secretive bird inhabits dense marshes and low-elevation wetlands.  During the breeding season, least bitterns range from New Brunswick west to Oregon, and south to South America (DeGraaf and Rudis 1986, Gibbs et al. 1992, Fragnier 1996).  In the northeast, least bitterns are absent from the mountainous areas of New York, Vermont, New Hampshire, and Maine (Gibbs and Melvin 1992a).  Populations winter south of areas with prolonged frost and range along the Atlantic coastal plain from Maryland south to southern Florida, west to Texas and southern California, and south to eastern Central America (DeGraaf and Rudis 1986, Gibbs and Melvin 1992a, Gibbs et al. 1992).

The diet of least bitterns consists primarily of small fish, crustaceans, insects, small amphibians, and occasionally small mammals (DeGraaf and Rudis 1986, Gibbs et al. 1992, Fragnier 1996).  They feed in dense stands of emergent vegetation near deep open waters, and may build foraging platforms of bent vegetation (Gibbs and Melvin 1992a).

Least bitterns breed in freshwater and brackish marshes with a mixture of dense emergent and woody vegetation, and in open water.  In general, courtship and breeding begin from early April to early May in the northeast, and eggs are laid in late May and June (NYSDEC 1994a, Andrle and Carroll 1988).  The breeding season may be delayed by the life cycle of their aquatic prey or the growth of emergent vegetation (NYSDEC 1994a).  Males build a well concealed nesting platform in dense stands of emergent plants by pulling down the vegetation.  The nest is an elevated platform with an overhead canopy (Gibbs et al. 1992).  Females add cattail down and feathers to the nest (NYSDEC 1994a).  Nests are usually built six to 30 inches above water that is three to 38 inches deep.  Preferred nesting sites are usually less than 33 feet from open water pools, channels, or muskrat trails (Gibbs et al. 1992).

Clutch sizes are generally four to five eggs, and incubation begins with the first or second egg.  Chicks leave the nest and begin foraging on their own after six to 14 days, and fledging occurs at 25 days (Gibbs et al. 1992, NYSDEC 1994a).  Parents may continue to provide food for up to 30 days (Gibbs et al. 1992).  Least bitterns usually lay the first clutch in early June, but some are as early as late May.  Second clutches are usually laid in mid-July.  Second clutches are often more successful due to an increase in the food supply at that time of year (Gibbs et al. 1992).  Some research suggests that nests built in areas with equal amounts of vegetation and open water have better production of offspring (Gibbs et al. 1992).

Least bitterns tend to avoid open marshes with low-lying vegetation and spend most of their time concealed in dense stands of tall emergent vegetation (Gibbs and Melvin 1992a, Fragnier 1996).  Cattail, sedges (Carex sp.), and bulrush (Scirpus sp.), interspersed with woody shrubs and areas of open water, are preferred.  Nest density may exceed one nest per 2.5 acres and some nests have been found only 12 feet apart (Woodliffe 1987).  The best least bittern habitat contains emergent vegetation greater than three feet tall and greater than 120 stems per square yard in density, with a water depth of 4 to 20 inches (Gibbs and Melvin 1992a).  Wintering habitat requirements are not well known, but they are probably similar to breeding habitat requirements.

Little is known about wintering least bitterns, except that they often occur in brackish and saltwater marshes and swamps (Gibbs and Melvin 1992a).  In New York they are rare but regular winter visitants; they are found along the coast and occasionally on open waters in the Finger Lakes and on large rivers in the western part of the state.

The leading cause of decline in least bittern populations is the loss of wetland habitat (Gibbs et al. 1992).  Least bitterns have been documented nesting in the marshes of Buckhorn Island State Park (NYNHP 2001).

5.3.4.2                                                                                                                                                    Pied-Billed Grebe

Podilymbus podiceps, Pied-billed Grebe. 

Pied-billed grebes (NYSDEC Threatened, USFWS Unlisted) are widespread throughout North America.  They are medium-sized birds (13 to 14 inches long) with a duck-like appearance.  Their lobed toes make them strong swimmers, and they dive from the water's surface for their prey.  Pied-billed grebes eat fish, aquatic insects, and crustaceans (DeGraaf and Rudis 1986, Gibbs and Melvin 1992b).

Pied-billed grebes are associated with ponds, sloughs, marshes, and marshy areas along rivers and lakes (Gibbs and Melvin 1992b, NYSDEC 1994b).  They breed across most of the United States and in southern Canadian provinces (DeGraaf and Rudis 1986, Cadman 1987, Gibbs and Melvin 1992b, Cotter and Spencer 1996).  Breeding populations extend as far south as central South America and the West Indies (NYSDEC 1994b).  The wintering range of these birds includes southern New York, particularly coastal areas; it extends southward along the Atlantic coast, and inland across the southern coastal states (NYSDEC 1994b, Connor 1988).  In the winter, pied-billed grebes inhabit a variety of open-water habitats, including freshwater rivers, lakes, and estuaries.  Dense populations may be found in open areas inland of the Atlantic coast.  The northern limit of the wintering grounds is determined by the availability of ice-free habitats (Gibbs and Melvin 1992b).

Adult grebes return to the breeding grounds from early April to June, depending on the amount of ice cover in the northeast (DeGraaf and Rudis 1986, NYSDEC 1994b).  Some birds may overwinter in the breeding range.  In general, where large areas of suitable habitat exist, they are solitary nesters, defending territories of about five acres around their nest site.  The pied-billed grebe is territorial and vigorously defends its nesting site (Muller and Storer 1999).  There is usually only one pair per small pond or wetland (DeGraaf and Rudis 1986, Gibbs and Melvin 1992b).

Breeding habitat for pied-billed grebes provides food, cover, and nesting sites (NYSDEC 1994b).  These birds need both open water and emergent vegetation.  Because they are heavy-bodied birds, open water is required for grebes to become airborne, and emergent vegetation is essential to provide cover and to protect the nests from wind and waves (DeGraaf and Rudis 1986, Gibbs and Melvin 1992b, Muller and Storer 1999).  Water depth in nest sites ranges from one to three feet, and aquatic (floating and submergent) vegetation is necessary for foraging (Connor 1988, NYSDEC 1994b, Muller and Storer 1999).  In the northeast, minimum occupied wetland size is approximately 12 acres.  Pied-billed grebes will colonize artificial wetlands, and, therefore, have a high potential for active management.

Pairs build floating nests of aquatic plant material and mud, which is often attached to live emergent vegetation (Kibbe 1985, Gibbs and Melvin 1992b, Muller and Storer 1999).  Nests stay afloat because air pockets in the fermenting vegetation give it buoyancy (Gibbs and Melvin 1992b, NYSDEC 1994b).  Nest site selection is a function of water depth and the density of emergent vegetation (Muller and Storer 1999).

Both sexes build nest platforms, and in as little as one day can construct a platform that will support eggs.  Normally, nest construction starts three to five days before egg-laying, and continues during and after egg-laying.  Most nesting material is collected within 165 feet of the nest, and consists largely of soft, flexible, fresh or partly decomposed plant materials from the bottom.  Initially, material is piled in one central spot, until the platform can support the weight of an adult grebe, and then material is placed on the rim.  The bird sits or stands on the nest platform and moves soft materials toward the center to build the nest bowl.

Egg-laying may start when the nest platform is barely above the water surface.  The nest height is gradually raised as material is moved from the nest rim underneath the eggs during egg-turning and incubation.  The nest gets larger as more vegetation is added to it during nest building and incubation.  The first eggs may be laid in a puddle of water, occasionally completely submerged.  As more eggs are laid and incubation begins, eggs are usually lifted above the water surface.  Toward the end of incubation, the nest is much larger, and eggs are usually two to three inches above the level of the water (Muller and Storer 1999).

Females lay four to seven eggs, usually in May or June, and the pair shares incubation duties (Kibbe 1985, DeGraaf and Rudis 1986, Andrle and Carroll 1988).  Pied-billed grebes are known to lay two clutches a year in some areas, and they usually re-nest if the first clutch fails (Gibbs and Melvin 1992b).  If the second nest also fails, a third clutch may be produced (Muller and Storer 1999).

During early egg-laying, before the full onset of incubation, new eggs are not covered with plant material when adults leave the nest, indicating that egg covering has more to do with temperature regulation than with concealment from predators.  During full incubation, the adults thoroughly cover the eggs with nest material when the nest is unattended.  The incubation period varies from 23 to 27 days.

Nest success is influenced by wind and wave action, water level fluctuations, predation on eggs or of adult birds on the nest, or damage to nest and loss of eggs as a result of spawning activity of common carp (Muller and Storer 1999).  Grebe chicks are extremely susceptible to drafts and chilling during the first two weeks after hatching, and may die of exposure.  In several states, egg and nest losses of 8 to 50% were attributed to weather, wave action, and drops in water levels.  Boat traffic, including non-motorized boat traffic, causes the loss of eggs and the destruction of nests when they enter wetland nesting habitat.  Waves from boats towing water-skiers are known to destroy nests as well (Muller and Storer 1999).

Predators of adult pied-billed grebes include bald eagles and peregrine falcons.  In addition, American coots have been observed eating eggs (Muller and Storer 1999).  USFWS management guidelines note that pied-billed grebe nesting wetlands are susceptible to boat wakes that may flood nests, and recreationists can disturb incubating birds (Gibbs and Melvin 1992b).  Breeding habitat is also susceptible to runoff, which can transport contaminants and silt, consequently reducing food supplies (Gibbs and Melvin 1992b).  Food supplies are enhanced by native floating-leafed and submergent vegetation, which may be affected by fluctuating water levels or the drawdown of reservoirs (Gibbs and Melvin 1992b).  The invasive plant species purple loosestrife (Lythrum salicaria) and common reed (Phragmites australis) may have negative effects on nesting pied-billed grebes because they outcompete native emergent plants such as cattail and bulrush.

Pied-billed grebes breed at Grass Island in Buckhorn Island State Park (NYNHP 2001).  NYSDEC surveys conducted in 2000 and 2001 recorded grebe nests with eggs and abandoned grebe nests, but no pied-billed grebe young.  Surveys conducted by Riveredge in 2002 (this study) recorded several successful nests and as many as six young were observed during individual monitoring events.

5.4         Land Management Practices, Water Level and Flow Fluctuations, and the Occurrences of RTE Species and Communities

Factors that could affect RTE species and significant occurrences of natural communities in the investigation area include land management and maintenance activities and water level and flow fluctuations.  Land management and maintenance activities conducted by the Project on NYPA-owned lands include the maintenance of buildings, roadways, and right-of-ways.  In addition, NYPA-owned lands are open to public recreation (Table 4.4-1).  The factors that cause water level and flow fluctuations may contribute to sedimentation, erosion, and entrainment, and these could affect RTE species and significant occurrences of natural communities.

5.4.1        Land Use and Maintenance Activities

NYPA-owned lands where land use and maintenance activities occur encompass 1,736.7 acres (not including the reservoir, forebay or ice boom areas) (Table 4.4.1-1).  Land use and maintenance activities conducted in this area include the maintenance of buildings, roadways, power line right-of-ways and other mowed areas, and recreational activities.  The largest use of these NYPA lands is public recreation (Table 4.4.1-1).  Some lands open to public recreation are subject to no maintenance activities at all.  An example of NYPA-owned land where no maintenance activities are conducted is the shoreline of the Niagara River in the Niagara gorge.

5.4.1.1                                                                                                                                                    Buildings, Roadways and Parking Lots

No RTE species occur in the immediate vicinity of Project buildings or roadways.  However, on lands not owned nor managed by NYPA, some RTE plants and significant occurrences of natural communities occur very close to roadways.  In particular, Aster oolentangiensis occurs close to the Robert Moses Parkway in the vicinity of Whirlpool State Park, and Interstate 190 bisects the deep emergent marsh at Buckhorn Island State Park. 

5.4.1.2                                                                                                                                                    Forebay and Reservoir

The forebay and reservoir areas are used for the storage and conveyance of water for the generation of electricity.  No RTE species are known to occur in the reservoir (NYPA 2002) or forebay areas, (Riveredge 2005a).

5.4.1.3                                                                                                                                                    Mowing and Right-of-Way Maintenance

Mowed areas range from areas adjacent to buildings and parking lots to the areas under power-line right-of-ways.  These areas total 301.4 acres (Table 4.4.1-1).  Some of these areas are maintained by NYPA and some are maintained by others including NYSOPRHP, the Town of Lewiston, and NIMO.  In areas near buildings or in public parks, such as Reservoir State Park, lawn mowing may occur more than once per month.  On other lands, mowing may occur once per month to once per year, and some areas are mowed less than once per year.  In addition to mowing, maintenance activities include brush-hogging, hazardous tree removal, seasonal use of pesticides and herbicides, gate maintenance, fence maintenance, sign maintenance, and painting of transmission towers.

No RTE species have been found in the vicinity of power-line right-of-ways, intake conduits, or other areas mowed by NYPA.  Some RTE plant species, however, occur in areas mowed or maintained as part of parks along the crest of the Niagara gorge (Whirlpool State Park, DeVeaux State Park, and Devil’s Hole State Park).  Small calcareous outcrops or depressions provide shelter from mowers, and the state-listed (endangered) Aster oolentangiensis and the state-listed (threatened) Pellaea glabella can be found in some of these areas along the gorge crest.  One occurrence of an RTE plant is located only a few feet from an area that is mowed, and others are less than 50 feet from mowed areas.  However, most occurrences of these and other RTE plants are in the calcareous cliff community and calcareous talus slope woodland community, neither of which is mowed.

Surveys conducted for grassland birds on and near NYPA-owned property did not record any RTE grassland bird species.  Most rare grassland bird species are area-sensitive and require relatively large areas of open grassland.  The largest non-Park NYPA-owned grassland covers approximately 70 acres.  The overall urban setting and small size of the undeveloped grassland parcels makes it very unlikely that rare grassland birds would ever nest at these sites.

5.4.1.4                                                                                                                                                    Landscaping and Tree or Shrub Planting

The planting of trees and shrubs by NYPA for landscaping purposes is limited to areas along roadways, adjacent to buildings, and in a few public parks.  All these areas are located away from the rim of the Niagara gorge.

5.4.1.5                                                                                                                                                    Recreation on NYPA-Owned Lands

Parklands available for active recreation total approximately 573.3 acres or about 33% of the total amount of NYPA-owned lands in the investigation area (Table 4.4.1-1).  The maintenance of these recreation lands includes the periodic upkeep of playgrounds, parks, and beaches during the warm-weather season.  These activities include lawn mowing, building and pavilion repair and maintenance, trash collection, tree and flower planting and maintenance, road and trail maintenance, maintenance of signs and security, occasional shoreline maintenance, and parking lot maintenance.  Some NYPA-owned lands open for recreation are not actively managed, particularly in the Niagara gorge along the lower Niagara River.

Three RTE plant species that occur in the talus slope woodland community are located on or very near NYPA-owned lands in the gorge.  These lands are not actively managed by NYPA, but they are open to public recreation.  Public access could have a negative effect on the long-term persistence of some RTE plants in readily accessible areas of the gorge.  Most RTE plants in and around the Niagara gorge are on lands owned and managed by NYSOPRHP.

5.4.2        Use of Niagara River Water to Generate Electricity

The principal effect of the use of Niagara River water to generate electricity is to contribute to water level and flow fluctuations in the Niagara River.  Flow and water level fluctuations in the upper and lower Niagara River result from a combination of natural and anthropogenic factors that often act simultaneously.  These include regional and long-term precipitation patterns that affect the level of Lake Erie, wind events, flow surges, ice conditions, regulation of Niagara River flows for scenic purposes, hydro operations on the U.S. and Canadian sides, and boat wakes.

5.4.2.1                                                                                                                                                    Flow Regulation for Scenic and Power Generation Purposes

The Niagara River Water Diversion Treaty of 1950 specifies that flow over Niagara Falls must be 100,000 cfs during tourist season daytime hours (April 1 through October 31).  During nighttime hours all year, and during daytime hours from November 1 through March 31, the minimum Treaty-mandated flow is 50,000 cfs.  The purpose of the regulation of water levels in the Chippawa-Grass Island Pool, just upstream of Niagara Falls, is to ensure the availability of sufficient flows to satisfy the requirements of the Treaty while still providing water for power production and for the maintenance of water levels in the pool within the specifications of a 1993 Directive of the International Niagara Board of Control.

The 1993 Directive of the International Niagara Board of Control requires that the International Niagara Control Structure (a linear array of sluice gates regulating flow between the Chippawa-Grass Island Pool and the Falls itself) be operated to ensure a specified operational long-term average pool level.  It also establishes certain tolerances for the pool’s water level as measured at the Material Dock gauge, located on the Canadian shore of the Chippawa-Grass Island Pool.  The Directive, applicable to both U.S. and Canadian hydropower operations, permits a daily fluctuation of surface water levels of up to 1.5 feet as measured at the Material Dock gauge.  This daily fluctuation must occur within a normal three-foot range, extendable to four feet under special conditions (e.g., high flow, low flow, ice) (URS et al. 2005).

Water level fluctuation in the lower river, measured downstream of Niagara Falls but upstream of the Project tailrace, can be as high as 12 feet per day (URS et al. 2005).  This is due to the Treaty-mandated control of flow over Niagara Falls for reasons of tourism (URS et al. 2005).  Water level fluctuations downstream of the Niagara Power Project are much less.  The average daily water level fluctuation during the 2002 tourist season, measured 1.4 miles downstream of the Robert Moses tailrace, was approximately 1.5 feet (URS et al. 2005).  Daily fluctuations decrease progressively further downstream.  Less than ¼ mile from the river’s mouth at Lake Ontario, the average daily fluctuation during the tourist season was measured at 0.6 feet (URS et al. 2005). 

5.4.2.2                                                                                                                                                    The Contribution of Natural Factors

There are natural causal factors that contribute to water level and flow fluctuation in the upper and lower Niagara River.  Contributing natural factors include regional and long-term precipitation patterns that affect the level of Lake Erie, wind events, flow surges, and ice conditions.  These factors often act simultaneously, and, because of this, their effects cannot be clearly differentiated (URS et al. 2005).

Because the Niagara River serves as the main outlet channel of Lake Erie, water levels and rate of flow in the river depend greatly on the elevation of Lake Erie.  The elevation of Lake Erie fluctuates on a seasonal and, due to wind effects, a daily basis.  Wind-caused variations can occur over the course of just a few hours.  Strong southwest winds blowing along the long axis of the lake can raise the water level at Buffalo by eight feet or more, increasing river flow at the same time.  This increased flow can result from sustained winds alone, without any input from snowmelt, high rainfall, or ice conditions, although these can and frequently do contribute (URS et al. 2005).

Despite being subject to all these natural and anthropogenic influences, water level fluctuation in the upper Niagara River from all causes amounts to less than 1.5 feet per day (URS et al. 2005).  Impact of water level regulation at the Chippawa-Grass Island Pool on Fort Erie water levels (near the river’s head at Lake Erie) is virtually undetectable (URS et al. 2005).

 

Table 4.1.1-1

RTE Plants and Potential Effects of Water Level and Flow Fluctuations and Land Management Practices

 

 

 

Species

NYS Legal Status

Area of Occurrence

Factors that Contribute to Potential Effects

1

Agastache nepetoides

(Yellow giant-hyssop)

T

Bond Lake County Park (2001); Niagara escarpment near Dickersonville (2001)

None (outside of investigation area)

2

Asimina triloba

(Pawpaw)

T

Bond Lake County Park (2001)

None (outside of investigation area)

3

Aster oolentangiensis

(Sky-blue aster)

E

Niagara gorge near Whirlpool State Park (2000)

Recreation (on NYPA-owned and managed lands)

4

Carex garberi

(Elk sedge)

E

Niagara Reservation State Park; Whirlpool State Park (1990)

Water level and flow fluctuations at sites along River shorelines

5

Carya laciniosa

(Shellbark hickory)

T

Buckhorn Island State Park; Niagara escarpment near Dickersonville, Gun Creek (Grand Island)

None (upslope of fluctuations and not in vicinity of land management practices)

6

Gentianopsis procera

(Lesser fringed gentian)

E

Niagara Reservation State Park (2001); Whirlpool State Park (1990)

Water level and flow fluctuations at sites along River shorelines

7

Iris virginica var shrevei

(Southern blueflag)

E

Beaver Island State Park, Buckhorn Island State Park, Niagara Reservation State Park, Jayne Park (City of Niagara Falls)

Water level and flow fluctuations at sites along River shorelines

 

 

Table 4.1.1-1 (cont.)

RTE Plants And Potential Effects Of water level and flow fluctuations and land management practices

 

Species

NYS Legal Status

Area of Occurrence

Factors that Contribute to Potential Effects

8

Liatris cylindracea

(Slender blazing-star)

E

Whirlpool State Park (2000)

Recreation (on NYPA-owned and managed lands)

9

Lysimachia quadriflora

(Four-flowered loosestrife)

E

Niagara Reservation State Park

None (upslope of fluctuations and not in vicinity of land management practices)

10

Quercus shumardii

Shumard’s Oak

U 1

Buckhorn Island State Park

None (upslope of fluctuations and not in vicinity of land management practices)

11

Pellaea glabella

(Smooth cliff brake)

T

Whirlpool State Park (2000); bluffs near Lewiston (2001)

Recreation (on NYPA-owned and managed lands)

12

Solidago ohioensis

(Ohio goldenrod)

T

near Earl W. Brydges Artpark

Site of occurrence not fully identified (Riveredge 2005a).  Large boat wakes could affect riparian areas of occurrence

13

Solidago rigida

(Stiff-leaf goldenrod)

T

Grand Island

None (upslope of fluctuations and not in vicinity of land management practices)

14

Zigadenus elegans ssp glaucus

(White camas)

T

Whirlpool State Park

None (upslope of fluctuations and not in vicinity of land management practices)

1 The unprotected plant Quercus shumardii is included because of its recent discovery in New York and the fact that it may be listed as a NYSDEC T&E species in the future

NYS Legal Status Codes: E=Endangered, T=Threatened, U=Unprotected

 

Table 4.1.1-2

T&E Birds and Potential Effects of Water Level and Flow Fluctuations and Land Management Practices

 

 

Species

NYS Legal Status

Area of Occurrence

Factors that Contribute to Potential Effects

1

Short-eared owl (Asio flammeus)

E

Niagara Falls Air Reserve Station (during winter)

None (not in vicinity of land management practices)

2

Upland sandpiper (Bartramia longicauda)

T

Niagara Falls Air Reserve Station

None (not in vicinity of land management practices)

3

Northern harrier (Circus cyaneus)

T

Formerly nested at Buckhorn Island State Park (1993); Niagara Falls Air Reserve Station

None (not in vicinity of land management practices, or no longer occurs at site potentially affected by fluctuations)

Sedge wren (Cistothorus platensis)

T

Formerly at Buckhorn Island State Park, not present since 1999

None (not in vicinity of land management practices, or does not currently occur at site potentially affected by fluctuations)

5

Peregrine falcon (Falco peregrinus)

E

Niagara Reservation State Park (Goat Island)

None (not in vicinity of land management practices)

6

Bald eagle (Haliaeetus leucocephalus)

T

Wintering individuals on Niagara River islands and shoreline

None (water fluctuations not known to affect foraging)

7

Least Bittern (Ixobrychus exilis)

T

Buckhorn Island State Park

Water level and flow fluctuations

8

Pied-billed grebe (Podilymbus podiceps)

T

Buckhorn Island State Park

Water level and flow fluctuations, recreation

Common tern (Sterna hirundo)

T

Artificial sites in the Niagara River (no nesting on natural islands or shoreline)

None (nesting sites well above influence of water level fluctuations; fluctuations not known to affect foraging)

NYS Legal Status Codes: E=Endangered, T=Threatened, U=Unprotected

 

Table 4.1.2-1

Special Concern Birds and Potential Effects of Water Level and Flow Fluctuations and Land Management Practices

 

 

Species

NYS Legal Status

Area of Occurrence

Factors that Contribute to Potential Effects

1

Cooper’s hawk

(Accipiter cooperii)

SC

Buckhorn Island State Park

None (nesting sites well above influence of water level fluctuations and not in vicinity of land management practices)

2

Sharp-shinned Hawk

(Accipiter striatus)

SC

Near Bond Lake Park

None (nesting sites well above influence of water level fluctuations and not in vicinity of land management practices)

3

Grasshopper Sparrow (Ammondramus savannarum)

SC

Niagara Falls Air Reserve Station

None (not in vicinity of land management practices)

Common Nighthawk (Chordeiles minor)

SC

In vicinity of Niagara Falls and Buckhorn Island State Park

None (any potential nesting sites would be above influence of water level fluctuations and not in vicinity of land management practices)

5

Horned Lark (Eremophila alpestris)

SC

Niagara Falls Air Reserve Station and Grand Island

None (not in vicinity of land management practices)

6

Red-headed woodpecker (Melanerpes erythrocephalus)

SC

Fort Niagara State Park

None (not in vicinity of land management practices)

7

Golden-winged warbler (Vermivora chrysoptera)

SC

Near Dickersonville and Bond Lake Park

None (not in vicinity of land management practices or water level fluctuations)

 

Table 4.1.3-1

Unprotected Mussels and Potential Effects of Water Level and Flow Fluctuations and Land Management Practices

 

 

Species

NYS Legal Status

Area of Occurrence

Factors that Contribute to Potential Effects

1

Fragile Papershell (Leptodea fragilis)

U

Beaver Island State Park, Buckhorn Island State Park, Niagara River Tonawanda Channel, Grand Island

Water level and flow fluctuations

2

Round Pigtoe (Pleurobema sintoxia)

U

Beaver Island State Park, Buckhorn Island State Park, Niagara River West River Parkway, Grand Island

Water level and flow fluctuations

3

Pink Heelsplitter (Potamilus alatus)

U

Buckhorn Island State Park, Niagara River Tonawanda Channel, Grand Island

Water level and flow fluctuations

NYS Legal Status Codes: E=Endangered, T=Threatened, U=Unprotected

 

Table 4.1.3-2

Significant Occurrences of Natural Communities and Potential Effects of Water Level and Flow Fluctuations and Land Management Practices

 

 

Community

NYS Legal Status

Area of Occurrence

Factors that Contribute to Potential Effects

1

Calcareous cliff

U

Niagara gorge

Recreation, landscaping, road sand and salt runoff

2

Calcareous talus slope woodland

U

Niagara gorge

Recreation, landscaping, road sand and salt runoff

3

Deep emergent marsh

U

Buckhorn Island State Park

Water level fluctuations in Niagara River and tributaries

4

Maple basswood rich mesic forest

U

Niagara escarpment near Dickersonville

None (located upslope of water level fluctuations and not in vicinity of land management practices)

5

Silver maple-ash swamp

U

Grand Island (Buckhorn Island State Park; Beaver Island State Park, Gun Creek) 

None (located upslope of water level fluctuations and not in vicinity of land management practices)

NYS Legal Status Codes: E=Endangered, T=Threatened, U=Unprotected

 

Table 4.4-1

Factors Related to Land Use and Maintenance Activities THAT Could Affect RTE Species and Natural Communities in the Investigation Area

Species or Community of Interest

On Lands Owned and Managed by NYPA

On Lands Not Managed by NYPA

Buildings, Roads, and Parking Lot Maintenance

Forebay and Reservoir Maintenance

Mowing and Right-of-Way Maintenance

Landscaping  (tree and shrub planting)

Recreation

 Sedimentation and Erosion

Buildings, Roads, and Parking Lot Maintenance

Mowing of Parks and Roadsides

Landscaping  (tree and shrub planting)

Recreation

Alien Invasive Species (AIS)

Sedimentation and Erosion

Natural Communities

X

 

 

X

X

 

X

X

X

X

X

 

Plants

X

 

 

X

X

 

X

X

X

X

X

X

Native Mussels

 

 

 

 

 

 

 

 

 

 

X

X

Fishes

 

 

 

 

 

 

 

 

 

 

 

 

Birds - Wetland

 

 

 

 

 

 

X

 

 

X

X

 

Birds - Grassland

 

 

 

 

X

 

 

X

 

X

 

 

 

Table 4.4.1-1

Categories and Acreages of Land Use and Maintenance Activities on NYPA-owned Lands

Land Use Category

Area (acres)

Percent of Total Area

Land open for public recreation

573.3

33.0

Project operations

473.6

27.3

Parking lots and roads

310.1

17.9

Mowed areas

301.4

17.4

No maintenance

59.3

3.4

Buildings

19.0

1.1

Totals

1736.7

100.0

Note:  These values do not include the acreage of the reservoir, forebay, or ice boom areas.

 

6.0     DISCUSSION

This section includes discussions of RTE species and significant occurrences of natural communities in the investigation area (Section 5.1), the habitat requirements of the RTE species (Section 5.2), and the potential effects of water level and flow fluctuations and land management practices on NYPA lands on these species and natural communities (Section 5.3).  In some cases, factors that are not related to water level and flow fluctuations and land management practices on NYPA lands but have the potential to affect RTE species and significant occurrences of natural communities are discussed briefly.

6.1         RTE Species and Significant Occurrences of Natural Communities in the Investigation Area

The literature search and field surveys conducted in 2000 by NYNHP and in 2001 and 2002 by Riveredge provide a good indication of which RTE species and significant occurrences of natural communities are potentially affected by water level and flow fluctuations and land management practices in the investigation area.

The RTE species and significant occurrences of natural communities with potential for being affected are those that occur on lands managed for public recreation or those that occur in or on the Niagara River and its tributaries.  Fluctuations in water level and flow caused by the combined influences of NYPA and OPG hydroelectric operations as well as other factors could affect RTE species that occur in the Niagara River and its tributaries or along the shorelines of the river and its tributaries.  RTE species and unprotected species of special interest known to occur in these areas include the plants Gentianopsis procera, Carex garberi, Solidago ohioensis, and Iris virginica var shrevei, three species of native mussels, lake sturgeon, and two species of wetland-nesting birds.  In addition, uncontrolled public recreation on NYPA-owned lands could affect the plants Aster oolentangiensis, Liatris cylindracea, and Pellaea glabella.  Significant occurrences of natural communities in these areas include calcareous cliff or calcareous talus slope woodland and deep emergent marsh habitats.

Most RTE species in the investigation area are found in the protected portions of state parks managed by NYSOPRHP.  Others, such as grassland birds, are found in the large open grasslands associated with the NFARS and airport (USFWS 2001).  Most RTE species occur in areas that are not affected by land management activities on NYPA lands or water level or flow fluctuations (Tables 4.1.1-1, 4.1.1-2, and 4.1.2-1).

6.2         Habitat Requirements of RTE Species

Most of the RTE species that occur in the investigation area require unique and undisturbed habitats that are rare in the urban landscape around Niagara Falls.  These species are concentrated in a few protected areas such as state parks or the undeveloped grasslands of the NFARS, but other high quality habitats in the area are rare.  The Niagara gorge has the greatest concentration of RTE species and contains one of the greatest assemblages of rare plants in the entire state of New York (Evans et al. 2001c).  Many RTE species require undisturbed or undeveloped land and are sensitive to human disturbance.  In addition, some of the birds are known to be area-sensitive and survive best in areas of 100 acres or more of their preferred habitat type, which is difficult to find in the vicinity of Niagara Falls.  The Niagara Falls area is largely developed and RTE species are uncommon; their occurrence is largely restricted to state parks or other protected areas.

6.3         Potential Effects of Water Level and Flow Fluctuations and Land Management Practices on NYPA Lands

Most RTE species and significant occurrences of natural communities are found outside of areas affected by water level and flow fluctuations and NYPA land management practices.  Some species, notably plants that occur near the river in the Niagara gorge and species associated with the river and its tributaries are potentially affected by public recreational use of Project lands and water level and flow fluctuations.  Recreational effects occur on NYPA-owned and managed lands as well as on other lands.  Water level and flow fluctuations occur in the upper and lower river, but most RTE species of the Niagara River are found in the upper river.  Upper-river water level fluctuations resulting from NYPA and OPG operations, other anthropogenic factors, and natural factors measured during the RTE bird breeding season (May, June, July) are typically less than 18 inches (URS et al. 2005). 

Land uses and recreational pressure are affecting some of the significant occurrences of natural communities in the investigation area.  In particular, recreational use or overuse of certain areas in the Niagara gorge is damaging the thin soils and sensitive plants of the calcareous cliff and calcareous talus slope woodland communities (Evans et al. 2001c).  These communities, and the deep emergent marsh at Buckhorn Island State Park, are also threatened by alien invasive species, some of which are horticultural plantings for landscaping purposes in public parks. 

6.3.1        Calcareous Cliff and Calcareous Talus Slope Woodland

In general, NYPA land management practices likely have little effect on the calcareous cliff or calcareous talus slope woodland communities, in large part because these are conducted in areas away from these communities.  One exception is the Project access road that descends from Hyde Park Boulevard across the gorge rim down to the Project tailrace north of Devil’s Hole.  This road is maintained by NYPA, may divert water from the adjacent cliff areas, and possibly contributes some winter road salt and sand to the river shoreline through surface water runoff.

The area around the access road and Devil’s Hole has been highly modified due to development, road construction, and the remediation of the Hooker Hyde Park landfill.  Hooker Hyde Park is a 15-acre site that was used to dispose of approximately 80,000 tons of waste, some of it hazardous, from 1953 to 1975 (USEPA 2002).  Contaminants from the landfill flowed into Bloody Run Creek and down the Niagara gorge face into the river (USEPA 2002).  The remediation plan involves the excavation of Bloody Run and the use of extraction wells to maintain an inward groundwater hydraulic regime at the site (USEPA 2002). Remediation activities have altered surface water and groundwater flow, and have dried up the seeps on the face of the cliff (NYWEA 2000).  The cliff face and the talus slope woodland in the vicinity of Devil’s Hole are now drier than they once were, and this likely has changed the plant species composition of the community (Eckel 1990).

Due to the area’s extensive development, this channelization of surface water runoff has occurred along the entire length of the gorge.  The presence of roads and highways changes drainage patterns and contributes road salt and sand to surface water runoff.  While some areas of the Niagara gorge have reduced moisture regimes, other areas experience high amounts of runoff from melting snow or rain.  These changes have modified the plant species composition of some areas.

Salt runoff from the Robert Moses Parkway and runoff from storm sewers and discharge pipes along the gorge walls and in the talus slope may account for the curious development of Phragmites australis in the rubble associated with seeps, often high up on the cliff face, especially in the poorer shale exposures in the northern part of the gorge, where highway interchanges occur as noted by Eckel 2003b.  NYNHP (Evans et al. 2001c) also noted that stormwater runoff from city streets and parking lots may introduce various types of chemicals and petroleum products into the calcareous talus slope woodland community at the base of the cliff.

The two greatest threats to the rare plants and natural communities of the Niagara gorge are human disturbance and the introduction of alien invasive species (Evans et al. 2001c, Eckel 1990).  NYNHP (Evans et al. 2001c) noted that the single greatest threat to RTE plants of the Niagara gorge is the impact of recreationists.  The soils of the Niagara gorge are thin and easily disturbed, and rare native plants may be trampled.  Recreationists have contributed to soil erosion and compaction both on and off designated trails.  In some areas the soils have been completely lost and only bare rock remains.  Larson et al. (2000) reported that recreational activities on the Niagara escarpment affected the recruitment, productivity, and survival of cedars along the gorge, some of which are over 1,500 years old.  In addition, recreationists or collectors are suspected of being responsible for the disappearance of several T&E plants that once grew along the edges of hiking trails in the state parks of the gorge.  At Whirlpool State Park, several historical T&E species no longer occur, probably in part due to picking or collection.  Trailside occurrences of the state-listed (endangered) plants Carex garberi and Gentianopsis procera disappeared between 1990 and 2001.  The showy blue flowers of the gentian attract collectors, and these plants may have been picked or collected out of existence at this site.  These two species still occur at other sites in the Niagara gorge and at Niagara Reservation State Park.

The planting of non-native trees and shrubs on the edges or rim of both sides of the Niagara gorge by agencies that manage parks and promote tourism represents a serious threat to the integrity of the gorge’s natural communities (Evans et al. 2001c;  Eckel 2003b).  Parts of the gorge are rapidly filling with alien species such as marsh sow-thistle (Sonchus uliginosus), bitter nightshade (Solanum dulcamara), garlic mustard (Alliaria petiolata), and other weeds and shrubs such as buckthorn (Rhamnus cathartica) (Eckel 1990).  Horticultural material planted on the gorge crest in both New York and Ontario contributes to this flora, such as lilac (Syringa vulgaris) at Devil’s Hole State Park.  Seeds of horticultural plants may be spread from the Canadian side of the gorge on the prevailing winds.  One such example is Catalpa speciosa (catalpa), which was once limited to the Canadian gorge crest, but is now established in the gorge itself.  Eckel (2003b) noted that the planting of introduced Eurasian species in Buffalo occurred as early as 1886 and this practice continues today.  She believes the planting of alien invasive trees and shrubs by government agencies that landscape public parks on both sides of the gorge represents a serious threat to the persistence of rare plants and the integrity of the natural communities in the gorge (Eckel 2003b).  NYNHP expressed similar concerns in a report to NYSOPRHP (Evans et al. 2001c).

Alien invasive species, which are prominent in the gorge, are displacing important native species.  Alien species that pose the greatest threat to the integrity of these communities are Rhamnus cathartica (common buckthorn), Lonicera tartarica (Tartarian honeysuckle), Alliaria petiolata (garlic mustard), Robinia pseudo-acacia (black locust) and Acer platanoides (Norway maple).  NYNHP noted that these species have devastating effects on the natural environments in which they become established, and recommended that the spread of exotic species in the gorge be monitored and controlled (Evans et al. 2001c).  NYPA’s landscaping and planting activities are largely limited to areas around Project structures and buildings and public parks away from the gorge.

6.3.2        Deep Emergent Marsh

Although NYPA does not own or manage land in the vicinity of the deep emergent marsh at Buckhorn Island State Park, water level fluctuations do occur in this area and could affect some RTE species and their habitats in the marsh.

The deep emergent marsh at Buckhorn Island State Park is the largest and highest quality remaining marsh along the Niagara River (NYSDEC and NYSOPRHP 1995, Evans et al. 2001b).  A number of state-listed threatened and endangered species occur in the marsh or very nearby.  In recent years, osprey, northern harrier, bald eagle, common tern and sedge wren have been seen in the marsh.  Other rare species, such as native mussels, have been documented in the area as well (NYSDEC and NYSOPRHP 1995, Riveredge 2005b).  NYSDEC conducted a review of historic aerial photographs and noted that the marsh was undergoing habitat changes and water levels were lower than in previous years (NYSDEC and NYSOPRHP 1995).  Because of the regional importance of Buckhorn marsh to fish and wildlife, NYSDEC and NYSOPRHP undertook a major habitat restoration project in the marsh beginning in 1993 (NYSDEC and NYSOPRHP 1995).

One of the primary goals of this restoration project was the reestablishment of a mixture of open water, emergent marsh and wet meadow habitats that could support an increased diversity and abundance of wetland species.  Other goals included increasing the public awareness and appreciation of the function and values of Niagara River wetlands, and to obtain the necessary resources to support programs and projects as identified by the Buckhorn marsh restoration committee.  This committee, made up of local stakeholders, developed a number of specific objectives for the project (NYSDEC and NYSOPRHP 1995).  Among the stated objectives was the restoration and maintenance of water levels conducive to increased abundance and diversity of species, the creation of an increased ratio of open water to marsh habitat, and the creation of a warm water fishery with emphasis on northern pike (NYSDEC and NYSOPRHP 1995).

The Buckhorn Marsh restoration project included the completion of a Plant Resources Assessment and a Wildlife Resources Assessment (NYSDEC and NYSOPRHP 1995).  The Plant Resource Assessment noted that the maintenance of higher stable water levels should favor the preservation and reestablishment of the former plant communities of the marsh.  The Wildlife Resource Assessment noted surprisingly low diversity and densities of breeding marsh birds and amphibians, although several threatened bird species were known to nest or forage at Buckhorn marsh including common tern, least bittern, northern harrier and sedge wren (NYSDEC and NYSOPRHP 1995).  One objective of the project was to restore and maintain water levels in the marsh at depths conducive to increasing the abundance and diversity of terrestrial and aquatic species by constructing water level control structures and excavating open water channels (NYSDEC and NYSOPRHP 1995).  On the east side of the marsh, two water level control structures were installed in Burnt Ship Creek to increase and stabilize water levels.  During the spring, high water levels would overtop the weirs, and this water would be retained on the marsh as the level of the river decreased during summer.  In addition, several thousand feet of open water channel were excavated throughout the marsh to create additional nesting habitat for marsh birds.  These habitat alterations would provide nesting, brooding, escape and resting habitat for waterfowl, as well as new and improved habitat for several species of threatened and endangered birds such as common tern, sedge wren, northern harrier, least bittern and possibly also pied-billed grebe.  The overall design for the marsh involved encouraging use of the east side of the marsh by threatened bird species, and use of the west side of the marsh by spawning fish.

Water level data indicate that the weirs were successful at increasing and stabilizing water levels in the marsh (URS et al. 2005, Stantec et al. 2005).  In the spring, water levels inside the water control weirs were typically about 1.0 foot higher than in the west side of the marsh and these levels were much more constant than in the portions of Burnt Ship Creek and Woods Creek open to the Niagara River (URS et al. 2005, Stantec et al. 2005).  These data suggest that the level of the marsh between the weirs is largely independent of the Niagara River and the marsh restoration project appears to have been successful at keeping these water levels higher and more stable than they were previously.

Two threatened bird species that could benefit from the Buckhorn marsh restoration are the sedge wren and northern harrier.  Sedge wrens prefer wet sedge meadows for nesting (Herkert et al. 2001) and northern harrier nests on the ground in wet meadows, fields or marshes (MacWhirter and Bildstein 1996).  These habitats occur at Buckhorn marsh and both species nested in the marsh in the 1990s.  Northern harriers bred in the marsh in 1993 (Evans et al. 2001b) and may have nested there in other years as well (NYSDEC and NYSOPRHP 1995).  Sedge wren was last recorded at Buckhorn marsh in 1999 (Evans et al. 2001b) but this species is well known for its tendency to nest in different areas from year to year and returning to a former nesting site after an absence of one or more years (Herkert et al. 2001).  Both northern harrier and sedge wren could return to Buckhorn marsh and nest there again in the future, and the increased water level between the weirs could make these habitats more attractive to these species.

Parts of the deep emergent marsh at Buckhorn Island State Park could be undergoing habitat change as a result of regulation of water levels and flows in the Niagara River (Stantec et al. 2005), the presence of alien invasive species (Evans et al. 2001b), or the influences of road salt from the highway bisecting the marsh.  In addition to the influence of river regulation, the marsh at Buckhorn Island State Park may be influenced by long-term precipitation trends and short-term storm events that affect the water levels in the Chippawa-Grass Island Pool.

Daily water level fluctuations in the Niagara River adjacent to Buckhorn marsh are normally 18 inches or less, although water level fluctuations could affect a zone greater than this (URS et al. 2005, Stantec et al. 2005).  Water level fluctuations can influence plant distributions in wetlands, primarily by influencing erosive forces and their effects on plants and substrates (Stantec et al. 2005).  Wetlands are dynamic ecosystems, and periodic extreme water levels maintain habitats and the diversity of plants and animals that occur in wetlands (Stantec et al. 2005).  The effects of smaller, short term water level fluctuations on the habitats of Buckhorn marsh are being addressed in a separate study.  The potential effects of these fluctuations on RTE plants are discussed in Section 5.3.3.

In addition to daily and seasonal water level fluctuations, the Niagara River and Buckhorn marsh may be influenced by long-term fluctuations resulting from cumulative effects of a prolonged and persistent deviation from average climatic conditions.  For most of the last 30 or so years of the twentieth century, the level of Lake Erie generally ranged above the long term average for the lake (Cashell 2002).  These persistently high water levels reflect the above-normal precipitation that consistently fell in the Great Lakes basin, especially during the 20-year period prior to the record-high level year of 1986.  During this 20-year period, precipitation accumulated to nearly 39 inches above normal (Cashell 2002).  This long period of relatively high precipitation was followed by drier years, and the declines in Lake Erie levels during the late 1990s are particularly notable.  Lake Erie had a net decline of nearly 4.2 feet between the June 1997 peak and the lowest level observed during February 1999.  This reflected a significant drop in water levels in the Great Lakes hydrologic system (Cashell 2002).  The significant decline in the level of Lake Erie can be attributed to below-normal precipitation during the second half of 1997 and throughout most of 1998, and to excessive evaporation, especially during the winter months during these same years (Cashell 2002).  In addition, precipitation in the Lake Erie basin was below normal during 1999, as many areas experienced drought conditions.  All these factors have contributed to declining lake levels, not only in Lake Erie and the Niagara River, but also in the entire Great Lakes system (Cashell 2002).

Long-term changes in precipitation such as those cited by Cashell (2002) could also affect the structure and composition of the vegetation of Buckhorn marsh, especially in areas where the vegetation is more dependent on rainfall and runoff for water than on the Niagara River.  This could be true of portions of the wet sedge meadow and some areas along Burnt Ship Creek, although the weirs may retain water on the marsh at higher levels and for longer periods and have probably helped to mitigate the overall effect of the lack of rainfall and drought conditions cited by Cashell (2002).

6.3.3        Plants

Most RTE plants in the investigation area are threatened by recreation and invasive alien species, factors that are largely unrelated to Project operations.  Exceptions are the plants growing along shorelines such as Iris virginica var shrevei, Carex garberi, Solidago ohioensis, and Gentianopsis procera where fluctuating water levels could affect these species.

Water level and flow fluctuations could also affect the plants Gentianopsis procera, Carex garberi, and Solidago ohioensis.  The first two plants occur on the shorelines of the upper Niagara River in Niagara Reservation State Park.  This area has been highly modified by man and most of the original forest has been removed (Eckel 1990).  These lands are neither owned nor managed by NYPA, but the shoreline areas experience water level fluctuations.  Carex garberi occurs along the water’s edge.  NYNHP (2003a) noted that plants there are under constant threat of being washed away during periods of high water.  The median water level at the American Falls water level gauge is 0.70 feet higher during tourist season than during non-tourist season due to the increased flow mandated over the falls during tourist season (URS et al.2005).  Solidago ohioensis occurs along the shoreline of the lower river on unstable clay banks downstream of Earl W. Brydges Artpark.  Although water level fluctuations are relatively small in this section of the lower river, boat wakes could undercut the banks, and the resulting erosion could cause the loss of some of the plants that occur in this area.  The overall extent of the occurrence of this plant is not known.

Gentianopsis procera occurs on the exposed dolomitic limestone flats within the spray zone of the falls.  This plant is most commonly found in wet areas.  The reduced mist at the falls from the combined influences of NYPA and OPG hydroelectric operations could affect the distribution of this plant.  Gentianopsis procera also occurs in the gorge at Whirlpool State Park.

Iris virginica var. shrevei is common along stream banks and shorelines, and along the edges of ponds, marshes, and sedge meadows.  This plant is known to occur in a wide range of habitats and to tolerate a wide range of conditions.  It grows in a variety of moisture regimes, ranging from moist soils to shallow water.  Day (1888) recorded this plant on Goat Island over 100 years ago, and it still occurs there today.  Throughout its range, this hardy plant is associated with rivers and wetlands where water level fluctuations are frequent.  The magnitude of the water level fluctuations caused by river regulation in upper river sites of occurrence is considerably smaller than those water level fluctuations caused by seasonal changes in the level of Lake Erie and other natural environmental factors.  On the Niagara River, this plant occurs in areas where substrates are fine and currents and wave action are low. This plant may be difficult to distinguish from a common congener, and closer scrutiny in the last ten years has found Iris virginica var shrevei in many areas around Lake Erie in Pennsylvania and Ohio, suggesting that the plant is more common than previously thought (Eckel and Bissell 2002).  No literature was found that addresses the issue of water level fluctuations on this wetland plant, although it has persisted along the Niagara River for over 100 years.  At Buckhorn marsh, NYNHP noted that heavy recreational use of the area may be a threat to fragile wetland soils and plants (Evans et al. 2001b).

6.3.4        Native Mussels

As a group, native mussels are among the most threatened organisms in North America and the world.  In New York, native unionid mussel populations are declining and are expected to continue to decline.  In the lower Great Lakes, the most serious threat to native mussels is the invasion of the zebra mussel (Strayer and Jirka 1997).  In Lake Erie, hundreds or thousands of zebra mussels may attach to a single native mussel.  Complete mortality of native mussels is common within one or two years of zebra mussel infestation (Schloesser et al. 1996).

Altered water level and flow regimes at hydroelectric dams can have major effects on native mussels (Williams and Neves 1995, Muir et al. 1997).  Most hydroelectric dams span their streams, blocking the passage of mussel host fish and creating impoundments that are subject to sedimentation, oxygen depletion and water level fluctuations.  At some impoundments, rapid large-scale fluctuations in water levels can leave mussels stranded and exposed.  Although native mussels can survive periods of exposure for many hours in moderate temperatures, extreme heat or cold will kill them.

On the Niagara River, the hydroelectric facilities of NYPA and OPG do not span the river and substantial river flow still occurs.  Daily water level fluctuations in the upper river are normally 18 inches or less (URS et al. 2005).  Moreover, the movement of fish hosts in the upper and lower river is not blocked by a dam, and movement between these two sections of river has always been naturally blocked by Niagara Falls.

Field surveys conducted in 2001 and 2002 found that the Niagara River was largely devoid of living native mussels (Riveredge 2005b).  Pre-dredging surveys conducted in late October 2001 at Beaver Island Marina also found no live native mussels (Normandeau Associates 2001).  Mussels are very sensitive to environmental degradation.  In the Niagara River region, the absence of natural shorelines and the presence of contaminants and zebra mussels have decreased the abundance and diversity of native mussels dramatically.  The Buffalo River drainage, which once supported at least seventeen species of native mussels, now contains only six species, a loss of 65% of the species that formerly occurred there (Strayer et al. 1991, Strayer and Jirka 1997).

In contrast to the Niagara River, the wetlands and creeks of Grand Island still contain native mussels.  In 1994, two species of mussels were found in Buckhorn marsh (NYSDEC and NYSOPRHP 1995) and four species were recently found in the creeks of Grand Island (Riveredge 2005b).  In portions of these tributaries, the regulation of the Niagara River and the combined influences of NYPA and OPG hydroelectric operations and local environmental factors cause water level fluctuations where live native mussels were found.  Water level and flow fluctuations in these tributaries could affect native mussels by increasing erosion and sedimentation, restricting the movements of host fish, or by reducing the survival of individual mussels if they become exposed during periods of low water.

Sedimentation is a known cause of mortality in native mussels (Muir et al. 1997).  No comprehensive survey of erosion or sedimentation sites or causes has been conducted in the occurrence areas of RTE species in the investigation area and the overall effects of sedimentation are unknown.  The loss of riparian habitat along streams can increase erosion and sedimentation.  Portions of some Grand Island streams have cleared shorelines and sediment loads are apparent.  However, the degree of erosion and sedimentation has probably decreased over the last 50 years as cleared agricultural areas on Grand Island have reverted to areas of successional forest.  Most live native mussels were found in substrates that contained gravel.  In general, the turbidity of Grand Island tributaries is much higher than that of the Niagara River.

Most of these tributaries have unobstructed fish passage, especially during the spring spawning period when local runoff from spring snow melt combined with higher spring levels of Lake Erie keep the depth of Grand Island tributaries and the Niagara River relatively high.  The potential for fish passage in several tributaries is under examination as part of the development of fish and wildlife habitat improvement projects.

Water level fluctuations in Grand Island tributaries are best described using water level data from the Tonawanda Island water level gauge.  Median daily water level fluctuations recorded at this gauge were less than seven inches (0.55 feet) during the April 1 to October 31 tourist season (URS et al. 2005).  Mussels in the tributaries on the east side of Grand Island were found at approximately two to three times this water depth during field surveys (Riveredge 2005b).  Tourist season water level fluctuations are unlikely to affect native mussels or to leave them exposed or stranded in the tributaries where they occur.

Some mussels are capable of considerable horizontal or vertical movement in response to changes in water temperature or water level.  Typically, native mussels move or burrow in the substrate in response to high water temperatures or low water levels.  Nichols and Wilcox (1997) reported that Leptodea fragilis (fragile papershell) and Pyganodon grandis (floater), two thin-shelled species found alive during field surveys, followed descending water levels during the dewatering of a Lake Erie wetland that was about four feet deep.  Some individual mussels were found to move several hundred meters, following the receding water level as the wetland was drained (S.J. Nichols, USGS, personal communication, December 22, 2003).  Mussels with thin shells were more mobile than those with thick shells (Nichols and Wilcox 1997).  In Maine, however, a relatively rapid eight-foot drawdown of a hydroelectric reservoir resulted in little movement by mussels and mortality was 100% in areas that dried out (Hanson 1998).  Water levels in this reservoir dropped eight feet in less than 12 hours and remained eight feet lower than normal for three months while maintenance activities were conducted.

Zebra mussel infestation interferes with the ability of mussels to move.  Zebra mussel infestation prevents native mussels from burying themselves in river substrates (Nichols and Wilcox 1997), either by attaching to the shell of the native mussel or by creating a mat of zebra mussels that the native mussels cannot penetrate.  Heavy mats of zebra mussels on river bars can make it impossible for native mussels to follow receding water levels.  In some areas of the Mississippi River, zebra mussels completely cover river bars and prevent native mussels from moving to safety when river substrates are exposed by river drawdowns.  Native unionids normally would have followed the descending water level by pushing their muscular foot into the soft substrates, but the impenetrable mat of zebra mussels prevents this movement and leaves them stranded and exposed (Tucker 1994).

Changes in water temperature also trigger movement or burrowing in unionid mussels.  As water temperatures rise or fall to stressful levels, mussels move or burrow into the substrate to reach areas where temperatures are more moderate.  Many small, shallow streams may reach water temperatures that are stressful or lethal to native mussels in summer, especially if the water is slow-moving and in areas where there are no overhanging trees and the stream receives direct sunlight.  As water temperature rises, the levels of dissolved oxygen fall.  Shallow streams exposed to direct sunlight may not have enough dissolved oxygen during the hot summer months for mussels to survive.

The depth to which unionid mussels will burrow is determined by the characteristics of the sediment.  If the sediment has good oxygen flow within interstitial spaces, the unionids might burrow deeper than in sediments with low oxygen levels.  Mussels also may burrow deeper in softer substrates (Nichols and Wilcox 1997).  Nichols (S.J. Nichols, USGS, personal communication, December 22, 2003) reported that she generally finds most individual mussels only a few centimeters deep in the sediment of a small river she has studied extensively, although some mussels could be as much as 12 inches deep in the sediment.  The cues that determine how far mussels will burrow are not known, although the size of the individual mussel and the levels of oxygen in the substrate likely play important roles.  Burrowing depth seems to vary more with individuals than with species, and summer burrowing appears to be more temperature driven than does burrowing in winter (S.J. Nichols, USGS, personal communication, December 22, 2003).

In winter, the water levels of the Niagara River are lower than in summer (URS et al. 2005).  Although these lower water levels may expose sand or gravel bars that are potentially suitable mussel habitat, there are virtually no native mussels currently present in the mainstem of the Niagara River due to zebra mussels, contaminants and the lack of natural shoreline (Riveredge 2005b).  In the Grand Island tributaries where native mussels still occur, these lower water levels are reached as the seasonal flow of the tributaries and the water level of Lake Erie decline over a period of weeks or months (URS et al. 2005), giving native mussels ample time to move or to burrow as water levels and water temperatures change.

On impounded lakes, large water level drawdowns of three to five feet or more may be used as a management tool to intentionally kill zebra mussels.  These drawdowns are performed both in winter and in summer.  When exposed, zebra mussels cannot burrow into soft substrates or move as easily as native unionid mussels can and their survivorship is much lower when shorelines become exposed by low water levels.  Experiments conducted in winter at the Black Rock Lock on the Niagara River indicated that even brief exposure (<24 hours) to freezing temperatures is lethal to zebra mussels (Miller et al. 1994).  In summer, Tucker et al. (1997) found that mid-summer (July) drawdowns on the Mississippi River killed zebra mussels, but native unionid mussel survivorship was generally unaffected by aerial exposure of up to 24 hours.

Most tributaries of Grand Island appear to contain water throughout the year, primarily due to runoff within the watershed caused by rain or the periodic melting of snow through the winter months.  If portions of the Grand Island tributaries that contain mussels are dewatered during winter periods of lower water levels, native mussels that did not burrow in soft substrates or that did not move to deeper water in the fall could be killed by exposure to freezing temperatures.  The site on Grand Island with the greatest concentration of live native mussels was characterized by cool water over a gravel bottom and the general absence of zebra mussels (Riveredge 2005b).  This cool water appeared to come from groundwater inflow since it was noticeably cooler than the surface water.  This cooler water from groundwater inflow may moderate water temperatures and oxygen levels throughout the year in comparison to areas without this groundwater inflow.

6.3.5        Fish

The potential effects of fluctuations in water level and flow on spawning and foraging activities of lake sturgeon in the lower Niagara River were examined.  Also examined was the potential for entrainment at the intakes on the upper Niagara River.

Entrainment of lake sturgeon through the upper river intakes has not been recorded.  However, it is possible that larval-stage and juvenile lake sturgeon could be be entrained.  No lake sturgeon have been recorded in Lewiston Reservoir and none were not observed during fishery surveys conducted in the 1980s or in 2000 (EA 1984, NYPA 2002) or during surveys of anglers fishing on the reservoir (Stantec et al. 2005).  The habitat adjacent to the intakes is quite dissimilar to the habitats where adult or juvenile sturgeon have been recorded in the Niagara River.  Proximal to the intakes the river bottom has been dredged and the shoreline has been protected with sheet-piling.  The conduits themselves are concrete.  These habitats are not preferred by sturgeon and it is unlikely that sturgeon are found there.  USFWS (1999) reported observations of a juvenile sturgeon concentration area near Grass Island.  Juvenile sturgeon were observed in habitats where river currents were reduced, average depths were 15.5 feet, and bottom substrates were sand and gravel with some cobble.  Adult sturgeon preferred areas of fine-grained or soft substrates.  Adults appeared to prefer the lake or main river, whereas juveniles preferred back eddy environments (Hughes 2002).  In contrast, the habitat adjacent to the conduits is characterized by higher velocities, deeper waters, and coarser substrates.  Because fishery and angler surveys of the reservoir have never recorded lake sturgeon (EA 1984, NYPA 2002, Stantec et al. 2005), it is unlikely that entrainment of larval, juvenile or adult sturgeon occurs at the Niagara Power Project.

Lake sturgeon move seasonally.  On small rivers, they move in response to changes in discharge flows during spring spawning periods.  On the Kettle River in Minnesota, a very small river with a mean daily discharge well under 1% of the Niagara River, sturgeon movement was highly correlated with river discharge due to spring runoff or passing rainstorms (Borkholder et al. 2002).  Upstream movements were recorded during periods of high discharge and downstream movements occurring during periods of diminishing discharge.  This movement was seasonal, occurring in the spring and fall.  Borkholder et al. (2002) reported that this behavior might be related to spring spawning movements or to feeding exploration of habitat.  Most of the Kettle River is less than five feet deep, and the mean daily discharge is only 719 cfs (Borkholder et al. 2002).  Spring upstream movements took place when discharge increased to 2,000 cfs or more.  One spring discharge event that triggered sturgeon movement was approximately 9,000 cfs, more than 12 times the mean daily discharge (Borkholder et al. 2002).

The sturgeon movement patterns described by Borkholder et al. (2002) in a small Minnesota river do not appear to occur in the lower Niagara River.  Although flow-related changes in movement patterns are theoretically possible in sturgeon of the lower Niagara River, they were not detected in or out of the spawning season in tagged sturgeon studied by USFWS (Hughes 2002, USFWS 2002).  USFWS (2002) attempted to determine differences in sturgeon movement patterns during daylight and darkness by tracking sturgeon for periods of twenty-four hours on three days during August and September 1998.  During these 24-hour periods, flows in the lower river change due to Project operations and river regulation.  Prior to performing this work, USFWS (2002) hypothesized that lake sturgeon may be utilizing deeper waters (> 33 feet) during the day and then moving into relatively shallow waters (< 33 feet) to feed at night.  They further hypothesized that some fish may occupy the lake during the day and move into the river at night, particularly at or near the river’s mouth.  These suspicions were not confirmed by tracking fish fitted with ultrasonic tags.  In general, fish did not exhibit large-scale movement patterns between day and nighttime hours.  However, fish did appear to be more active at night, when discharges are lower, as indicated by increased localized movements.  These experiments were conducted on days when lower river flows ranged from 170,638 cfs to 275,754 cfs (USFWS 2002, URS et al. 2005).  The USFWS (2002) data suggest that changes in flow regime have little effect on the movements of sturgeon, although they note that they were unable to draw significant conclusions due to the small sample size of the study.

  Most studies of sturgeon behavior are conducted in rivers with much lower discharges and lower velocities than the Niagara River.  Rivers considered by Auer (1996), Borkholder et al. (2002), Knights et al. (2002) or Seyler (1997) have velocities and discharges considerably less than the lower Niagara River.  The Sturgeon River studied by Auer (1996) has an average discharge of 795 cfs during the May spawning period, and the Kettle River studied by Borkholder et al. (2002) has an even lower discharge (719 cfs).  In contrast, the average Niagara River discharge in May is 223,590 cfs (URS et al. 2005).  For May and June, mean monthly flows recorded over the 77-year period from 1926 to 2002 were in excess of 215,000 cfs (URS et al. 2005).

In large rivers such as the St. Lawrence River, Hayes (2000) documented sturgeon spawning in the tailrace of NYPA’s St. Lawrence-FDR Power Project at velocities of 1.6 to 3.9 fps and water depths of approximately 21 to 23 feet.  Further downstream near Montreal, LeHaye et al. (1992) found St. Lawrence River sturgeon spawning in shallower water with current velocities of 1.3 to 4.6 fps, with most eggs found in water velocities of 2.0 to 2.8 fps.  In Great Lake connecting rivers such as the Detroit and St. Clair rivers between Lake Huron and Lake Erie, sturgeon spawn at depths of 29 to 39 feet (Manny and Kennedy 2002).  In the Niagara River, if sturgeon spawn in the shallow waters of the upper or lower river where substrates are periodically exposed by fluctuating water levels, the hatching rate of eggs and the survival rate of larvae could be reduced.  However, there is no indication that sturgeon frequent these areas for spawning, for foraging, or for any other reason (Hughes 2002).

If sturgeon spawn in areas below Joseph Davis State Park, where tagged sturgeon were found to concentrate at temperatures appropriate for spawning in mid-May to mid-June, they would experience water level fluctuations of less than one foot (URS et al.2005).  In the lower River, Hughes (2002) found the majority of sturgeon at depths of 23 to 36 feet, well below the influence of water level fluctuations.  Changes in flow during this spawning period typically range from approximately 150,000 cfs to 250,000 cfs (URS et al. 2005).  On a daily basis, flows typically change by a factor of less than two (i.e., they increase or decrease by less than a doubling or halving of the flow).  On the river studied by Borkholder et al. (2002), where sturgeon movements were highly correlated with flow, flows changed by factors from greater than two to more than 12 times the average daily flow.

In the lower Niagara River, Hughes (2002) found that sturgeon moved more during the warmer months, but tended to be found in a few well-defined areas.  Hughes (2002) recorded 77% of sturgeon captures in only two locations, Peggy’s Eddy and the Queenston drift, and believed that these two areas were used for feeding and resting.

The use of activity centers (Borkholder et al. 2002) or core areas (Knights et al. 2002) by sturgeon has been documented.  Borkholder et al. (2002) observed that that 80% of the time during daylight hours adult sturgeon were found in four activity centers and all tagged fish showed some affinity for specific pools.  Like Peggy’s Eddy and the Queenston drift, the preferred habitats for sturgeon were areas along transition zones from high current to low current where deposition may occur, such as back eddies.  All studies found sturgeon to preferentially use areas over soft substrates such as silt or sand (Borkholder et al. 2002, Knights et al. 2002, Hughes 2002).  In the lower Niagara River, fine-grained depositional habitats like this are uncommon (Mudroch and Williams 1989).  Interestingly, fish that were captured and released showed some ability to home to their preferred activity centers (Knights et al. 2002).

Sturgeon activity centers generally have low current velocities (Seyler 1997, Borkholder et al. 2002, Hughes 2002).  Current velocities were under 1.3 fps in Minnesota (Borkholder et al. 2002).  Seyler (1997) found that adult lake sturgeon did not prefer habitats with current velocities exceeding 2.0 to 2.3 fps, and Hughes (2002) suggests that juvenile sturgeon prefer areas where current velocities are even lower.  In the upper river, young-of-the-year sturgeon appear to concentrate in the waters around Buckhorn Island State Park, where currents are lower than in the main river channel (USFWS 1999).

Lake sturgeon are benthivores, feeding on small invertebrates such as insect larvae, crayfish, snails, mussels, and leeches (USFWS 2002).  Sturgeon have a protrusible tube-like mouth that sucks food and other material from the soft substrates of the river bottom.  In the Kettle River, upstream movements following rainstorms could allow sturgeon to encounter more food (Borkholder et al. 2002).  Hughes (2002) does not believe food to be a limiting factor in the lower Niagara River and notes that seasonal dieoffs of smelt and alewives, as well as salmon eggs, provide abundant food for lake sturgeon.  Hughes (2002) examined length-weight data for sturgeon in the lower Niagara River and reported that the population is demonstrating excellent growth, and appears to grow longer and heavier than lake sturgeon of the same age from the Lake Huron basin.

It is not known how often sturgeon move up the lower Niagara River upstream of the Project where water level and flow fluctuations are the greatest.  Hughes (2002) believed that ultrasonically tagged sturgeon that could not be detected in the river probably moved into Lake Ontario, but could not rule out the possibility that some moved upstream of the tailrace.  USFWS (1999) reported observations of sturgeon in the vicinity of Devil’s Hole State Park and Whirlpool State Park, but because the violent rapids above the Project make the deployment and use of ultrasonic tracking gear almost impossible in this reach, nothing is known about sturgeon behavior or use of this section of the lower river.

This examination of water level and flow data and movement data from tagged sturgeon suggests that water level and flow fluctuations in the lower river below the Project do not affect sturgeon behavior or movement patterns as they might in other, smaller rivers.  The effects of water level and flow fluctuations above the Project remain unknown.

6.3.6        Birds

The floating nests of pied-billed grebes are more susceptible to the effects of water level fluctuations than are the elevated nests of least bitterns.  Least bitterns build their nests approximately 24 inches above water level and nest in portions of Buckhorn Island State Park where river water level fluctuations are dampened by the marsh.  In the May and June nesting season, water levels recorded by a temporary gauge near known nesting areas recorded water level fluctuations of less than 0.75 feet.  NYSDEC surveys in 2000 and 2001 recorded nests with eggs and chicks as well as observations of a fledgling, indicating that least bitterns are successfully breeding in the marsh.  Some nests were depredated, although the type of predator is unknown.  Because NYSDEC felt they had sufficient data on this species from the 2000 and 2001 surveys, they requested that least bittern nests not be monitored or disturbed as part of this investigation. 

The floating nests of pied-billed grebes are susceptible to rapid water level fluctuations, and these are a known cause of nest failure in this species (Muller and Storer 1999).  Grebe nests are floating platforms constructed of aquatic vegetation, and the eggs are only a few inches above water level.  These nests, although floating, are vulnerable to rapid and repeated changes in water levels, especially those caused by wind-generated waves and boat wakes that can wash over the sides of the floating nest or shake it with enough force to cause it to fall apart.  The slower and more gradual water level changes caused by power generation are less likely to destroy nests, but could potentially flood a nest if it lost buoyancy and was grounded on the bottom for some reason.

Grebes continuously add new vegetation to their nests throughout the incubation period.  Newly constructed nests are small and barely extend above the water surface.  The eggs in newly constructed nests may actually be in contact with the water, making them especially vulnerable to wave or wake action.  Once incubation begins in earnest and the incubating adults build the nests to a greater size and height, they are less likely to be destroyed by water level fluctuations and waves.

            Water levels at the Grass Island nesting site are a function of lake and river level, river regulation, wind surge, wind set-up, wind-generated waves, and boat wakes.  Fluctuations at Grass Island due to NYPA and OPG power production and these other factors are 18 inches or less (URS et al. 2005).  During the grebe nesting season water levels are typically highest at about 7 AM and decrease during the day as power is produced.  Water levels are typically lowest at about 9:00 PM.  In comparison to wind-generated waves and boat wakes, these changes in water levels occur relatively slowly.

Windstorms can cause large fluctuations in Lake Erie water levels and these fluctuations send surges of water down the Niagara River.  As the flow surge progresses downstream, much of the potential for change in water level is reduced.  On December 3, 1991, a windstorm caused a 6.74-foot rise in water level at Fort Erie.  As the flow surge progressed downstream, water level increases were reduced to 3.95 feet at Frenchman’s Creek, 3.59 feet at Tonawanda Island, and 2.51 feet at the NYPA Intake gauges.  Another storm event on November 2, 1992, caused a 10.22-foot water level increase at the Fort Erie gauge.  This surge was followed by a rise to only 6.70 feet at the Peace Bridge, 1.59 feet at Frenchman’s Creek, and 1.05 feet at the NYPA Intake gauges.  These extreme events happened outside of the breeding season, but such events can and do occur occasionally during the breeding season, especially in the spring (URS et al. 2005).

Of the highest recorded fluctuations for the eight upper-river gauges (Material Dock, NYPA Intake, LaSalle, Black Creek, Tonawanda Island, Huntley, Frenchman’s Creek, and Fort Erie), 76 of the 90 values (84%) were attributed to rapid flow surges at Fort Erie.  The remaining 14 fluctuation values (16%) were attributed to regulation but may also be partially caused by localized environmental conditions such as surface waves caused by wind.  For instance, 1.30 feet of the 2.69 feet extreme event at the NYPA Intake gauge on May 2, 1996, may be attributed to waves resulting from wind speeds between four and 20 mph.  This event occurred at a time when grebes nest at Grass Island.  Regardless of the exact cause, fluctuations of this magnitude could affect the breeding productivity of pied-billed grebes.

Wind events in the Chippawa Grass Island Pool can cause water levels to increase by 0.6 feet due to wind set-up and can generate waves over four feet high (URS et al. 2005).  Maximum theoretical wave height was calculated to be 4.7 feet at the NYPA intakes, produced by a 60-mph westerly wind sustained for approximately 40 minutes across a fetch of 3.5 miles (URS et al. 2005).  Storm events of this magnitude are infrequent, and are more common in the winter and spring, although several have been recorded in April when grebes may be building nests.

Field surveys of grebe nests were conducted in 2002 and recorded both successful nests and nest failures.  Nests were checked periodically by Riveredge or by NYSDEC staff in mid-April, during May and early June, and in July.  The locations of nests with eggs and platforms without eggs were recorded with GPS.  The contents of each nest or platform were recorded on April 16, April 17, May 3, May 17, May 20, May 24, May 27 (Memorial Day), June 3, June 10, July 4 (Independence Day), July 5, July 6, July 19, July 21, and July 22.  To minimize investigator disturbance, some nests were not surveyed more than once on subsequent days in July, and some nests or platforms could not be relocated on subsequent surveys.

The first grebe nest with eggs was found on April 16, the first day of field surveys.  Christmas Count data from Niagara Falls and Buffalo suggest that some grebes overwinter in the area (BirdSource 2003), and some grebes start courtship and nesting activities in early April or even in March.  These early-season nests are especially vulnerable to wave or wake action.  Wind gusts over 30 mph occurred on five days during the last two weeks of April, and at least one grebe nest failed during this period.  Winds of 30 mph can raise water levels by 2.44 feet in the vicinity of Buckhorn marsh (URS et al. 2005).  Windstorms during periods of high water, whether from a Lake Erie storm surge or due to river regulation, can be particularly damaging.  Although winds tend to be strongest during daylight hours when water levels are lower, a single extreme storm event early in the season could cause newly constructed nests to fall apart and eggs to fall to the bottom of the river.  During April, one grebe nest, located on the river-side of Grass Island, fell apart and grebe eggs were found on the river bottom underneath the nest.  Other grebe platforms may have suffered the same fate since some were found on one survey but could not be found on subsequent surveys.  The effects of wind-generated waves and boat wakes are reduced when the emergent aquatic vegetation grows above the level of the water later in the spring and summer. 

Through the breeding season, nine individual grebe nests were found on more than one survey.  One nest appeared to be used twice, making a total of ten nesting attempts by grebes at Grass Island in 2002.   Of these ten nesting attempts, three are known to have failed.  These failed nests were all early nests and were first recorded between April 16 and May 3.  At two nests, chicks were found or observed in the nest, near the nest and/or on the backs of the adults.  Eggshell fragments, presumably from hatching, were found at other nests.  The fate of the remaining nests is unknown, but most of the nests were substantial and well attended, and at least some eggs from them probably hatched.  Because grebe chicks can leave the nest within hours of hatching (Muller and Storer 1999), the confirmation of successful hatching by finding chicks in the nest is very difficult.  The earliest known nest hatching was recorded on May 27.  Other nests hatched in June, and a newly hatched chick was also found in late July.  Field surveys suggest that at least four nests produced chicks, probably more.  Later season grebe nests were more successful than early season nests.  This is possibly due to the reduction in wind-generated waves as the nesting season progresses combined with increased growth of emergent vegetation that helps dissipate wave energy.  By the third week of July, young produced at Grass Island were observed and photographed foraging independently on the north side of the island. 

Boat wakes are a known cause of nest failure in grebes (Muller and Storer 1999).  Although New York State law requires “no-wake” zones within 100 feet of all shorelines, boaters, and especially operators of personal watercraft, were frequently observed during field surveys at Grass Island to ignore this law.  Paradoxically, the incidence of large boat wakes was lower on busy weekends when more boaters were on the river, perhaps because most boaters do not want to be seen leaving a large wake that presents a danger or inconvenience to other boaters rafted together and/or anchored in this area.

High-amplitude fluctuations that occur repeatedly over a short period have the most potential to destroy nests, especially during early spring before emergent vegetation is present.  Wind-generated waves and boat wakes, especially during periods of high water due to Lake Erie storm surges or river regulation, have the greatest potential to destroy grebe nests.  In addition, spawning carp are a documented cause of nest failure in grebes (Muller and Storer 1999) and Grass Island is loaded with carp during certain times of the year.  No nest failures could be attributed to carp, although nests only were checked periodically and were not monitored continuously in a quantitative manner.

In addition to boat wakes, grebes at Grass Island are vulnerable to other forms of human disturbance.  On some summer weekends, nearly 100 recreational boats were observed in the vicinity of Woods Creek and Grass Island.  Many boaters anchor at the upstream end of Grass Island and wade in the shallow water.  While most boaters avoid entering the posted and protected nesting area, intrusions were not uncommon.  Most intrusions were individuals on foot, often with dogs, or occasionally carp and pike anglers in canoes and boats.  In one case, a couple set up lawn chairs in the shallow water for sunbathing, and in another, two individuals walked well inside the cattails in search of a lost Frisbee.  On the other hand, researchers conducting nest surveys at Grass Island were sometimes stopped and questioned by concerned boaters who were aware of the posted signs and of the fact that entry into the marsh was prohibited.  With a few exceptions, recreational boaters at Grass Island and other parts of Buckhorn Island State Park were observed to police themselves.  In general, intrusions into the posted area appeared to be of short duration and occurred during calm, warm weather.

 

7.0     CONCLUSIONS

The 49 extant RTE species and significant occurrences of natural communities in the Niagara Falls area are largely concentrated in parks and public lands that are not affected by water level and flow fluctuations or land management practices on NYPA lands.  Of these, 12 threatened and endangered species and six unprotected species or significant occurrences of natural communities occur in the investigation area in areas where water level and flow fluctuations occur or land management practices (such as public recreation) occur on NYPA-owned lands.  The remaining 31 RTE species and significant occurrences of natural communities do not occur in areas of water level and flow fluctuations or land management practices on NYPA lands.

The 18 RTE species or communities examined in this report include three significant occurrences of natural communities, seven plants, four birds, one fish, and three native mussels.  Water level and flow fluctuations probably do not directly affect the plant Iris virginica var shrevei, least bittern, bald eagle, common tern, or native mussels.  Fishery and angler surveys found no evidence that entrainment happens to lake sturgeon or that erosion and sedimentation are affecting the few remaining native mussel species in the investigation area.

Other species and significant occurrences of natural communities in the investigation area have higher potential for being affected by water level and flow fluctuations and land management practices on NYPA lands including six plants, one fish, one bird and three significant occurrences of natural communities.  Three species of plants and portions of two significant occurrences of natural communities occur on or very near lands owned and managed by NYPA.  Land use and maintenance activities that could affect these species and communities include the use of NYPA lands for recreation, and road sand and salt and other surface runoff from the main Project access road.  In addition, the fluctuations in water levels and flows caused by the combined influences of NYPA and OPG hydroelectric operations, other anthropogenic factors, and natural factors may affect the structure and composition of the vegetation in the deep emergent marsh at Buckhorn Island, the distribution of three species of plants that occur along the Niagara River shoreline, the behavior and productivity of lake sturgeon and the breeding success of pied-billed grebe.  The greatest threats to RTE species in the vicinity of the Project are the impacts of public recreational activities that occur on land and on the river, and the impacts associated with the increase of alien invasive plant species. 

 

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