Feasibility Study for the Restoration of Native Terrestrial Plants in the Vicinity of the Niagara Gorge
Niagara Power Project FERC No. 2216
January, 2008
Prepared for: New York Power Authority
Prepared by: TRC Engineering, LLC.and Riveredge Associates, LLC.
TABLE OF CONTENTS
EXECUTIVE SUMMARY
1.1 Background
1.2 Objectives
1.3 Study Area
2.1 Agency Consultation
2.2 Literature Review
2.3 Field Surveys
3.1 Historical Baseline
3.2 Current Conditions
3.2.1 Calcareous Cliff Community
3.2.2 Calcareous Talus Slope Woodland
3.2.3 Commercial
3.2.4 Limestone Woodland
3.2.5 Oak-Hickory Forest
3.2.6 Outdoor Recreation
3.2.7 Successional Shrubland
3.3 Identification of Potential Sites for RTE Plant Restoration
3.3.1 Literature Review
3.3.2 Field Surveys
3.4 Relative Percentage of Non-native Species in the Niagara Gorge
3.5 Identification of Potential Threats to Native Plants
3.5.1 Recreation in the Gorge
3.5.2 Park/Trail Management
3.5.3 Storm Drain/ Combined Sewer Overflow (CSO) Discharge
3.5.4 Alien Invasive Species
3.5.5 Gull Nesting Colony
4.1 Feasibility of RTE Plant Restoration
4.2 Feasibility of Natural Community-Level Restoration
4.2.1 Large-Scale Community-Level Restoration
4.2.2 Small-Scale Restoration
4.3 Identification of Potential Sites for Small-Scale Native Plant Restoration
4.4 Possible Plant Materials Sources
4.4.1 Transplantation
4.4.2 Seed/Corm Collection
4.4.3 Nursery Propagation
4.5 Identification of Best Management Practices
4.5.1 Plant Restoration Team
4.5.2 Park/Trail Management
4.5.3 Phragmites (and Other Non-native Species) Management
4.5.4 Introduction/Management of Supporting Hydrology
4.5.5 Treatment/Management of Storm Water Run-off and Storm Drain/CSO Discharge
4.5.6 Public Awareness Education
Figure 1: Niagara River Gorge Native Vegetation Assessment
Figure 2: Niagara River Gorge Native Vegetation Assessment
Figure 3: Niagara River Gorge Native Vegetation Assessment
Figure 4: Niagara River Gorge Native Vegetation Assessment
Figure 5: Niagara River Gorge Native Vegetation Assessment
Figure 6: Niagara River Gorge Native Vegetation Assessment
Figure 7: Niagara River Gorge Native Vegetation Assessment
Figure 8: Niagara River Gorge Native Vegetation Assessment
Figure 9: Niagara River Gorge Native Vegetation Assessment
APPENDIX B: List of Native Plant Nurseries
As part of the Niagara Power Project Comprehensive Relicensing Settlement Agreement, NYPA agreed to conduct a post-licensing study of the feasibility of protecting and restoring state-listed rare, threatened, and endangered (RTE) terrestrial native plants and non-listed native plants in the vicinity of the Niagara Gorge. Unless specifically described, the term “native plants” as used in this document is meant to include both native RTE plants and non-listed native plants.
The feasibility of restoration and protection of various native plants was assessed based on available information from peer reviewed literature, publications, discussions with knowledgeable individuals and agencies, site-specific data collected during May and September 2007, and professional judgment and working knowledge of habitat in the vicinity of the Niagara gorge. This report describes potential constraints to undertaking certain restoration and protection efforts, and provides an assessment of overall project feasibility. The feasibility of options was ranked from poor to good and was based on factors such as the potential for implementation success, potential of removing and or/controlling non-native plant species (particularly alien invasive species) in the vicinity of the gorge, desirability of planting native vegetation propagated by nurseries, implementation safety, the need and extent for long-term monitoring and/or maintenance, and risk.
The restoration of some specific species of RTE plants at certain discrete locations in or near the Niagara gorge is feasible, but not necessarily desirable due to concerns over the introduction of new genetic material. Community-level native plant restoration throughout the Niagara gorge and gorge rim is not feasible, primarily due to the continued influx of alien invasive species over such a large geographic area with difficult access. However, pilot-level restoration efforts may be possible and could be successful on a smaller scale in selected areas with important physical and biological features. Even on a small scale, native plant restoration will require a long-term, dedicated, cooperative effort among local, state, and Canadian provincial agencies in conjunction with recognized local experts and non-governmental organizations (NGO’S) and institutions. These efforts would not likely be successful without a significant commitment of staff, resources, and volunteers from cooperating entities.
The Niagara Power Project (NPP or Project) in Lewiston, Niagara County, New York, is one of the largest non-federal hydroelectric facilities in North America. The Project is constructed on the Niagara River (River), which is a 37-mile strait that connects Lakes Erie and Ontario, and forms the boundary in this region between the United States and Canada. In 1957, operation of the Project was licensed by the Federal Power Commission to the Power Authority of the State of New York (now the New York Power Authority, or NYPA) for a term of 50 years. The Project first produced electricity in 1961. A new operating license for the Project was issued in 2007.
As part of the Niagara Power Project Comprehensive Relicensing Settlement Agreement, NYPA agreed to perform an investigation of the feasibility of protecting and restoring listed rare, threatened, and endangered (RTE) terrestrial plants and non-listed native plants (hereinafter refereed to as “native plants” unless specifically described or listed) in the vicinity of the Niagara Gorge. NYPA contracted TRC Engineering, LLC (TRC) and Riveredge Associates, LLC (Riveredge) to perform this study.
It should be noted that, in keeping with the policy of the New York Natural Heritage Program (NYNHP), the specific locations of RTE plants are considered sensitive and are not discussed in this document. The release of information which identifies the locations of rare species may lead to the collection or disturbance of the plants at those locations. Location information in this document is limited to the general context of occurrence (for example the name of the state park where a given species may occur) that could not be used to specifically locate, collect or disturb the plant discussed.
Niagara Falls and the Niagara gorge have a long history of development, industry, and tourism that spans almost 200 years. The spectacular cataracts of the falls and the Niagara River attracted industry with hydropower and tourists with hotels, casinos, and commercial development. By around 1865, Niagara Falls had become the most popular tourist attraction in the United States. The tourists were a large unorganized constituency (Eckel, 1986). By the early 1900s, over a million visitors came to see the Falls each year. Visitors who wrote of their experiences deplored the environmental abuses, and the painter Frederick Church "warned of the rapidly approaching ruin of the scenery," (Todd, 1982 in Eckel, 1986).
To make the Falls more accessible to millions of tourists and to facilitate transportation between Buffalo and Toronto, railroads were built along both sides of the Niagara gorge. In New York, both an upper and lower railroad bed was constructed along the gorge. From 1895 to 1937, tourists traveled from Lewiston to Niagara Falls along the lower Niagara River on The Great Gorge Railway. Over 100 years ago, the railroads and the tourists they carried drastically modified the natural environment of the gorge. Native vegetation was cleared, rock was blasted, and the gorge vegetation was replaced with a variety of alien species. Botanists and plant collectors rode the railways and collected the rarest plants in the area. By the late 1800s, some of the rarest plants in and near the gorge may have been locally eliminated and several species of non-native and alien plants had been introduced and planted (Day, 1888 in Eckel, 2002).
Today, tourism and development continue, and almost 30 million visitors come to see the Falls (American and Canadian sides, collectively) each year. As such, tourist facilities and development are extensive on both sides of the Falls and gorge. This high degree of human activity and environmental modification has affected the local species composition; vegetation currently includes many alien invasive species. Only remnants of the gorge and rim forests are evident in a few isolated pockets located away from the primary tourist attractions. Presently, most extant RTE native plants in the vicinity of the Niagara Falls are associated with Goat Island (Niagara Reservation State Park) and the Niagara Gorge (Whirlpool State Park) downstream to and including Earl W. Brydges Artpark State Park.
The original general objectives of this investigation were to: (1) determine the feasibility of protecting and restoring native terrestrial RTE plants in specific areas that exhibit preferred habitat characteristics for such plants (i.e., seeps), (2) identify RTE species for which protection and restoration would have the greatest potential for success, (3) identify candidate sites where protection and restoration measures could be implemented, and (4) assess the feasibility of restoring native plants at the natural community-level.
Agency and NGO consultation and extensive literature review later resulted in the identification of tasks that could be performed in order to meet the above-mentioned objectives. These included the following:
(1) establish a historical baseline of native plant occurrence in the study area;
(2) establish current conditions in the study area including an assessment of the relative percentage of alien invasive plants in the gorge;
(3) identify potential threats to native plant species;
(4) assess the feasibility of restoring native plants at the natural community-level versus the pilot-level (small-scale), and identify candidate sites where small-scale protection and restoration measures could be implemented;
(5) identify species for which protection and restoration would have the greatest potential for success and identify potential means of obtaining plants for restoration efforts (including an assessment of possible establishment of a nursery specific to restoration of Niagara gorge vegetation);
(6) define potential best management practices for restoration efforts (including examination of vegetation management methods as a means of restoring native plant communities and assessment of the use of biological methods for controlling Phragmites in the gorge)
As mentioned, agency consultation, literature review and field survey efforts were the primary means of gaining the information needed to meet these objectives. These efforts are further described in Section 2.0 – Methods.
The general study area for this effort included Goat Island (Niagara Reservation State Park) and the Niagara Gorge downstream to and including Earl W. Brydges Artpark State Park. Terrestrial habitats examined in this study included areas above the gorge rim, woodland, shrub, and grassland habitats associated with Goat Island and Artpark, and the calcareous cliff and talus slope habitats located within the Niagara gorge. The study area is depicted on Figures 1 through 9 in Appendix A.
As described in Section 1.2, this study addresses various objectives en route to determining the feasibility of restoring native plants in the Niagara gorge. Each objective has been addressed based on information gained as a result of three major initiatives including: agency consultation, literature searches and field surveys. Each of these major initiatives is described below.
Scientists from NYPA, Riveredge, and TRC met with staff scientists with the New York Natural Heritage Program (NYNHP) on June 21, 2007 to discuss the general purpose and goals of this study and to discuss the feasibility of restoring native plants to the gorge area. NYPA personnel showed a PowerPoint presentation and described the rationale behind pursuing this feasibility study. This consultation provided background information on the vegetation of the gorge, and guided the development of field surveys and additional investigations. Information obtained as a result of this meeting was also applied to the various assessments performed as part of this study. However, this report contains no sensitive NYNHP location data, nor any NYNHP digital data.
Reasonably available literature and mapping regarding existing and historical plant species and habitat types in the study area were examined as part of this study. This effort was performed subsequent to agency consultation, and prior to any fieldwork being conducted. Literature that was reviewed included (but was not limited to): reports prepared as part of the relicensing effort for the Niagara Power Project; reports and other documents prepared by the Niagara Frontier Botanical Society; information from the Buffalo Museum of Science; reports prepared by local botanists and researchers familiar with the Niagara Gorge; the most recent rare plant species lists and occurrence records as maintained by NYNHP, and information on potential vegetation restoration efforts and possible plant material sources. Land use and cover type mapping from Beak (2002) was used for all map figures in this report.
Field surveys involved two major components: aerial reconnaissance and ground surveys. The methods employed for each of these efforts are described, below. The data obtained as a result of these surveys was used in concert with the results of agency consultation and literature review to address the various objectives of this study.
Aerial Reconnaissance
Aerial reconnaissance was performed via helicopter on May 15, during leaf-off conditions. The purpose of this flight was to preliminarily identify and map possible groundwater seeps that could serve as candidate locations for restoring RTE plants.
Ground Surveys
For several days after the May 15 helicopter flight, biologists from TRC and Riveredge performed follow-up ground surveys to verify the occurrence of seeps that were identified during the aerial reconnaissance effort. This effort involved walking the entire American side of the gorge with the exception of a short, inaccessible section located just upstream of the whirlpool rapids. Biologists verified/mapped seeps with a pen tab computer. In addition, notes were taken to document vegetation species, soil/talus conditions, and the general size of the seeps. The resultant data were incorporated into the project GIS.
Additional field surveys were performed in September. These field surveys involved establishing transects and collecting vegetation within randomly selected sample plots. Plots were established such to characterize vegetation above the gorge rim, and in the cliff and talus habitats of the gorge. All species within the sample plots were documented onto standardized data forms. The purpose of this effort was to identify dominant and non-dominant vegetation within the sample plots to determine the ratio of native to non-native plants in the study area. Vegetation data were collected within a total of 37 sample plots during the September 2007 surveys. The breakdown of sample plot locations is as follows:
· Two plots at Art Park, one on Scoville’s Knoll and one on the spoil piles;
· Three plots of the gorge calcareous cliff community;
· Fourteen plots of talus woodland community, and two of talus-associated successional old-field and shrub habitat types;
· Twelve plots of successional old field, shrub, and woodland habitats of the gorge rim;
· Two plots at DeVeaux Woods; and
· Two plots at the limestone woodland habitat at Goat Island.
The results of agency consultation, literature review and field surveys were used to: establish a baseline on the historic condition of vegetation in the Niagara gorge; define the current condition of the vegetative communities in the Niagara gorge; and define potential threats to native plant species in the study area. The resultant information is presented in the following subsections. In turn, this knowledge has been applied to address the remaining objectives of this study, including (but not limited to) assessment of the feasibility of plant restoration and identification of best management practices. These subjects (and others) are addressed in Section 4.0 Discussion.
The purpose of determining a historic baseline is to assist in establishing possible restoration goals for the Niagara gorge.
Much of our current knowledge of the flora of the Niagara gorge and vicinity stem from the detailed and comprehensive work of Eckel (1986, 1988, 2001, 2002, 2003a, 2003b, 2003c, 2004). Eckel reviewed over 25,000 plant specimens collected during the last two centuries and conducted field surveys to provide new information on rare plants of the Niagara gorge and vicinity (Eckel 2001, 2002). Rare plants of the four state parks along the Niagara Gorge (Niagara Reservation, Whirlpool, Devil’s Hole, and Earl W. Brydges Artpark State Parks) were documented and summarized by NYNHP in 2000 (Evans et al., 2001). New York’s rare plant records are continuously updated and the rare plant status list is published annually (Young, 2007). Rare plants of the Niagara gorge area are listed in Table 3.1-1. This list was compiled from Eckel (2001, 2002), Evans et al. (2001) and other sources.
While several rare species are still present in and near the Niagara gorge, several other species have disappeared and are considered historical (Young, 2007). This local extirpation of species may be due, in part, to over-collection some 100 years ago (see Section 1.1). In 1888, Day noted (as summarized by Eckel, 2002) that some species possibly had already been extirpated at that time. Evans et al. (2001) listed 17 species that occurred in the vicinity of Goat Island and the gorge, but are now considered historical (Table 3.1-2).
Of the 17 historical species (Evans et al., 2001; Young, 2007) (Table 3.1-2), four are considered extirpated in New York State. Species extirpated from the state (i.e., they are thought to no longer occur in New York State) are assigned a state rank of SX by NYNHP (Young, 2007) (Table 3.1-2). The other 13 species still occur in New York in other locations, and these species have been assigned a legal status code by NYSDEC such as endangered (E) or threatened (T) (Young, 2007) (Table 3.1-2). Two of these species still occur in either Niagara or Erie Counties, but not in the State Parks along the Niagara gorge (Evans et al., 2001; Young, 2007).
Endangered (E) native plants in New York are those species in danger of extirpation throughout all or a significant portion of their ranges within the state and requiring remedial action to prevent such extinction (Young, 2007). Listed plants are those species with five or fewer extant sites, or fewer than 1,000 individuals, or restricted to fewer than four U.S.G.S. 7 1/2 minute series topographic maps, or species listed as endangered by the United State Department of Interior in the Code of Federal Regulations.
Threatened (T) native plants in New York are those species that are likely to become endangered within the foreseeable future throughout all or a significant portion of their ranges in the state. Listed plants are those with six to fewer than 20 extant sites, or 1,000 to fewer than 3,000 individuals, or restricted to not less than four or more than seven U.S.G.S. 7 1/2 minute series maps, or species listed as threatened by the United State Department of Interior in the Code of Federal Regulations.
Data suggest that several of the RTE plants that currently occur or have historically occurred within the study area are/were typically found in areas where moisture is present. This moisture may be from groundwater seeps along the calcareous cliff face, surface water runoff, or the spray zone near the falls.
Table 3.1-1: Extant T&E Plants in the Vicinity of the Niagara Gorge
|
Scientific Name |
Common Name |
NYS Legal Status |
|
1 |
Carex garberi |
Elk sedge |
E |
|
2 |
Gentianopsis virgata |
Lesser fringed gentian |
E |
|
3 |
Iris virginica var. shrevei |
Southern blueflag |
E |
|
4 |
Liatris cylindracea |
Slender blazing-star |
E |
|
5 |
Lysimachia quadriflora |
Four-flowered loosestrife |
E |
|
6 |
Oligoneuron ohioense |
Ohio goldenrod |
T |
|
7 |
Pellaea glabella |
Smooth cliff brake |
T |
|
8 |
Poa sylvestris |
Woodland bluegrass |
E |
|
9 |
Physocarpus opulifolius var. intermedius |
Ninebark |
E |
|
10 |
Symphyotrichum oolentangiense var. oolentangiense |
Sky-blue aster |
E |
|
11 |
Zigadenus elegans ssp glaucus |
Mountain death camas |
T |
Taxonomy and legal status codes (E=Endangered, T=Threatened) from Young (2007)
Table 3.1-2: Historical Threatened and Endangered Plants from the Vicinity of the Niagara Gorge
|
Scientific Name |
Common Name |
NYS Legal Status or State Rank |
|
1 |
Agastache nepetoides |
Yellow giant-hyssop |
T |
|
2 |
Aplectrum hyemale |
Puttyroot |
E |
|
3 |
Boechera stricta |
Drummond’s rock-cress |
E |
|
4 |
Calamintha arkansana |
Calamint |
SX |
|
5 |
Carex retroflexa |
Reflexed sedge |
E |
|
6 |
Castilleja coccinea |
Scarlet Indian-paintbrush |
E |
|
7 |
Cornus drummondii |
Rough-leaf Dogwood |
E |
|
8 |
Draba arabisans |
Rock-cress |
T |
|
9 |
Hypericum kalmianum |
Kalm’s St. John’s wort |
SX |
|
10 |
Monarda clinopodia |
Basil-balm |
E |
|
11 |
Muhlenbergia capillaris |
Long-awn hairgrass |
SX |
|
12 |
Phlox pilosa ssp. pilosa |
Downy phlox |
E |
|
13 |
Polygala incarnata |
Pink milkwort |
SX |
|
14 |
Potamogeton alpinus |
Northern pondweed |
T |
|
15 |
Pterospora andromedea |
Giant pine-drops |
E |
|
16 |
Sphenopholis pensylvanica |
Swamp oats |
E |
|
17 |
Triglochin palustre |
Marsh arrow-grass |
T |
Legal status codes (E=Endangered, T=Threatened) and state ranks (SX) from Young (2007)
Species list and taxonomy following NYNHP (Evans et al., 2001; Young, 2007)
Human impacts over the past 200 years (see Section 1.1) have drastically altered the extent and composition of historic vegetative communities in the Niagara gorge. Review of existing literature indicates that very little of the original forest cover remains on the American side of the River. Most of the woodland at the base of the Gorge is replacement woods, regenerating after denudation for the Gorge railway (Eckel, 1986). In addition to Eckel, others have noted the presence of non-native species, including alien invasive species, in the vicinity of the gorge and Goat Island (e.g. Evans et al., 2001).
Nonetheless, Eckel’s catalogue of the flora of the Niagara gorge and vicinity of Niagara Falls (Eckel 2001, 2002) noted that the area is exceptionally rich in species. Many of the rare plant records from this area stemmed from collecting locations at Goat Island, Three Sisters Islands, Luna Island, Terrapin Point, Whirlpool State Park, DeVeaux (College) Woods, Devil's Hole, Lewiston, and other sites (Eckel, 2001). Despite the years of development and tourism, Eckel (1990, 2002) noted that the number and diversity of rare species in the vicinity of the Niagara gorge is still exceptional for New York State. Literature suggests that many extant RTE plant species in the gorge are associated with moisture, principally with groundwater discharge (seeps) from the calcareous cliff face. Evans et al (2001) expressed similar findings, noting that the combination of misting, wet seepage areas interspersed with dry open rock faces and calcareous bedrock produces the greatest assemblages of rare plants within New York State.
Vegetative community and land-use types (as described by Reschke 1990 and LUNR (1970) that have been documented and mapped in the study area are described in detail, below. These descriptions include lists of some of the more common plants associated with each vegetative community or land use type.
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). Other species commonly observed during field surveys included Toxicodendron radicans (poison ivy), Centaurea maculosa (spotted knapweed), Melilotus alba (white sweet clover), and Parthenocissus quinquefolia (Virginia creeper).
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).
In addition to the descriptions and species presented above, Eckel (2002) documented that many other plant species are common to this community type. In addition, many areas in this community type are best described as replacement forest of the original forest that was cut. As observed during the fieldwork portion of this investigation, many areas in this community type are dominated by a combination of native and non-native plant species. Other documented common trees, saplings, and shrubs included Acer negundo (box elder), Acer platanoides (Norway maple), Aeculus hippocastanum (horse chestnut), Tilia americana (basswood), Ulmus rubra (slippery elm), Prunus avium (bird cherry), Populus deltoides (eastern cottonwood), Tsuga canadensis (eastern hemlock), Salix babylonica (weeping willow), Rhus typhina (staghorn sumac), Lonicera tatarica (tartarian honeysuckle), Physocarpus opulifolius (ninebark), Prunus virginiana (choke cherry), Sambucus pubens (red-berried elder), Rhamnus cathartica (buckthorn), and Crataegus spp. (hawthorns). Vines and herbaceous plants included Parthenocissus vitacea (Virginia creeper), Vitis riparia (river grape), Toxicodendron radicans (poison ivy), Solidago flexicaulis (zig zag goldenrod), Dryopteris marginalis (marginal wood fern), Arisaema triphyllum (Jack-in-the-pulpit), Geranium robertianum (herb Robert), Solanum dulcamara (bittersweet nightshade), Allaria officinalis (garlic mustard), Rubus odoratus (purple flowering raspberry), and Eupatorium rugosum (white snakeroot).
Common plant species observed in the land-use cover type included native (natural occurring) and horticultural trees and shrubs, and typical species of lawns and disturbed areas. These included Tilia americana (basswood), Quercus rubra (red oak), Platanus occidentalis (sycamore), Viburnum recognitum (arrowwood), Ambrosia artemisiifolia (common ragweed), Bromus inermis (brome grass), Verbascum thapsus (common mullein), Hypericum perforatum (common St. Johnswort), Poa compressa (Canada bluegrass), Dactylis glomerata (orchard grass), and Taraxacum officinale (common dandelion).
Dominant tree species can include Thuja occidentalis (northern white cedar), Pinus strobes (white pine), Picea glauca (white spruce), Abies balsamea (balsam fir), Ostrya virginiana (hop hornbeam), Acer saccarum (sugar maple), Carya ovata (shagbark hickory), Quercus alba (white oak), Quercus macrocarpa (bur oak), Quercus rubra (red oak), and Tilia Americana (basswood). The shrub stratum can be variable and generally becomes more dense where canopy is open and soils are deeper. Shrub species can include Cornus racemosa (gray dogwood), Lonicera dioica (wild honeysuckle), Rhamnus alnifolia (alder-leaf buckthorn), Ribes cynos-bati (prickly gooseberry), Rubus spp. (raspberries), Staphylea (bladdernut), Amelanchier spp. (juneberry), and Toxidendren radicans (poison ivy). The herb layer can include Carex eburnea, C. pensylvanica, C. platyphylla (Sedges), Dryopteris marginalis (marginal wood fern), Botrychium virgianum (rattlesnake fern), Pteridium aquilinum (bracken fern), Waldsteinia fragariodes (barren strawberry), Aster macrophyllus (big-leaf aster), Fragaria virginiana (wild strawberry), Sanicula marilandica (black snakeroot), Geranium robertianum (herb-robert), Maianthemum canadense (Canada mayflower), Smilacina racemosa (false Solomon’s-seal), Thalictrum dioicum (early meadow-rue), Trilium grandiflorum (white trillium), and Solidaga caesia (blue-stem goldenrod). In addition, Polypodium virginianum (rock polypody), and Asplenium trichomanes (maidenhair spleenwort) can often by found growing on shaded rock surfaces and in crevices (Reschke 1990).
Other common species observed in this community type at Goat Island included Fraxinus americana (white ash), Ulmus americana (American elm), Acer platanoides (Norway maple), Acer negundo (box elder), Salix alba-fragilis (white willow), and Populus deltoides (cottonwood) trees and saplings. Shrubs, vines, and herbaceous plants included Cornus alternifolia (alternate-leaved dogwood), Rubus odoratus (purple-flowering raspberry), Sambucus pubens (elder), Rhamnus cathartica (buckthorn), Parthenocissus quinquefolia (Virginia creeper), Morus alba (white mulberry), Lindera benzoin (spicebush), Prunus virginiana (choke cherry), Sambucus canadensis (common elderberry), Rhus typhina (staghorn sumac), Vitis riparia (riverbank grape), Allaria officinalis (garlic mustard), Arisaema triphyllum (jack-in-the-pulpit), Eupatorium rugosum (white snakeroot), Geum canadense (white avens). In addition, patches of Lythrum salicaria (purple loosestrife) and various species of sedges and grasses were observed in areas subject to inundation by river water.
Dominant tree species can include Quercus rubra (red oak), Quercus alba (white oak), Quercus velutina (black oak), Carya glabra (pignut hickory), Carya ovata (shagbark hickory), and Carya ovalis (sweet pignut). Common associated tree species include Fraxinus Americana (white ash), Acer rubrum (red maple), and Ostrya virginiana (eastern hop hornbeam). The shrub stratum can be quite variable and can include Cornus florida (flowering dogwood), Hamamelis virginiana (witch hazel), Amelanchier arborea (shadbush), Prunus virginiana (choke cherry), Viburnum acerifolium (maple-leaf virburnum), Vaccinium angustifolium, V. pallidum (blueberries), Rubus idaeus (red raspberry), Cornus racemosa (gray dogwood), and Corylus cornuta (beaked hazelnut). Common herbaceous plants include Aralia nudicaulis (wild sarsaparilla), Smilacina racemosa (false Solomon’s seal), Carex pensylvanica (Pennsylvania sedge), Desmodium glutinosum, D. paniculatum (tick-trefoil), Cimicifuga racemosa (black cohosh), Prenanthes alba (rattlesnake root), Solidago bicolor (white goldenrod), and Hepatica Americana (hepatica) (Reschke 1990).
Much of the land that comprises this land-use type along the upper river (including the eastern third of Goat Island) is made-land with various species of horticulturals and native and non-native pioneer species.
Plants documented in this land-use type on the western end of Goat Island, the gorge rim, and Art Park included Tilia americana (basswood), Quercus rubra (red oak), Viburnum recognitum (arrowwood), Cornus amomum (silky dogwood), Amelanchier spp. (shadbush), Picea glauca (white spruce), Ambrosia artemisiifolia (common ragweed), Bromus inermis (brome grass), Verbascum thapsus (common mullein), Hypericum perforatum (common St. Johnswort), Poa compressa (Canada bluegrass), Dactylis glomerata (orchard grass), and Taraxacum officinale (common dandelion).
Typical shrub species include Cornus racemosa (gray dogwood), Juniperus virginiana (eastern red cedar), Rubus spp. (raspberries), Crataegus spp. (hawthorne), Amelanchier spp. (serviceberries), Prunus virginiana (choke cherry), Prunus Americana (wild plum), Rhus glabra, R. typhina (sumac), Viburnum lentago (nanny-berry), Viburnum recognitum (arrowwood), and Rosa multiflora (multiflora rose). In the investigation area this habitat type occurs upslope of the calcareous cliff communities along the lower Niagara River (Reschke 1990). Shrub species documented during fieldwork were consistent with those listed above.
Literature was reviewed to gain an understanding of the historical and current presence of RTE plants in the gorge and where they likely occurred, or occur today. Literature suggests that many extant RTE plant species in the gorge are associated with moisture, principally with groundwater discharge (seeps) from the calcareous cliff face. In addition, historical records also indicate that many RTE plant species likely occurred in seeps.
Much of our current knowledge of the flora of the Niagara gorge and vicinity stem from the detailed and comprehensive work of Eckel (1986, 1988, 2001, 2002, 2003a, 2003,b, 2003c, 2004). Eckel reviewed over 25,000 plant specimens collected during the last two centuries and conducted field surveys to provide new information on rare plants of the Niagara gorge and vicinity (Eckel 2001, 2002). Eckel’s work was updated by NYNHP in 2000 (Evans et al., 2001). Rare plant records for the gorge continue to be updated by Young (2007) for the NYNHP.
Eckel’s catalogue of the flora of the Niagara gorge and vicinity of Niagara Falls (Eckel 2001, 2002) noted that the area is exceptionally rich in species. Many of the rare plant records from this area stemmed from collecting locations at Goat Island, Three Sisters Islands, Luna Island, Terrapin Point, Whirlpool State Park, DeVeaux (College) Woods, Devil's Hole, Lewiston, and other sites (Eckel, 2001).
A helicopter flight and ground reconnaissance were preformed in order to observe, verify, and map significant groundwater seeps in the Niagara gorge. A number of potential groundwater seeps were identified during the helicopter flight. These were identified through the observation of areas that appeared to be wet such as portions of the calcareous cliff face, flowing water, and erosion features that appeared to have been formed by water. Over a dozen such features were observed from Art Park to the Canadian Falls (Horseshoe Falls). These features were photographed, sketched onto field maps, and their general locations recorded with a hand-held GPS unit. This information was used to locate and verify these features during the ground reconnaissance effort.
Following the helicopter flight, the majority of the gorge was examined on foot. As previously stated, the exception was a short, inaccessible stretch just upstream of the Whirlpool Rapids that was too steep and dangerous to examine. Specifically, biologists from Riveredge and TRC walked from Art Park to the Maid of the Mist observation tower and assessed and mapped groundwater discharge seeps and documented vegetation. This effort revealed that the majority of the seeps that had been preliminarily identified during the helicopter flight were actually discharges from, or erosional features caused by flow from, storm drain discharge pipes located along the top of the gorge cliff face. Some of these were discharging water at the time of the survey and it was evident based on the observed “gully” erosion that they likely discharge high-energy flow during rainstorms or snow melt.
This effort also revealed that there are several groundwater seeps that occur between Art Park and the NPP that could be candidate sites for a small-scale (pilot-level) restoration. The reasons for this are 1) these are broad-front, low-energy seeps that appear to provide consistent flow, 2) they are fairly accessible, and 3) they are associated with talus of various grain size and accumulated soil that could serve as a planting medium. Between the NPP and the Whirlpool, there are a number of seeps; however, they generally occur much higher on the gorge cliff face and are largely inaccessible. The portion of the gorge between the Whirlpool and the Maid of the Mist Observation Tower is much drier and very few seeps of any significant size were observed during the field surveys. The seeps that were observed were high up on the face of the gorge cliff, were inaccessible, and generally were not associated with significant talus or soil accumulation.
During consultation with NGO’s, it was recommended that NYPA determine the relative percentage of non-native plants in the gorge. Therefore, an effort was undertaken to sample vegetation within randomly selected sample plots, document dominant and non-dominant vegetation by strata (i.e., trees, saplings, shrubs, herbs), and calculate the percentages of native and non-native plants. For purposes of this report, the distinction between native and non-native plants is as follows:
· Native plants are those that are known to be native to the north eastern and mid-western United States and adjacent Canada;
· Non-native plants are those that are known to be from areas outside of the north eastern and mid-western United States and adjacent Canada.
Analysis and review of quantitative sample plot data collected during September field surveys revealed the following general information: of the dominant vegetation documented in the sample plots, the overall percentages of native to non-native vegetation species were 76 and 24 percent, respectively; of the non-dominant vegetation, the overall percentages of native to non-native vegetation species were 75 and 25 percent, respectively. These numbers are averages of all plots. The overall percentages of native versus non-native plant species varied from sample plot to sample plot, particularly when comparing more mature habitat samples such as talus woodland to early-successional habitat such as old field. One notable trend was the increased presence of Norway maple in the southern end of the Niagara gorge when compared to the northern portion. Overall, for dominant plant species, sample plot composition of native plants ranged from 25 to 100 percent; whereas, sample plot composition of non-native plants ranged from zero to 75 percent. For the non-dominant plant species, sample plot composition of both native and non-native plants ranged from zero to 100 percent.
A detailed discussion of alien invasive plant species and their impact on vegetation in the Niagara gorge is presented in Section 3.5.
This task was accomplished through the review of existing literature and direct observations during the field surveys. 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. 2001, Eckel 1990). In addition, a large nesting colony of Ring-billed Gulls (Larus delawarensis) located at the base of Goat Island poses a threat to vegetation in that area. Human disturbance (including recreation, park maintenance, storm water runoff, etc.), alien invasive species, and the impacts of the Goat Island gull colony are discussed, below. The potential impacts of bank erosion along the lower river clay banks where Oligoneuron ohioense occurs on private property are not considered here.
NYNHP (Evans et al. 2001) noted that the single greatest threat to RTE plants of the Niagara gorge is the impact of recreationists. Recreational activities such as hiking, site seeing, biking, and fishing (accessing fishing areas) are extremely common due to the urban nature of the area, high population density (tourists and residents), and accessibility.
The soils of the Niagara gorge are thin and easily disturbed, and rare native plants may be trampled. Human traffic has 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 RTE plants that once grew along the edges of hiking trails in the state parks of the gorge. At Whirlpool State Park, several historical RTE species no longer occur; this is likely due, in part, 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.
Rare plants on Goat Island may also be affected by recreation and tourism. Elk sedge occurs in the Niagara Reservation State Park at Goat Island (NYNHP, 2007). Threats to this species include invasive species, trampling, and alteration of the habitat. Habitat alterations such as scraping of the cliffs for safety concerns and natural erosion were identified by NYNHP as potential threats (NYNHP, 2007). Evans et al (2001) noted that any removal of rock along the cliff face affects the cliff community by potentially removing vegetation and suitable rooting substrate.
As noted above, the most immediate threats to rare species and communities in the Niagara gorge are trampling and degradation due to recreational overuse. Park and trail management activities that could affect rare plants and communities include control of rockfalls, not closing unofficial trails, and landscaping with aggressive alien invasive species, particularly those that are habitat pioneering species.
Park management also tends to include various degrees of landscaping. This, in turn, can lead to the introduction of non-native and potentially invasive plant species. The impacts of horticultural introductions are further discussed in Section 3.5.4 - Alien Invasive Species.
NYNHP (Evans et al. 2001) 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.
Due to the area’s extensive development, 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.
A number of CSOs are found in the gorge and several are in severe disrepair. During the September 2007 surveys, garden tomato and cucumber plants were observed growing near and in the raw sewage discharge from one or the CSOs. It is possible that tomato and cucumber seeds were deposited into the gorge from this CSO.
Salt runoff from the Robert Moses Parkway and runoff from storm sewers and discharge pipes along the gorge walls