Proposed Stormwater Management & Mitigation Wetland Plan Ithaca College Proposed Sports Complex
Project Contributors This report is the product of Tom Whitlow’s Restoration Ecology course offered through the Cornell Horticulture Department. The class is composed of landscape architecture, environmental engineering, urban planning, and natural resources students, both undergraduate and graduate. Restoration Ecology is a one semester, 5‐credit course. Professor Tom Whitlow Teaching Assistant Fred Cowett Kate Bentsen Maureen Bolton Hannah Carlson Inga Conti‐Jerpe Matthew Doro Eden Gallanter Karli Gallow Adam Ganser Ying‐Tuan Hsu Jason Johnson Christopher Keil Shichun Ni Lee M. Pouliot Zac Rood Peter Sigrist
Table of Contents I. II.
Introduction Methods & Materials
Ithaca College Slope Forest
Ithaca College Hilltop: a. Swamp White Oak Swamp b. Red Pine Plantation
Ithaca College Parking Lot: a. Wetland Corridor b. Downstream Corridor
VI. VII. VIII.
Proposed Stormwater Management Plan RPM Old Field in Dryden Special Considerations a. Amphibian Breeding Habitat b. Amphibian Habitat Recommendations
Recommendations & Conclusions
Introduction This report is in response to the proposed sports complex at Ithaca College, which will destroy several acres of wetland, necessitating the creation of mitigation wetlands. The Army Corps of Engineers has stipulated that, in accordance with the Clean Water Act, three acres of wetland shall be created for every one acre destroyed by development. We have met with Ron LeCain, Rick Couture, and Jason Hamilton of Ithaca College in order to assess and respond to their needs and agenda. Our project parameters include research and data collection for the purpose of identifying an appropriate site for constructed wetlands in the following areas: 1. The Ithaca College slope forest 2. The Ithaca College hilltop swamp and red pine communities 3. The Ithaca College parking lot wetland corridor 4. The old field in Dryden – adjacent to the RPM nursery 5. Multiple wetlands at the Ithaca College sports arena site & associated down slope stream 6. Bull Pasture Pond There are three possible sites for the proposed wetlands; the Ithaca College slope forest, the hilltop communities at Ithaca College, and the old field site in Dryden. The other sites we studied were for reference and research purposes. All data was gathered with the intent to determine where a new wetland could be most useful for the community, water quality issues, to threatened species such as salamanders, and/or to the surrounding ecosystems as a whole. The project has the possibility of offering biofiltration, habitat, and stormwater control elements to the region. As a class, we have extensively discussed our values and associated goals for the field of Restoration Ecology. Our values begin with the question: what do we want the new ecosystem to do? In other words, we examine the desired function of the system to be restored. This functional goal then provides a framework for research, design,
construction, and maintenance. We are committed to specifying the operational definitions which form the foundation of such projects. Our work has lead to questions such as; what is ecology? What does restoration mean? What are the needs of the community and/or of the client? What is the path of least resistance, so that we can have the least possible financial and environmental costs? Our goal for this project is to enhance existing plans for wetland development in order to get as much value as possible from ecosystem functions, services, and species preservation.
Materials & Methods Species Area Curves: Rarefaction Rarefaction is the practice of using nested quadrads to determine species composition and diversity. The process also assists in understanding the species‐ area relationship of the community in question. Quadrads are carefully measured and laid out with stakes and wooden frames, after which plant species are identified (or sampled for identification later in the lab) and recorded. Over story Transects This technique is designed to sample forest trees and collects data based on species, basal area, diameter and dominance. Basal area is the total cross‐sectional area of a trunk from diameter at breast height (DBH), or horizontal cross section from about four feet above ground level. Transects are oriented along a compass bearing and stationed at regular intervals based on the largest tree’s measurements. Soils Soil data was collected using pH measurement kits, Munsell soil color identification charts for determining mineral composition, soil texture classification, and soil identification using USGS soil maps. Several sample cores of soils were taken with soil augers to study soil horizon strata in the area. Cover and Land Use History: Aerial Photography Chronosequences & Maps Aerial photography was collected from the New York State GIS Clearinghouse, and soil maps were collected from the Olin Library Maps and Geospatial Information Collection.
Ithaca College Slope Forest
The Ithaca College slope forest is directly uphill from the parking lot wetland where the sports complex will be built (Figure 1a). Though the area is not large enough on its own to fulfill mitigation requirements, its close proximity to the impacted land does makes it desirable for mitigation, provided that the site lends itself to the creation of a wetland. Research on this site sought to determine its land‐use history and suitability for mitigation wetlands. This analysis was based upon a 1937‐2007 chronosequence as well as soils data available from the USDA Natural Resources Conservation Service. In addition, this project collected original field data in order to determine species composition on the site. This species data provides additional insight into the history of the site and its suitability for various kinds of plant species. The slope forest includes two distinctly different plant communities ‐ the flat lower reaches are dominated by herbaceous plants, whereas the slope is dominated by woody species that exhibit a clear transition to mature upland forest. To capture the ground plants, we utilized nested quadrads, from which data was used to create species area curves; to capture the tree community, we ran transects uphill through the forest, which we used to determine basal area percentages (Figure 1b). In both cases, biodiversity was calculated according to the Shannon‐Weiner index. (Figure 1a)
Figure 1: Ithaca College slope forest (a) The IC slope forest as seen in a 2007 aerial photograph. (b) Basal area transect points are superimposed in yellow and pink on a slope map. Corner points of a nested quadrad for finding species area curves are superimposed in blue.
The 1937‐2007 chronosequence provides a good overview of the site’s history and characteristics, especially when combined with NRCS soils data (Figure 2). The white signature visible in the 1937 aerial photograph indicates that the lower reaches of the site were being used to actively cultivate row crops (Figure 2a). Within these areas, it is interesting to note the presence of dark patches, which may indicate wet spots where water collected. This would support the idea that the site has historically experienced periodic wetting and could thus lend itself to a mitigation wetland. Meanwhile, forest is visible on the slope in the southwest corner. The white fields are no longer visible in the 1954 and 1964 photos (Figures 2b, 2 c). Though vertical lines are still visible in the land—a legacy from the planting of row crops—it is clear that the process of succession has begun. At this stage, the lower reaches could be characterized as retired agricultural fields, or possibly hay fields. The forest is still visible in the southwest. It appears that a small area of woods was cleared after 1936 (in the northern half of the area where transects were taken), but overall, the forest has been largely undisturbed over the years. By 2007, succession appears to have reclaimed the former agricultural land to a great extent (Figure 2d). The boundaries delineating the old fields are no longer obvious in the aerial photo, and trees have taken root throughout the site. In addition to the chronosequence, the soils information available for the site says a great deal about the site’s suitability for wetland mitigation. There is a clear delineation in which the forested slope consists of Lt soils; whereas the flat lower reaches are a mosaic of RkB and HsB soils (Figures 2a, 2d). Lt soils are “Lordstown, Tuller, and Ovid soils” that are shallow and very shallow (20 inches deep over bedrock) — LtB indicates a 0‐15% slope and LtC indicates a 15‐35% slope. Such soils are somewhat poorly drained; however, due to the slope of land and the shallow depth to bedrock, LtB and LtC soils are distinctly unsuitable as a wetland soil. This is important as it reinforces the conclusion that only the lower reaches exhibiting RkB and HsB soils are good candidates for mitigation. The RkB and HsB soils are, respectively, a Rhinebeck silt loam and a Hudson silty clay loam, both very deep and of a 2‐6% slope. The two soil types are geographically associated, being typical of cultivated fields, and although they are not typical wetland soils,
their siltiness means that they would lend themselves to this purpose more readily than a coarser soil would. In its current state, the site already exhibits a mosaic character in which certain areas are periodically saturated and thus support wetland‐like characteristics, whereas other areas are dry year‐round. This is likely because the Rhinebeck soil, with higher clay content, is “somewhat poorly drained” according to the NCRS, whereas the Hudson soil is “moderately well‐drained.” Thus, Rhinebeck soils are more likely to be wet and exhibit wetland characteristics. This interpretation is in agreement with Figure 2a, in which the darker wet patches are seen to appear over RkB soils. rker wet patches are seen to appear over RkB soils. HsB
Figure 2: Chronosequence Aerial photographs for (a) 1936, (b) 1954, (c) 1964, and (d) 2007. Soil types are superimposed on 1936 and 2007 photos, depicting the presence of Rhinebeck silt loam (RkB); Hudson silty clay loam (HsB); and shallow to very shallow Lordstown, Tuller, and Ovid soils (LtB and LtC).
In order to obtain a more complete understanding of the HsB/RkB mosaic and its potential as a wetland, we performed nested quadrads that allowed us to catalog the ground plants at the site and plot a species area curve. From the species area curve (Figure 4), the number of species found appears to saturate at a point between 15 and 20 species, giving a minimal area of about 10 square meters. This relatively high level of species diversity is consistent with successional old fields that have many lingering perennials, a finding that corroborates what we are able to observe from the chronosequence. The species list (Figure 3) shows that, although no obligate wetland species were found, several facultative wetland species were identified. These are plants that are able to grow in wetland conditions but can survive in non‐wetland conditions, unlike obligate species. This finding reinforces the site’s promise as a potential mitigation wetland.
Fraxinus pennsylvanica Green Ash
Hieracium caespitosum Meadow Hawkweed
Marginal Shield Fern
Common Speedwell Taraxacum laevigatum
Common Yellow Woodsorrel
Vaccinium corymbosum Highbush Blueberry
Figure 3: Nested quadrad species list Facultative wetland (FACW) species are highlighted in green
Figure 4: Slope forest species area curve Plants species saturation seems to occur between fifteen and twenty species.
Transects, meanwhile, allow us to observe the transition from these lower reaches to mature upland forest. In running these transects, we were interested in the ages of the trees, their species composition, and how these factors change with elevation as we move away from the HsB/RkB mosaic and into sloping LtB and LtC soils. The Shannon‐Weiner diversity index was plotted versus transect point number, along with elevation, in order to obtain a general view of how species composition changes with elevation (Figure 5). From this figure, there does not appear to be any discernible trend in overall species diversity as one moves up the��slope. However, a more detailed plot depicting how individual species change in prevalence along the slope show clear patterns (Figure 6). Certain species, such as Acer saccharum (Sugar maple) and Fraxinus americana (White Ash), are clearly more numerous in the lower half of the slope, whereas others like Quercus rubra (Red Oak) and Carya ovata (Shagbark hickory) become more dominant in the upper half of the slope. This suggests that the slope forest is in a state of transition. The lower half of the slope was cleared sometime between 1936 and 1954, and the trees that have grown in since that time are clearly not the same species that were dominant before that time.
(Figure 5b) Figure 5: Diversity change with elevation along western and eastern transects
IC slope forest—Change in Species Composition
from Transect Point P1- P15
Number of individuals
Figure 6: Change in species prevalence along eastern transect
In addition to plotting transitional changes up the slope, we also sought to characterize the wooded slope as a whole, in the interest of “looking upstream” of the potential mitigation site. Figure 7 depicts species dominance in terms of both percent basal area and number of individuals found. It can be seen from these figures that, although 13 different species were recorded, most of the basal area consists of just four dominant species. Furthermore, comparing the two dominance plots reveals interesting successional details. Although Acer saccharam (Sugar maple) is most dominant by both metrics, the difference is far more dramatic when comparing number of individuals, indicating that its dominance is achieved by having large numbers of relatively young trees. By contrast, both dominant oak trees Quercus rubra and Quercus alba (Red & White oak) diminish when comparing numbers of individuals, indicating that its presence is in the form of a smaller number of very large, very old trees. This point is made even more explicit when one plots the size distribution for the top four most dominant (Shagbark hickory) specimens are less than 46 inches in diameter, whereas most of the Quercus rubra and Quercus alba (Red & White oak) are larger than 41 inches. This reveals a clear portrait of a forest in successional flux—an old oak forest gradually being supplanted by younger maples and hickory.
15 (Figure 7a)
(Figure 7b) Figure 7: Species dominance in forest in terms of (a) percent basal area and (b) number of individuals
QuickTime™ and a decompressor are needed to see this picture.
(Figure 8d) Figure 8: Size distribution of three most dominant tree species (a) Acer saccharaum ‐ sugar maple (b) Quercus rubra ‐ red oak (c) Quercus alba ‐ white oak (d) Carya ovate ‐ shagbark hickory
Ithaca College Hilltop: Swamp White Oak Swamp & Red Pine Plantation
The swamp white oak swamp and the red pine plantation are located on a hilltop of about four acres, just south of the Ithaca College campus. According to chronosequence photography, the site was an open, abandoned field in 1934, followed by the spread of swamp white oak specimens by 1964. The red pine plantation was planted in 1964. Tree core samples confirmed that the oak specimens were approximately seventy years old while the red pines approximately forty‐five years old. The site falls within a Unique Natural Area (UNA‐154) (Figure 1). These areas are so named because they possess rare or valued plants, animals, or topography. They also tend to include some old‐growth trees, which some of the existing swamp white oaks could be considered. However, the area should not be considered “pristine” wilderness as it has a history of clearing, farming, and replanting.
Figure 1: Ithaca College Hilltop location in Unique Natural Area
The red pine plantation exhibits a flat topography while the swamp white oak area is topographically varied with hummocks and dips filled with water. The soil is similar in both areas: Eerie Cannery Silt Loam with little sand content and a pH level around 5. Soils
are not considered hydric; however area is still suitable for a wetland because of a high fragipan layer that prohibits water from draining quickly from the site. If swamp white oak were found to be more conducive to biodiversity, it might be advisable to allow the species to replace the existing red pines. One method to achieve this is to pull down the red pines with a bulldozer from the road (by keeping the bulldozer on the existing road, damage to soil structure and existing plants can be reduced and/avoided). The felled trees would create micro‐topography necessary to create a wetland similar to what currently exists while opening space for white oaks and other species. However, as can been seen in Figure 2, the red pine plantation does not adversely affect bio‐diversity in the area. Also, the cost of such a conversion would outweigh the small increase in bio‐diversity that such a conversion could produce. Therefore, it is our recommendation to allow the red pine plantation to co‐exist with the swamp white oak swamp.
(Figure 2b) Figure 2: Ithaca College hilltop ShannonWeiner Index data (a) Red pine plantation (b) Swamp white oak swamp
References Hurt, G.W., and Vasilas, L.M. (2006) Field Indicators of Hydric Soils in the United States, US Department of Agriculture and the Natural Resources Conservation Service. Other Site Concerns A major issue with the sites on top of South Hill is the presence of the invasive species Japanese stilt grass (Micostegium vimineum). This aggressively invasive, non‐native grass has formed large patches mostly along the road that runs between the red pine stand and the swamp white oak swamp. Stilt grass persists under a wide range of conditions from moist to dry and low light to high light levels1. It is avoided by all major herbivores in the area, including white tailed deer which exacerbate the problem through browsing native species and allowing stilt grass to spread more easily1. Removal of stilt grass is complicated by the fact that its seeds persist in the soil for five years1. Stilt grass most easily invades
areas subject to disturbance which explains why the majority of the infestation on South Hill is along the road1. There are three main techniques used to remove stilt grass: manual removal, systemic herbicides, and a combination of manual removal and pre‐emergent herbicides1. Stilt grass is relatively easy to remove by hand. It has a shallow root system that is easily pulled from the soil7. Since it is a grass, however, dealing with a stilt grass infestation requires the removal of many individual plants which can require a greater work force. When seeds are not present on the plant, stilt grass can be left to dry on site1. If seeds are present, the plant must be bagged and removed from the area1. The two herbicides recommended in New York state for use on stilt grass are Roundup Pro® (Rodeo® in aquatic systems) and Pendulum AquaCap®2. Roundup Pro® is a non‐selective systemic herbicide that kills nearly all herbaceous plants with the chemical glyphosate3. It can be applied to stilt grass as either a spray or with a wipe‐on applicator5. Since this herbicide is non‐specific, using a spray increases the risk of killing non‐target species. While wipe‐on applicators do reduce this risk, they are slightly more labor intensive.
Pendulum AquaCap® is a pre‐emergent herbicide that selects for grasses and some broadleaf weeds6. It uses the chemical pendimethalin to kill seeds in the soil4. It is available only as a spray; however the selective nature of Pendulum® reduces the risk of this method of application4. Pendulum® should not be used in aquatic systems as pendimethalin has been shown to be somewhat toxic to fish and aquatic invertebrates6. Stilt grass isn’t listed as a controlled species on the Pendulum AquaCap® label; however studies performed by BASF Chemical Company have demonstrated that Pendulum® is effective against stiltgrass2, 4. It is recommended that the stilt grass on South Hill be eradicated through manual removal over a period of five years in order to ensure full eradication. Herbicides are not recommended due to the chance of contamination and accidental death of native plants. If, however, herbicide use is deemed desirable, Pendulum AquaCap® is recommended over Roundup® or Rodeo® due to its selective nature. This will be most effective if combined
with one‐time manual removal. Even if herbicides are used, the site should be monitored for at least 2 years to ensure that all stilt grass has been removed. Once the stilt grass is removed from the south hill sites, it needs to be replaces with other plant species in order to deter the stilt grass from returning. The areas of stilt grass on South Hill seemed unable to displace two species of fern identified as wood fern (Dryopteris intermedia) and sensitive fern. Many fern species, including the wood fern, are capable of allelopathy, or producing chemicals that kill off neighboring plants allowing the fern to live healthily and spread easily8. As the situation on South Hill suggests, it is possible that the allelochemicals produced by the wood fern are effective against stilt grass. It is recommended that any stilt grass removed from South Hill should be replaced with wood ferns since it a native species already present on South Hill that is likely resistant to stilt grass invasions. References 1 Swearingen, J.M., 2008. Least Wanted: Japanese Stilt grass. Plant Conservation Alliance. http://www.nps.gov/plants/ALIEN/fact/mivi1.htm. Accessed Nov. 14, 2008. 2 BASF Corporation, 2005. A Better Approach to Controlling Japanese Stiltgrass. http://www.vmanswers.com/lib/PDF/japanesestiltgrassss.pdf. Accessed Nov. 19, 2008. 3 Tu, M., Hurd, C., Robinson, R., and Randall, J.M., 2001. Weed Control Methods Handbook: Tools and Techniques for Use in Natural Areas. The Global Invasive Species Team. The Nature Conservancy. Chapter 7, Section E: 115‐125. http://tncinvasives.ucdavis.edu/handbook.html. Accessed Nov. 15, 2008. 4 BASF Corporation, 2006. Herbicide Pendulum AquaCap. http://www.cdms.net/LDat/ld3BO006.pdf. Accessed Nov. 18, 2008. 5 Monsanto Company, 2007. Roundup Original Max Herbicide. http://www.monsanto.com/monsanto/ag_products/pdf/labels_msds/roundup_ori g_max_label.pdf. Accessed Nov. 18, 2008. 6 Extension Toxicology Network, 1993. Pesticide Information Profile: Pendimethalin. http://pmep.cce.cornell.edu/profiles/extoxnet/metiram‐propoxur/pendimethalin‐ ext.html. Accessed Nov. 15, 2008. 7 Arlington, VA: Parks, Recreation, and Cultural Resources. 2008. Japanese Stilt Grass Alert. http://www.arlingtonva.us/departments/ParksRecreation/scripts/parks/ParksRec reationScriptsParksInvasiveJapaneseAlert.aspx. Accessed Nov. 18, 2008. 8 Munther, W.E. and Fairbrothers, D.E., 1980. Allelopathy and autotoxicity in three eastern North American ferns. American Fern Society, 70:124‐135.
Ithaca College Parking Lot: Wetland Corridor & Downstream Corridor
The Ithaca College Parking Lot Wetland is being destroyed during the construction of the new Ithaca College athletic facility. It was important to examine the history and vegetation and soil characteristics of this wetland both because of the potential to build some of the elements of the original wetland into the stormwater management wetlands that will be constructed as part of the athletic facility project and because the purpose of a mitigation wetland is to replace the functions provided by the wetland that has been lost.
Figure 1: Ithaca College parking lot wetland area: blue dots indicate the station points of the plant species transect.
(Figure 2c) Figure 2: Ariel Chronosequence of the Ithaca parking lot wetland (a) 1936, Area largely cultivated. Transect is noted in red dots. (b) 1964, Ithaca College’s Lower Quad has been constructed. (c) 2007, Land use changes (parking lots have increased runoff) have relatively recently introduced hydromorphic soil processes.
The soil data and aerial chronosequence images suggest that there has been a greater water accumulation on the site over time. In the 1936 aerial, the site does not appear to be a wetland – it is clearly an agricultural area. The soil type specified in the soil maps for the area also does not indicate a classic wetland soil type (Figure 3 and Table 1). RkB, standing for Rhinebeck Silt Loam, is typically found in areas with slopes of 2‐6%, and the depth to a root restrictive layer is greater than 60”. This soil is somewhat poorly drained, but not ponded or flooded, and the seasonal zone of water saturation is at 10” from November to May. Typically, this soil does not meet hydric criteria. Given that the site in 1936 does not appear to be a wetland (Figure 2a), and that the soil would not typically support a wetland, it would seem that the wetland conditions currently existing
on this site are due to a larger volume of water entering the site. As posited above, this is likely due to the increased impervious area adjacent to the site, which has in turn increased runoff into the site. The inundation of the site over the past few decades has resulted in more hydric soil conditions and fostered the success of an increased number of typical wetland plants (Table 2) , which currently share the site with species indicative of old field sites.
Figure 3: Soils map overlaid on an aerial of the site. Plant species transect is indicated by blue dots.
29 Soil Sample Horizon pH 1
Soil Color Mottling Soil Type
6.4 Silty Clay
6.6 Silty Clay
Table 1: Soil Sample Characteristics
Because of the density of vegetation on this site, a nested quadrad system was not used to look at species diversity and community makeup. Instead, a 100m transect was laid out with stations every 10m. At each station a 2m‐by‐2m square was laid out centered on and perpendicular to the transect line. Each species found within the square was counted once, to create a data set that would capture the variety of species and their spatial distribution across the transect. This method of data collection does not provide insight into species distribution density, as with the nested quadrad data gathered for the other sites studied. The plant species data collected on this site is intended to provide insight into the character of the wetland that is being lost (How wet is it? Is the plant community indicative of a wetland or old field condition, or a combination of the two?), to inform the decisions about what the functions and plant community makeup of the mitigation wetland(s) should be.
Number of Species at Each Plot
Number of Species Collected
30 Figure 4: Plant species varied at each transect point across the wetland.
Species Collected Most Frequently Across Transect Plots *blue‐highlighted species are invasive
Species Botanic Name
Solidago canadensis var. canadensis
Aster spp. 1
Solidago patula var. patula
Table 2: Most common species collected.
# of Times Collected
Meets Six‐Mile Creek
Figure 5: The stream exiting the wetland and joining SixMile Creek. The red dots are station marks at inlets and outlets.
(Figure 6 – a)
Figure 6: Downstream Area Photography (a) Station 1. At the outlet from the wetland, the bank has been eroded, as shown by the bank character and the exposure of the roots of this tree. The bank under the tree has been undercut to a depth of 0.5m. (b) Station 9. After the stream passes through a series of culverts on the I.C. campus, it daylights again between road crossings. Here there begins to be stands of Japanese Knotweed along the banks of the stream. (c) Station 11. At this point the stream flows between two yards in a very flat area. In the photo you can see young Japanese Knotweed starting to come up from what seemed to be an eradication effort. (d) Station 20. Here the stream has carved out a deep gully – approximately 10’ deep. Dense scrub lines the banks of the gully. The streambed flattens out as it enters an area of denser undergrowth, and flows in to fenced‐off private property.
35 (e) End: Meets Six‐Mile Creek. The stream eventually flows into Six‐Mile Creek, which in turn runs through downtown Ithaca into Lake Cayuga.
Stations Marking Downstream Path 1. N42° 25' 28", W76° 29' 26" ‐ head of stream 2. N42° 25' 28", W76° 29' 26" ‐ 2.1 m wide + .5 m under tree 3. N42° 25' 28", W76°29' 26" ‐ drainage grate‐ catch basin 4. N42° 25' 30", W76° 29' 27" ‐ catch basin/grate 5. N42° 25' 31", W76° 29' 26" 6. N42° 25' 32", W76° 29' 25" ‐ from culvert‐out 7. N42° 25' 34", W76° 29' 24" ‐ <6" standing water 2' bfd 8. N42° 25' 34", W76° 29' 24" ‐ (.7 m big) culvert in 0.8 m water frogs! 9. N42° 25' 35", W76° 29' 23" ‐ (2 m big) culvert out 0.3 m deep water bfd 1.4 m 10. N42° 25' 37", W76° 29' 22" ‐ (.7 m big) culvert in 2.5 m stream width 1.4 m bfd 11. N42° 25' 37", W76° 29' 22" ‐ culvert out .6 m depth 12. N42° 25' 37", W76° 29' 21" ‐ 1.1 m width 1" deep water 13. N42° 25' 38", W76° 29' 20" ‐ culvert in 3 m wide can't tell how deep‐stones 14. N42° 25' 38", W76° 29' 20"‐ culvert out .7 m depth 15. N42° 25' 40", W76° 29' 18" ‐ (2.5') culvert in 2.2 m width 16. N42° 25' 40", W76° 29' 18" ‐ culvert out 17. N42° 25' 40", W76° 29' 18" ‐ 2.3 m bfd 3 m wide 2" deep water 18. N42° 25' 41", W76° 29' 17" ‐ culvert in 3 m wide 2" water depth 2' bfd 19. N42° 25' 41", W76° 29' 17" ‐ culvert out 20. N42° 25' 42", W76° 29' 15" ‐ 3.9 m wide 1' bfd (deeply cut banks) 21. N42° 25' 43", W76° 29' 13" ‐ 3 m wide bfd 6" 2" deep water 22. N42° 25' 52", W76° 29' 17" ‐ culvert in 2.3 m wide 6" bfd no water gabions
23. N42° 25' 51", W76° 29' 14" ‐ (3' tall) culvert in 3.2 m width 2' bfd24. N42° 25' 49", W76° 29' 11" ‐ culvert in 5 m wide .5 m bfd culvert out is about 50' downhill End: Meets Six‐Mile Creek. Conclusion The destruction of the I.C. parking lot wetland will certainly have impacts downstream. The stream flowing out of the wetland already shows signs of instability and invasive species, and the stormwater management plan for the new athletic complex project will have to account for this. The aerial photographs, USGS soil data and plant species information for the I.C. parking lot wetland indicate that this site was not historically a wetland, but has more recently become one. This is likely due to the site receiving increased amounts of water that has come from the parking lots and other impervious surfaces built adjacent to the site. Because of this history of change, the site currently has a mix of old‐field vegetation and wetland vegetation. In constructing the mitigation wetland, it should be considered that the current function of this wetland has been to detain and filter runoff from parts of the Ithaca College campus. Additionally, the plants that are surviving in this wetland are a naturally surviving community that have been capable of establishing themselves, successfully propagating, and surviving in the conditions on‐site. While the plant species found in the parking lot wetland do not seems to be species of particular value, they can serve as an example of a community of plants that would function well and without significant maintenance in constructed wetlands that are designed to serve the same purpose: detention and infiltration of stormwater runoff.
Proposed Stormwater Management Plan
Ithaca College is in the process of building a new athletic facility and fields on their South Hill campus. This project will displace the parking lot wetlands mentioned earlier. These wetlands served the valuable function of handling the runoff from the impervious surfaces as well as providing habitat for various organisms. In this section we examine how the proposed stormwater management strategy will effectively replace the functions the parking lot wetland provided.
Figure 1: Proposed Ithaca College sports complex
Figure 2: Ithaca College Planned Athletic Facility Site
Stormwater Management Strategy
The storm water plan incorporates a series of bioretention filters to capture runoff from fields and facilities, parking lots and roads. These infiltration areas are designed to capture the water quality volume for the 2 year 24‐hour storm. The treatment train begins with a series of 8 small bioretention filters and terminates in one larger retention pond. A sand filter is incorporated to handle runoff from the playing field. According to the plan it appears that three of the smaller bioretention filters actually tie directly into the larger pond, two of the filters outfall directly into the landscape as overland flow, and three outfall into the existing piped stormwater system.
Figure 3: Ithaca College Athletic Facility Proposed Stormwater Management Plan
Figure 4: Detail of a Bioretention Filter from Project Design Development Document
Figure 5: Detail of the Detention [sic: Retention] Pond from Project Design Development Document
One of the elements of the landscape plan that could be modified is the planting plan, particularly concerning the plants associated with the bioretention filters and retention pond. The planting strategy revealed in the construction documents seems to be one of incorporating a broad array of diverse species to create a sort of wetland mosaic. In order to assess how effective this strategy will be, we cross referenced the plant list to the USDA PLANTS database to see how they classified the plants in terms of wetland hydrologic zones. Most of the species fell under the categorization of obligate (OBL), meaning they occur almost always under natural conditions in wetlands, facultative wetland (FACW), meaning they usually occur in wetlands but are occasionally found in non‐wetlands, or facultative (FAC), meaning they are equally likely to occur in wetlands or non‐wetlands. The planting plan for the bioretention filters and retention pond were broken into specific zones with the following proportions of species types: •
Emergent shallow planting – 4 OBL & 2 FACW
Emergent deep planting – 4 OBL
Bio‐swale seed mix (for the bioretention filters) – 11 OBL & 10 FAC or FACW
Upland moist seed mix – 8 OBL & 6 FACW
Figure 6: Plant list from Proposed Planting Plan Cross Checked Against the USDA PLANTS Database
Due to reliance on meteoric inputs the retention areas will experience prolonged periods of dryness, which suggests that they are not suitable areas for obligate wetland species. Obligate species live in areas of nearly constant soil saturation. We recommend selecting plants that can tolerate the stresses inherent in storm water management structures such as these. In particular, plants should be selected for tolerance to prolonged drought and intermediate flooding, as well as possibly high inputs of nutrients and other pollutants carried in runoff. Based on the relatively high amount of species included in the planting list, it seems that the strategy for the plantings is to have a diverse mosaic of species. However, we predict that a strategy that employs lower density plantings of multiple species is likely to
be taken over by a narrow range of more aggressive species like Typha, Phragmites, and Phalaris. We know that Typha is present in the existing parking lot wetlands. It is likely that their propagules are ubiquitous throughout the site as well. If the intention is to avoid a monoculture of these more aggressive species, then we suggest that fewer species are chosen and planted in higher densities to promote establishment and resist invasion.
Figure 7: Crosssection of proposed Detention [sic. Retention] Pond
Figure 8: Juncus effusus in a roadside swale. This condition is analogous to the bioretention filters, a shallow depression receiving runoff from a paved surface. The high plant density resists invasion from typical ditch species like Typha, Phragmites, and Phalaris.
Figure 9: Typha sp.
Figure 10: Phragmites sp.
Figure 11: Phalaris arundinacea (Reed canary grass)
Use Existing Resources
As Figure 12 indicates, the parking lot wetlands that are going to be demolished contain several species that were listed in the proposed plant list. Before the existing wetland is demolished there is an opportunity to transplant some of these species into the new biofiltration ponds.
Figure 12: Plants on the proposed planting list found in the Ithaca College parking lot wetlands
Figure 13: Surveying the shallow slopes at Bull Pasture Pond, a potential reference site.
Figure 14: Mixed wetland species
Plant selection should target a biological benchmark with regards to saturation levels and duration.
A smaller more selective plant list and higher density planting can help compete with local invasives.
Choose and collect beneficial plants from the existing wetland before demolition.
The stormwater plan includes features that should be celebrated as a part of the Ithaca College Campus’s functional landscape. Although the area comprised of the constructed wetlands planned for stormwater management will not count towards the required legal mitigation effort,��they will serve a functional role in mitigating stormwater runoff generated by increased impervious surfaces. This feature should be highlighted as an effort which goes above and beyond the baseline best management practices.
The need for continued monitoring and maintenance should be heeded. Possibly tying the functions of the stormwater retention areas to research agendas presents another angle for in‐depth monitoring. Creating functional landscape that will serve as habitat space could generate interest on the part of resident researchers; the effect being more holistic monitoring practices.
RPM Old Field in Dryden
Ithaca College's initial assessment of the potential onsite mitigation wetland
location determined that slope; cost and future expansion interests posed problems with that option. The College then began to look elsewhere and came to consider an old field adjacent to Route 13 west of the village of Dryden. The owner of this property is RPM Ecosystems LLC, a native plant nursery which grows plant material specifically for restoration and conservation projects using their patented Root Production Method (RPM). 1 The class was informed that RPM was interested in having a wetland constructed on their property and even entertained having it sized larger than the area mandated by the United States Army Corps of Engineers (USACE). The Dryden site is 10.7 acres and located in the Virgil Creek Watershed which drains into Fall Creek and eventually Cayuga Lake. (Figure 1a and 1b) It is important to note that the site is in a different sub‐watershed from the proposed wetland impact on Ithaca's South Hill. From analyzing Geographic Information System (GIS) data and USGS Quads it was determined that the Dryden site as a whole was less than 5% slope and that perennial streams bordered the site in the form of drainage ditches.
1 RPM Ecosystems LLC. http://www.rpmecosystems.com/about_rpmecosystems.html Visited November 25, 2008.
52 Figure 1: Watersheds (a) Large scale watershed of Dryden site (b) Local watershed of Dryden site (c) Diagram of the water flow on through Dryden site and the adjacent wetlands
To determine whether the site would make a suitable wetland, the class pursued a line of questioning related to the history and physical characteristics of the site. One critical question that we sought to answer was whether the site ever was a wetland previously. This would mean that transforming the site back into a wetland would be much easier. Through a combination of remote sensing and field investigation we hoped to determine the sites suitability as a wetland. Through assembling an aerial photograph chronosequence with a first image dating from 1938, it was clear that the land use on the site had been consistently agricultural for the past 70 years. (Figure 2a and 2b) This did not discount the possibility that the site was a wetland prior to this period, as hydrologic modifications often accompany agricultural activities. In the aerial photographs, adjacent sites did revert to wetlands over time and are now identified on the National Wetland Inventory. In studying the area's soil map, we determined that because of poor drainage, low slope, the Halsey Silt Loam soil group which comprises the bulk of the site meets hydric criteria. 2 (Figure 2c) This fact coupled with a high zone of water saturation and low relief make the Dryden site more suitable for wetland creation than some of the other sites we investigated.
2 USDA Natural Resources Conservation Service, soil descriptions available. http://soildatamart.nrcs.usda.gov/State.aspx Visited November 15, 2008.
54 Figure 2: Site Maps (a) 1938 Aerial photo showing history of site as a farm field (b) 2007 Aerial photo (c) Soils map showing that Halsey silt loam dominates site and meets criteria for a wetland
After examining soil characteristics and historical conditions a closer look at the topography and hydrology was necessary. According to a longitudinal cross‐sectional transect using rod and level, it was established that the field sloped 2.9% towards the North. (Figure 3) A slight natural terrace occurred 250 feet to 350 feet from the road edge. It was determined that two culverts conveyed surface runoff from the upper portion of the watershed underneath Route 13 and discharged the flow into drainage ditches loosely forming the western and eastern edges of the site. Redirecting flow from these constructed drainage structures is one possible way to create wetland conditions on the old field. We then briefly investigated what level of grading would be necessary to create a redirection swale, small reservoir, dike, water control structure and subsequent wetland area; essentially a schematic design. (Figure 3) It was determined that these structures could effectively be built in the area provided. However, if wetland area is to be maximized beyond the 4.4 acres required, there will be a great deal of excess cut material. Alternately, if the construction is formed closer to the natural slope, the total dedicated wetland area will be diminished.
Figure 3: Wetland Scheme These diagrams show some of the principle concepts that would be involved in creating a wetland on the Dryden site. The bottom graph shows the change in slope that would be needed on site to create a wetland.
Existing plant communities are indicators of wetland conditions, successional history and biodiversity. The class established two nested quadrads at the Dryden RPM site. One was higher on the slope to the southern end of the site and the second test area was downhill to the north. (Figure 4a and 4b) No facultative wetland or obligate wetland species were discovered nor were any rare or threatened upland species. No basal‐area curve data collection was performed at this site since the vegetation was predominantly herbaceous. Solidago species represented the highest percentage of overall cover in both quadrads. The lower site had slightly greater plant diversity based on the Shannon‐Weiner Index. (Figure 4c) Cattail (Typha sp.) and Purple Loosestrife (Lythrum salicaria) were
identified and photographed in the drainage ditch along the western boundary of the field. (Figure 4d and 4e) These aggressive species could effect and displace the desired plant communities of a mitigation design on this site.
(d) (e) Figure 4: Dryden Plant Data (d) (e) (f) (g) (h)
Upland Meadow Species Area Curve Lowland Species Area Curve Species area Curve data used to make Shannon‐Weiner Index at both locations Purple Loosestrife Cattails
Conclusion: Finally it is important to consider what function the Dryden RPM Field could serve as a wetland. It could play a role in stormwater management, runoff treatment, or as habitat for a species such as Ambystoma Salamanders. From observing the drainage ditches at the field edges it did not appear that erosion was a serious problem. Route 13 and other impervious surfaces related to development account for only a small percentage of the upstream watershed area. There is an auto‐mechanic shop and a great deal of agricultural land in the catchment that could potentially be targeted for treatment in a wetland on the site. In terms of habitat, the site is not suitable for salamanders until some forest cover is able to develop but it may prove to be valuable for frogs. So ultimately, it is possible to construct a wetland on this old field. Stakeholders must evaluate if the functional gains are worth the cost. In terms of replacing the functionality of the Ithaca College wetlands, location alone discounts this site.
Special Considerations: Amphibian Breeding Habitat & Amphibian Habitat Recommendations
Habitat loss and fragmentation as a result of land use change contribute to
amphibian population declines on a global scale (Collins and Storfer 2003). In North America, small wetlands, including vernal pools, are destroyed at a significant rate. These ponds support a diversity of amphibian populations, which use the ponds for breeding and metamorphosis (Semlitsch and Bodie 1998). Creation of breeding pond habitat can act to counter wetland loss and connect patchy or isolated amphibian populations. Amphibians also prove useful indicators of habitat quality due to their sensitivity to environmental changes and toxicity. Amphibians use cutaneous respiration in that they can breathe through their skin, which means that environmental toxins are also absorbed through their skins. Additionally, amphibian populations can be used to assess restoration success due to their sensitivity to altered hydrology (Petranka et al. 2003).
Several species of amphibians, which includes salamanders and frogs, utilize ponds
for different stages of their life cycle. Mole salamanders in particular depend upon pond habitat. Locally, there are two species of mole salamander: the spotted salamander (Ambystoma maculatum) and Jefferson’s salamander (Ambystoma jeffersonianum). Aptly named, mole salamanders burrow underground in hardwood forest habitat for most of the year. In early spring once the spring rains begin, these salamanders migrate to permanent or ephemeral ponds where they breed and deposit egg masses in the water. Salamanders then develop and metamorphose within the pond and migrate back to the forest habitat (Conat and Collins 1998). The Eastern newt (Notopthalmus viridescens) and several frog species, such as the wood frog (Rana sylvatica) and gray treefrog (Hyla versicolor) also utilize terrestrial‐aquatic habitat linkages for breeding and development aspects of their life histories. Reference site: Bull Pasture Pond Bull Pasture Pond, located on the Robert Trent Jones golf course in Ithaca, New York serves as a reference site for local salamander breeding habitat (Figure 1b). The two local
Ambystomid species, the spotted salamander (Ambystoma maculatum) and Jefferson’s salamander (Ambystoma jeffersonianum), migrate across the golf course between forest and pond habitats during breeding season.
(b) Figure 1: Bull Pasture Pond: (a) Aerial view of Bull Pasture Pond and surrounding golf course and woodland. The distance required for migration between the pond and forest is about 320 feet. (b) Panoramic view of Bull Pasture Pond and surrounding landscape. The right pond was surveyed as a reference site and offers shallow sloped sides and a vegetated perimeter.
Proximity to upland forest provides the necessary aquatic‐terrestrial linkage for different stages of the Ambystomid life cycle. Distance from Bull Pasture Pond to the nearest patch of woodland is about 320 feet (Figure 1a). Transects through the woodland were used to determine species composition; mature hardwood trees dominate the upland forest (Figure 2a). A soil profile was also characterized with regard to pH, texture, and
color (Figure 2b). Vegetation along the perimeter of the pond consists of several herbaceous species, including the invasive purple loosestrife (Lythrum salicaria) (Figure 2c). This vegetated buffer around the pond acts for primary production and habitat for salamanders. Vegetation overhanging or submerged in the shallow water can be utilized for salamander egg deposition. Topography of the pond also influences its suitability for salamander breeding habitat. Three cross sections were surveyed along the stream, with elevation measurements taken at regular intervals (Figure 2d). A topographic profile was created with height and depth data from cross‐sectional surveys (Figure 2e). The profile indicates a shallow pool with gently sloping sides and an irregularly shaped perimeter contour. Shallow water depths allow for growth of submerged aquatic vegetation (SAVs), which provides food and habitat for salamander populations. The sloping sides allow for ease of access to and from the pond as necessary for breeding and development. An irregular perimeter provides habitat heterogeneity and complexity.
Eastern hemlock (a)
Bidens cernua / (laevis?)
Nodding beggartick (c)
65 Figure 2: Graphs and Tables (a) Tree species found in the upland forest surrounding Bull Pasture Pond (b) Soil characteristics of a core sampled in woodlands adjacent to Bull Pasture Pond. Soil horizons were distinguished based on color differences, as determined with a Munsell color chart. Soil texture was determined by the texture-by-feel method. A field test kit was used to measure soil pH. Fragipan was present at a depth of 16 inches. (c) Vegetation present along the perimeter of Bull Pasture Pond. (d) Sampling transects across Bull Pasture Pond to determine topographic profile. Each measurement was recorded from a single survey point on the pond edge. (e) Topographical profiles of Bull Pasture Pond, with proportional height and depth scales.
Invasive species concerns Invasive plants and animals are opportunistic and frequently colonize disturbed sites. Monitoring and control methods are recommended to stem the spread of invasive species. Two invasive species of potential detriment to Ambystomid breeding habitat are bullfrogs and cattails.
Bullfrogs (Rana catesbeiana) were originally introduced into the United States for
their culinary value; since introduction the animal has successfully and persistently spread throughout many habitats. Bullfrogs will eat any animal that can be swallowed, including juveniles of their own species. This voracious predator negatively affects native species, as adults and young may be eradicated from an area as they fall prey to the bullfrogs. Institution of a desiccation regime in pond habitat has been demonstrated to reduce bullfrog populations (Maret et al. 2006). For example, in Arizona’s San Rafael Valley, bullfrogs colonized cattle ponds originally intended as habitat for the native Sonoran tiger salamander (Ambystoma marortium stebbinsi). Manipulation of pond water levels to mimic seasonal changes showed a negative effect on bullfrogs, as constant water inundation is beneficial for bullfrog growth and development. Bullfrog tadpoles require more than one season to mature and the adults over winter in the mud at the bottom of the pool. Desiccation of the pool and underlying sediments thus works to reduce bullfrog populations (Maret et al. 2006). Fencing has also been proposed as a method to exclude bullfrogs from habitat (Bovinderajula et al. 2005), although this technique would have detrimental effects on other species, including the salamanders.
Cattails (Typha latifolia) are another species of potential invasive threat to wetland
habitat. Although this is a valuable species for water quality and waterfowl habitat in some
cases, it quickly forms a monoculture and creates a barrier along the shoreline. Manipulation of the water level, timed to the annual cycle of carbohydrate storage, works to control cattail colonization. Leaf and stem cell aerenchyma provides air passage from both living and dead leaves to the rhizomes. Submergence of the shoots and dead leaves in the spring will thus cause stress to the plant growth and eventually kill it (Sojda and Solberg 1993). Site suitability analysis Suitability of a site for amphibian habitat depends upon a number of factors, including the context of the surrounding upland and soil characteristics. Different communities of amphibian populations should be expected based on the upland context within which the pond is created. Ambystomid, or mole, salamanders prefer mature, hardwood forests for growth and development when not in breeding season. This type of forest provides necessary leaf litter decomposition and invertebrate communities for the spotted and Jefferson’s salamander. Acidity also influences salamander survival success and rate of metamorphosis. At pH levels less than 4.5, Ambystomid salamanders exhibit decreased survival and slower rates of development in breeding ponds (Sadinski and Dunson 1992). Salamanders typically prefer pH levels above 6.
Of the mitigation sites, the Ithaca College wooded slope site provides the most
appropriate context for Ambystomid salamanders. The forest is predominately comprised of hardwood trees, and has existed for several decades, allowing maturation of forest soils. The Ithaca College red pine site also provides a woodland context, although located within a pine forest instead of hardwood upland. Pine needles produce acidic leaf litter, which is detrimental to salamander growth and development. Soil samples at the red pine site were around pH 5; this is less than ideal for amphibians, but not unmanageable.
Another site in the process of consideration for mitigation, the RPM‐Dryden field,
presents different issues for amphibian habitat. This site lacks woodland habitat necessary to support salamanders that require both terrestrial and aquatic habitat. Spotted salamanders, Jefferson’s salamanders, and Eastern newts should not be expected to populate a pond created at this site. The field site, however, could be use for frog habitat,
as many local frog species utilize pond habitat that do not require adjacent woodland. Some frog species that might be expected to colonize such a site include spring peepers (Pseudacris crucifer), green frogs (Rana clamitans), pickerel frogs (Rana palustris), and leopard frogs (Rana pipiens). Soil tests at this site indicate a range of pH values, from moderately acidic (5.3) to circumneutral (6.8). These pH levels are more conducive to amphibian habitat than sites with strongly acidic soils. Amphibian pond recommendations Wetland creation for amphibian habitat should take into account factors of pond size, quantity, spatial arrangement, complexity, and hydroperiod (Petranka and Holbrook 2006). Prior studies indicate that wetland hydroperiod is a more significant predictor of amphibian colonization than wetland size (Snodgrass et al 2000). The wetland hydroperiod determines the timing and duration of water inundation and drawdown within a wetland. Hydroperiods occur along a gradient from permanent water inundation to ephemeral, in which water is only present for a short period of time. Amphibians are adapted to capitalize on available water sources, for which variable hydroperiod might be present. Variation in hydroperiod also allows a balance between the threats of desiccation and predation. Permanent ponds offer a constant habitat for breeding and development throughout the year, albeit a characteristic also conducive for invasive species such as bullfrogs. Ephemeral ponds hold water primarily over the seasons when pond habitat is utilized, although rate of desiccation due to size or other factors presents a stress to amphibian development rate. Wetland hydroperiod, coupled with surrounding terrestrial landscape, will determine amphibian assemblages following wetland creation (Petranka and Holbrook 2006).
Creation of the wetland habitat should exhibit structural and functional
heterogeneity, such that a variety of amphibian species colonize the wetland for different attributes. Fish should not be introduced to the created pond, as they prey upon amphibian individuals and egg masses and reduce species richness (Hecnar and M’Closkey 1996). Variation of wetland depth, size, micro‐topography, and hydroperiod along a spatial
gradient will provide the greatest habitat complexity suitable to a wide variety of organisms. The perimeter of the pond should be complex and vegetated to provide further food and habitat resources.
Literature Cited Bovinderajula, P., R. Altweggot, and B.R. Arholt. 2005. Matrix model investigation of invasive species control: bullfrogs on Vancouver Island. Ecological Applications 15(6): 21612170. Collins, J.P. and A. Storfer. 2003. Global amphibian declines: sorting the hypotheses. Diversity and Distributions 9: 89-98. Conat, R. and J.T. Collins. 1998. A field guide to reptiles and amphibians of eastern and central North America. Houghton Mifflin. Hecnar, S.J. and R.T. M’Closkey. 1996. The effects of predatory fish on amphibian species richness and distribution. Biological Conservation 79: 123-131. Maret, T.J., J.D. Synder, and J.P. Collens. 2006. Altered drying scheme controls distribution of endangered salamander and introduced predators. Biological Conservation 27(2): 129138. Petranka, J.W. and C.T. Holbrook. 2006. Wetland restoration for amphibians: should local sites be designed to support metapopulations or patchy populations? Restoration Ecology 14(3): 404-411. Petranka, J.W., C.A. Kennedy, and S.S. Murray. 2003. Response of amphibians to restoration of a southern Appalachian wetland: a long-term analysis of community dynamics. Wetlands 23(4): 1030-1042. Sadinski, W.J. and W.A. Dunson. 1992. A multilevel study of effects of low pH on amphibians of temporary ponds. Journal of Herpetology 26(4): 413-422. Semlitsch, R.D. and J.R. Bodie. 1998. Are small, isolated wetlands expendable? Conservation Biology 12(5): 1129-1133. Snodgrass, J.W., M.J. Komoroski, A.L. Bryan Jr., and J. Burger. 2000. Relationships among isolated wetland size, hydroperiod, and amphibian species richness: implications for wetland regulations. Conservation Biology 14(2): 414-419.
Sojda, R.S. and K.L. Solberg. 1993. Management and control of cattails In Waterfowl management handbook. < http://www.nwrc.usgs.gov/wdb/pub/wmh/13_4_13.pdf>
Conclusions and Recommendations
General Recommendations: It is important for mitigation wetland goals to reflect desired functions. Stormwater management, treatment, and the successful establishment of an appropriate plant community can all be primary elements of any goal statement. Habitat, specifically for endangered animal species, such as Ambystomid salamanders, would then add further value to this project. Conclusions: The slope forest at Ithaca College does not have the required acreage to satisfy Ithaca College’s mitigation wetland needs, however the conditions in lower topographical areas are conducive to wetland creation. The contiguous nature of the existing wet areas (currently seasonal wetlands) and the location of the site within the same watershed/ hydrologic system as the existing wetlands make this site viable for our purposes. Also, evidence of succession is available for this site resulting in the ability to make general predictions as to what plant association is developing. This data could be used to inform any planting scheme for the site. Therefore, we recommend considering the possibility of locating a portion of the required mitigation wetland acreage on this site. Remaining acreage could then be located on a separate project site. The swamp white oak swamp and the red pine plantation are functional ecosystems which are working components within the watershed. These areas cannot fulfill the required acreage of mitigation wetland needed. Further, extending the swamp white oak swamp into the red pine plantation seems extremely costly when compared to gained benefits. We do, however, recommend the protection of these communities by removing and creating a management plan to control Japanese stilt grass. This highly invasive species poses an extreme threat to the existing community structure. The Ithaca College parking lot wetland’s existing plant association is an appropriate reference community with regards to a functional wetland created by increased overland
runoff from impervious surfaces. All present plants are not obligate wetland species; understanding biological benchmarks will help determine where desired obligate species will best perform and then help inform the inclusion of other species that will successfully establish in the various areas of a created wetland system. Once identified, desired plant species can be harvested and stored for planting in new areas, serving to protect the local gene pool and reducing project costs. We recommend using this site as one of the models for the creation of mitigation wetlands. This site functions as a natural filtration and stormwater control system for a developed area while containing a functional community of plants. The old field near RPM, in Dryden, does not show evidence of ever supporting a wetland system. Moist upland areas as well as road drainage provide a steady source and directional flow of water through a possible wetland system. We recommend using the site as a reference for upslope vegetation and as a possible site for the treatment of highway runoff. The area also seems viable for wetland amphibian habitat. However, for the site to be viable for Ambystomid salamander habitat, a mature hardwood forest would first need to develop nearby.