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The Vascular Flora of a Transect Across the Beaver Creek Wetlands, Greene County, Ohio
| Content Provider | Semantic Scholar |
|---|---|
| Author | Schmalhofer, Victoria R. Amon, James P. Runkle, James R. |
| Copyright Year | 1992 |
| Abstract | During the 1989 growing season we surveyed part of the Beaver Creek Wetlands in Greene County, OH, to describe and catalog the vegetation and to determine if a transect oriented through the study site satisfied the mandatory technical criteria for vegetation used by Federal agencies to delineate wetlands. We established 14 plots along the transect and compiled a list of the species occurring within the plots and throughout the rest of the study site. We identified 198 species, including five species on the Ohio list of threatened and endangered species. A majority of species occurring within the study site were classified as hydrophytes. A wetland index was calculated for each plot using weighted percentages of vegetation indicator-categories. Wetland-index values, which expressed changes in wetland character (degree and duration of soil saturation as reflected by proportions of hydrophytes and nonhydrophytes occurring in the plots), were significantly correlated with first-axis scores from a detrended correspondence analysis (DECORANA). This correlation indicated that DECORANA first-axis scores also reflected changes in wetland character along the transect. The wetland index also identified areas that showed a tendency towards seasonal or spatial transition between wetland and nonwetland. According to federal criteria, wetland areas included the 12 interior plots along the transect and part of plot 14, while nonwetland areas included plot 1 and most of plot 14. Ohio J. Sci. 92 (1): 14-24, 1992 INTRODUCTION Section 404 of the Clean Water Act designates wetlands as "waters of the United States." The United States Army Corps of Engineers, which has jurisdiction over waters of the United States, and the Environmental Protection Agency define wetlands as follows: Wetlands are those areas inundated or saturated by • surface or groundwater at a frequency and duration sufficient to support, and under normal conditions do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas (Federal Interagency Committee for Wetland Delineation [FICWD] 1989). Thus wetlands are described as having three essential characteristics: 1) wetland hydrology, 2) hydric soils, and 3) hydrophytic vegetation (FICWD 1989). Wetland hydrology describes a situation where water saturates the soil for at least seven consecutive days during the growing season (FICWD 1989). Hydric soils develop when prolonged soil-saturation generates anaerobic conditions, resulting in a decreased rate of decay and an increased accumulation of organic matter. Thus hydric soils generally have a high organic content. Hydrophytes are plants which tolerate saturated soil and low oxygen levels in the root zone. The term hydrophytic vegetation indicates that over 50% of species occurring in an area are hydrophytes and that hydrophytes are dominant species in the area (FICWD 1989). Federal agencies use these characteristics, 'Manuscript received 22 July 1991 and in revised form 27 January 1992 (#91-16). Present address: Graduate Program in Ecology and Evolution, Rutgers University, Piscataway, NJ 08855-1059 termed the mandatory technical criteria, to identify wetlands. To qualify as a wetland, an area must satisfy all three requirements of the mandatory technical criteria. The primary purpose of this project was to describe and catalog the vegetation of a transect across the Beaver Creek Wetlands, a natural wet area located in Greene County, OH. Since no part of the Beaver Creek Wetlands has ever been officially designated as a wetland, a secondary goal was to determine if the study site satisfied the mandatory technical criteria for wetland delineation. Although the features along one transect cannot describe the entire wetland corridor, information gathered in this survey can serve as a baseline for future studies in the Beaver Creek Wetlands and provide a basis for comparison with other Ohio wetlands. The goals of this study were met by making two sets of observations: 1) observations along a transect using plots which were investigated according to federal criteria for wetland vegetation; and 2) less structured observations of species composition in a 20 ha area surrounding the transect in order to characterize the main vegetation types present and to generate a more complete species list. MATERIALS AND METHODS The Beaver Creek Wetlands, located in the northwestern portion of Greene County, OH, in Bath and Beavercreek townships, include a corridor of about 400 ha bordering the Big Beaver Creek. The wetlands are roughly bounded by Dayton-Yellow Springs Road to the north, DaytonXenia Road to the south, Trebein Road to the east, and Beaver Valley Road to the west. The study site is an approximately 20 ha section of the wetlands immediately south of New Germany-Trebein Road, located on the Fairborn Quadrangle of the United States Geological Survey 7.5 minute series at approximately 39°46' N latitude and 84°0' W longitude in section 23 of Beavercreek Township. OHIO JOURNAL OF SCIENCE V. R. SCHMALHOFER, J. P. AMON, AND J. R. RUNKLE 15 The Big Beaver Creek lies over a river valley buried when glacial outwash filled the Hamilton River, a tributary of the preglacial Teays River drainage system (Regional Planning and Coordinating Commission of Greene County, Ohio 1976). Dredging and channelization in about 1917 produced a levee that partially isolates both the Big Beaver Creek from the surrounding wetlands and the wetlands from surface runoff carried by the creek. A small creek originating in Fairborn crosses the northern section of the study site and empties into the Big Beaver Creek. Like the Big Beaver Creek, this tributary has a levee. The primary water source for the wetlands is alkaline groundwater, and the water table is at or above ground level throughout most of the wetland corridor. Also, numerous springs supply water to the surface. In March of 1989, we chose an approximately 20 ha section (hereafter referred to as the study site) of the Beaver Creek Wetlands for our survey based on ease of access and cooperation of the property owners. A 600 m transect was oriented across the study site (northwest to southeast), and 14 plots were marked for detailed study (Fig. 1). Plots were chosen by visually assessing living and dead vegetation and determining when a new vegetation patch-type was encountered along the transect. Since the FIGURE 1. Aerial photograph of the study site showing plot locations and soil types. Soil descriptions are taken from Garner et al. (1978): So = Sloan silty clay loam, hydric; Ws = Westland silty clay loam, hydric; OcB Ockley silt loam, 2-6% slopes, nonhydric; EnC3 = Eldean clay loam, 6-12% slopes, severely eroded, nonhydric; Ag = Algiers silt loam, nonhydric. plots were used for wetland delineation, we measured their dimensions according to the 1987 U. S. Army Corps of Engineers' guidelines: plots composed of herbaceous species had a 5 ft (1.5 m) radius; plots containing shrubs or saplings had a 10 ft (30 m) radius; and forested plots had a 30 ft (9.1 m) radius (Environmental Laboratory 1987). Federal criteria required a single survey of several east-west transects across the Big Beaver Creek. Since the main goal of this study was to conduct an extensive floral survey of the study site, we used a single transect, oriented to intersect many vegetation patch-types (estimated from aerial photographs) and visited multiple times throughout the growing season. From 1 April through 15 October, weekly visits were made to each plot to record species present, to collect voucher specimens for preservation and identification, to keep records of blooming phenology and soil saturation, and to measure the diameter at breast height (dbh) of all trees. At the end of each month, the percent-area covered by each herbaceous species in each plot was estimated. We identified species not occurring in the plots during weekly walks through the study site (primarily the area marked as having Sloan soils in Fig. 1). A cover class was assigned to each herbaceous species in each plot using the maximum percent-area covered: 1 = <5%, 2 = >5-25%, 3 = >25-50%, 4 = >50-75%, 5 = >75-95%, and 6 = >95% (Environmental Laboratory 1987). For trees and shrubs, we used relative basal area to assign cover classes. In instances where relative basal area alone did not provide an adequate estimate of a species' cover class (numerous saplings or shrubs with a small total basal area for example), we treated the species as herbaceous and visually determined its percent-area covered and assigned it to a cover class. Dominant species were designated as having a minimum cover-class of three. Taxonomic keys by Fernald (1950), Newcomb (1977), Weishaupt (1971), Braun (1961, 1967), and Fisher (1988) were used to identify species, and a regional wetlandplant list by Reed (1988) was used to determine the indicator category of each species. Based on a species' probability of occurring in a wetland or nonwetland, the species is assigned to one of five indicator categories: obligate wetland species (OBL) occur in wetlands more than 99% of the time; facultative wetland species (FACW) occur in wetlands 67% to 99% of the time; facultative species (FAC) occur with equal frequency in both wetlands and nonwetlands; facultative upland species (FACU) occur in nonwetlands 67% to 99% of the time; and upland species (UPL) occur in nonwetlands more than 99% of the time (Federal Interagency Committee for Wetland Delineation 1989). Wetland indicator species (hydrophytes) belong to the categories OBL, FACW, and FAC (FICWD 1989). Species not listed by Reed (1988) were assumed to be UPL. The National Technical Committee for Hydric Soils list of hydric soils of the United States (Environmental Laboratory 1987) and enlargements of Greene County soil survey maps (Garner et al. 1978) were used to identify the soil type of ea |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://kb.osu.edu/dspace/bitstream/handle/1811/23490/V092N1_014.pdf;jsessionid=F80CA00A3E2E2C7738D97E0C5D4A1DD4?sequence=1 |
| Alternate Webpage(s) | https://kb.osu.edu/bitstream/handle/1811/23490/V092N1_014.pdf?isAllowed=y&sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
