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Ohio Wetland Bioassessment Program
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Last Updated: March 2000 Contact Information
Purpose(s) of Project
The initial objective of this study is to provide the reference data needed to implement the wetland water quality standards and wetland antidegradation rule. The pilot metrics developed from this study should enable Ohio wetlands to be assigned to one of the three regulatory categories. Generally, the study objectives are as follows:
Ecoregions** of Ohio and Indiana and Neighboring States
Project HistoryOhio has well-developed biological criteria (or biocriteria) for streams, e.g., the Invertebrate Community Index (macroinvertebrates), the Index of Biological Integrity (fish), and the Modified Index of Well Being (fish) (Ohio EPA 1988a, 1988b, and 1989). These indices are codified in Ohio Administrative Code Chapter 3745-1. Until recently, however, surface waters of the state that are jurisdictional wetlands were only generically protected under Ohio's water quality standards. On May 1, 1998, Ohio adopted wetland water quality standards and a wetland antidegradation rule. These wetland quality standards developed narrative criteria for wetlands and created the "wetland designated use." All jurisdictional wetlands are assigned the "wetland designated use." Ohio did not attempt, at this time, to identify multiple wetland functions as wetland uses because of the lack of data to develop quantitative water quality criteria for wetlands. The development of such biocriteria, however, is the ultimate goal and the primary thrust of this project. The key part of Ohio's current regulatory program for wetlands is found in the wetland antidegradation rule. The wetland antidegradation rule categorizes wetlands based on their functions, sensitivity to disturbance, rarity, and irreplaceability, and scales the strictness of avoidance, minimization, and mitigation to a wetland's category. Three categories were established:
Category 2: Wetlands with moderate wetland function and/or integrity. Category 3: Wetlands with superior wetland function and/or integrity. In order to implement the wetland standards and antidegradation policy, wetlands must be assessed on their relative quality. Ohio EPA has developed a draft Ohio Rapid Assessment Method. The Ohio Rapid Assessment Method has proved to be a fast, easy-to-use procedure for distinguishing between wetlands of differing quality. It does not and was not, however, intended to substitute for direct, quantitative measures of wetland function (i.e., biocriteria). Ohio began development of sampling methodologies and began sampling reference wetlands for biocriteria development in 1996. To date, Ohio has sampled 56 wetlands located primarily in the Eastern Cornbelt Plains Ecoregion located in central and western Ohio. These wetlands have included depressional emergent, forested, and scrub-shrub wetlands, flood plain wetlands, fens, kettle lakes, and seep wetlands. The wetlands being studied span the range of condition from "impacted" (i.e., those that have sustained a relatively high level of disturbance) to "least impaired" (i.e., the best quality sites available). Based on the results to date (See Fennessy et al., 1998a 1998b; Mack et al., unpublished data), Ohio's research supports the use of vascular plants, macroinvertebrates, and/or amphibians as biological metrics in wetlands, and also the continued use and development of the Ohio Rapid Assessment Method as a rapid assessment tool. This work has been funded since 1996 by several EPA Region 5 Wetland Program Development Grants.
Study DesignFifty-seven wetlands were sampled during the 1996, 1997, 1998, and 1999 field seasons. The first two years of data laid the groundwork for standardizing sampling methodologies, classifying wetlands, identifying potential attributes and developing metrics using vascular plants, amphibians, and macroinvertebrates. In 1996, Ohio EPA monitored a series of riparian forested across a gradient of disturbance (i.e., least impacted to impaired) (Fennessy et al., 1998b). Estimates of the relative level of disturbance were made on a scale of 1 (most disturbed) to 10 (least disturbed), based on visual evidence of disturbances, review of aerial photographs of the wetland and the surrounding area, and interviews with staff from the Natural Resource Conservation Service and/or the landowner. In 1996 and 1997, Ohio EPA monitored 21 forested and emergent depressional wetlands. Relative disturbance was evaluated using a tiered flow chart to assign a relative disturbance score and also with the score from the Ohio Rapid Assessment Method (Fennessy et al., 1998a, Figure 2.2). Ohio EPA found a good correlation between the scores of the Ohio Rapid Assessment Method score and level of disturbance a wetland site has experienced. Higher ORAM scores correlate well with lower levels of disturbance based on our model, as do lower ORAM scores with disturbed sites. In 1999, the ORAM score of the site was used as measure of the level of disturbance. So far, this appears to be a highly effective "x-axis" disturbance gradient for the development of IBIs for wetland plants. Reference wetlands are sites or data sets from sites that typify a class of wetlands within a relatively homogeneous physiographic region. Reference sites should include wetlands that have been degraded or disturbed. Site selection in this study is made using an ecoregional approach and to reflect a gradient of disturbance (i.e., least impacted to impaired).
Reference sites are selected such that relatively similar proportions of low, medium, and high disturbance sites are sampled. To date, almost all the wetlands studied by Ohio EPA have been located in the Eastern Cornbelt Plains (ECBP) ecoregion. For the year 2000 and 2001 field seasons, Ohio EPA will be studying reference sites in the Erie Ontario Lake Plain (EOLP) ecoregion of northeastern Ohio. Assemblages MonitoredLessons Learned |
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