Ohio Wetland Bioassessment Program

Last Updated: March 2000

Mike Gray

(macroinvertebrates, amphibians)
Aquatic entomologist
Ohio Environmental Protection Agency
Division of Surface Water
Ecological Assessment Unit
4675 Homer-Ohio Lane
Groveport, OH 43125
Office: (614) 836-8773
Email: mike.gray@epa.state.oh.us

John J. Mack
(plants, rapid assessment method)
Wetland Ecologist
Ohio Environmental Protection Agency
Division of Surface Water
122 South Front Street
P.O. Box 1049
Columbus, Ohio 43216-1049
Office: (614) 644-3076
Email: john.mack@epa.state.oh.us

Mick Micacchion
(amphibians, rapid assessment method)
Wetland Ecologist
Ohio Environmental Protection Agency
Division of Surface Water
122 South Front Street
P.O. Box 1049
Columbus, Ohio 43216-1049
Phone: (614) 644-2327
Email: mick.micacchion@epa.state.oh.us

Purpose(s) of Project

• Test and develop biological criteria for wetlands using vascular plants, macroinvertebrates, and amphibians as indices of biotic integrity (IBIs) for eventual adoption into the state's water quality standards.
  
  
• Use results from IBIs to calibrate the Ohio Rapid Assessment Method for Wetlands to support regulatory decision making under the state's Wetland Antidegradation rule, which requires that wetlands be assigned to one of three categories based on the wetland's quality and functionality.

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:

1. To develop pilot biological metrics that may be used to evaluate the function and ecological integrity of a wetland. These metrics will be based on the vegetation, macroinvertebrate, and amphibian data, and will form the basis for wetland biocriteria.
   
   
2. To identify and describe reference wetlands in the Ohio's four main ecoregions: Eastern Cornbelt Plains, Erie/Ontario Drift and Lake Plain, Huron-Erie Lake Plain, and Western Allegheny Plateau. These reference wetlands will be used to develop biocriteria and will also be used as "goals" for wetland mitigation projects.
   
   
3. To continue to assess whether the Ohio Rapid Assessment Method correlates well with the more in-depth measures of wetland quality, and to test and refine breakpoints between the wetland categories.
   
   
4. To begin to assess the sensitivity of different methods in evaluating the relationship between wetland quality and the degree of disturbance.

Ecoregions** of Ohio and Indiana and Neighboring States

Project History

Ohio 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:

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 Design

Fifty-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 Monitored

• Macroinvertebrates
• Amphibians
• Vascular plants

Lessons Learned

• Macroinvertebrates and Amphibians
• Vascular plants