Primary purpose
To provide a standardized, cost-effective method for assessing the impact of urbanization on permanently flooded freshwater wetlands. May also be used to inventory wetlands within a watershed, evaluate the success of restoration, monitor progress in created wetlands, and guide watershed management for risk assessment.
Expertise needed
Trained wetland ecologists with an aquatic entomology background. Alternatively, a group leader with this expertise can train and coordinate volunteers working as team members.
Applicable habitat types
Permanently flooded, non-tidal freshwater wetlands in the New England area.
Categories assessed
Fourteen metrics/indices are used to assess ecological integrity: habitat assessment score; total organisms; total taxa richness; EOT richness; EOT/Chironomidae ratio; family biotic index; percent tolerant / percent intolerant; percent contribution dominant family; other Odonates/Coenagrionidae ratio; percent Chironomidae; percent Oligochaeta; community taxa similarity index; community trophic similarity index; and invertebrate community index (ICI).
Procedure
The user(s) selects reference sites, assembles available information (e.g., topographic maps, NWI maps, soils maps), visits the reference sites and project wetland(s), and completes the landscape and wetland characterization field sheets for each site. Using this data, the users complete wetland habitat assessment protocol indicators and criteria forms that (a) identify the individual indicators, (b) list criteria for each indicator, (c) assign a wetland score (scale 0-6) to criteria for each indicator, and (d) provide a space for calculating the habitat assessment score. Next, the aquatic invertebrates are sampled, sorted, identified, and enumerated for all sites. The data is used to calculate the following 13 metrics. The habitat assessment scores and each metric/index are analyzed separately to determine relative impairment of the wetland(s) being assessed. The habitat assessment score(s) and invertebrate community index (ICI) are plotted on a wetland status summary graph which is used to describe impairment of ecological integrity, if any, to each site.
Key Terminology
Biological condition score: a derived score that provides a relative measure of a wetland site metric compared to the metric value for the reference wetlands (e.g., biological condition score = [metric score for a wetland site / metric score for reference] x 100).
Ecological integrity: a measure of the extent to which the natural ecosystem has been altered.
Habitat assessment score: a score that quantifies relative impairment of a wetland habitat based upon characteristics wetland and surrounding landscape.
Index: a numerical end point that is a composite value summarizing several community attributes into a single value without loosing the information from the original measurements.
Indicator: an observable characteristic that corresponds to an identifiable variable condition in a wetland or the surrounding landscape.
Invertebrate community index (ICI): an index that summarizes overall biological integrity within a wetland derived by aggregating multiple metrics that describe community condition (e.g., total number of organisms, taxa richness, etc.).
Metric: a measure of one aspect or attribute of a biological community.
Contact person
Anna L. Hicks, NREC Program, Forestry & Wildlife Mgt. Department, Holdsworth Hall, University of Massachusetts, Amherst, MA 01003-4210 phone: (413) 545-1884; fax: (413) 545-3943 e-mail: ahicks@umext.umass.edu
Reference wetland: a wetland or one of a group of wetlands within a relatively homogeneous biogeographical region that represents typical, representative, or common examples of a particular hydrogeomorphic wetland type.
Wetland function: processes that are necessary for the self-maintenance of an ecosystem such as primary production, nutrient cycling, decomposition, flood control, sediment trapping, erosion control, wildlife habitat provision, and other society values: recreation, aesthetics, historical/cultural significance, etc.
Output
Measure of biological integrity of a site relative to reference wetlands from the same wetland class and watershed.
Estimated time to assess 1 acre site
Total 72-76 hours per study
40 hours: Set goals and objectives (step 1), determine study area (step 2), select reference sites (step 3), set date for fieldwork (step 4), and obtain equipment and organize team (step 5).
16 hours: (4 hours per 4 sites, i.e., 3 reference sites + 1 project site). Collect field data for reference wetlands and project sites (step 6). Complete habitat assessment (step 7).
8-12 hours: (2-3 hours per 4 sites, i.e., 3 reference sites + 1 project site). Conduct aquatic invertebrate sampling (step 8), sample preservation and transportation (step 9), sample sorting and preservation (step 10), and sample identification and enumeration (step 11).
8 hours per study: Data entry and analysis (step 11).
Comparison of habitat types
Can directly compare similar habitats (same classification) within the same geographic region. Cannot directly compare different habitats (i.e., as defined by classification) or similar habitats from different regions.
Use as guide to design
NEFWIBP should not be used as a guide to design, but may be useful in guiding site selection. The habitat assessment protocol contains properties that limit its application for this purpose. For example, it does not provide validated threshold values for many variables, although some of the indicators may provide useful information. Users can refer to the indicators to determine which conditions increase or decrease biological integrity. This can be translated into design criteria with explicit measurements (e.g., design for > 4 Cowardin classes). The aquatic invertebrate protocol uses samples of living organisms to assess biological integrity. It does not address or provide information on habitat structure or other elements important to design. The aquatic invertebrate metrics/indices could be used to select restoration/creation sites. A high ICI near a potential site would indicate that the area is not impaired and therefore has a good potential for successful creation. A low ICI at an existing site could indicate that it has good potential as a restoration site. Alternatively, a low ICI might suggest that an area is unsuitable for creation since its ecological integrity is severely impaired.
Related procedures
NEFWIBP is directly related to IBI (Karr 1991, Karr and Chu 1998) and may be considered a subset. Following the EPA definition, IBI is an integrative expression of site conditions across multiple metrics. It is often composed of at least seven metrics and can be compared to IBI in the following ways (source: Pers. Comm.: A. Hicks, University of Massachusetts Extension, August 18, 1998):
Steps to Establish an IBI NEFWIBP
Select an assemblage Aquatic Invertebrtates
Test and evaluate metrics 12 metrics and minor indices
Combine metrics into an IBI Combined metrics and indices
=ICI (Invertebrate Community Index)
Test and validate IBI NEFWIBP has been tested and validated for EPA in field studues conducted in CT and for CZM in field studies conducted in Massachusetts (Cape Cod and North Shore).
Extent of use/field testing
The habitat indicators and the accompanying numerical criteria, together with the invertebrate metrics and indices have been field tested in central Connecticut and Cape Cod, MA. NEFWIBP has been used approximately five times during the last two years for watershed planning and management research and a high school environmental science investigation of wetland health.
Proposed future revisions
A draft revision is now in review and may become the accepted procedure for training volunteer monitoring the New England Region. If accepted, it will be printed for training workshops planned in 1999 and 2000.
Key References
Hicks, A.L. 1997. New England Freshwater Wetlands Invertebrate Biomonitoring Protocol (NEFWIBP). The Environmental Institute, University of Massachusetts, Amherst, MA. 42 pp.
Additional references
Brinson, M.M. 1993. A Hydrogeomorphic Classification for Wetlands. Wetlands Research Program Technical Report WRP-DE-4. US Army Corps of Engineers, Waterways Experiment Station, Vicksburg, MS. 79 pp. ppen.