Primary purpose
To evaluate the quality of wildlife habitat in deciduous palustrine forested wetlands in Maryland. Developed for use in evaluating these wetlands for impact assessment and resource management.
Expertise needed
Biologist experienced with Maryland deciduous palustrine forested wetlands.
Applicable habitat types
Deciduous palustrine forested wetlands in Maryland.
Categories assessed
Tract suitability, plot suitability, and native richness.
Procedure
The user(s) identifies evaluation area(s) and calculates the plot suitability index (PSI) for each. The PSI model (a) identifies four variables, (b) assigns a suitability index (scale 0-1.0) to conditions for each variable, and (c) includes the equation for calculating the PSI. The user(s) visits the study area to measure the habitat features listed in the models. Remotely sensed data is used to calculate the tract suitability index (TSI) and native richness index. Habitat units (HUs) may also be calculated for certain applications.
Key Terminology
Core area factor: factor used to calculate the TSI; core area is the area of a tract that is 100 m or more from a tract boundary that is bordered by nonforested habitat.
Effective tract area: a measure of a tract area, calculated by adjusting the actual measure of tract area by factors (i.e., core area and isolation) that modify the effective use of the tract by wildlife.
Foliage height diversity index: measure of how equally distributed the vegetation is in the three layers.
Habitat unit (HU): a value derived from multiplying the native richness index by the size of the plot (HU = native richness index x area).
Isolation factor: factor used to calculate the TSI, which is a function of permeability of the edge of a tract and the amount of deciduous palustrine forested wetland habitat within a two-km buffer of tract.
Plot: a sampling area within a tract for the purposes of estimating values for internal habitat variables.
Plot suitability index (PSI): unitless number bounded by 0 and 1 where 0 represents no habitat and 1 represent optimum habitat for a plot.
Microhabitat diversity: average number of elements of microdiversity per 0.1 ha (e.g., seeps, logs).
Native richness: the combined richness of birds sensitive to fragmentation, and reptiles and amphibians.
Native richness index: an index scaled from 0 to 1, where 1.0 represents a deciduous palustrine forested wetland that has the habitat and landscape conditions necessary to support maximum native richness over time. (Native richness index = PSI X TSI).
Tract: a contiguous unit of deciduous palustrine forested wetland, including the combined habitat of forested wetlands joined by corridors, bounded by an area > 10m wide and consisting of either nondeciduous palustrine forested wetland habitat or barrier to species movement.
Tract suitability index (TSI): unitless number bounded by 0 and 1 where 0 represents no habitat and 1 represents optimum habitat for a tract.
Output
Measures of tract suitability (TSI), plot suitability (PSI), and native richness for each evaluation area. Each index measures suitability relative to optimum habitat suitability for forest interior birds, reptiles, and amphibians in deciduous palustrine forested wetlands in Maryland.
Contact person
Richard Schroeder, National Biological Service, Midcontinent Ecological Science Center, 4512 McMurry Avenue, Fort Collins, CO 80525-3400 phone: (970) 226-9417; fax: (970) 226-9230; e-mail: rick_schroeder@usgs.gov
Estimated time to assess 1 acre site
Time variable. Depends upon the user needs for statistically rigorous samples.
Comparison of habitat types
Can directly compare deciduous palustrine forested wetlands within Maryland.
Use as guide to design
The WCHE models may be used as a guide to design. Users can refer to the model variables to determine which conditions increase or decrease native richness. Plot suitability is increased when the wetland is designed to have at least six microhabitat diversity elements per 0.1 ha (variable PV4). Each variable provides information on conditions that should be avoided. For example, the soil moisture regime should not be type D - typically dry (variable PV3). Finally, the information in the WCHE models is useful because it provides design criteria with explicit measurements (e.g., soil moisture regime A = seasonally inundated 15 to more than 30 consecutive days during the growing season).
Related procedures
WCHE is scaled from 0 to 1 to be used with HEP (USFWS 1980).
Extent of use/field testing
Extent of use in not known. A study of the relation of the tract variables to the richness of forest interior birds in 18 Breeding Bird Census plots in eastern deciduous forests was conducted to provide a test of several important model hypotheses (see explanation in Schroeder 1996).
Proposed future revisions
None.
Reference
Schroeder, R.L. 1996a. Wildlife Community Habitat Evaluation: A Model for Deciduous Palustrine Forested Wetlands in Maryland. Technical Report WRP-DE-14, US Army Engineer Waterways Experiment Station, Vicksburg, MS. 30 pp. + appen.