Landscape-based Wetland and Riparian Habitat  Modeling for Amphibians and Reptiles

 
 
 

Introduction

Methods

Results

Contacts

The West Virginia Gap Analysis Project is currently mapping the predicted distribution of all terrestrial vertebrates native to West Virginia.  Certain reptiles and amphibians rely on small wetland or riparian habitat features which may not be adequately mapped using standard Gap Analysis land cover products.  A special wetland and riparian habitat model is necessary to model the predicted distributions of these species.

Stream hydrology, percent slope, and digital elevation data are combined to produce relative cost path distance grids (example shown below) for headwater, small, and large streams.

Path distance grids are derived from the “cost” incurred by movement from source cells (streams) to non-source cells.  The cost of movement between cells is weighted by an impendance factor (slope) applied over surface distances (derived from digital elevation data). The resulting grids can be used to approximate riparian areas surrounding streams.

Forested land cover and existing wetlands data are also inputs to the model of potential wetland and riparian habitats.

The model of potential wetland and riparian habitats is created from the combination of the riparian areas surrounding streams, existing wetlands data, and forested land cover data.  This model is used as an input for species distribution modeling.  For each species, predicted distribution is derived from:

• habitats preferred or utilized by species (from species habitat relationship database)
• wetland and riparian habitat model
• statewide EMAP hexagonal distribution data (to limit species range)

Predicted species richness within all habitat polygons is shown below.  Highest species richness is found along the Ohio River, along the western border of the state.  Other locations supporting high numbers of species include Canaan Valley (a large wetland complex), the Kanawha River valley, and the far eastern panhandle.  Accuracy assessment has been performed for the results of this model at four different sites throughout the state.  Overall site accuracy ranges from 52.5 % to 90.0%, with an average of 70.6%.

CONTACT INFORMATION

Jackie Rowe
WV Gap Analysis
West Virginia University
Morgantown, WV  26506-6108
jrowe@wvu.edu
http://www.nrac.wvu.edu/gap/