Cooperative Fish and Wildlife Research Units Program: Virginia
Education, Research and Technical Assistance for Managing Our Natural Resources

PROJECT DESCRIPTION: This project will develop a range-wide quantitative model (ie, species distribution model) to estimate suitability of stream segments and watersheds (12-digit USGS hydrologic units) for the endangered Candy Darter (CD), which is a habitat specialist occurring in fast-flowing, cool-water streams with little siltation. CD’s range in Virginia is now limited to four widely separated streams. Comprehensive assessments of which landscape features (eg, watershed size, land use, channel gradient, network position, connectivity) predict CD occurrence have not been performed, thereby precluding development of range-wide maps of habitat suitability. The proposed species distribution model will assist managers (eg, VDWR, USFWS) in identifying streams and watersheds that are most likely to a) support undiscovered populations, b) be suitable reintroduction sites, and c) provide refugia from invasion by Variegate Darter.
OBJECTIVES:
1) Synthesize all existing geo-referenced presence/absence data on CD range-wide;
2) Use publicly available GIS data to relate CD occurrence (presence and absence) to a suite of instream, near-stream, and upland watershed features via statistical models;
3) Conduct field surveys to test model predictions and facilitate model refinement.