Using multiscale spatial models to assess potential surrogate habitat for an imperiled reptile

Area of Science:

• Ecology
• Conservation Biology
• Wildlife Management

Background:

• Eastern diamondback rattlesnakes (Crotalus adamanteus; EDB) are imperiled apex predators native to declining longleaf pine ecosystems.
• Habitat loss and degradation due to anthropogenic changes are primary drivers of EDB decline.
• Surrogate habitats are increasingly considered for species conservation in highly modified landscapes.

Purpose of the Study:

• To evaluate marsh as a potential surrogate habitat for the eastern diamondback rattlesnake (EDB) at two spatial scales: home range (HR) and within home range (WHR).
• To quantify EDB habitat requirements in the Coastal Plain tidewater region.
• To assess the role of habitat structure in EDB selection.

Main Methods:

• Radiotelemetry was used to track EDB movements.
• Spatial habitat models were employed to analyze habitat selection.
• An information-theoretic approach and logistic regression were used to model habitat use versus availability.

Main Results:

• No positive association was found between EDBs and marsh at the home range scale; EDBs showed negative associations with most landscape patches except pine savanna.
• Within home range selection indicated a negative association with forest and a positive association with ground cover.
• These findings suggest EDBs may utilize habitats with similar structural characteristics, potentially including marsh, at finer scales.

Conclusions:

• Tidal marsh was not supported as a surrogate habitat for EDBs at the home range scale.
• Marsh may provide crucial resources for EDBs at smaller, within-home range scales.
• Habitat structural similarity may be a key factor in EDB selection of potential surrogate habitats.