Estimating occupancy in large landscapes: evaluation of amphibian monitoring in the Greater Yellowstone Ecosystem

Publication Type:

Journal Article

Source:

Wetlands, Springer, Volume 32, Issue 2, p.379-389 (2012)

Call Number:

A12GOU01IDUS

URL:

http://www.fs.fed.us/rm/pubs_other/rmrs_2012_gould_w001.pdf

Keywords:

Ambystoma tigrinum, boreal chorus frog, Columbia Spotted Frog, Pseudacris maculata, Rana luteiventris, tiger salamander

Abstract:

Monitoring of natural resources is crucial to ecosystem conservation, and yet it can pose many challenges. Annual surveys for amphibian breeding occupancy were conducted in Yellowstone and Grand Teton National Parks over a 4-year period (2006-2009) at two scales: catchments (portions of watersheds) and individual wetland sites. Catchments were selected in a stratified random sample with habitat quality and ease of access serving as strata. All known wetland sites with suitable habitat were surveyed within selected catchments. Changes in breeding occurrence of tiger salamanders, boreal chorus frogs, and Columbia spotted frogs were assessed using multi-season occupancy estimation. Numerous a priori models were considered within an information theoretic framework including those with catchment and site-level covariates. Habitat quality was the most important predictor of occupancy. Boreal chorus frogs demonstrated the greatest increase in breeding occupancy at the catchment level. Larger changes for all 3 species were detected at the finer site-level scale. Connectivity of sites explained occupancy rates more than other covariates, and may improve understanding of the dynamic processes occurring among wetlands within this ecosystem. The authors' results suggest monitoring occupancy at two spatial scales within large study areas is feasible and informative.

Notes:

ELECTRONIC FILES - Zoology