Skip to main content
U.S. flag

An official website of the United States government

Influences of Availability on Parameter Estimates from Site Occupancy Models with Application to Submersed Aquatic Vegetation

January 1, 2013

Site occupancy models are commonly used by ecologists to estimate the probabilities of species site occupancy and of species detection. This study addresses the influence on site occupancy and detection estimates of variation in species availability among surveys within sites. Such variation in availability may result from temporary emigration, nonavailability of the species for detection, and sampling sites spatially when species presence is not uniform within sites. We demonstrate, using Monte Carlo simulations and aquatic vegetation data, that variation in availability and heterogeneity in the probability of availability may yield biases in the expected values of the site occupancy and detection estimates that have traditionally been associated with low-detection probabilities and heterogeneity in those probabilities. These findings confirm that the effects of availability may be important for ecologists and managers, and that where such effects are expected, modification of sampling designs and/or analytical methods should be considered. Failure to limit the effects of availability may preclude reliable estimation of the probability of site occupancy.

Publication Year 2013
Title Influences of Availability on Parameter Estimates from Site Occupancy Models with Application to Submersed Aquatic Vegetation
DOI 10.1111/nrm.12012
Authors Brian R. Gray, Mark D. Holland, Feng Yi, Leigh Ann Harrod Starcevich
Publication Type Article
Publication Subtype Journal Article
Series Title Natural Resource Modeling
Index ID 70103396
Record Source USGS Publications Warehouse
USGS Organization Upper Midwest Environmental Sciences Center