Estimating Site Occupancy Rates When Detection Probabilities Are Less Than One
Mackenzie DI, Nichols JD, Lachman GB, Droege S, Royle JA, Langtimm CA. 2002. Estimating Site Occupancy Rates When Detection Probabilities Are Less Than One. Ecology. 83(8):2248-2255
Nondetection of a species at a site does not imply that the species is absent unless the probability of detection is 1. We propose a model and likelihood-based method for estimating site occupancy rates when detection probabilities are 0.3). We estimated site occupancy rates for two anuran species at 32 wetland sites in Maryland, USA, from data collected during 2000 as part of an amphibian monitoring, program, Frog-watch USA. Site occupancy rates were estimated as 0.49 for American toads (Bufo americanas), a 44% increase over the proportion of sites at which they were actually observed. and as 0.85 for spring, peepers (Pseudacris crucifier), slightly above the observed proportion of 0.83.
- Type
- Journal Article
- Authors
- Mackenzie, Darryl; Nichols, James; Lachman, Gideon; Droege, Sam; Royle, J.; Langtimm, Catherine
- Units
- SODN
- Keywords
- Animals, anurans, Bootstrap, Bufo Amricanus, Demographic-Models, Detection Probability, Extinction, maximum likelihood, Metapopulation, Metapopulation Dynamics, Monitoring, patch occupancy, Populations, Pseudacris Crucifer, Site Occupancy, Size, time, Vary