Spatial Capture-Recapture Models
J. Andrew Royle, USGS Patuxent Wildlife Research Center
Capture-recapture methods are widely used to obtain basic demographic information for many species using encounter history data from spatial arrays of traps or other devices. Despite the ubiquitous use of capture-recapture methods in this context, they suffer from a number of deficiencies that impair their effectiveness for estimating population density. Importantly, the area from which individuals may be captured cannot be delineated precisely and thus it is not possible to infer density directly from such models. In addition, individuals experience variable exposure to trapping as a result of the juxtaposition of their home ranges with traps. New classes of spatial capture-recapture methods accommodate the spatial organization of traps and individuals to (1) model individual heterogeneity in encounter probability mechanistically, based on spatial proximity of individuals to traps and (2) obtain direct estimates of density by associating individuals with explicit spatial locations. I will review conceptual and methodological aspects of spatial capture-recapture models, discuss some recent developments, and provide some thoughts on future research directions and applications.