Closed mark-recapture models to estimate species richness: An example using data on epigeal spiders

Species richness is a fundamental ecological property. The problem of estim ating the number of species is quite similar to that of estimating the popu lation size of a single species. Some authors of mark-recapture statistics have proposed using some of these methods to estimate species richness. Thi s necessitates understanding how the recording probabilities of individuals differ from those of species. In particular, the species of a species pool are likely to exhibit a wide range of recording probabilities. Depending o n sampling conditions, temporal or spatial variation in species detection p robability may also occur, making model M-th estimators particularly useful . Empirical detection probabilities and estimates of species numbers using three coverage, one point, and two jackknife estimators are presented for s eries of spatial and temporal trapping occasions of epigeal spiders.