HOW SHOULD ONE COUNT SPECIES

We must find rigorous yet feasible ways to monitor biodiversity if we wish to critically evaluate the success of biological conservation, re storation, or reserve design. One of the most important components of biodiversity in a reserve is the number of species (species richness). Unfortunately, it is impossible to develop complete species lists for reserves more than several hectares in size. We thus need to deal wit h uncertainty and to settle for estimates rather than exact values. On e way to estimate species richness is by extrapolation, that is, infer ring richness based on subsamples within the area of interest. Another way is by interpolation, or inferring richness based on comparisons w ith other areas. This paper reviews some methodological developments f or extrapolation and interpolation. Further advancement of statistical ecology and geostatistics is necessary before these methods can be pu t into widespread use.