Estimating species richness through three dimensions

Extrapolation techniques allow more accura.te estimates of species richness than are possible through simple species counts alone. Similarly, sampling through three dimensions in dimensionally complex ecosystems gives more reliable estimates of species richness and diversity than samples taken at only one level. This paper examines three-dimensional spatial patterns of Coleoptera in primary rainforest in Sulawesi (Indonesia) and demonstrates how adding extra levels in a sampling area (i.e. volume) significantly increases estimated species richness. Evidence for stratification of assemblages at di fferent heights is also examined. Implications for species-area relationships (SARs) are discussed, and how such sampling and extrapolation techniques may impact species-richness measurements in derived ecosystems.