EXPLAINING LOCAL SPECIES-DIVERSITY

In this paper we examine the explanations for local species diversity. Using six extensive data-sets for drosophilid flies (which include bo th temperate and tropical species) we compare three major categories o f explanation (Cornell and Lawton 1992): niche heterogeneity (resource partitioning), spatial heterogeneity (intraspecific aggregation), and the fullness of the niche space (saturation level). We conclude that these Drosophila communities are dominated by intraspecific aggregatio n, not by resource partitioning, and they are not fully saturated.