The species pool hypothesis: the necessity to shift emphasis

The species pool of a biological community is determined as a group of species that inhabit some area and potentially can be included in a given community. The species pool hypothesis, i.e. the assumption that the size of species pool strongly influences species richness of local community can be confirmed if there is positive linear relationship between these two variables. The results of hypothesis testing however are not obvious. For example, correlation between local richness and species pool size can be caused by their dependence on the third variable--capacity of environment. It seems that in case of decreasing area occupied by local community the environmental conditions become more important than species pool size. If that is true, the influence of species pool on local species richness is not significant. However one can estimate the degree of unsaturation of species pool on the basis of relationships between the number of species in small locations occupied by similar local communities and their species pool. We think, that study of local and regional species richness should shift the emphasis--from the analysis of species pool influence on local community richness to the estimation of historical, ecological and anthropogenic factors in variation of species pool size. The local species richness should be considered rather as a tool (allowing to compare the species capacity of biological communities), than as an object of such study.