Species Diversity and Perturbations

Résumé du livre

The typical decline in community species diversity following an environmental perturbation is often explained by appeal to interspecific biological interactions which effect a dynamic functional reorganization of the community. A neutral (non-interactive) model is developed to calculate the expected effect of a perturbation on the species diversity of a community in which component species are mutually independent. In this non-interactive model, (1) the probability of a drop in diversity is shown to be great and (2) the expected species diversity is shown to decline as an immediate result of mortality, even though all species react independently and with equal probabilistic susceptibility to the perturbation. Consequently, in studies of the effects of any perturbation one cannot view the decline in diversity due to immediate mortality as evidence of an interactive reorganization of community structure.