Neutral model analysis of patterns of marine benthic species diversity

Caswell (1976) proposed a neutral model which calculates a theoretical diversity for a sample of a given number of individuals and species assuming no biological interactions between species. Disagreement with the neutral model predictions have been suggested as a method of detecting disturbance or stress. To test these theoretical considerations, 98 samples of marine benthic organisms were subjected to neutral model analysis. Deviation from the predicted diversity was generally found to be negative less diverse than expected. Where disturbance was known to have occurred, spatial or temporal variations in the degree of dev~ation were in accordance with a hypothesis of diversity based on a combination of the Intermediate Disturbance Hypothesis (Connell 1978) and the General Hypothesis of Diversity (Huston 1979). Artificially created log-normal patterns of species abundance distribution gave a diversity greater than that predicted by the neutral model. But in no cases where the diversity of actual samples exceeded the neutral model prediction were the species abundance distributions log-normal.