Shared preference niche organization: Implications for community organization and diversity.

Abstract

Patterns of resource partitioning have been widely described, but the causes of these patterns are incompletely understood. To explore how the patterns are formed, I did a quantitative literature survey. In Chapter One, I (1) discuss current misconceptions in the literature, (2) document and describe five ways in which resource partitioning can occur, and (3) establish guidelines for predicting the two most common ways in which patterns of partitioning are formed. In Chapter One, the most common way in which patterns of resource partitioning were formed was through shared preference niche organization. Centrifugal organization extends shared preference organization from one resource gradient to multiple gradients. In Chapter Two, experimental evidence supporting the validity of the centrifugal organization model is reviewed and predictions of the model are presented. The centrifugal organization model predicts how the size of species pools changes along a resource gradient. Two other models from the literature make contradictory predictions. The three models were tested in Chapter Three using biomass/species composition data from 33 eastern North American wetlands. The resulting 640 quadrats produced a pattern of pool size consistent with a previously untested model, the species pool model. This model states that the pattern of pool size is the same as the pattern of alpha diversity along a biomass gradient. This suggests that (1) the more easily measured alpha diversity values can be used to predict where large species pools occur and (2) ecological processes that are associated with changes in alpha diversity may also influence the species pool.