Changes in Community Structure in Oklahoma Old Field Succession

Species composition and community structure of four fields characteristic of pioneer weed, annual grass, bunch grass, and climax tall grass prairie communities (seral stages of old-field succession in central Oklahoma) were studied over a 5-yr period. Diversity indices and dominance-diversity curves were evaluated as a means of assessing certain ecological processes of the communities. The dominance-diversity curves for early pioneer weed and early annual grass stages revealed a geometric distribution indicative of a niche-preemptive situation. This pattern appears to be a reliable indicator of strong dominance influenced by allelopathic processes.