Habitat stability determines the length of time available for community development (see Chapter 10). E. Wilson (1969) proposed four stages in community development. The noninteractive stage occurs on newly available habitat or immediately following a disturbance, when numbers of species and population sizes are low. As species number rises during the interactive stage, competition and predation influence community structure, with some species disappearing and new species arriving. The assortative stage is characterized by persistence of species that can co-exist and utilize resources most efficiently, facilitating species packing. Finally, the evolutionary stage is characterized by co-evolution that increases the efficiency of overall utilization and species packing. Community development in frequently disturbed habitats cannot progress beyond earlier stages, whereas more stable habitats permit advanced community development and increased species richness. However, the most stable habitats also allow the most adapted species to preempt resources from other species, leading to a decline in species richness (see the following sections). This trend has led to the development of the intermediate disturbance hypothesis, which predicts that species richness peaks at intermediate levels of disturbance (e.g., Connell 1978, Sousa 1985, but see Reice 1985). Community recovery from disturbance is described more fully in Chapter 10.
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