PARENT SESSION
Oral Session #80: Plant Ecology .
Presiding: G. Platenkamp
Thursday, August 8. 9:00 AM to 11:30 AM. Grand Ballroom West, Radisson.

Species diversity on terrestrial "islands": Do successional landscapes follow the predictions of island biogeography theory?

Cook, William^*,1, Holt, Robert², ¹ University of Kansas, Lawrence, Kansas² University of Florida, Gainesville, Florida

ABSTRACT- The conceptual framework for study of landscape variation in plant succession is derived from island biogeography theory, as succession can be seen as the summation of many colonization and local extinction events by many different species. Species moving into successional patches set into a sharply contrasting matrix should most readily colonize habitat patches near to the source of colonists, and also be more likely to colonize and persist on large patches. Thus, if the landscape is initially uniform, species richness is expected over time to become greater on large patches and those near to the source of colonists than on patches that are small and far away, and richness should increase over the first stages of succession. We here report results from the first 18 years of succession at a site on the prairie-forest ecotone of eastern Kansas. Species richness overall increased steadily over time, except for two sharp peaks in years with unusual numbers of weedy species. Patch size effects were initially variable, but large patches developed consistently greater species richness than small patches during the latter third of the study. Near patches quickly developed greater species richness than far patches, and maintained that status for the majority of the study. While some predicted landscape effects appeared only after a time lag, the species diversity patterns of our successional "islands" generally followed the expectations of island biogeography theory.

KEY WORDS: island biogeography theory, plant succession, habitat fragmentation, species richness