PARENT SESSION
Oral Session #11: Biodiversity and Ecosystem Function. Presiding: A. Downing.
Monday, August 6, 2001. 1:00 PM to 4:45 PM. Madison Ballroom C.
Local division rules for taxonomic diversity and biomass across tree dominated communities.
HASKELL, JOHN1, ENQUIST, BRIAN2, TIFFNEY, BRUCE3, 1 2 3
ABSTRACT- We use two forest datasets to identify the relative importance and generality of the ecological, evolutionary, and historical processes shaping the taxonomic structure and partitioning of biomass within local plant communities across the globe. We find consistent scaling relationships of species within genera and species within families from 227 contemporary tree communities from around the globe, and a similar relationship in forest communities from 4.5 to 45 Ma. Both exponents for local taxonomic structure are invariant with respect to biogeographic region, continent, geologic time, and total biomass. Furthermore, Monte Carlo simulations show that the results differ from the predictions of a number of randomization models indicating a significant role for local processes in determining systematic structure. Contrary to prior speculation, total community biomass is invariant with richness; the division of biomass among species, genera and families within ecological communities increases with diversity. These observations suggest that consistent features govern the local structuring of biological diversity across time and space.
KEY WORDS: biodiversity, macroecology, taxonomic structure, niche partitioning