Coexistence of Competitors in Spatial Habitats: Theory and Experimental Tests in Grasslands

Wednesday, April 21, 1999 - 11:00am - 12:00pm
Keller 3-180
David Tilman (University of Minnesota, Twin Cities)
Joint work with Clarence Lehman, University of Minnesota, Department of Ecology.

One solution to the paradoxically large number of competing species that coexist in most ecological communities is provided by models that either implicitly or explicitly consider the effects of space on the outcome of competition. Spatial models that assume an interspecific tradeoff between competitive abilities and colonization abilities predict the stable coexistence of unlimited numbers of species. We show that such models are evolutionarily robust and predict several related patterns that occur in natural communities. However, field experiments demonstrate that additional factors are needed to explain the high diversity of coexisting plants in native grassland communities.