PARENT SESSION
Organized Oral Session 39: Consequences of dispersal and colonization: What happens when communities are opened?
Organizer(s): CG Guthrie and DA Yee
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 516 C, Level 5, Palais des congrès de Montréal

Consequences of varying regional heterogeneity in source-sink metacommunities.

Mouquet, Nicolas^*,1, Miller, Thomas², Daufresne, Tanguy³, Kneitel, Jamie⁴, ¹ ISEM - CNRS - Université de Montpellier, Montpellier, France² Department of Biological Science, Florida State University, Tallahassee, USA³ Department of Ecology and Evolutionary Biology, Princeton University, Princeton, USA⁴ Department of Biological Sciences, California State University, Sacramento, USA

ABSTRACT- We demonstrate the effects of both dispersal and regional heterogeneity on local and regional diversity in source-sink metacommunities. Although the influence of dispersal on metacommunities has received great emphasis, few studies have addressed the consequences of varying heterogeneity. We therefore built a mechanistic model of resource competition in a metacommunity based on a well-known Tilman (1982) model of competition in which species interact through consumption of two shared limiting resources. We defined regional heterogeneity as the differences in resource supply rates (or resource availability) among local communities. As suggested by previous work, the highest diversity was at intermediate levels of dispersal among local communities, but our model shows how the effects of dispersal depend on the amount of heterogeneity among local communities and vice versa. Regional and local species richness were highest when heterogeneity was intermediate. Empirical studies that have not found evidence for source-sink or mass effects at the community level may have examined communities with limited ranges of dispersal and regional heterogeneity.

Key words: Metacommunity, Dispersal, Heterogeneity, Coexistence