Plant coexistence without asymmetry in competitor–colonizer abilities or spatial heterogeneity in resource distribution

Abstract

AbstractSpecies coexistence is a central issue in plant community ecology. Among processes potentially promoting coexistence is the competition–colonization trade‐off: the idea that inferior competitors can coexist with superior competitors if they are better colonizers. The competition–colonization trade‐off usually assumes superior competitors have an impact on inferior competitors, but not vice versa. In the absence of spatial heterogeneity in resource distribution, this absolute asymmetry often is considered a necessary condition for coexistence. We used a spatially explicit, individual‐based model to demonstrate that coexistence is possible without strict asymmetry in competitor–colonizer abilities in a habitat in which distribution of resources is spatially homogeneous through time. Our results (1) indicated a strong tendency for spatial clustering of similar plant types (better competitor or better colonizer) due primarily to local intraspecific competition, (2) identified characteristics of competition–colonization trade‐offs that permit long‐term coexistence vs. those that lead to relatively rapid extinction of one plant type, and (3) suggested range of trade‐offs permitting coexistence decrease as a power function of length of competition time.