Community monopolization: local adaptation enhances priority effects in an evolving metacommunity

摘要

The diversity and composition of biological communities might often depend on colonization historybecause early colonists can exclude future colonists through a priority effect. These priority effects,which have been observed across a wide variety of ecosystems, often arise because early colonists havesufficient time to use available resources efficiently and subsequently withhold them from invaders.Here, we explore the extent to which rapid local adaptive evolution contributes to the pervasiveness ofthese priority effects. Using an individual-based simulation, we show that early colonization allows thedescendants of colonists to adapt to novel conditions and reduce the establishment success of an initiallyecologically equivalent competing species. Our model predicts that slight differences in colonizationtiming and adaptive capacity between species can substantially alter the dynamics and diversity of com-munities. We also show that priority effects and gene flow can generate a novel mechanism for theexpansion and retraction of species distributions in a metacommunity. Our results suggest that local adap-tation combined with stochastic colonization events can obscure direct relationships between speciesdistributions and environmental gradients. Given the increasing recognition of rapid, microgeographicevolution in natural populations, we expect that evolutionary priority effects could affect the structureand dynamics of many natural metacommunities.