Evolutionary Novelty Is Concentrated at the Edge of Coral Species Distributions

Abstract

Don't Forget the Edges Reef-building corals are highly diverse, and many are threatened with extinction. In order to make predictions about coral survival, Budd and Pandolfi (p. 1558 ) examined morphological changes occurring over the evolutionary history of Caribbean corals. Long-term evolutionary patterns, including hybridization between species and diversification into new species (so-called lineage fusion and splitting) differed depending on the geographical location within the colony, with higher change occurring at a species' geographic margin relative to those in central locations. Thus, edge zones, which often experience limited gene flow, are responsible for the predominance of evolutionary innovation. If conservation strategies are biased toward biodiversity hotspots, which represent centers of high species richness, they may miss important sources of evolutionary novelty during global change.