U. IOWA (US)—Conservation efforts aimed at protecting endangered Caribbean corals may be overlooking regions where corals are best equipped to evolve in response to global warming and other climatic challenges.
“Current conservation priorities are calculated on the basis of species richness, endemism (geographical uniqueness), and threats,” says Ann Budd, professor of geoscience at the University of Iowa.
“However, areas ranked highly for these factors may not represent regions of maximal evolutionary potential.”
The predominance of evolutionary innovation occurs at the outlying edges of Caribbean coral species ranges, where gene flow is limited, as opposed to the well-connected central part of the Caribbean, Budd says.
She and John Pandolfi of the University of Queensland, Australia, focus on understanding the biodiversity of reef-building corals—organisms which are highly diverse and seriously threatened.
If conservation strategies protect only the centers of high species richness, then they will miss important sources of evolutionary novelty during periods of global change, they conclude.
Details are published in the June 18 issue of the journal Science.
“Conservation efforts in corals should focus not only on the centers of diversity but also peripheral areas of species ranges and population connectivity,” Budd says.
Budd and Pandolfi analyzed the relationship between geography and evolutionary innovation in a dominant complex of Caribbean reef corals where morphological and genetic data concur on species differences.
Based on geometric morphometrics of Pleistocene corals and genetically characterized modern colonies, they found that morphological disparity varies from the center to the edge of the Caribbean, and that lineages are static at well-connected central locations but split or fuse in edge zones where gene flow is limited.
“The results show that edge zones are critical to speciation and the generation of biodiversity,” Budd says. “These results conform with studies of the molecular biogeography of sea urchins and butterfly fishes and other marine invertebrates and are relevant for understanding the evolutionary ecology of the sea under projected global climate change.
“We argue for a conservation strategy that not only takes biodiversity hotspots into account, but also focuses on evolutionary processes and the preservation of peripheral areas and connectivity among populations.”
The Science article builds on previous research on corals showing that biodiversity hotspots do not correspond with centers of endemism. However, the work differs from earlier research in that it focuses on evolutionary processes documented in the fossil record from significantly longer time periods that encompass global environmental change.
The research was funded by grants from the National Science Foundation (NSF).
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