June 17, 2010
PHOTO: Shown are the fossilized remains of the Montastraea annularis species complex found in Barbados at the geographic edge of Caribbean reef coral distributions -- an example of relatively greater coral evolution taking place at the outlying edges of Caribbean coral species ranges. Photo by Ann Budd.
UI researcher finds Caribbean coral protection efforts miss the mark
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.
Budd and Pandolfi focus on understanding the biodiversity of reef-building corals -- organisms which are highly diverse and seriously threatened. They show that 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.
They conclude that 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.
“Current conservation priorities are calculated on the basis of species richness, endemism (geographical uniqueness), and threats," said Budd. "However, areas ranked highly for these factors may not represent regions of maximal evolutionary potential.
"Thus, conservation efforts in corals should focus not only on the centers of diversity but also peripheral areas of species ranges and population connectivity.”
Budd and Pandolfi conducted their study by analyzing 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. 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," she said.
"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," she said.
Budd noted that the article builds upon previous research on corals showing that biodiversity hotspots do not correspond with centers of endemism. However, her 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 title of the article is “Evolutionary novelty is concentrated at the edge of coral species distributions.”
The research was funded by grants from the National Science Foundation (NSF).
STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500
CONTACTS: Ann Budd, Department of Geoscience, 319-335-1817, firstname.lastname@example.org; Gary Galluzzo, writer, 319-384-0009, email@example.com