Research shows life in coral reef far richer than expected

Ronald H. Karlson

4:52 p.m., July 14, 2004--A scientific team from the University of Delaware and James Cook University in Townsville, Australia, has spent the last seven years collecting and analyzing data from coral reefs in one of the most remote and biologically diverse regions of the world. The results document rich coral life far beyond expectations.

“Previously published work suggested there was a limit to local species richness,” Ronald H. Karlson, UD professor of biological sciences, said. “Our data clearly show that there is no such limit. At our richest sites, there were four times as many species in local communities than we expected.”

Karlson, who made a presentation at the International Coral Reef Symposium held June 28-July 2 in Okinawa, Japan, said the study was undertaken to characterize local species richness of corals in reef flat, crest, and slope environments.

The researchers also wanted to characterize regional richness, something that had not been done before, and to consider the relationship between local and regional richness across a vast expanse of the Pacific from French Polynesia in the east to Indonesia in the west.

Developing a more accurate understanding of coral reef ecosystems is of vital importance, Karlson said, because the world’s reefs are “under assault” by threats from human impacts: global warming, forestry practices that cause sedimentation, pollution and overfishing.

Their findings show that the preservation of coral reef ecosystems is going to require a regional perspective because the problems are beyond local solutions, Karlson said.

A portion of the research, that concerning regional enrichment of coral communities along an oceanic biodiversity gradient, is featured in a letter in the June 24 issue of the scientific journal Nature, which has as its cover story “Coral Reefs in Crisis.” In it, the research team notes that the study was of “unprecedented geographical scope,” with samples taken along a transect covering about one-quarter of the circumference of the Earth.

They wrote, “Local coral assemblages are embedded in regions with different histories, geographies and human influences, and they are influenced jointly by both local and regional factorsŠ. Recent assessments of the status of coral reefs verify that they are globally threatened, and efforts to manage them will require international cooperation. As most conservation efforts by policy makers and managers begin with attempts to preserve local coral reefs, it is imperative that we learn how coral communities function at these local, ecologically important scales while maintaining a regional perspective.”

Karlson said the project has been “something you dream of” as a researcher, one that has taken the team to a variety of tropical locales. While working at a remote diving camp in Indonesia’s Irian Jaya, they learned that the famous English naturalist Alfred Russel Wallace had stayed in a nearby village while conducting research in the 19th century. Wallace developed the dividing line between two major zoogeographic regions, the Oriental and the Australian.

The project has received funding from the Australian Research Council, the National Science Foundation and the National Geographic Society.

Article by Neil Thomas
Photo by Kathy F. Atkinson

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