Thursday, January 23, 1997
Managing For Many Species Crucial To Head-Off Threats Of Extinction Says Director Of National Biological Service
**EDITORS NOTE: EMBARGOED UNTIL 4 P.M., THURSDAY JAN. 23, 1997**
ATHENS, Ga. -- Managing for a single endangered species may put other species at risk and is no longer a reasonable policy option, according to a paper published today in the journal Science.
Knowing which species are most vulnerable and which human activities threaten them is crucial to saving species, according to an article by U.S. Secretary of the Interior Bruce Babbitt and Dr. Ron Pulliam, director of the National Biological Service and science advisor to Secretary Babbitt.
"The idea is to protect species that are already endangered, but to take steps to help prevent future endangerment and therefore allow more local control over conservation issues," said Pulliam, who is on leave from his post as professor of ecology at the University of Georgia. He will return to work at UGA following the end of his term at the NBS in mid-February.
Pulliam said that a crucial element in preventing further species endangerment is to have a good idea of which species are currently neither endangered nor threatened but may be in the future. That has been one of the goals of the National Biological Service under Pulliam, who served as its first director.
Until recently there has been no systematic study of such cases, and Pulliam said much evidence is anecdotal rather than based on solid science. Still, a considerable amount of evidence has been uncovered in the past few years in identifying species that could be threatened. He said one federal program has been using data gathered by the U.S. Fish and Wildlife Service to determine candidates for the list of endangered species.
"We really must learn about these species early enough so that we can develop conservation plans for them," said Pulliam.
The article by Pulliam and Babbitt is a companion piece to an article by Dr. Andy Dobson and colleagues from Princeton University in the same issue of Science. Dobson shows that "hot spots" for endangered species tend to occur where the ranges of many endemic species overlap with intensive urbanization and agriculture." Pulliam and Babbitt note that endemic species, by definition, have a restricted geographic distribution. Dobson and his colleagues say that endemic species are prone to extinction, and especially, say Pulliam and Babbitt, "in the face of rapid habitat loss or degradation."
"Hawaii, Florida and California have both the most endemic species and the most endangered species," write Pulliam and Babbitt. "The high number of Hawaiian endemics is a result of the small size of the islands and their extreme isolation." Because coastal Florida was under water much of the past 10 million years, higher ridges of land were isolated and excellent for the development of species.
California has unusual habitat features and a Mediterranean climate that has led to a development of high numbers of endemic species.
Pulliam and Babbitt note that the introduction of exotic species has led to species declines, particularly in areas such as Hawaii. The problem is serious in the continental U.S. as well. Problems have been caused by such exotic species as the sea lamprey, grass carp, Asian clam and zebra mussel. These, along with river dredging, impoundments and other river developments may be responsible for the "endangerment of hundreds of fish, mollusks and other aquatic species."
Not all the news is bad, the authors say. Some species have recovered and others are doing so. The bald eagle, for instance, has recently been downgraded in status from endangered to threatened.
What is needed most, they say, is a "sounder scientific basis for ecosystem-based habitat conservation plans."