CORVALLIS, Ore. - Two new studies suggest that ecosystems can be far more vulnerable than often assumed, subject to disruption by fairly small environmental changes or loss of "minor" species not traditionally thought to be important - and in considerable peril from global change.

Both research efforts were done by ecologists from the Department of Zoology at Oregon State University on the marine rocky intertidal shores of the Oregon coast.

One report, to be published Friday in the journal Science, indicates that some ecological impacts of global warming might be abrupt, significant, and generally underestimated - not just a slow shift of species from one region to another. It found that small changes in ocean temperature could affect important or "keystone" species and trigger large, relatively rapid changes in intertidal ecology.

The other report, published today in the journal Nature, suggests that measures to protect ecosystem health and function must consider not only those keystone species known to play dominant roles, but also many less prominent species which, at various times, may actually be highly important.

Together, the research findings imply that the function of complex ecosystems is both difficult to predict and sometimes surprisingly easy to disrupt, especially with the advent of human-related stresses such as over-exploitation, increased species extinctions and climate change.

"As we consider the impacts of global warming, many people assume the effects will be gradual, a shift to new regions by various plant and animal species," said Eric Sanford, an OSU ecologist. "But this study shows that if you have an important species which is highly sensitive to temperature, then the effects of small temperature changes on an ecosystem can be amplified by species interactions."

In his research, Sanford looked at the ochre sea star, which feeds on the California mussel and in the P
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Contact: Eric Sanford
sanforde@ava.bcc.orst.edu
541-737-5359
Oregon State University
25-Mar-1999