Scripps scientists Enric Sala and Michael Graham have produced a new study showing that so-called "intermediate" players in natural communities can often have as much and greater impacts than larger species.

Sala and Graham conducted field experiments and lab studies evaluating interactions between predators and prey (also called "interaction strengths") in a kelp forest community. They found that previous conclusions about interaction strength in natural communities may not be as general as some believe, and that intermediate-sized predators, pound for pound, can represent the ecosystems most significant consumers.

The research is featured as the cover story of the March 19 issue of the Proceedings of the National Academy of Sciences.

"In this paper we have shown that species that were previously overlooked can also be important players," said Sala, deputy director of the new Center for Marine Biodiversity and Conservation at Scripps. "Although these species may be less important at certain time periods because of their size and interaction strength, they may have been important in the past or will be important in the future, as natural and unnatural shifts in density occur."

The research addresses the importance of biological diversity, or "biodiversity," the number and types of species in an environment. Some argue that only a few species, such as the "keystone predators," are most important in ecological communities because they impose the strongest effects. Other species, which are labeled as "redundant" under this idea, are not necessary in a given environment. If these species become extinct, the notion contends, other species will simply move in to take their place and function, and the ecosystem will not suffer significant chang
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Contact: Mario Aguilera
scrippsnews@ucsd.edu
858-534-3624
University of California - San Diego
3-Apr-2002