Ecologists have tackled this challenge for decades, erecting various hypotheses and debating their plausibility. In an important paper featured in the current issue of the Proceedings of the National Academy of Sciences (PNAS), an international team of ecologists describes a fundamental theory that unites several patterns that previously had been viewed as unrelated.

The theory simplifies various aspects of ecological complexity with an elegant model that unites all of them. It provides a theory for quantifying biodiversity.

George Sugihara of Scripps Institution of Oceanography, UCSD, (USA) led a team that included Lord Robert May and Sir Richard Southwood of Oxford University (United Kingdom), Louis-Flix Bersier of the University of Neuchtel (Switzerland), and Stuart Pimm of Duke University (USA).

The first pattern they considered involves the relationships between various roles played by the species present in an area (their niches). These relationships are often described in ecology as something akin to an "evolutionary tree" in which the branches reflect how ecological communities are organized--a tree-like organizational chart of ecological roles. One "branch" might be all those bird species that feed on insects, another "branch" those species that feed on seeds.

From these main branches, different small branches might be the various insect-feeding species that glean insects from leaves (such as warblers) or bark (such as nuthatches), or those species that catch insects in flight (such as flycatchers). As niches are specified more exactly, we move to the "terminal twigs" in the analogy: the individual species themselves. One "twig" might be a particular bird that gleans insects from the top leaves of a tree, ano
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Contact: Mario Aguilera
scrippsnews@ucsd.edu
858-534-3624
University of California - San Diego
14-Apr-2003