The Issues
Biological diversity is declining in many ecosystems. Beyond the ethical issues this raises and the potential economic loss this represents, some scientists are arguing that there could be negative consequences for the functioning of ecosystems and the associated goods and services they provide. Does the functioning of ecosystems -such as cycling of nutrients, carbon and water - depend on the number and kind of species that are present? Eight hundred of the world?s leading environmental scientists attending a meeting sponsored by GCTE/LUCC in Barcelona, Spain, on March 14-18, 1998, will examine the consequences of the loss of biodiversity on ecosystem functions.

The Science

• Results from new experiments specifically designed to address the effect of biodiversity on ecosystem functioning suggest that the answer to these questions is a qualified "yes". Dr. Shahid Naeem, from the University of Minnesota, USA, will review the experimental evidence available on the ecosystem consequences of a biodiversity loss, and address future reseach needs. Dr. J. Lawton, from the NERC Center for Population Biology, Ascot, UK, will present the first results from a European Community project, BIODEPTH, that features the same field manipulation of plant biodiversity across two gradients in eight countries across Europe. These results show that a reduction in plant species number has a negative effect on many ecosystem functions at some of their research sites. Clear relationships between diversity and ecosystem functioning are, however not found at all of the BIODEPTH sites, and several other recent studies will show that the kind of species can be a more important determinant of ecosystem function than species number.

• Experimental evidence also suggests that diversity provides an in
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