Conservation implications of the link between biodiversity and ecosystem functioning.

Oecologia v.129, n.4 Dec01

A. Hector¹, , J. Joshi², S. P. Lawler³, E.M. Spehn⁴ and A. Wilby⁵

¹ NERC Centre for Population Biology, Imperial College at Silwood Park, Ascot, Berkshire, SL5 7PY, UK 
² Institut für Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, Zürich 8057,Switzerland 
³ Department of Entomology, University of California at Davis, 1 Shields Avenue, Davis, CA 95616, USA 
⁴ Institute of Botany, University of Basel, Schoenbeinstrasse 6, Basel 4056, Switzerland 
⁵ CABI Bioscience and NERC Centre for Population Biology, Silwood Park, Ascot, Berkshire, SL5 7PY, UK

Abstract
The relationship between biodiversity and individual ecosystem processes is often asymptotic, saturating at relatively low levels, with some species contributing more strongly than others. This has cast doubt on arguments for conservation based on maintenance of the functioning of ecosystems. However, we argue that the link between biodiversity and ecosystem functioning is an important additional argument for conservation for several reasons. (1) Although species differ in importance to ecosystem processes, we do not believe that this argues for preservation of just a few species for two reasons: first, it is nearly impossible to identify all species important to the numerous systems and processes on which humans depend; second, the important species themselves may depend on an unknown number of other species in their communities. (2) Arguments for conservation based on ecosystem functioning are complementary to other utilitarian, ethical and aesthetic justifications. No single reason will convince all people or protect all species, however the combination produces a strong case for conservation of biodiversity. (3) Even if the relationship between biodiversity and ecosystem functioning is asymptotic at local spatial scales and in the short term, effects of biodiversity loss are likely to be important at larger temporal and spatial scales. (4) Initial arguments for the importance of biodiversity for ecosystem functioning were largely based on a precautionary approach (points 1-3). However, we are now moving to a scientific position based on accumulating experimental evidence. The future challenge is the integration of this scientific research with policy.

Keywords. Diversity - Species richness - Ecosystem processes - Precautionary principle - Conservation ecology

E-mail: a.hector01@ic.ac.uk
Phone: +44-20-75942494 
Fax: +44-1344-873173

source: http://link.springer.de/link/service/journals/00442/tocs/t1129004.htm 26nov01