Loss of Biodiversity decreases aboveground biomass in European Grasslands
Prepared by Pep Canadell

The debate about the relationship between biodiversity and its relation to ecosystem function has been in full swing over the last few years. The main hypothesis is that lost of plant diversity will be detrimental to ecosystem function affecting negatively key processes such as primary productivity. The implication is that the continuous loss of biodiversity due to human intervention will cause lostsof ecosystem services fundamental for the human enterprise and well being. The hypothesis is highly controversial and has been proven by some research and rejected by others.

To test this hypothesis a major effort has taken place in Europe under the umbrella of BIODEPTH, a European Union funded project with experiments in six countries. The team of scientists used standardized protocols in all experiments with assemblages of grassland species with different plant richness. Some of the results of this project have been recently published in Science (Hector et al. 1999, Science 286: 1123-1126). The results show an overall reduction of aboveground biomass with loss of species supporting the above hypothesis. In addition, they found that for a given amount of species, communities with fewer functional groups were less productive. The experiments also reveal the relative effect of other variables on the overall biomass production: plant richness, location, and species composition explained approximately 18, 28, and 39% of the aboveground productivity.

For further information on BIODEPTH, please refer to "Hector et al. (1999) Plant Diversity and productivity experiments in European grasslands. Science 286: 1123-1126" or check http://forest.bio.ic.ac.uk/cpb/cpb/biodepth/contents.html

GCTE is also developing other initiatives to further test the functional biodiversity hypothesis. A new Network of functional groups removal experiments will be launched in August 2000 in Snowbird, Utah (USA). For further information on this network, please contact Sandra Diaz sdiaz@gtwing.efn.uncor.edu or Terry Chapin fschapin@bonanza.lter.uaf.edu