Brussels, 23 Oct 2002
Scientists studying the effects that different types of animal species have on plant communities have produced unexpected results, which may suggest that the ecosystem is less susceptible to change than previously thought.
Researchers from the UK, Germany and Finland are conducting a study on the effects of global change on soil biodiversity at the Ecotron facility in England. They found that although plant communities are dramatically altered according to the size and type of animal life present among their roots, key ecosystem measurements, such as overall agricultural yield or the amount of carbon stored, are unaffected.
Lead author of the experiment, Dr Mark Bradford, explains: 'The study suggests that if you mess about with soil communities, say from the impacts of global change, you may alter the way that systems work but this has no major consequences in terms of the system's outputs, for example the amount of grass produced.'
The study was conducted using 16 walk-in chambers with computer-controlled climates, each containing one square metre of Scottish grassland. For nine months, conditions were set to mimic summer temperatures, akin to a continuous growing season, and small, medium and large soil fauna, ranging from bacteria to beetles, were introduced.
Based on previous experiments, the scientists had expected that those communities where larger fauna were introduced would produce higher yields and store more carbon. Instead they found little variation in such measurements, despite vastly differing animal species composition. One possible explanation for these results is that the positive and negative effects of the fauna in the soil cancel each other out, causing no net ecosystem change.
However, Dr Bradford did warn that more research needed to be carried out before the full impact of changes in animal species on soil communities was known. 'Further studies may reveal that these changes have an impact over a longer time scale, and our current investigations suggest that this could well be the case,' he said.
For further information, please consult the following web address: http://www.cpb.bio.ic.ac.uk/ecotron/ecot ron.html