Loss of Biodiversity Will Devastate Grasslands
11/5/99
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RELAYED TEXT STARTS HERE:
Title: Loss Of Biodiversity Seen As Devastating To Grasslands
Source: UniSci
Status: Copyright 1999, contact source for permission to reprint
Date: November 5, 1999
Loss of biodiversity in European grasslands will make them less
productive, reducing the amount of energy available to the rest of
the food chain and threatening the overall health of the ecosystem.
This is the inevitable conclusion from one of the world's most
extensive ecological studies, published in Science today.
A team of scientists from eight European countries, led by Professor
John Lawton at the NERC Centre for Population Biology at Imperial
College of Science, Technology and Medicine, say that their
experimental evidence should send a clear message to European
policymakers that preserving and restoring biodiversity is beneficial
to maintaining grassland productivity -- particularly if reductions
in fertilizer and pesticide usage are to be achieved.
The Centre for Population Biology, established in 1989, is funded by
the UK Natural Environment Research Council (NERC), and is hosted by
Imperial College, where it is part of the Department of Biology on
its Silwood Park campus. Its core mission is to conduct basic
research in population biology and related disciplines to understand
and predict the functioning of ecosystems.
Imperial College of Science, Technology and Medicine is the largest
applied science and technology university institution in the UK, with
the largest annual turnover and the largest research income. It is
consistently rated in the top three UK university institutions for
research quality.
At eight European fieldsites, the impact of loss of plant diversity
on primary productivity was simulated by synthesizing grassland
communities with different numbers of plant species.
Results differed in detail at each location but there was an overall
reduction of average aboveground biomass with loss of species. For a
given number of species, communities with fewer functional groups
were less productive.
About half of Europe's farmland is grassland (60 million hectares),
used as grazing pastures, hay meadows and as set-aside land. "Loss of
species is playing a key role in the gradual erosion of the quality
of our environment. In addition to moral and aesthetic reasons to
conserve biodiversity, our results now provide strong scientific
reasons, too," says Dr. Andy Hector of Imperial College, lead author
of the group's report in Science. "These results provide the type of
general ecological principles needed for European conservation and
agricultural policies."
The significance of the fall in productivity that accompanies the
loss of biodiversity is explained by Professor Lawton, who recently
became Chief Executive of the Natural Environment Research Council
(NERC). "Plant communities are solar power stations that produce food
energy for everything else. Ultimately we are all dependent on plant
productivity for our energy," he said.
(NERC is the UK's leading body for research, survey, monitoring and
training in the environmental sciences. It sponsors research and
postgraduate training in universities, and has a network of Centres
and Surveys across the UK.)
The results of the project, named BIODEPTH, clearly show that plant
communities grow better in species-rich teams, and that their
productivity decreases when diversity declines. Harvest yields were
found to increase when there was a range of plants with different
characteristics growing together. Similar patterns occurred in a
broad range of European grasslands, making the findings applicable on
a continental scale.
These findings represent the latest development in the scientific
debate about how the loss of biodiversity affects the way in which
ecosystems function -- recently a major focus of ecological research.
The BIODEPTH evidence provides a vital contribution to the debate by
demonstrating that both numbers of species and the types of plant
play important roles in ecosystems.
To reach these conclusions, the team of 34 scientists assembled
miniature experimental grasslands at eight field sites across Europe,
ranging from Greece to Sweden. The grasslands were varied in plant
diversity to mimic the gradual loss of species seen throughout
Europe.
BIODEPTH field sites are in Bayreuth, Germany; Lisbon, Portugal;
Lupsingen, Switzerland, Lesbos, Greece; Cork, Ireland; Umea, Sweden;
and Sheffield and Ascot in the UK. The project consortium includes a
mathematical modelling group in Paris, France.
The reviewers of the Science paper describe BIODEPTH as pioneering
ecological experiment because it is the most extensive multinational
collaboration to perform the same standardized experiment at a
continental scale. Funded by the European Commission at a cost of 2
million Euros, it signals the beginning of a new era by demonstrating
the power of "big ecology" to underpin environmental policymaking.