- Climate change will rearrange wildlife say researchers.
Computer models of shifts in animals' homelands show that many areas may
have radically different inhabitants within 50 years.
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- The results could help conservationists cope with global
warming. But they also reveal that no one policy will protect every species
- to assume that everything will move either north or uphill, for example,
is simplistic, says ecologist Townsend Peterson of the University of Kansas1.
"Each species is its own man, so to speak."
-
- Peterson and his colleagues looked at Mexico, whose wildlife
is exceptionally well studied. They used specimens in museums around the
world to plot the geographical ranges of 1,870 mammals, birds and butterflies.
-
- They combined this with information on the environment
of each location, matching each species to its preferred climate.
-
- Powerful computer simulations calculated how each location
might change over the next half-century, and so where each species would
be able to survive. The researchers compared two climate-change scenarios,
and varied their assumptions about the animals' mobility.
-
- The most realistic models left most animals with smaller
ranges in 2055 than now. Up to 2.4% of species lost 90% or more of their
range, placing them in grave danger of extinction. But there were no overarching
trends in what moved where.
-
- The effects of climate change were weakest in the mountains,
and strongest in flatlands such as the Chihuahuan desert, where as many
as half of all species may change.
-
- This reshuffling of ecosystems may be the most important
consequence of climate change. "We're going to see new hosts and parasites,
and new predators and prey coming together," says Peterson. "There'll
be a lot of novel biological situations."
-
- Conservation priorities may need to change, says evolutionary
biologist Craig Moritz of the University of California, Berkeley.
-
- "The current trend is to create geographically dispersed
protected areas," he says. Instead, networks of reserves should let
species migrate and keep track of the climate. There is also a risk that
reserves set up today will lose the species and environments they were
meant to protect.
-
- The changes in climate and biology are comparable, although
much more rapid, to those seen at the end of the last ice age, comments
ecologist Eric Post, of Pennsylvania State University.
-
- Peterson's team has "seen big changes using a fairly
conservative approach", Post concludes. "This is probably the
minimum."
-
-
- References Peterson, A.T. et al. Future projections for
Mexican faunas under global climate change scenarios. Nature, 416, 626
- 629, (2002).
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- © Nature News Service / Macmillan Magazines Ltd
2002
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