February 18, 2009

Butterfly Experiment Suggests Wildlife Can Be Relocated Safely

Scientists said on Wednesday that an experiment involving the relocation of butterfly colonies in Britain shows that animals and plants can be moved to new, cooler habitats to help them survive global warming, Reuters reported.

Chris Thomas, professor of Conservation Biology at the University of York, said many species around the world are moving because of climate change.

"But they are often moving slowly, lagging behind shifts in the climate," he said.

He said groups have already begun "assisted colonization," a process that involves moving creatures or plants to a habitat that has become suitable because of global warming, in an effort to help safeguard wildlife and avert extinctions.

Researchers began catching batches of marbled white and small skipper butterflies throughout Northern England in 1999 and 2000. The butterflies were then taken up to 40 miles north of the northernmost edges of their ranges to areas that computer climate models identified as suitable.

Brian Huntley, a professor of environmental changes at the University of Durham who was among the authors of a study published in the journal Conservation Letters, told Reuters that both populations have become established and are thriving.

The study found that certain types of animals and plants were simply unable to search out new habitats. Marbled whites, for instance, like limited habitats such as grass growing on a limestone base.

The study was the first example of assisted colonization linked to climate change, including assessments in advance to discern whether the new arrivals would disrupt the new habitat.

As global warming increases, many species are being driven towards the poles as part of shifts that could disrupt food production.

But experts say assisted colonization can be applied anywhere, from Australian tropical forests to coral reefs. "It could be costly but cheaper than allowing species to dwindle to numbers where they had to be bred in zoos," Thomas said.

So-called "green corridors" are being developed so that wildlife can migrate if their habitats get too warm and cities, roads or farmland are in the way. Assisted colonization could be a backup, mainly for rare species.

Huntley said some plants with wind-borne seeds such as grasses or dandelions would have few problems. But other plants rely, for instance, on ants to disperse seeds.

"They don't get moved very far -- meters or tens of meters at most," he said. "They will experience considerable difficulty as the climate warms."

Some environmentalists feel that moving butterflies could disrupt ecosystems by introducing "alien" species. But Huntley said such cases are unlikely.

"Within the European continent animals have moved around a lot in the past as conditions change," he said. "Introducing a creature from another continent may be more of a threat."


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