Western Hemisphere Monkeys Likely to Perish in Climate Squeeze
SEATTLE, Washington, May 15, 2012 (ENS) - As the climate heats up across the Western Hemisphere, many animals will not be able to move fast enough to find safe habitats cool enough for their survival.
Safe havens may be out of reach for nine percent of the Western Hemisphere's mammals, and as many as 40 percent in some regions, finds new research from the University of Washington.
Hardest hit will be primates, including tamarins, spider monkeys, marmosets and howler monkeys, some of which are already listed as threatened or endangered.
Nearly all the hemisphere's primates will experience severe reductions in their ranges, on average about 75 percent, said Carrie Schloss, University of Washington research analyst in environmental and forest sciences.
Schloss is lead author of the paper out online today in the journal "Proceedings of the National Academy of Sciences," the first study to consider whether mammals will actually be able to move to new habitats before climate change catches up to them.
"Because climate change will likely outpace the response capacity of many mammals, mammalian vulnerability to climate change may be more extensive than previously anticipated," the scientists write.
"We underestimate the vulnerability of mammals to climate change when we look at projections of areas with suitable climate but we don't also include the ability of mammals to move, or disperse, to the new areas," Schloss said.
Western Hemisphere primates take several years to mature sexually, which is one reason they appear to be especially vulnerable to climate change, Schloss said.
Another reason is that the territory with suitable climate is expected to shrink. Animals in the tropics must go farther to find suitable habitat than those in mountainous regions that can more quickly move up to a cooler climate.
"Indeed, more than half of the species scientists have in the past projected could expand their ranges in the face of climate change will, instead, see their ranges contract because the animals won't be able to expand into new areas fast enough," said co-author Josh Lawler, UW associate professor of environmental and forest sciences.
Winners in the climate change race are likely to come from three groups of mammal species - carnivores such as coyotes and wolves, ungulates like deer and caribou, and xenarthrans, the group that includes armadillos and anteaters, the scientists conclude.
The analysis looked at 493 mammals in the Western Hemisphere ranging from a moose that weighs nearly two tons to a shrew that weighs just a few ounces. Only climate change was considered and not other factors that cause animals to disperse, such as competition from other species.
To determine how fast climate change might occur, the UW researchers integrated 10 global climate models and a mid-high greenhouse gas emission scenario developed by the UN Intergovernmental Panel on Climate Change.
To calculate how quickly species must move to new ranges to survive climate change, they used previous work by Lawler that shows the areas with climates suitable to each species.
The scientists found that 87 percent of mammal species are expected to experience reductions in range size and 20 percent of these range reductions will likely be due to limited dispersal abilities as opposed to reductions in the area of suitable climate.
"Our figures are a fairly conservative - even optimistic - view of what could happen because our approach assumes that animals always go in the direction needed to avoid climate change and at the maximum rate possible for them," Lawler said.
The researchers also were conservative, he said, in taking into account human obstacles such as cities and crop lands that animals encounter as they try to escape the heat.
They used a previously developed formula of "average human influence" that pinpoints regions where animals are likely to face intense human development.
"I think it's important to point out that in the past when climates have changed - between glacial and interglacial periods when species ranges contracted and expanded - the landscape wasn't covered with agricultural fields, four-lane highways and parking lots, so species could move much more freely across the landscape," Lawler said.
The study does not account for transit time if animals must go completely around human-dominated landscapes. For these animals, conservation corridors will serve as life-savers that may contribute to the survival of entire species.
"Conservation planners could help some species keep pace with climate change by focusing on connectivity - on linking together areas that could serve as pathways to new territories, particularly where animals will encounter human-land development," Schloss said.
"For species unable to keep pace," she said, "reducing non-climate-related stressors could help make populations more resilient, but ultimately reducing emissions, and therefore reducing the pace of climate change, may be the only certain method to make sure species are able to keep pace with climate change."
Endangered golden lion tamarin, native to the state of Rio de Janeiro, Brazil (Photo by Stephen Davis)
Wild buck, North Park, Chicago, Illinois, 2006 (Photo by Mary Anne Enriquez)
Armadillo at Moses Creek Conservation area St. Augustine Shores, Florida (Photo by Rafal Lisinski)