University of Maryland Research Shows

COLLEGE PARK, MD - Are you feeling confused about the weather, global warming or La Nina? You're not alone. Climate changes have led animals to exit hibernation and birds to flock north while there's several feet of snow on the ground. A University of Maryland study reported in the Feb.15 issue of the http://www.pnas.org/Proceedings of the National Academy of Sciences indicates that such animal and bird confusion has become common place over the last 25 years as a result of global warming.

The study is the first to suggest and document that species that spend part of the year at low altitude and part at high altitude may be encountering problems because of differences in the effects of global climate change at different altitudes. It also provides the first reported evidence of the effects of climate change on hibernation and confirms earlier findings about bird migration. The findings show:

• Marmots (close relatives of woodchucks), which usually hibernate for eight months during the long winter at high altitudes, are emerging from hibernation earlier (38 days earlier over the past 23 years) and may risk starvation as they wait longer for snow to melt before they can feed.

• American Robins that migrate from low altitude wintering grounds to high-altitude summer breeding grounds in Colorado are arriving earlier in the spring (14 days earlier over the past 19 years), and must also wait longer for snow to melt before they can feed and nest.

"There is growing evidence to support that climate change is resulting in earlier and longer growing seasons at low altitudes, earlier migrations by some bird species, and earlier reproduction in both plants and animals," said David Inouye, lead investigator and director of Maryland's graduate program in sustainable development and conservation biology. Inouye found a striking contrast at altitudes greater than 9,500 feet in the Colorado Rocky Mountains where spring has not been arriving any earlier, and the growing season started later over the past 25 years.

"In the past, marmots' ability to detect warmer temperatures was advantageous because it signaled an early spring, which resulted in a longer growing season and a longer growing season enhances animal survival and production," said Kenneth Armitage, co-author and University of Kansas distinguished professor emeritus of systematics and ecology.

Armitage continued, "Now, it appears the marmots response to temperature may have a negative effect, reducing chances for survival and reproduction."

According to Inouye this kind of long-term study has high value, particularly when only one data point can be collected each year, because it shows the slow rate of significant changes that are occurring over recent decades.

"A relatively simple observation, such as the first sighting of a robin each spring, can be made almost by anyone, and if continued for a long enough time, can provide important insights into global change,"said Inouye.

The research will continue with investigations of the low to high altitude migration of hummingbirds that migrate from Mexico to Colorado; other hibernating mammals, such as chipmunks and ground squirrels; and the effects of climate e on wildflowers. Funding has been provided by the National Science Foundation and Earthwatch Institute.

Editors: Digital images of the Rocky Mountain Biological Laboratory, marmots, and a robin on snow are available at the following address: www.inform.umd.edu/EdRes/Colleges/LFSC/FacultyStaff/dinouye/pictures.html

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