Climate change makes food hunting difficult for animals in seasonal environments

Washington, May 22 : A new research has determined that plant-eating animals in highly seasonal environments, such as the Arctic, are struggling to locate nutritious food as a result of climate change.

The research, led by Eric Post, Penn State Associate Professor of Biology, focused on a reindeer known as Caribou, in West Greenland.

It suggests that not only are the animals in this region arriving at their breeding grounds too late in the season to enjoy the peak availability of food, but they are also suffering from a reduced ability to locate the few high-quality plants.

According to Post, "This combination of time and space constraints is a double-whammy for species in highly seasonal environments."

"Moving through space, across the landscape, is a strategy used by these animals to deal with shifts in the time their forage plants are available. But now, climate change is really putting this strategy to the test," he added.

The team focused their research on caribou in West Greenland as an example of an herbivore species in a seasonal environment.

Closely related to wild reindeer, caribou are dependent on plants for all their energy and nutrients. In the spring, they switch from eating lichens buried beneath the snow to munching the new growth of willows, sedges, and flowering tundra herbs.

As the birth season approaches, they are cued by increasing daylight to migrate into areas where this newly emergent food is plentiful.

Global warming, however, is beginning to undermine this routine.

According to previous research conducted by Post and Mads Forchhammer, a professor at the University of Aarhus in Denmark, the plants, which initiate growth in response to temperature, not in response to daylight hours, reach their peak nutritional value dramatically earlier in response to rising temperatures.

When the animals arrive at their calving grounds now, pregnant females find that the plants on which they depend already have reached their peak productivity and have begun to decline in nutritional value.

This "trophic mismatch" - a predicted consequence of climate change in which the availability of food shifts in response to warming temperatures, is leading to fewer births and to more deaths among caribou calves.

"Variation in the landscape provides an insurance policy for animals, like caribou, that count on being able to climb to the top of the next hill or go across the next valley to find plants that are still newly emergent and highly nutritious," said Post.

"Climate change is reducing the value of that insurance policy," he added.

ANI