Thrasher wisely hid in a bush near Kel Well Well in Inyo County, California. The Mojave Desert bird population is experiencing climate change, but new research shows that small mammal populations are stable. Physiological modeling shows that small mammals have lower “cold costs” than birds because they can escape the sun through the holes in the ground, protecting them from the warming effects of climate change / Chelsea Hofmeier

Editor’s note: The following story was made from a press release from the University of California, Berkeley.

Although birds may fly to cooler temperatures during hot weather, research shows that animals buried in places such as Death Valley National Park and the Mojave National Preserve in California are more likely to withstand higher temperatures than their furry counterparts.

The point, researchers say, is that species such as kangeroo rats, white-tailed antelope squirrels, and cactus rats can easily cool down into holes, while birds do not have a naturally cool environment to retreat to.
But now the animal is found to have a variety of strategies to reduce the heat and dry, professor of environmental science, policy and management environments and researcher at the Museum of Vertebrate Zoology campus. “You have to see that difference strongly in a harsh environment like a desert, where life is really close.”

When looking at the Mojave Desert, an area in Southern California and Nevada where Death Valley and Joshua Tree and Mojave National Parks are located, researchers found that with the desert, the desert had an average temperature rise of about 3.6 degrees Fahrenheit. average and precipitation decrease 10-20 percent over the last century.

said study author Lori Hargrove, an ecologist at the Museum Natural History of San Diego. “Climate change may seem small, only to a few degrees, but it does exist, and it has a direct and significant effect on many species, each of which can affect other species, with a cascade effect that has not yet been realized.”

Eric Riddell, assistant professor of ecology, evolution and organism at Iowa State University who co-authored the study, said, “(I) make it clear that animals around the planet are responding to climate change by changing living places and changing times. grow, and we will start with evidence of declining population in certain areas that may be related to warmth.Some estimates now show that one in six species will be threatened with climate change in the next century.Looking at these species, the nature of what they will become critical. ”
Riddell created a computer model to determine how different species of birds can cope with heat in desert settings. He found that these species with the greatest “cooling costs” – for example, the water needed to cool themselves – are species that often suffer during hot weather and dry climates. “The decline in bird species is positively associated with an increase in the need for water for evaporation and increasing body size, especially for species that have animal-based foods,” the researchers said in a previous study.

“Thermal conductivity is generally how fast heat transfer is to the environment,” Riddell said in a recent study. “Large, soft mammals can move heat slowly, while very hairy or short animals, such as squirrels, can quickly transfer heat.”

According to computer models, the average cooling cost is about 3.3 times more for birds than for small mammals. Higher temperatures associated with climate change increase cooling costs by up to 58 percent for birds, but only 17 percent by mammals. This is largely due to the fact that small mammals can retreat to the ground hole during the hottest day, researchers say.

“Many of the differences in cooling costs are related to the so-called microhabitat. Small mammals can enter colder soils, and are exposed to direct sunlight, which warms the bird’s body,” Beissinger said. “Micrographographic variations in these exposures make a huge difference, and these variations need to be considered when we think about climate change for each species.”
To prevent further losses, Beissinger said it is important to identify local refugees in deserts where species will be able to protect themselves as temperatures rise. Reducing the demand for aquifers in these areas could also prevent more dry desert sources, producing more water into the dry landscape.

“This study makes me understand how complicated the forecast of the effects of climate change is,” Riddell said. “It’s not just about the warm landscape and where it’s not warm. It’s a very complex process that involves many aspects of the organism’s biology, including physiology, behavior, evolution – all related. You have to take an integrative approach to understand it.”

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