Massive die-offs reported from Australia and India; southwestern U.S. could be hit in the future
By Summit Voice
SUMMIT COUNTY — Heat waves, possibly intensified by global warming trends, could have huge impacts on bird populations, researchers from the University of New Mexico and the University of South Africa announced last week after studying how increasing global temperatures will impact desert bird populations.
Based on the most commonly accepted scenarios for global warming, the average temperature of the planet will rise between 3.5 and 6.5 degrees Fahrenheit during the next hundred years. This may not seem like much to the average person, but these changes could be disastrous for birds and some mammals because of the increased intensity and frequency of heat waves that will result.
During heat waves, increases in air temperatures of as little as two degrees can double the rate of water loss in small birds and impact their survival time. For small birds, survival times may be reduced by as much as 30-40 percent. For all species of birds under 100 grams (the average American Robin weighs about 77 grams) the increase rate in water loss may decrease their survival time by 25 percent.
Although North America hasn’t yet experienced large-scale bird die-offs, such events have been reported from Australia and India. A similar phenomenon has also been noted with fruit bats dropping from the trees during heat waves in Eastern Australia.
“We don’t have good research on these die-offs,” said Blair Wolf, an associate professor of biology at the University of New Mexico. Together with Andrew McKechnie from the University of Pretoria, South Africa Wolf discussed their findings last week at a global warming conference in Westminster.
“No researchers have actually been present during these incidents and no one has actually done the autopsies, so we don’t even know the exact cause of death of these animals; whether it was dehydration or heat-stroke,” Wolf said.
Local knowledge suggests that die-offs can result in the loss of some species from regions for decades and the long-term effects these die-offs have on other groups of plants and animals are as yet unknown.
Wolf said the American Southwest, filled with a large and diverse bird populations and pre-existing heat, could be the first part of the U.S. to experience similar events.
“These incidents illustrate a need for more basic research on how animals function so that predictions can be made and measures can be taken to preserve our biodiversity,” says Wolf.