researchers have claimed that giant heat waves caused by global
warming will kill
off desert bird communities over the next one hundred years,
and even believe that mass amounts of warming-related deaths have
already begun to occur.
Blair Wolf, an associate professor of biology at the University
of New Mexico, and Andrew McKechnie, from the University
of Pretoria in South Africa, have discovered that
temperature increases as low as two degrees Fahrenheit can affect
desert bird populations in a large way.
to these researchers' findings, massive heat waves claim the lives of
several desert bird populations because these birds release body heat
by panting and evaporating water across the skin, and with increasing
temperatures and not enough places for these birds to find shelter
and water, large numbers are dying off due to heat stroke.
and McKechnie found that water is scarce in deserts, obviously, and
birds become inactive when temperatures rise. Since these heat waves
cover large areas, the birds cannot just fly away to avoid the
better understand the future of these bird populations, Wolf and
McKechnie have devised a
model based on the Intergovernmental Panel on Climate
Change's predictions that Earth's temperature will rise 3.5 to 6.5
degrees Fahrenheit over the course of the next one hundred years.
This model estimates survival rates (and supposedly future water
costs for birds in this region, though no actual figures have been
provided) for birds that will live during the 2080's during heat
waves in comparison to those who live in the two hottest desert
regions today: Birdsville, Australia and Yuma, Arizona.
to this model's results, small birds in the 2080's will show
significantly less survival rates than larger birds due to their
increased amount of water loss. As much as 30 to 40 percent of small
desert bird populations could die off in this time period. Their
research also shows that all birds under 100 grams will experience a
decreased survival rate of 25 percent due to an increase in water
researchers are blaming
global warming for the increased temperatures that lead to
heat waves, causing desert bird populations to perspire too much
without enough water to rehydrate. Both Wolf and McKechnie say these
increased temperatures will be overwhelming to birds, and have
already claimed the lives of several desert bird populations in
Western Australia and India.
their research has led them to these conclusions, Wolf and McKechnie
admit that these results are not exactly 100 percent finished or
accurate at this point. So far, their models only apply to birds that
are already in hot, dry desert climates.
don't have good research of these
die-offs," said Wolf. "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.
models allow for making somewhat educated guesses at this point, but
real data on bird tolerances to heat and water stress are lacking."
in Australia and India have reported these die-offs. Wolf and
McKechnie are looking further into these dying populations to see
exactly how many are being killed due to heat, and how this will
affect other plant and animal species.
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," said Wolf.
presented his abstract, "Climate change increases the likelihood
of catastrophic avian mortality events during extreme heat waves and
droughts" at the Global Change and Global Science: Comparative
Physiology in a Changing World conference from
August 4-7 in Colorado.