Birds Could Signal Mass Extinction
ScienceDaily (Oct. 12, 2010) — The first detailed measurements of current extinction rates for a specific region have shown that birds are the best group to use to track the losses. The study also reveals Britain may be losing species over ten times faster than records suggest, and the speed of loss is probably increasing: the losses from England alone may exceed one species every two weeks.
The study, by Oxford University researchers, shows that many types of obscure organism in Britain are going extinct at the same rate as the birds -- evidence supporting fears of a global mass extinction. A report of the research is published in an upcoming issue of the journal Biological Conservation as countries prepare to meet in Japan 18-29 October to discuss biodiversity conservation targets.
'Biodiversity loss is arguably much more serious and more permanent than climate change,' said Clive Hambler of Oxford University's Department of Zoology, lead author of the research.
But it's impossible to know if policy targets to reduce the loss are being met without accurate measures of extinction rates. Until now, we had only crude estimates for a very few types of organism. Now we've got evidence that many groups of living things -- lichens, bugs, moths, fish, plants and so on -- are going extinct at a very similar rate to the birds.'
Using Britain's uniquely detailed natural history records, the researchers found that 1-5% of the region's species in many groups were lost since 1800, with higher losses in the Twentieth Century compared to the Nineteenth. Using further data from the USA and across the whole globe, the researchers show that the patterns of extinction in Britain are likely to be typical of those found on land and freshwater elsewhere.
Mr Hambler said: 'The birds are beautiful creatures, but they are also diverse, and many of them are specialised to particular habitats. This makes them sensitive to changes in their environment -- such as loss of mature trees, or the drying out of swampy ground, or coastal development. And what makes them really special for monitoring extinction is that they are also exceptionally easy to study, anywhere in the world -- so we can detect declines in their populations long before we notice losses of the more obscure things like slime moulds or mosses. It's no coincidence they can signal environmental change.'
'The underlying reason for the similarity of extinction rates in birds and the other living things is that habitat loss affects them in the same way. Our work supports the use of birds to indicate extinction rates in Britain, the USA and globally, and they should now be tried in places such as tropical forests where the bulk of other species will never be recorded.'
'The recorded extinctions in any region are just the tip of the iceberg, because there are not enough observers,' said Mr Hambler. For example, in March this year the British government's advisory body, Natural England, reported about 500 species lost from England since 1800. 'The losses reported by Natural England are under 0.5% per century, from England's 55,000 species,' notes Mr Hambler. 'Our research suggests that the actual losses could be over ten times this number, with about one species going extinct in England every fortnight.'
Natural England also reported species losses in England had apparently declined in recent decades, but the Oxford study suggests that this is not the case. Hambler and colleagues found there are about 1000 endangered species on the brink of extinction in Britain -- indeed many of these may already be extinct.
'People tend to be hesitant in declaring extinction, which leads to problems assessing the current rate,' said Mr Hambler. 'Many ancient and important habitats in Britain are threatened today because of human activity and population growth -- whether it's an increase in water use, growing use of wood fuel, or the growth of urban sprawl. Despite conservationists' efforts it's very likely extinction rates will continue to rise in Britain and globally for many years. These losses will impact on human welfare, and I'd say conservation needs a profile and resources even bigger than climate change.'
Alongside studies of birds, the researchers believe that recording rates of habitat loss will provide a good, simple measure of some elements of biodiversity loss.
Mr Hambler said: 'This work strengthens the claim that the world is suffering a mass extinction. We can now be much more confident that across the planet the less conspicuous and less well-known species are going extinct at a similar high rate to that already witnessed in birds, fish and amphibians.'
Journal Reference:
1. Clive Hambler, Peter A. Henderson, Martin R. Speight. Extinction rates, extinction-prone habitats, and indicator groups in Britain and at larger scales. Biological Conservation, 2010; DOI: 10.1016/j.biocon.2010.09.004
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An 'Unprecedented' Bat Die-Off Could Devastate U.S. Agriculture
By BRUCE KENNEDY
Posted 9:45 AM 10/12/10 Technology, Economy
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EmailShare on FacebookShare on TwitterShare on DiggShare on LifestreamMost people don't love bats, but like good health, you'll realize that you miss them after they're gone. Experts believe many species of bats may vanish pretty soon, and their disappearance could bring profound and long-term changes not only to the environment but also to agriculture, landscaping and gardening across North America.
For several years now, scientists have been sounding alarms about a devastating fungus, White-Nose Syndrome (WNS), that has literally decimated bat populations in the Northeastern U.S. The fungus leaves a white substance on the bat's nose, wings and body, and disrupts the bat's hibernation patterns, forcing it to burn through its fat reserves, which quickly leads to starvation. Earlier this year, a survey of the bat population in New Jersey estimated that 90% of that state's bats had been killed off.
"This is on a level unprecedented, certainly in mammals," says Rick Adams, a biology professor at the University of Northern Colorado and a renowned bat expert. "A mass extinction event, a thousand times higher than anything we've seen. It's going through [bat colonies] like wildfire, with 80% to 100% mortality."
"The disease is absolutely devastating, it's unprecedented," says Mylea Bayless, a biologist with Austin, Texas-based Bat Conservation International. "It's causing population declines in wildlife that we haven't seen since the passenger pigeon."
Bayless notes that bats have slow reproductive rates, usually giving birth to just one pup a year. So bat populations, she says, are going to be very slow to recover, "if they ever do recover." The disease, adds Bayless, "is moving at a pace that's astonishing, about 450 miles per year. In four short years, it's now closer to the Pacific Ocean than it is to its point of origination in Albany, N.Y."
Your Billion-Dollar Bug Eaters
You might be saying good riddance, but think again. Bats are the primary predator of night-flying insects. That not only includes pests like mosquitoes but also insects like corn earworm moths and cotton bollworms. In their caterpillar forms, those insects can destroy crops. A 2006 study of several counties in South-Central Texas concluded that the local bat population had an annual value of over $740,000 a year as a pest control -- or up to 29% of the value of the local cotton crop.
A bat eats 60% to 100% of its body-weight in insects every day. Adams says one colony of Mexican free-tailed bats in Colorado's San Luis Valley, an important agricultural region, "pulls about 100 metric tons of insects out of the air in a year." And having bats in agricultural areas, he says, tends to move insects out of those areas, creating less need for dangerous and expensive pesticides.
And like honey bee colonies -- which have also been facing massive die-offs in recent years -- some bats are important pollinators and seed-distributors. Adams says bats are crucial to the reproduction of tropical fruits like mangos, papayas, figs and wild bananas. And in Arizona, bats are the primary pollinators for three large cactus species that support much of the region's ecosystem.
Government and Researchers Fight Back
The fungus associated with WNS is widespread in Europe, but it doesn't affect bats there. No one is sure yet how it became so lethal to North America's bat population -- but there's a possible human element. Scientists says WNS spores have been found on the clothing and gear of people exploring caves containing bat colonies. The pattern of its spread is also inconsistent with bat migration. "It went from Tennessee to Missouri and then to Western Oklahoma," says Adams, "and it doesn't seem like it would be moving like that if it was just bats."
In the meantime, humans are fighting back. Adams is hosting a conference on the crisis later this month in Denver. The event is expected to draw hundreds of bat experts from around the world. The Forest Service is banning visitors to the thousands of caves and abandoned mines that dot the landscape in at least five Rocky Mountain and Great Plains states. And the Fish and Wildlife Service has awarded $1.6 million in grants for WNS research and control.
"But we all know that's a drop in the bucket for a disease that's sweeping the country and killing 95% of an entire group of animals," says Bayless. "For some people, that may seem like money. . .not well-spent, but [what are] the economic and ecological consequences of losing an entire species? A little bit of money spent now will save us in the long term."
Tagged: agribusiness, agriculture, bat, bat colony, bat die-off, bat disappearance, bat fungus, bats, bees, colony collapse disorder, conservation
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