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VOA常速英语:New Model Predicts Mammal Extinction

2009-06-19来源:和谐英语

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Researchers have developed a new computer model that they say helps determine which mammals are headed for extinction as a result of human activity.  

Earth is undergoing its sixth mass extinction, threatening about a quarter of all mammal species, according to Ana Davidson, an international conservation researcher with the University of New Mexico in Albuquerque and the University of Mexico in Mexico City.

Davidson says the threat to mammals is being driven by a number of factors, including climate change, deforestation and poaching.

"You name it, we're doing it. We are having widespread impacts on the Earth. Right now, 83 percent of the land surface is impacted in some way by humans. And so, that means that the millions of species that we share this planet with are being constrained and impacted by our activities," she said.

Davidson and several other animal conservationists developed a model to predict the extinction rates of endangered mammals identified by the International Union for the Conservation of Nature, or IUCN.  

The list includes more than 1,100 threatened animals, some of which have been put in the critically endangered category, such as the Iberian lynx. Others, including the Fishing Cat of Southeast Asia, are listed as endangered because of habitat loss.

Davidson says the model is designed to keep track of which mammals are at risk in the future by factoring in a number of ecological considerations, such the amount of land where they roam.

"If an animal lives in the ground or in trees or in the ocean that kind of thing. Also, [we] use group size, which is a measure of an animal's sociality. We use life history data, which tells us how fast an animal species reproduces; things like that," she said.

Davidson says larger animal species are at greater risk of extinction than smaller mammals because they are frequently in conflict with carnivores for land and food, and they do not produce many offspring.

Davidson says the model is an attempt to help animal preservationists target their resources.

"Our funding is very limited, right? So to be able to have these sorts of guidelines, to be able to focus in and hone our efforts, is really important," said Davidson.

The researchers describe their animal conservation model in the Proceedings of the National Academy of Sciences.
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