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托福听力练习-科学美国人60秒:气候变化牛犊遭殃

2017-04-26 10:59:00来源：科学美国人60秒

点击查看>>科学美国人60秒音频：气候变化牛犊遭殃

　　科学美国人60秒听力练习：气候变化牛犊遭殃

　　科学美国人60秒英文文本

　　Climate change affects seasonal events—spring flowers open earlier, songbirds breed sooner. But what about mammals? A new study documents the effect on a special breed of cows in the U.K.

　　Northumberland’s Chillingham cattle were once domesticated, but now roam free. And they offer a unique opportunity for study. Because owners started keeping detailed records on them in 1860, due in part to the urging of none other than Charles Darwin. The cattle are thus an excellent source of long-term info on how earlier springs affect what’s called phenology—seasonal lifecycle events.

　　The Chillinghams can give birth all year, not just spring and summer like most U.K. mammals. And the data show that over the past few decades, there’s been an increase in winter births. Which the researchers correlated to warmer springs the previous year: plants grow earlier, the cattle have more access to nutrition and they conceive earlier.

　　But winter babies are more likely to die before they turn one. The research was published in the Journal of Animal Ecology. [Sarah Burthe et al., "Demographic Consequences of Increased Winter Births in a Large Aseasonally Breeding Mammal (Bos taurus) in Response to Climate Change]The researchers say that even mammals that breed year round—which should offer protection against seasonal shifts—may still feel the impact of climate change.

　　—Cynthia Graber

　　中文翻译请点击下一页

本文关键字: 托福听力 科学美国人60秒

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