Beavers have been busy sequestering carbon一直节能减排的是

Beavers aren't going to save the world – but they are doing their bit for carbon capture and storage. The dams they build, and the wetlands produced as a result, lock away a surprising amount of carbon. "Beavers offer a mechanism of carbon storage," says Ellen Wohl of Colorado State University in Fort Collins. Beaver dams cause water to breach riverbanks, creating areas of wetland known as beaver meadows, which contain large amounts of sediment and organic material. If the dam breaks the meadows dry out, exposing the material to the air and releasing some of the carbon stored within them. Using previously published carbon-content values, Wohl estimated the total organic content from dried-up beaver meadows in 27 drainage basins in Rocky Mountain National Park, and found it accounted for 8 per cent of the carbon in the landscape. She estimated that when the meadows were flooded they may have sequestered as much as 23 per cent of the carbon. Beaver numbers have been declining in the park since the 1940s. Wohl says there were once between 60 and 400 million beavers in North America – a number that would have had a significant effect on the ecosystem. There are now thought to be 6 to 12 million, and the park service is working towards reintroduction. "Beavers can transform systems extremely quickly and the long cascading list of feedbacks and impacts of their ecosystem engineering is extensive," says Joseph Wheaton of the department of watershed sciences at Utah State University in Logan. "With some subtle and cheap shifts in how we manage landscapes and rivers, allowing beavers to do a lot of the work for us can have profound impacts," he says – but ecologists will have to manage people's expectations about just how much beavers can do.  译文 “可以说，水獭为人类提供了一整套成熟的温室气体的解决方案。”科罗拉多州立大学的Ellen Wohl在小镇柯林斯接受采访时说道。她解释说，水獭的水坝抬高了水位，漫过河岸，进而形成了湿地，一般我们管它叫做“水獭的小草坪”。这些“草坪”蕴涵着大量的沉积物和有机物质。一旦水坝破裂，湿地干涸，那么其中的温室气体将会被无情地排放到空气中。 根据已发布的碳含量数据，Wohl估测了落基山国家公园里27处流域盆地中的早已干涸不少的“水獭草坪”，发现其碳含量占该地区总碳量的百分之八。她进一步大胆地断言，如果这些湿地不是干涸而是浩浩汤汤的话，那么最多可以减排百分之二十三的温室气体！ 可糟糕的是国家公园中水獭的数量自二十世纪四十年代起开始逐渐减少。Wohl说之前最高峰时整个北美大陆生活着六千万到四亿只水獭——这个数量的水獭本来蛮可以把北美洲变成一块和谐可爱的大草坪的！但随着美国成为超级大国，水獭的圈子越来越小，数量锐减至可怜的六百万，最多不会超过一千二百万只。这使得公园方面不得不考虑重新引进一些水獭用以繁殖。 “水獭改造生态系统的能力快得出奇，而且它们的生态工程带来的作用和反馈具有级联效应，影响深远。”位于洛根的犹他州立大学流域科学系的Joseph Wheaton介绍道。 “我们只需要在景观和河流管理上作出一些细微而且廉价的调整，就能让水獭为我们分忧不少。”他继续说道——但首先生态学家需要解决一个问题，那就是我们还剩下多少水獭可以利用。