McMenamin Sarah K, Hadly Elizabeth A, Wright Christopher K
Department of Biology, Stanford University, 301 Serra Mall, Stanford, CA 94305-5020, USA.
Proc Natl Acad Sci U S A. 2008 Nov 4;105(44):16988-93. doi: 10.1073/pnas.0809090105. Epub 2008 Oct 27.
Amphibians are a bellwether for environmental degradation, even in natural ecosystems such as Yellowstone National Park in the western United States, where species have been actively protected longer than anywhere else on Earth. We document that recent climatic warming and resultant wetland desiccation are causing severe declines in 4 once-common amphibian species native to Yellowstone. Climate monitoring over 6 decades, remote sensing, and repeated surveys of 49 ponds indicate that decreasing annual precipitation and increasing temperatures during the warmest months of the year have significantly altered the landscape and the local biological communities. Drought is now more common and more severe than at any time in the past century. Compared with 16 years ago, the number of permanently dry ponds in northern Yellowstone has increased 4-fold. Of the ponds that remain, the proportion supporting amphibians has declined significantly, as has the number of species found in each location. Our results indicate that climatic warming already has disrupted one of the best-protected ecosystems on our planet and that current assessments of species' vulnerability do not adequately consider such impacts.
两栖动物是环境退化的晴雨表，即使在美国西部黄石国家公园这样的自然生态系统中也是如此，在那里，物种受到积极保护的时间比地球上其他任何地方都要长。我们记录到，近期的气候变暖以及由此导致的湿地干涸，正致使黄石公园原产的4种曾经常见的两栖动物数量严重下降。超过60年的气候监测、遥感以及对49个池塘的反复调查表明，年降水量减少以及一年中最温暖月份的气温升高，已显著改变了地貌和当地生物群落。干旱如今比过去一个世纪的任何时候都更加常见和严重。与16年前相比，黄石公园北部永久干涸的池塘数量增加了4倍。在留存下来的池塘中，支持两栖动物生存的比例大幅下降，每个地点发现的物种数量也是如此。我们的研究结果表明，气候变暖已经扰乱了地球上保护得最好的生态系统之一，而且目前对物种脆弱性的评估并未充分考虑到此类影响。
