Demographic compensation and tipping points in climate-induced range shifts
Demographic compensation and tipping points in climate-induced range shifts
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DOI：
10.1038/nature09439
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发表时间：
2010-10-21
期刊：
影响因子：
64.8
通讯作者：
Morris, William F.
中科院分区：
文献类型：
--
作者：
Doak, Daniel F.;Morris, William F.
为了持续存在，物种预计将随着地球气候变暖而向极地或更高海拔地区转移（1 - 4）。然而，尽管许多物种的分布范围在历史上发生了变化，但许多其他物种并没有发生变化，或者只在高纬度或高海拔地区发生了变化，导致了分布范围的扩大而不是收缩（5 - 11）。考虑到这些对气候变暖的特殊反应，以及它们对物种对气候变化的脆弱性的各种影响，一项关键任务是了解为什么一些物种没有改变它们的范围，特别是在赤道或低海拔极限，以及随着变暖的继续，这种恢复能力是否会持续下去。在这里，我们表明，人口增长率的补偿性变化正在缓冲两个北美冻原植物的南部人口对气候变暖的负面影响，减缓其向北的范围转移，但这种缓冲不太可能无限期地持续下去。这两个物种的南部种群表现出较低的生存和招聘，但较高的增长个别植物，可能是由于较长的，温暖的生长季节。由于这些和其他补偿性变化，南方种群的种群增长率目前并不比北方种群低。然而，持续的变暖可能会被证明是有害的，因为大多数在温和温暖年份改善的人口增长率在最温暖的年份下降，有可能推动未来的人口下降。我们的研究结果强调，需要长期的，范围广泛的测量所有人口的过程，以检测人口补偿，并确定非线性响应，可能导致突然的范围变化的气候临界点被超过。
To persist, species are expected to shift their geographical ranges polewards or to higher elevations as the Earth's climate warms(1-4). However, although many species' ranges have shifted in historical times, many others have not, or have shifted only at the high-latitude or high-elevation limits, leading to range expansions rather than contractions(5-11). Given these idiosyncratic responses to climate warming, and their varied implications for species' vulnerability to climate change, a critical task is to understand why some species have not shifted their ranges, particularly at the equatorial or low-elevation limits, and whether such resilience will last as warming continues. Here we show that compensatory changes in demographic rates are buffering southern populations of two North American tundra plants against the negative effects of a warming climate, slowing their northward range shifts, but that this buffering is unlikely to continue indefinitely. Southern populations of both species showed lower survival and recruitment but higher growth of individual plants, possibly owing to longer, warmer growing seasons. Because of these and other compensatory changes, the population growth rates of southern populations are not at present lower than those of northern ones. However, continued warming may yet prove detrimental, as most demographic rates that improved in moderately warmer years declined in the warmest years, with the potential to drive future population declines. Our results emphasize the need for long-term, range-wide measurement of all population processes to detect demographic compensation and to identify nonlinear responses that may lead to sudden range shifts as climatic tipping points are exceeded.