Woods Hole Research Center, Falmouth, MA 02540, USA.
Ecol Lett. 2011 Apr;14(4):373-9. doi: 10.1111/j.1461-0248.2011.01598.x. Epub 2011 Feb 21.
Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline.
全球植被模型预测，在 21 世纪，北方森林对生物群落转变尤其敏感。这种转变首先会在生物群落的边缘表现出来，随着常绿森林向当前的冻原扩张，生物群落的南部边缘会被草原或温带森林所取代。我们通过将初级生产力的卫星估算值与一个大型树木年轮数据集相联系，评估了自 1982 年以来在阿拉斯加北部的森林生产力变化。这两个记录中的趋势都显示出在北方森林-冻原生态交错带的持续增长，这与整个阿拉斯加内陆地区因干旱导致的生产力下降形成鲜明对比。这些模式支持生物群落转变的假设效应。最终，树木的扩散速度、栖息地的可利用性以及未来气候变化的速度，以及它如何改变干扰机制，都将决定北方森林的地理范围将如何逐渐发生转变，以及在哪些地方会更快地衰退。
