Harsch Melanie A, Hulme Philip E, McGlone Matt S, Duncan Richard P
The Bio-Protection Research Centre, Lincoln University, PO Box 84, Lincoln 7647, New Zealand.
Ecol Lett. 2009 Oct;12(10):1040-9. doi: 10.1111/j.1461-0248.2009.01355.x. Epub 2009 Aug 13.
Treelines are temperature sensitive transition zones that are expected to respond to climate warming by advancing beyond their current position. Response to climate warming over the last century, however, has been mixed, with some treelines showing evidence of recruitment at higher altitudes and/or latitudes (advance) whereas others reveal no marked change in the upper limit of tree establishment. To explore this variation, we analysed a global dataset of 166 sites for which treeline dynamics had been recorded since 1900 AD. Advance was recorded at 52% of sites with only 1% reporting treeline recession. Treelines that experienced strong winter warming were more likely to have advanced, and treelines with a diffuse form were more likely to have advanced than those with an abrupt or krummholz form. Diffuse treelines may be more responsive to warming because they are more strongly growth limited, whereas other treeline forms may be subject to additional constraints.
林线是对温度敏感的过渡带，预计会随着气候变暖而向当前位置以外的地方推进。然而，在上个世纪对气候变暖的响应却是喜忧参半，一些林线显示出在更高海拔和/或纬度有新树木生长的迹象（推进），而另一些林线则显示树木生长上限没有明显变化。为了探究这种差异，我们分析了一个全球数据集，该数据集包含自公元1900年以来记录了林线动态的166个地点。52%的地点记录到林线推进，只有1%的地点报告林线后退。经历强烈冬季变暖的林线更有可能推进，与具有陡峭或矮曲林形式的林线相比，具有扩散形式的林线更有可能推进。扩散林线可能对变暖更敏感，因为它们受生长限制更强，而其他林线形式可能受到额外的限制。
