Mountain landscapes offer few opportunities for high-elevation tree species migration
Mountain landscapes offer few opportunities for high-elevation tree species migration
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DOI：
10.1111/gcb.12504
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发表时间：
2014-05-01
影响因子：
11.6
通讯作者：
Lauenroth, William K.
中科院分区：
文献类型：
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作者：
Bell, David M.;Bradford, John B.;Lauenroth, William K.
预计气候变化将改变植物物种的分布。区域背景，特别是气候梯度的空间复杂性，可能会影响物种的迁移潜力。虽然高海拔物种可能受益于山区陡峭的气候梯度，但它们的持久性可能受到有限的适当生境的威胁，因为土地面积随着海拔的升高而减少。为了解开这些明显矛盾的预测山区，我们评估了美国西部的针叶林树种的气候适宜性的基础上，物种分布模型（SDM）和研究气候适宜地区的变化预测的气候变化。我们使用的森林结构信息与树种优势，生产力和人口从一个广泛的森林资源清查系统，以评估与SDM方法的推理强度。我们发现，树种优势度，生产力和招聘是最高的气候适宜性（即，物种在某些气候条件下出现的可能性）很高，支持在审查物种对气候变化的风险时使用预测的气候适宜性。通过预测下世纪气候适宜性的变化，我们发现气候适宜性可能会下降，无论是在目前被每一个树种所占据的地区，还是在未来物种可能迁移到的附近未被占据的地区。这些趋势在高海拔物种中最为显著。预计下世纪的气候变化将大大减少高海拔树种的气候适宜区域，而较低海拔的物种，黄松，将很好地定位到整个地区的上坡。高海拔物种适宜区域的减少意味着，即使是无限制的迁移也不足以抵消预计的栖息地丧失，这突出表明这些高海拔物种对气候变化的脆弱性。
Climate change is anticipated to alter plant species distributions. Regional context, notably the spatial complexity of climatic gradients, may influence species migration potential. While high-elevation species may benefit from steep climate gradients in mountain regions, their persistence may be threatened by limited suitable habitat as land area decreases with elevation. To untangle these apparently contradictory predictions for mountainous regions, we evaluated the climatic suitability of four coniferous forest tree species of the western United States based on species distribution modeling (SDM) and examined changes in climatically suitable areas under predicted climate change. We used forest structural information relating to tree species dominance, productivity, and demography from an extensive forest inventory system to assess the strength of inferences made with a SDM approach. We found that tree species dominance, productivity, and recruitment were highest where climatic suitability (i.e., probability of species occurrence under certain climate conditions) was high, supporting the use of predicted climatic suitability in examining species risk to climate change. By predicting changes in climatic suitability over the next century, we found that climatic suitability will likely decline, both in areas currently occupied by each tree species and in nearby unoccupied areas to which species might migrate in the future. These trends were most dramatic for high elevation species. Climatic changes predicted over the next century will dramatically reduce climatically suitable areas for high-elevation tree species while a lower elevation species, Pinus ponderosa, will be well positioned to shift upslope across the region. Reductions in suitable area for high-elevation species imply that even unlimited migration would be insufficient to offset predicted habitat loss, underscoring the vulnerability of these high-elevation species to climatic changes.