Local adaptation of trees at the range margins impact range shifts in the face of climate change

The ability of tree species to track their climatic niche at rates comparable to global warming is concerning, particularly if they are constrained by local adaptation. If a species is locally adapted at its range margin it could be beneficial for range expansion as it ensures that the genotypes colonizing new areas are the fittest because environmental conditions are more similar to the current ones. In trees, local adaptation can slow range expansion when climate change happens much faster than their ability to migrate. We investigate experimentally a series of factors thought to constrain the seedling phase at the leading edge of the distribution of a dominant tree species, sugar maple (Acer saccharum Marshall.). We established a seed transplant experiment using six provenances, representing the latitudinal species range, and transplanted them to 12 sites within, at, and beyond the current northern species range margin. Northern provenances currently provide the best opportunity for ...林木物种以与全球变暖相当的速率追踪其气候生态位（climatic niche）的能力令人担忧，尤其是当它们受到本地适应（local adaptation）的限制时。若物种在其分布范围边缘发生本地适应，则可能对分布范围扩张有利，因新区域的环境条件与物种当前分布区更为相似，故而能确保定植新区域的基因型为最适基因型。在林木中，当气候变化的速率远快于其迁移能力时，本地适应会延缓分布范围的扩张。本研究通过实验探究了一系列被认为会限制优势林木物种——糖枫（*Acer saccharum* Marshall.）——分布前沿幼苗阶段的因素。我们选取了代表该物种纬度分布范围的6个种源（provenance），开展种子移植实验，将其移栽至当前该物种北部分布范围边缘以内、边缘处及边缘以外的12个试验点。目前，北部种源为[...]提供了最佳机遇。