Tree species distributions are shifting due to climate change. Various environmental factors can explain these distribution shifts, but their relationship to climate change is not well understood yet. To better understand such relationships, Morgane Urli, a postdoctoral fellow in Mark Vellend's lab, is leading a project at Mont-Mégantic focusing on a tree species of economic interest in southern Quebec: the sugar maple. This project aims to determine the factors controlling sugar maple regeneration along an altitudinal gradient including the boreal-temperate forest ecotone. The abundance of mature trees decreases with elevation up to the tree line, but they observed that seedling density is greater at high elevation than at low elevation. Climate change might make habitats more favourable to seedlings than they were previously. However, it is surprising to observe weaker seedling regeneration at lower elevation right in the center of the sugar maple distribution area. Two principal hypotheses to explain such observations are a greater herbivory pressure from insects at lower elevation and a varying water availability for seedlings along the altitudinal gradient. A transplant experiment is currently underway to test these hypotheses. More information on this experiment is available at chercheurjourapresjour.blogspot.ca. Click here for more info.