Dynamics at the treeline: differential responses of Picea mariana and Larix laricina to climate change in eastern subarctic Québec

摘要: Treelines are known to be temperature-sensitive ecotones, and therefore could rapidly expand their range limits in response climate warming. Observations of lack expansion, however, indicate that ecological constraints partly control the treeline ecotones. The main objectives this study were evaluate Picea mariana Larix laricina recruitment growth at above altitudinal Kangiqsualujjuaq (Nunavik), where warmer temperatures since 1990s have already triggered shrub expansion. We mapped, harvested, dated measured tree individuals along two gradients from forested stands below hilltops. Since 1990s, a pulse L. laricina seedling establishment has occurred treeline. Dendrochronological analysis revealed underwent rapid vertical radial accelerated 1990s. No was observed for P. mariana regional warming, suggesting regeneration failure species. Our results indicated colonization recent decades warming should modify landscape physiognomy area near future.