Vegetation at northern high latitudes under global warming

Abstract

Northern areas are warming at a rapid rate. Global warming may disturb plant overwintering in the northern hemisphere in several ways: (1) Preparation for winter may be delayed, (2) warm spells in winter may prematurely interrupt dormancy, (3) extreme changes in temperature may result in lethal freezing, as well as (4) activity beginning too early in spring at high temperatures. In addition, (5) some species may e damaged due to thinning or lack of snow cover. Patterns predicted for global warming will undoubtedly extend the growing season, thus increasing plant biomass and productivity, but incidence of forest fires and pathogen attacks will reduce the significance of any positive impacts. In addition, invasion of aggressive alien species is one potential threat for northern biodiversity. Temperature is the most important ecological filter for range shifts in species and populations towards northern areas. Thus, under a warmer climate, temperate vegetation may replace parts of boreal vegetation, with boreal vegetation shifting partly to tundra, although summer droughts may cause confounding effects on these expectations. In addition, photoperiod and other light related factors (light quality and quantity), may modify the adaptation of a given species or population to the new environment. Thus, the overall prediction on a vegetation community level is unpredictable without experimental studies. Unerstanding of the mechanisms behind vegetation range shifts is important from the biodiversity, forestry, and agricultural points of view.