The Scandes Mountain range is one of the longest in Europe, 1 700 km long and up to 300 km wide, located on the western side of the Scandinavian peninsula, with substantial variations in climate depending on latitude, elevation, lee and wind side. The ecosystem includes a variety of different vegetation types, from rich and moist deciduous forests to tundra in alpine areas. Biodiversity hotspots are located in both the south and the north.
Continued temperature increase, including fewer cold and more warm extremes, is expected, including rainfall events in the winter that can change the ecological conditions. More precipitation is generally projected, but wet and dry extremes are expected to become more pronounced. Snowfall is projected to be reduced everywhere except for high-altitude sites in winter. Reduction in snow cover will amplify the climate warming.
During recent decades Scandinavian mountain regions have experienced an advancement of the tree-line. Above the tree-line, a higher abundance of medium to tall shrub species is observed in moist to wet areas. In dry communities, there has been an increase in semi-prostrate evergreen shrubs like heather and crowberry. Changes in winter conditions are also common, with more frequent episodes of winter warm spells, ground icing and rain-on-snow events damaging vegetation and altering ecosystem services such as carbon storage and grazing grounds for reindeer husbandry.
Initial modelling results (using LPJ-GUESS) suggest that increasing temperatures during the 21st century will likely lead to increased vegetation productivity, driven by the generally taller and denser vegetation, with shrub expansion in the milder regions, and expansion of grasses in the coldest, and the continued upwards and northward movement of tree and shrub vegetation. This advance will proceed more slowly than climate change, due to the competition from prevailing vegetation and a threshold for establishment of new species. Furthermore, the niche for cold adapted species will shrink and an overall loss of biodiversity is expected for the mountainous region of the Scandes.
Awareness of the adverse impacts on vegetation of near-surface ozone and nitrogen deposition has been one of the drivers to decrease in human emissions of nitrogen oxides in Europe since the 1980s. This decrease is projected to continue until mid-21st century, leading to decreased nitrogen deposition and to a reduction in the highest ozone concentrations in Fennoscandia, while ozone concentrations in the low to moderate range may continue to increase. Nitrogen deposition impacts biodiversity adversely by promoting specific species over others, while the impact of ozone on wild plants in the Scandes is poorly understood.
In the next phase we will proceed with detailed analyses of how climate change, air pollution load and management combine to impact biodiversity in the Scandes Mountains.