Plant–soil interactions in a deglaciated landscape: roots reflect environmental severity

Abstract

Root exudation, influenced by root tissue environment, enhances the expansion of shrubs in the Arctic. It plays a part in nutrient acquisition by plants and thus the growth of whole communities. However, the extent to which exudation and root tissue environment develop to achieve sufficient nutrient uptake in deglaciating and shrubifying Arctic tundra remains unknown. We studied the content of biogenic elements in soils of different maturities following deglaciation, the age structure of the climax species Salix polaris, exudation by its roots, and the concentrations of different nutrients in its roots and leaves in the forefield of the Nordenskiöld glacier in the Svalbard archipelago. Polar willow shrubs have a greater relative propensity towards exudation under more severe environmental conditions. The least developed root system of shrubs in the youngest soils as well as the highest vegetation competition level increases the potential of exudation.