With climate change, shrubs and trees expand northwards in the Subarctic

Shrubs expand in the tundra in northern Scandinavia. And it is known that fixation of nitrogen from the air is in the tundra to a high degree performed by cyanobacteria associated with mosses. Also enhanced nitrogen fixation stimulates plant growth. New research shows that as taller shrubs expand into the tundra, nutrients in their leaf litter will either promote or reduce the nitrogen fixation, depending upon which shrub species that will dominate.