Microbial communities decreased from soil, to streams, to lakes. About half of the common lake bacteria detected were rare species in soils and headwater streams. Initial inoculation from soils was followed by species sorting downslope. With warming, microbial trophic structure has become more homogenous across soil horizons, and plant biomass and woody plant dominance has increased. Arctic LTER researchers have found that, in lakes, warming caused fish populations to cycle between large and small individuals. Models predicted faster growth, which would require more food, increased reproduction, and decreased generation time.