Belowground plant biomass allocation in tundra ecosystems and its relationship with temperature

Climatewarming is known to increase the aboveground productivity of tundra ecosystems.Recently, belowground biomass is receiving more attention, but the effects of climate warming onbelowground productivity remain unclear. Enhanced understanding of the belowground componentof the tundra is important in the context of climate warming, sincemost carbon is sequesteredbelowground in these ecosystems. In this study we synthesized published tundra belowgroundbiomass data from36 field studies spanning amean annual temperature (MAT) gradient from−20 °C to 0 °C across the tundra biome, and determined the relationships between different plantbiomass pools andMAT. Our results show that the plant community biomass–temperaturerelationships are significantly different between above and belowground. Aboveground biomassclearly increased withMAT, whereas total belowground biomass and fine root biomass did not showa significant increase over the broadMATgradient. Our results suggest that biomass allocation oftundra vegetation shifts towards aboveground in warmer conditions,which could impact on thecarbon cycling in tundra ecosystems through altered litter input and distribution in the soil, aswellas possible changes in root turnover