Sensitivity of Inner Mongolia Grasslands to Climate Change

Abstract

We investigated the effects of global climate change and doubled atmospheric CO2 concentration to plant primary production and soil organic matter of typical steppe (Leymus chinense steppe and Stipa grandis steppe) and meadow steppe (Filifolium sibiricum steppe, S. baicalensis steppe and L. chinense steppe) at individual sites in Inner Mongolia, using the CENTURY ecosystem model. In the simulation of climate change, loss of soil organic C ranges from 783 gC.m-2 in meadow steppe to 1485 gC.m-2 in typical steppe, and annual above-ground net primary production (ANPP) decreases by 17.6 gC.m-2 in meadow steppe to 29.5 gC.m-2 in typical steppe under CCC (Canadian Climate Center). While under GFDL (Geophysical Fluid Dynamics Laboratory), loss of soil organic C varies from 584 gC.m-2 in typical steppe to 1164 gC.m-2 in meadow steppe, and ANPP decreases in the range of 18.3 gC.m-2 in typical steppe to 32.1 gC.m-2 in meadow steppe. In the simulations of climate change plus elevated CO2 (from 350 p.p.m. to 700 p.p.m.), ANPP decreases by 5.4 gC.m-2 in meadow steppe to 11.3 gC.m-2 in typical steppe under CCC +CO2, while ANPP varies from an increase of 1.8 gC.m-2 in S. grandis steppe to a decrease of 20.6 gC.m-2 in meadow steppe under GFDL + CO2. Losses of soil organic C are slightly lower (in the range of 42 gC.m 2 to 248 gC.m -2) than losses of soil organic C under climate