PARENT SESSION
Contributed Oral Session 50: Restoration Management and Modeling
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 521 A, Level 5, Palais des congrès de Montréal
Connecting global change studies to ecosystem restoration and management using cross-scale modelling.
Gao, Qiong*,1, Yu, Mei2, Zhang, Xinshi1, 1 MOE Key Lab of Environmental Change and Disasters, Beijing, China2 Institute of Botany, Beijing, China
ABSTRACT- We adopted and applied a simulation model TESim to analyze responses of ecosystem processes and functions in northern China crop-pasture band (CCPB) to possible future climate and land use changes at patch, landscape, and regional scales. The model was tested against a large amount of field data, and was shown to be able to explain significant amount of variations in productivity and soil erosion data. Simulation with unchanged land use and climate from 1976 to 1999 indicates that the regional net primary production (NPP) and net ecosystem production (NEP) are positively correlated with annual precipitation, but negatively correlated with temperature. Given topography and land use patterns, regional soil erosion is also significantly and positively correlated with precipitation. No significant correlation was found between the soil erosion and temperature. Regional NPP varied between 82.6 and 137.2 gC m-2 a-1 with mean value of 108.3 gC m-2 a-1, regional NEP between -8.5 and 22.6 gC m-2 a-1 with mean value of 5.6 gC m-2 a-1, and annual soil erosion between 1313 and 2467 t km-2 a-1 with mean value of 1868.7 t km-2 a-1. Crop fields were gradually converted to wild grasslands (steppes) in a series of 4 land-use change scenarios, Simulations for altered climate and land use show that a 20% decrease in precipitation decreased the regional NPP by 15.1 gC m-2 a-1, NEP by 5.6 gC m-2 a-1, and soil erosion by 339.2 t km-2 a-1 A 2 degree centigrade increase in temperature with unaltered relative humidity decreased the NEP by 7.8 gC m-2 a-1 and soil erosion by 152.1 t km-2 a-1, but did not significantly affect the NPP. Converting crops progressively to wild steppes increased regional NPP and NEP, but decreased regional soil erosion. Interactions between climate and land use changes tend to intensify the effects of climate change by decreasing the regional NPP and NEP, but did not affect the regional soil erosion. The regional NEP is more sensitive to the interactions between climate and land use changes than regional NPP.
Key words: cross scale modeling, ecosystem degradation, climatic and land use changes, restoration