An Analysis of Sensitivity of Terrestrial Ecosystems in China to ClimaticChange Using Spatial Simulation

A computer simulation model of regional vegetationdynamics was applied to the terrestrial ecosystems ofChina to study the responses of vegetation to elevatedCO₂ and global climatic change. The primaryproduction processes were coupled with vegetationstructure in the model. The model was parameterizedand partially validated in light of a large number of fieldobservations made throughout China on primary productivity,10 years of monthly meteorological data, 5 years of monthlynormalized differential vegetation index observed byNOAA-11 satellite, and digital vegetation and terrainmaps. Eight different climatic scenarios, set byperturbations from the present climate, 100% inatmospheric CO₂ concentration, 2 °C inmonthly mean temperature, and 20% in monthlyprecipitation, were applied to analyze the sensitivityof the Chinese terrestrial ecosystems to climaticchange. Simulation results were obtained for each ofthe climatic scenarios with the model running towardequilibrium solutions at a time step of 1 month.Preliminary validation indicated that the model wascapable of simulating the net primary productivity ofmost vegetation classes and the potential vegetationstructure in China under present climatic conditions.The simulations for the altered climatic scenariospredicted that grasslands, shrubs, and conifer forestsare more sensitive to environmental changes thanevergreen broadleaf forests in warm, wet southeastChina and desert vegetation in cold, arid northwestChina. For less than 150% of changes in vegetationstructure under altered climatic conditions, aboutthree quarters of the changes in net primaryproductivity of individual vegetation classes wereshown to be attributed to the changes in thecorresponding distribution area.