The Impacts Of Land Use/Land Cover Change On Urban Vegetation Net Primary Productivity In Shanghai, China

Vegetation net primary productivity (NPP) has been suggested as an integrative measure of ecosystem functioning. It can reflect different responses of vegetation to human activities. Study of vegetation NPP is of great significance for promoting the sustainable urban development. Rapid urbanization has intensively influenced land use/land cover(LULC), resulting vegetation reduced rapidly. This undoubtedly will affect vegetation NPP. LULC and vegetation NPP dynamics of Shanghai were simulated in this paper. The results were as follows:(1) LULC of Shanghai changed dramaticly between 2000 and 2013. The area of urban land increased 1155.8km2, which was nearly equal to the area of urban land in 2000. While water and cropland have been reduced 303.5km2 and 991.4 km2, respectively. The area of green space has increased 139.1km2.(2) Among all districts and counties in Shanghai, the highest vegetation coverage occurred in Chongming county, the lowest was in central urban area. The vegetation areas of all districts and counties had reduced except for Chongming county. Songjiang, Jiading, Pudong and Minhang were the districts with large reductions. The central urban area showed the most substantial changes with vegetation area.(3) Between 2000 and 2013, urban land became more and more aggregate, while water, cropland and green space were fragmented.(4) From 2000 to 2013, the average NPP of Shanghai increased by 20.3gC/(m2-y), whereas the total NPP decreased by 231.8 Gg C/y. Cropland was the largest contributor to the total NPP of Shanghai.(5) The NPP of Shanghai ranged from 0 to 467.5gC/(m2·y),0 to 527.0 gC/(m2·y),0 to 482.7gC/(m2·y) and 0 to 531.5gC/(m2·y) in 2000,2005,2009 and 2013, respectively and presented obvious spatial heterogeneity. Higher NPP values occurred in Chongming, Jinshan and Nanhui, while the lower values located in the areas surrounding the downtown and the Dianshan Lake.(6) The total NPP of all districts and counties had reduced ecxept for Chongming county. Minhang was the district with the largest reduction in total NPP and Fengxian district was the one with the smallest.