Impacts of Urbanization on the Net Primary Productivity and Cultivated Land Change in Shandong Province, China

Abstract

With rapid social and economic development, pressure on the land ecosystem in Shandong Province, China, is becoming more and more obvious. This study aimed to gain insight into the impacts of urbanization on several ecosystem and land characteristics. Carnegie-Ames-Stanford Approach was used to estimate the terrestrial vegetation net primary productivity (NPP) from 2001 to 2010 in Shandong. The spatio-temporal pattern of NPP was analyzed. Subsequently, the pressure index of cultivated land in Shandong was calculated and used to analyze the spatiotemporal characteristics and the problem of supply and demand for cultivated land by using geographical information system technology. The relationship between NPP and the pressure index of cultivated land was further analyzed, and the influence of both natural and manmade factors was discussed. Based on the above, some suggestions have been proposed for the sustainable development of land use/cover change in Shandong Province. A weak increasing trend in the overall NPP has been observed over the study period, and the NPP in the southwest was higher than in other regions. Impacts of the land use types on NPP were different. About 34.6 × 1012 g of carbon was absorbed every year, of which nearly 75% was absorbed by farmland. Cultivated land initially decreased and then increased during the period. With the help of technology, science, macroeconomic policy, and other developments, the total grain yield increased with some fluctuation. Moreover, the actual area of cultivated land has increased. These changes improved the theoretical minimum cultivated land area per capita, while the pressure index decreased. The pressure on cultivated land also showed obvious regional differences during this period, which is mainly concentrated in the coastal regions and the cities of Jinan and Laiwu. In the western and northern regions, on the other hand, the pressure was relatively lower due to slower economic growth. These results reflect that the urbanization has huge impact on the cultivated land resources.