The Dynamic Change Of Land Use Pattern And An Optimization Design

Global change has aroused worldwide interest as a subject of research. Among the many issues, land use/cover change (LUCC) is so important a topic that it forms a major part in international research schemes for global change, as it is now generally agreed that LUCC is the most important factor to affect the ecological system (Vitousek,1992*; NRC,1994). Spatial characteristics, temporal dynamics, and environmental effects are the major aspects of LUCC research. Domestic and international achievements are many both in theory and in methodology. This present dissertation draws upon landscape ecological theories and uses the geographic information system to investigate the land use/cover change in the Three Gorges Projects area.Long years of human interference have constantly changed the landscape pattern of the Three Gorges Projects area. As a result this mountainous region has been reduced to an area fragile in ecological environment and backward in social economy, where the human-land relationship is made extremely tense. The Three Gorges Projects, when completed, will change the present ecological pattern, narrow the space available for human survival, and thus further intensify the human-land conflict. Therefore, this dissertation uses landscape ecology as its theoretical and methodological basis to investigate this area. After an thorough analysis of the dynamic state of landscape pattern and its ecological-economic effects the paper advances a proposal, which is strongly supported by the land-ecological adaptability principle, ecological-economic effects principle, and landscape heterogeneity and diversity principles, for a spatial optimization of the present landscape elements with full consideration of the submergence to be caused by the projects. The spatial optimization, or an optimized spatial design for landscape pattern, aims to create a new, land-use sustainable, and economic-development sustainable landscape pattern.The investigation reveals that during the past 50 years, the landscape in this area tends to be increasingly fragmented; change of landscape proportion is dramatic toward a decrease of diversity and an increase of dominance; and the fractal dimensions of patches differ greatly at different stages. This change of ecological landscape pattern many have brought some benefits to the local economy, as the gross agricultural output and vale and the gram production per capita have seen some increase. But owing to natural, social, and historical reasons, grain production per person has long been fluctuating around 250kg, not enough to enable the local economy to provide adequate food and clothing to the local population. At the same time, the above said landscape change has resulted in serious ecological problems which impaired the landscape ecological function and forced the system into a non-virtuous circle. The landscape pattern optimization will greatly alleviate the landscape fragmentation. The present dominance of bush will be replaced by the dominance of economic forest, which at present ranks only secondary. Forestland will increase to become, together with economic forestland, the matrix of the sample area. With a rational interlocking pattern of varied patches, the optimization will bring about a landscape pattern in which different patches are mosaiked to allow for the healthy co-existence of different landscape elements while the forest land and economic forest land function as the matrix. Thus a heterogeneous landscape pattern will be produced by the optimization. These tremendous changes will ensure sustainable land use and economic development as well as greatly improve the productive potential of the ecology system to increase its economic effectiveness.