| Earth vegetation change is an important content of global climate change research and a hot issue to which scholars from all over the world pay attention. In recent years, with the development of RS technology and the accumulation of historical RS data, and the mature of vegetation change aimed at regional long time series, and the study of driving mechanism of vegetation changes go deeper using dates of observation stations and social economy, LUCC is becoming a hot issue of driving force research as one important factor of regional vegetation change. The arid region in central part of Ningxia province is a part of the ecological fragile zone in north China. This area is transitional zone of semi-arid region to arid region from climate, dry steppe to desert from vegetation. And from the history of resource utilization, the production mode of this area has been agriculture and husbandry alternatively. The geographical transitivity is the reason of the diversity, typicality and fragility of natural resources. So studying the change of vegetation over a long period and how the change affects LUCC are of great importance.With the help of RS and the GIS technology, this research used the NDVI time series remote data, monthly precipitation data, data of land use and Landsat TM RS data during2000-2010of arid region in central part of Ningxia to analyse the landscape process and trend of vegetation based on the principles of landscape ecology, and the relationship between the process and climate factors with Geographic information system spatial statistics on the basis of summarizing spatial and temporal variation of vegetation in the arid region in central part of Ningxia. And then, Yanchi county, Hongsipu county and Shapotpu county were picked as typical county, the research used Decision Tree Classification whose accuracy is relatively high to obtain land use data of2000and2010on the basis of Landsat TM data. Some results are as follows:(1) Most area’s NDVI in Arid-region in central part of Ningxia changed frequently between0.15and0.45. The amplitude of variation of the areas whose NDVI were greater than0.45were small but rose slightly as a whole. In those areas with NDVI higher than0.15and less than0.35, they play a dominant role in landscape. In areas with NDVI higher than0.35and less than0.55, regional fragmentations were relatively high and the areas were significantly affected by rainfall. The areas with NDVI that higher than0.65were relatively stable and centralized.(2) From2000to2010, the trend of vegetation change in Arid-region in central part of Ningxia has recovered as a whole. The degenerate and recover trend of oasis landscape area was not obvious, while in desert steppe where was mainly spontaneous recover and New irrigation area of Guhaiyanghuang project, the recovery of vegetation was especially significant.(3) In research area, more than50%of the regional vegetation stayed in a stable situation, the acreage of recover area took up more than30%of the research area while the degenerate area took up6.68%. Although the whole situation was improved, regional degeneration still exist.(4) Rainfall played an important role in the process of vegetation change. But the recovery or degeneration of vegetation was not totally match rainfall fluctuation because of inhomogeneity of spatial change and hysteresis quality of time.(5) The study divided research area into different landscape types depending on different vegetation coverage to study the process of landscape change of vegetation with the research method of landscape ecology. The landscape in arid-region in central part of Ningxia is not very stable. Main trend is integrity—pieces, which means the complement of low NDVI aeras have changed to the Interspersed distribution of high NDVI areas. Human activities promoted the improvement of the ecological environment in a certain extent, and prevent the deteriorate of the environment.(6) LUCC is the antecedent factor of vegetation change, which decides the intensity, pattern and process of vegetation change. Vegetation index of irrigable land, forest and sand were relatively stable while the index of arid zone and grassland was fluctuated with the rainfall. Vegetation index of long cultivated land was more stable than the short one. Vegetation index increased significantly in the prophase period. |
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