| Nowadays the global climate changes and its impacts is one of the most rigorous challenges that human is confronted with. Climate changes can take great effect on environment and ecosystem, so the research on climate changes and its impacts on ecosytems have attracted great attention of government, science field and public in all countries. But the research on impacts of climate changes on karst ecosystem hasn't been studied systematically at home now.Karst ecosystem is a kind of vulnerable ecosystem, its vulnerability including mainly: 1 environment capacity is small, vegetation is difficult to recover after having been destructed, hydrologic movement is rapid and floods and droughts often occur; 2 vegetation growth depends on the conditions of eco-environment overly, which are affected by environment obviously; 3the positive evolve of eco-environment relies on the recover of vegetation, 4the methods of water resource use and land use lack of rationality. These vulnerabilities are be magnified by climate changes.As these vulnerabilities in karst areas, vegetation type and cover rate become the most important and sensitive natural factor, at the moment the problem on hydrology and water resource is very important. Because Different climate results in different vegetation and climate is decisive factor of hydrology and water resource, it is representative to study on the impacts of climate changes on karst ecosystem from the aspects of vegetation and hydrological regimes and water resource.The earth's surface area of carbonate in Chongqing is about 32038.14km2, makingup of 38.9% of the overall land and distributing mostly in northeast and southeast area of Chongqing. The land resources of karst region in Chongqing is mainly rock mountain and slope land, with serious soil erosion, converse vagetation succession and low cover rate, lesser water retention and lacking water, where ecosystem is difficult to recover after vegetation being destructed, land coming forth landification and sandification heavy. In this paper, the impacts of climate changes on karst ecosystem were studied from the aspects of vegetation and hydrologic regimes and water resource, taking karst areas in Chongqing as an example. The results were shown as follows:(1) Based on weather data, the space-time changes of climate in Chongqing karst region were analyzed applying regression analysis and Kriging interpolation and the future climate was forecasted by wavelet analysis. The results were summarized below:As a whole, the trend of annual average air temperature was descendent in recent 40 years, especially in the 1980's, which was the coldest period. This kind of degressive tendency appeared mainly in spring and summer. But the air temperature change in Chongqing karst region was complicated, not only occuring warming region, but also colding region. The region getting warm appeared in the northeast of Chongqing, the characteristics of which was that maximum air temperature became warmer than minimum air temperature. The regions getting cold took place in the middle and southeast of Chongqing, mainly resulting from maximum air temperature.The precipitation in recent 40 years decreased slightly, mainly in spring and autumn for each period and each region, the changes of precipitation and air temperature showed a kind of reverse tendency. For example, in the coldest 1980's, precipitation was the richest. Precipitation decreasing occurs mainly in the north of Chongqing, where air temperature increased.The air temperature and precipitation in next 8 years would take on fluctuant change around average value. However, the trend of temperature would be ascending, and the trend of precipitation would be descending.(2) Combining NDVI data with above analysis, the impacts of climate changes on vegetation were discussed with mathematics statistics methods. As a result:Either in multi-year average or multi-year season average, the results of NDVI responses to climate change showed that temperature was more influential than pr...
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