Land Use/Land Cover Change In Jiantang Township, Shangri-La County, Yunnan Province, China

Wetlands are ecological landscapes with abundant biodiversity and serve as one of the living environments to human beings, playing important ecological functions in regulating floods, purifying water quality and modulating climate, which have significant effects on climate change, economic development at the local, regional or global levels. Wetlands have been compartmentalized one type of land covers in global change conference. Land use structures and processes of wetland landscape have also been one of key research fields of landscape ecology and wetland ecology, since land use researches are important contents of landscape ecology.Generally, wetland landscape means wetland cells with spatial heterogeneity at the different scales. And wetland landscape patterns mean spatial arrangement of wetland landscape patches with different sizes and shapes, and have higher spatial heterogeneity, which are caused by comprehensions of all ecological processes at the different levels and have great impacts on ecological functions and processes of landscapes. Therefore, spatial structure of wetland landscapes has become one of core contents. Changes in wetland landscape patterns are closely linked to climate changes, land use/land cover changes and biodiversity at the regional or global scales. Wetland ecosystems have been proved to be one of ecosystems which are seriously endangered, and most wetlands have been transformed or lost because of natural processes and human activities.There's a close relationship between landscape dynamics and land use/land cover change. This study analyzed spatial and temporal changes of land use/land cover in Jiantang Township of Shangri-La County, where three plateau wetlands (Napahai Lake, Bitahai Lake and Shudu Lake) are located, by comparing classified Landsat TM (ETM) images from 1974, 1987 and 2000 through GIS analysis, and patterns of landscape dynamics by using the spatial pattern analysis software (FRAGSTATS).The results indicated that the land use/land cover in this area has changed significantly during 1974 and 2000. The most obvious change was the decrease in dominant cover of forest (annual deforestation rate of 822hm²/a) and an increase in shrub-lands. Shrub-lands expanded more than 17 times in the past 26 years and mainly came from forest. The built-up and farmland increased more than 6 and 2 times respectively while the grassland and snow-land substantially deceased 31.55% and 38.54% in area. The water area shrank markedly near the Napahai Lake.Accordingly, the landscape pattern quantitative analysis showed increasing landscape fragmentation, particularly during the 1974-1987. There was a markedly increase in patch density (0.61 to 1.93 km^-2) of shrub-lands and mean patch area (2 to 11 hm²), while grassland made an contrary change. Furthermore, increase in the patch density (0.17 to 0.52 km^-2 of forest was association with decrease in the mean patch size (454 to 117 hm²). However, the decrease in patch density of the farmland and increase in mean patch area exhibited aggregation. The patch shape of the landscape types changed most distinctly in 1987 and the landscape pattern tend to be more complicated.The driving forces of the LUCC in plateau wetland area were the economic development, the pressure of the increase of population, adjustment of the macro policy and the construction of the various exploitative projects. We compared the variability of regional climatic factors and its social-economic factors in the past 26 years. The results show that affected by the global environmental change, regional climate has a trend of becoming warmer and drier. But the social-economic factors is the main force which leading landscape change of study area, and human activities are the efficient approach which threatened the safety of wetland ecosystem.