Vulnerability Evaluation Of Landscape Pattern Change In Mountain Watershed Area Based On GIS

Wujiang river north source is an important area of Wujiang river upstream source,and it is also the ecological barriers and the key area of ecological environment construction in the west of Guizhou。The economic development of water environment security in Wujiang has an important position. So the article study the landscape pattern change and evaluated the vulnerability, in order to provide theoretical foundation and scientific advice for the ecological protection and sustainable development of study area. It is important to ensure the ecological construction of Wujiang river north source, and maintain human long-term survival and development. The study is based on ARCGIS software platform, use land cover data and 30 m* 30 m DEM data, classified the land use type into six types:forest land, grassland, wetland, cultivated, construction land and unused land and then overlay with the terrain factors to attain landscape features under terrain factors differentiation.Using FRAGSTATS attains landscape index in plaque scale and landscape scale and analyze landscape pattern dynamic change under different plaque scale. Under the background of ecological vulnerability, and on the basis of fully understand the vulnerability of landscape pattern, from the angle of combine landscape sensitivity and land adaptability, then, building theappraisal model of landscape pattern vulnerability of the study area. On this basis, with the help of Geoda software it analyzes the spatial correlation pattern of landscape vulnerability of Wujiang north source, and put forward some countermeasures and suggestions to the construction of ecological research, so as to provide a scientific basis for the improvement of fragile ecological environment and rational utilization of resources. The results showed:(1) Watershed landscape change presented plaques broken degree slow,distribution of landscape patches became more and more uniform,landscape diversity and heterogeneity characteristics became more higher as a whole. This change is related with the humans’ increased disturbance to landscape. From 2000 to 2010,significant changes taken place in every landscape types, forest land, grassland, wetland and construction land area ratios were increased, cultivated land area ratio showed a trend of decrease,but the advantage landscape types is forest land. Mean patch fractal dimension of forest land, construction land and unused land reduced, patch fractal dimension of forest land decreased the most and wetland patch fractal dimension increased.(2) Relationship between different landscape types and terrain factors. From 2000-2010. Relationship with the slope: forest land is mainly concentrated in gentle slope, the second is hill and then step flat slope has the smallest distribution. Grassland aremainly distributed in the flat slope and gentle slope increased;cultivated land distributed mainly in gentle slope and hill area;construction land are mainly distributed in the flat slope and gentle slope area; unused land are mainly distributed in the steep slope and gentle slope. The relationship with the elevation shows:The first elevation zone forming forest land- wetland-cultivated land landscape, and cultivated was the main landscape;the second elevation zone with the woodland- cultivated land- grass- construction land alternately landscape present situation, forest land and cultivated land are the main landscape types; the third elevation zone is primarily woodland-cultivated land- grassland landscape pattern, forest land, grassland area increased to maximum; the fourth elevation zone mainly formed the woodland- grass- unused landscape.(3) Landscape vulnerability evaluation results showed that,from 2000-2010 landscape vulnerable degree became larger, but the sorting of landscape vulnerable degree unchanged. Landscape vulnerability degree in 2000 is 0.6631- 1.0029, different landscape types register as: grassland > cultivated land > unused land > forest land > construction land > wetland; In 2010,landscape vulnerable degree range is from 0.6595 to 0.9994, sort for: grassland > cultivated land > unused land > forest land >construction land > wetland.It divided the frangibility into four levels, Ⅱ, Ⅲ, Ⅳ levelshave the largest area ration, from 2000-2010, grade Ⅰ area became smaller, distribution moved to east and south; grade Ⅱand Ⅲ area increased, grade Ⅳ area reduced, grade Ⅴ area stayed the same level.(4) Frangibility spatial autocorrelation results showed: the global Moran ’sI values in 2000 and 2000 is 0.385, 0.403, that’s to say spatial distribution isn’t random distribution. In 2000,H- H area are mainly distributed in border of Qi Xiangguan and Hezhang, middle of Hezhang and Dafang county; L-L value area’s distribution was scattered, and mainly distributed in the west of Weining and west of Dafang.in view of the landscape vulnerability characteristics of wujiang river north source to set up the system of ecological compensation, policy measures according to local conditions and make function partition, build economic forest, make the whole people participate in ecological protection construction, set up perfect rewards and punishments system of forestry etc, and then put forward the protection countermeasures in the construction of river basin ecological environment.(5) in view of the landscape vulnerability characteristics of wujiang river north source to set up the system of ecological compensation, policy measures according to local conditions and make function partition, build economic forest, make the whole people participate in ecological protection construction, setup perfect rewards and punishments system of forestry etc, and then put forward the protection countermeasures in the construction of river basin ecological environment.