Settlements Evolution In Pastoral Area And Its Effect Of Resources Environment In Dangqu Watershed

The average altitude of the Qinghai Tibet Plateau is above 4000 m,which is the highest plateau in the world.Given the pastoral areas ecologically fragile,urban and rural settlements scattered,backward infrastructure,low ability of public service,outstanding issues,the country launched a series of regional development and ecological protection policy,such as a fence grazing prohibition,grassland ecological barrier construction and protection,especially the implementation of the nomads settlement project,from "routes and house" to "nomadic settlement",make the herdsmen living conditions improved,to improve the public facilities,directly affect the spatial pattern of pastoral areas settlements and the surrounding resources and environment effect.Based on the data in Google earth in 2010 and ZY-3 high resolution remote sensing images in 2015,this paper depicts the evolution of pastoral settlements in the Dangqu watershed in Damxun county of Tibet autonomous region in village-courtyard scale,analyzes the influencing factors and influencing mechanism of the settlements and discusses the path and measures of the optimized regulation of pastoral settlements with ENVI and ArcGIS.Also used such as rainfall,potential evaporation data and plant available water content,with the help of INVEST model of water supply module to evaluate the basin of water conservation function,analysis of different land cover and small range of resources and environment effect.The main conclusion lies in:(1)When Dangqu watershed pastoral settlements has been migrating from the traditional nomadic evolution to settled grazing stages from 2010 to 2015,The scale of the settlements was significantly increased,the distribution of elevation was reduced,and the location was improved,and nearest neighbor index of the settlements distribution in villag e-courtyard scale plaques in 2010 and 2015 respectively 0.28 and 0.269.According to the reference data in 1990,the spatial distribution pattern of the basin changed from the m odel to the cluster type.(2)Urbanization,settlement,industrialization and ecology have a profound influence on the distribution pattern and development of pastoral settlements.Water,grassland,transportation and so on are the gravitational factors of the pastoral settlements agglomerati on,high altitude,geological disasters,ecological protection is the dissipation factor of the pastoral settlements agglomeration.Dangqu watershed pastoral settlements is mainly distr ibuted in the valley terrace and piedmont alluvial fan under the altitude of 4500m.The settlement distribute surround the cold season pasture winter pasture accounted for 63.4%of the total settlements.The settlements distanced from water within 500 m were accounted for 66.8% of the total of settlements.The settlements within 400 m from transportation line accounted for 73.6% of the total of settlements.(3)By water rate of INVEST model module,it is concluded that when the total living river basin water conservation is 3.2914 x 108 m3,The amount of water supply per unit area in Dangqu watershed is between 50 mm to 333 mm.The supply of water supply per unit area was 265.309 mm,which was greater than that of grassland and wetland,which shows that the water conservation function is better than the latter.the actual evapotranspiration perpixel amount of Dangqu watershed concentrated in 124 mm to 405 mm,the wetland actual evapotranspiration is higher than that of other area,the actual evapotranspiration is 383.597 mm on average,the actual evapotranspiration in the basin a verage value from big to small in order: wetland,grassland,shrub,water,unused land,snow,traffic land and residential land.