The Koshi River Basin is in the middle of the Himalayas,a tributary of the Ganges River and a very important cross-border watershed.Across the basin there are large changes in altitude,habitat complexity,ecosystem integrity,land cover diversity and regional difference and this area is sensitive to global climate change.Based on Landsat TM images,vegetation mapping,field investigations and 3S technology,we compiled high-precision land cover data for the Koshi River Basin and analyzed current land cover characteristics.We found that from source to downstream,land cover in the Koshi River Basin in 2010 was composed of water body（glacier）,bare land,sparse vegetation,grassland,wetland,shrubland,forest,cropland,water body（river or lake） and built-up areas.Among them,grassland,forest,bare land and cropland are the main types,accounting for 25.83%,21.19%,19.31% and 15.09% of the basin＇s area respectively.The composition and structure of the Koshi River Basin land cover types are different between southern and northern slopes.The north slope is dominated by grassland,bare land and glacier;forest,bare land and glacier are mainly found on northern slopes.Northern slopes contain nearly seven times more grassland than southern slopes;while 97.13% of forest is located on southern slopes.Grassland area on northern slope is 6.67 times than on southern slope.The vertical distribution of major land cover types has obvious zonal characteristics.Land cover types from low to high altitudes are cropland,forest,Shrubland and mixed cropland,grassland,sparse vegetation,bare land and water bodies.These results provide a scientific basis for the study of land use and cover change in a critical region and will inform ecosystem protection,sustainability and management in this and other alpine transboundary basins.
Climate warming and economic developments have created pressures on the ecological systems that human populations rely on,and this process has contributed to the degradation of ecosystems and the loss of ecosystem services.In this study,Landsat satellite data were chosen as the data source and the Koshi River Basin（KB） in the central high Himalayas as the study area.Changes in land cover and changes in the value of ecosystem services between 1990 and 2010 were analyzed and the land cover pattern of the KB in 2030 and 2050 was modeled using the CA-Markov model.Changes in land cover and in the value of ecosystem services in the KB for the period 2010–2050 were then analyzed.The value of ecosystem services in the KB was found to decrease by 2.05×10~8 USD y^（-1） between 1990 and 2010.Among these results,the services value of forest,snow/glacier and barren area decreased,while that of cropland increased.From 1990 to 2050,forest showed the largest reduction in ecosystem services value,as much as 11.87×10~8 USD y^（-1）,while cropland showed the greatest increase,by 3.05×10~8 USD y^（-1）.Deforestation and reclamation in Nepal contributed to a reduction in the value of ecosystem services in the KB.Barren areas that were transformed into water bodies brought about an increase in ecosystem services value in the lower reaches of the Koshi River.In general,this process is likely to be related to increasing human activity in the KB.
Because of its landscape heterogeneity,Koshi Basin（KB） is home to one of the world＇s most abundant,diverse group of species.Habitat change evaluations for key protected species are very important for biodiversity protection in this region.Based on current and future world climate and land cover data,MaxE nt model was used to simulate potential habitat changes for key protected species.The results shows that the overall accuracy of the model is high（AUC 0.9）,suggesting that the MaxE nt-derived distributions are a close approximation of real-world distribution probabilities.The valley around Chentang Town and Dram Town in China,and Lamabagar and the northern part of Landtang National Park in Nepal are the most important regions for the protection of the habitat in KB.The habitat area of Grus nigricollis,Panax pseudoginseng,and Presbytis entellus is expected to decrease in future climate and land cover scenarios.More focus should be placed on protecting forests and wetlands since these are the main habitats for these species.
