Study On The Repones Relationship Between Ecological Water Requirement And Landscape Pattern In The Manas River Basin

Manas River basin, a typical oasis region of arid area in northwestern China, haschanged greatly with the dramatic exploitation of cultivated land. Ecological water has beenoccupied by agricultural water, which leads to the seriousregional ecological environment. Inorder to use the water reasonably, it is necessary to discuss the relationship betweenecological water requirement and landscape pattern in Manas river basin.First of all, based on the technical method both Geographical Information System (GIS)and Remote Sensing (RS), we carry out landscape ecology research, using three periods ofland use classificated with TM data in1990,2000and2010in Manas River basin. Weanalyzed their spatial and temporal evolution during1990-2010in the watershed through theclass metric and land metric, respectively. Based on GIS and RS technology, the observedweather data and FAO56Penman Motith method, we calculated the ecological waterrequirement in the study area. The spatial distribution and dynamic variation of ecologicalwater requirement were obtained during1990-2010. Finally, this paper analysis therelationship between ecological water requirement and the landscape pattern tentatively.According to the relationship between ecological water requirement and landscape pattern,some conclusions have been obtained as follows:(1) Analysis of landscape characteristics with space-time evolution in Manas river basinThe land types in Manas river basin have transformed gradually from bidirectionaltransition to one-way transition during1990-2010. Human activities has made grassland andunused land converte to cultivated land and construction land. Landscape types convertedduring1990-2000were more than that in the later10years. The arable land increasesgradually, while the grassland and unused land in the basin decreases gradually. Llandscapediversity elevates, and dominance declines have a separation and crushing tend.(2) Space-time evolution of ecological water requirement in Manas river basinEcological water requirement for controlled area, the ecological water requirement wastowould reduce about29million m3/10a. Ecological water demand quota of central plain wasobviously higher than that of the southern mountain. The change trend in space was different.Ecological water requirement would increase in the mountains, and reduce in the plain area asthe main performance. It is obvious the variation of ecological water requirement during1990-2000is higer than the later10years.(3) The relationship between ecological water requirement and the landscape pattern inManas river basinIn the mountains area, the increase of ecological water consumption resulted in thevegetation diversity index increasing and contagion index decreasing in the space. Also, itcaused to the surrounding contagion index increasing and diversity decreasing with time. Inthe oasis, there is no obvious relationship between ecological water demand quota andlandscape pattern index in space. Althought ecological water consumption is increased, the influence of human activity resulted in the surrounding contagion index decreasing anddiversity increasing with time, which is in contrast to the mountains conclusions. Reduceingecological water requirement quota would be conducive for the growth of vegetation.Otherwise, the ecological environment would be destroyed because of the influence of humanactivity.