| Qinghai Lake is the biggest salt water lake and interior lake in China. QinghaiLake basin lies to the northeast of Qinghai-Tibet Plateau and possesses essentialgeographical location, which is excellent pastures and base of animal husbandry inQinghai province. Under the background of the climate changes, phenomenon such aslake withering, grassland degradation and sandy land expansion occur in QinghaiLake in recent years, which led to the deterioration of eco-environment. Regarding tothe situation of the degradation of eco-environment in Qinghai Lake basin, moststudies focus on the single eco-environment issue, but relatively less comprehensivestudy.In order to study the changes of the eco-environment in Qinghai Lake basin byquantitative analysis, this thesis reveals the driving factors that cause the changes ofthe eco-environment from natural and human these two factors. Constructs databaseof land use and land cover change (LUCC) in Qinghai Lake basin on the basis ofArcGIS software and the date from Landsat Tm and MODIS, and completely analyzethe spatial-temporal regulation of the LUCC in Qinghai Lake basin. Also it indicatesthe characteristic of climate changes from the climate and hydrological stations dateof Gang cha, Tianjun, Haiyan, and Goneghe these four counties. In addition, thisthesis collects and analyses the change regulation of the population and livestockcarrying capacity in Qinghai Lake basin and reveals the reasons of eco-environmentchanges from human perspective.Based on the above analysis, this thesis estimates the dynamic change offollowing functions of provisioned service, regulation service, supporting service andcultural service of eco-system during the1977-2010. The main conclusion is asfollowings:Obtain LUCC data in Qinghai Lake Basin from the Landsat TM/MSS date of1977,1987,2000,2004and2010and man-computer interactive interpretation.Calculate the vegetation cover change of Qinghai Lake Basin during the2001-2010on the basis of MODIS remote sensing data. And finally construct the LUCC database of Qinghai Lake basin.During the1977-2010, the LUCC of Qinghai Lake basin changes significantly,ecological land reduces constantly, land degradation and unused land increasegradually. The area of construction land, cultivated land and unused land increaseconstantly, accordingly, the areas of grassland, forestland water reduce gradually.Grassland cultivation is the main resource, which increase the cultivation area aroundthe lake. The construction land increases and shows one-way conversion; the waterarea increases during the2004-2010and the area of Qinghai Lake expands; the baresand around the lake is submerged, all above mentioned are main reason of thereduction of unused land area during this study phase. Generally, the vegetationcoverage shows slight increased tendency during2001-2010, and exists spatialdifference, the vegetation in high aptitude area of southern mountain in Qinghai issignificant.Warm and wet climate in Qinghai Lake basin leads to somewhat increase of thevegetation coverage in recent10years, meanwhile the increased rainfall threats theconversation of water and soil in high aptitude and high relief amplitude area andresults in land degradation. The increase of population and the overloading oflivestock carrying capacity are also important reasons of grassland degradation andeco-environment deterioration.Modify the values per unit area of eco-system service and estimate the valuechanges of provisioned service, regulation service, supporting service and culturalservice, annual and total service value changes of each eco-system Type on the basisof area changes of eco-system Type. The values of ec0-system service in QinghaiLake basin shows a decreased tendency in general and slightly increases since2004.According to above research findings, under the background of climate changes,the eco-environment in Qinghai Lake basin is in a state of deterioration, but shows anupward trend since2004. |
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