Study On Landscape Structure And Variation Of Inland Lake Watershed And Its Relationship With Environmental Factors In Arid Region

The excessive development of soil and water resources intensifies the ecologicaldegradation and water resource shortage in arid region. This caused river end lakesshrinking rapidly or dried up, and formed a series of ecological environment problemsin inland lake watershed in arid region. The Ebinur Lake Watershed is a inland lakewatershed. Its ecological environment is fragile, carrying capacity of natural resourcesis low, and stability of ecological system and ability of anti-interference is poor. In thedeveloping process of thousands of years, human activity has a strong intervention onthe changes of water resources and ecological environment. Especially in the pastmore than half a century, because of the rapid growth of population, the husbandryproduction mode of agricultural and animal, and the irrational exploitation of waterresources, ecological and environmental problems has been very prominent in thewatershed. The Ebinur Lake Watershed has become the second largest region ofecological degradation after the Tarim River watershed. These problems have affectedthe sustainable development of society and economy.This research mainly analyzes the landscape structure characteristics and itschange process from1990to2011in Ebinur Lake Watershed, and the relationshipbetween the changes of landscape structure and environment factors. It reveals theimpact of human activities on landscape structure. The full text is divided into sixchapters. The first chapter is the introduction, and it mainly introduces the background,purpose and significance of the study, research process, research contents, methodsand technical route. The second chapter is the general situation of research area, and itmainly introduces the physical geography of research area (geographical location,climatic characteristics, hydrology and water resources, geological andgeomorphologic, ecological landscape, soil and plant type), general situation of socialand economic and ecological environment. The third chapter is the selection and treatment of dates, and it mainly introduces the sources of data, pre-processing andinterpretation of remote sensing image, selection and calculation of landscape index,the classification and mapping of landscape, and the set of research sample. Thefourth chapter is the analysis of landscape structure and change in the Ebinur Lakewatershed, and it mainly analyzes landscape classification, landscape structure,change of landscape structure, change of different landscape types, the changecharacteristics of different landscape structure, offset of gravity center of differentlandscape types, and transformation of different landscape types. The fifth chapter isthe relationship between the characteristics of the landscape structure and itsenvironmental factors. And it mainly analyzes the characteristics of the landscapestructure, the characteristics of environment factors in Ebinur Lake watershed and therelationship between landscape structure and its environmental factors. Through theanalysis on landscape structure and changes in the Ebinur Lake Watershed and itsrelationship with environmental factors, the main conclusions are as follows:(1) Landscape heterogeneity is strong, different region has differentcharacteristics of landscape structure in the Ebinur lake watershed. The zonalstructure shows east-west band structure, but also the structure was to a ring structurenear the catchment center. The basic character is that landscape structure is relativelysimple, landscape was pieced by the adjacent large patch, the proportion of differentlandscape type is balance, and degree of fragmentation is low. The dramatic changeregion of landscape structure is the transition zone between the two differentlandscape types. Desert as the matrix occupy the dominant position in the regionallandscape types.(2) In the common role of human activities and natural factors, landscapefragmentation was increased first and then decreased, the patch shape becomes simpleand then complex, the landscape contagion is increased first and then decreased,landscape connectivity becomes small and then increase, the landscape diversity is increased year by year between1990and2000years. In short, the change trend ofecological environment was deterioration between1990and2000years, andgradually towards a good direction between2000and2011years in the perspective oflandscape structure change.(3) In the period of1990-2011, the fragmentation of water, salt desert anddesert was increased and then decreased, salt desert area was increased first and thendecreased, large plaque area percentage was increased year by year, and patch densityof salt desert was increased year by year. The change trend of farmland was verysignificant, edge density more and more uniform, continuous to the large-scaletendency, connection degree increased year by year in1990-2011. The connectivity ofwoodland was decreased year by year, the area declined in first10years, basicallyunchanged in last11years between1990and2011years. Woodland had thedegradation trend. Patch shape complexity in human activities frequent zone is largethan in unfrequented zone. The impact of human activities on landscape is mainlymanifested in the plain area, and the landscape fragmentation was increased year byyear. Landscape connectivity in the natural landscape was decreased year by year, butwas increasing in farmland.(4) Between1990to2000years, the gravity center of different landscape typeshad shifted. The migration distance of gravity center of grassland is farthest, thenfarmland, and then salt desert. The migration of farmland gravity center is forward toEbinur Lake. The gravity center of salt desert is forward to farmland. The gravitycenter of farmland and desert is close to each other. From2000to2011years, thegravity center of water is continued forward to farmland in the southeast direction.The gravity center of the salt desert is continued to promote the northeast. The gravitycenter of farmland is shifted back to the original. The gravity center of desert isforward to the northwest direction, and compared to1990, migrated northward. Thegravity center of forestland continues to advance toward the southwest. （5) The transformation between landscape types between1990and2000wasmore intense than between1990and2000. Spatial variation degree between1990-2000and2000-2011are different, but the change trend of different landscapetypes showed a consistency. The landscape types that change greatly is farmland andsalt desert during the two time periods. That is the human activity that makes thechanges of these two landscape types become lively.(6) Natural environment and social environment have different effects tolandscape structure. Human activities mainly affect the contagion. The air temperatureand land suface temperature mainly affects the patch area of landscape. Land sufacetemperature and air temperature mainly affects the patch area. Rainfall and elevationaffect more landscape index, and they have larger impact on landscape structure. In aword, the effect of the natural environment on landscape structure is greater than ofthe social environment in the Ebinur Lake Watershed. Natural environment plays aleading role on the landscape structure mode, and social environment transforms itsoriginal structure characteristics.