Abstract:
Abstract: For discussing the change of land use/cover and landscape patterns in Kayrakkum Reservoir during the past 40 years, remote sensing images, i.e., MSS in 1975, TM in 1990, ETM+ in 2000, and TM in 2011, were used as the data source. The transfer matrix of land use/cover type map superposition was obtained using ENVI software, to study the land use area change, the single type of land use dynamic degree, and the indices of land use dynamic degree model of regional land use. Furthermore, the spatial-temporal characteristics of land use and landscape pattern changes in the Kayrakkum Reservoir area were systematically analyzed by using the landscape pattern quantity analysis method and by selecting different indices in type and landscape levels. Results showed that tremendous changes had taken place in the past 40 years for the land use/cover in Kayrakkum Reservoir area. Construction land area showed a sustainable increase; while low coverage grassland and unutilized land area tended a 'V' shape over time. However, water, arable land and middle coverage grassland areas were all with inverted 'V' shapes. Overall, the construction land and arable land expanded largely, while the middle coverage grassland, low coverage grassland and unutilized land decreased. Also, a large number of middle coverage grassland and unused land were changed into cultivated land. At the same time, part of the cultivated land was changed into construction land, which resulted in a significant increase in construction land and farmland. The study area changed with a 'V' shape, with a gradually accelerating trend, The active land use/cover type changed from water at early and middle time to low coverage grassland recently, whereas the stable type of land use/cover changed from middle coverage grassland and arable land at an early time, to unutilized land at the middle time, and then recently to arable land. Landscape pattern analysis indicated that middle coverage grassland and arable land hold dominant positions in the whole landscape. More landscape elements were detected adjacent to aquatic land. Construction land showed more patch numbers and was relatively scattered in the trend of concentration distribution. The patch size tended to be uniform, landscape fragmentation and diversity of landscape types tended to increase, and the landscape aggregation degree tended to decrease under the influence of human activity. Moreover, low coverage grassland and arable land played a controlling role of the whole landscape. Because water is the source of an oasis's life, Kayrakkum reservoir has occupied an important position in the region's ecological system. With the changes in the economic system and the impact of human activities in nearly 40 years, the area of the reservoir and the water level had experienced tremendous changes, which had an important impact on the dynamic change of land cover and landscape pattern. The result could provide a scientific basis for ecological environment protection, as well as sustainable use of water and land resources.