Dynamic Analysis Of Land Change And Landscape Ecological Security In Yinchuan Basin

Ecological environment is the foundation for people’s survival and socio-economic development. Land use and cover change which directly or indirectly impacts the material recycling and energy exchange in ecosystems, has closely relationship with human development and the stability of human society. With the acceleration of urbanization and industrialization process, the scope of land use continues to expand, and the intensity of land use becomes strength.The contradictions between human beings and resources, environmental protection and socio-economic development have become increasingly prominent, so that ecological problems have triggered a serious threat to human socio-economic sustainable development. The landscape is the resource for human economic activities and the object of human exploitation. The effect of ecological processes produced by different types and intensity of landscape patterns has regional and cumulative characteristics, and directly reflects the structure and composition of the ecosystem, thus affecting the ecological safety. The effects of land use change to the landscape ecological security can help us understand the impact of human activities on the ecological environment, and provide a reference for the development of land policies and measures for sustainable development.Yinchuan basin is the political, economic and cultural center of Ningxia Province, which is also the important industrial and agricultural production bases in the upstream areas of Yellow River basin, and it is also the important core areas which drive the economic development of Ningxia and the surrounding areas. As the economy continues to develop in Yinchuan Basin, ecological and environmental problems have become increasingly prominent. Firstly, this paper gets the land use data of Yinchuan basin by interpreting the remote sensing images, and then analyzes the situation of land use change. Secondly, after calculating the landscape pattern index, soil erosion index and vegetation coverage index, we use them to structure the model of the degree of ecological security aiming at getting the degree of ecological security of Yinchuan basin in different times. Finally, choose the land use degree composite index, integrated land use dynamic degree and the vegetation adjusted NTL urban index to analysis how the land use change and the economic and demographic development impact the landscape ecological security, and then give reasonable suggestions. The main conclusions are as follows:(1) During the research period, the construction land of Yinchuan basin expands rapidly, increasing 32726.97hm2, the forest land growths fast, increasing 27365.58hm2, the grassland, the arable land and the unused land reduce a little, decreasing 49691.07hm2,9045hm2 and 5229.18hm2, and the water area is essentially unchanged. Yinchuan basin dominant shares of the arable land and grassland, followed by the construction land, the forest land and the water area, and the smallest proportion is the unused land. The transfer matrix tells that the conversion between arable land, forest land and grassland is the most intense. In terms of land use degree composite index, find that Yinchuan urban (Xixia District and Jinfeng District) and Shizuishan urban (Dawukou District) most dramatic change, due to the increase of the construction land.(2) The degree of landscape ecological security of Yinchuan basin is high, the western part Helan Mountain is lower, and the basin plain district is higher. The degree of landscape ecological security of middle and south of Yinchuan basin has gradually increased and the north is contrary. From 2001 to 2012, the proportion of lower level grids of landscape ecological security decreased, low and general level first decreased and then increased, the high level first increased and then decreased and the higher level increased obviously. The ecological environment shows a good development trend.(3) The degree of landscape ecological security of research area is positive correlation between the spaces and has obvious global spatial autocorrelation, which shows strong spatial concentration and the spatial concentration trend first decreased and then increased. The type of spatial concentration is High-High concentration and Low-Low concentration, which is positive correlation between spatial association patterns. In LISA terms, the Helan Mountain is Low-Low concentration, the significance is 0.01. The High-High concentration mainly distribution in middle and south of the basin, and the significance is 0.01 inside and 0.05 outside.(4) The land use change has closely relationship with landscape ecological security. The lower the degree of landscape ecological security is, the lower the degree of land use. With the degree of land use increasing, the degree of landscape ecological security increases, but it will decrease after the degree of land use increasing to a certain level. The integrated land use dynamic degree represents the change speed of land use. The higher the value is, the more intense the landscape ecological security is impacted, and the direction of theimpactis uncertain.(5) Different types of land transfer have different effectson the landscape ecological security. The forest can increase the landscape ecological security. The expanding arable land with the proportion of construction land and grassland increasing may decrease the landscape ecological security. The expanding grassland with the proportion of construction land increasing may also decrease the landscape ecological security. The expanding construction land while increasing the forest and grassland is benefit for increasing the landscape ecological security.(6) The landscape ecological security is also impacted by population and economic development. Population and economic development will lead the ecological environment become well, but the same as the degree of land use, population and economic development may destroy the environment to a certain level.