Dynamics Changes And Driving Forces Analysis Of Landscape Pattern Of Otindag Sandy Land

Desertification has been affecting the natural resources, environment, every aspect of socio-economic and human survival and development. Otindag sandy land, one of four biggest sandy lands in Inner Mongolia, is the main sandstorm source of Beijing and Tianjin. Located in ecotone between agriculture and animal husbandry, Otindag sandy land have typically environmental sensitive and vulnerable, leading to becoming sensitive areas in response to global change. Based on previous studies, using Landsat sensing images in the summer of 1994,2001 and 2014 by the method of a single band threshold segmentation and visual interpretation and software of Argis10.0, Envi5.0 and Fragstats4.2, the spatial distribution information of Otindag sandy land was extracted in nearly 20 years. In addition, dynamic change process of sandy land was analyzed by spatial overlay, and the driving force of quantitative analysis from climatic and socio-economic factors was based on Logistic regression model. Driving mechanism of dynamics changes was fundamentally understanded, which can provide theoretical basis for restoration and reconstruction of Otindag sandy land. In this study, the main conclusions are as follows:(1) The results indicated that the area of fixed sandy land decreased and then increased, showing an overall decreasing trend; semi-fixed sandy land increased; bare sandy land firstly increased and then decreased, showing an overall decreasing trend; the area of wetlands reduced, especially the decreasing trend of water and meadow was obvious.(2) In Otindag sandy land, fixed land degraded into semi-fixed land and bare sand from 1994 to 2001; in 2001-2014, bare sand recovered to semi-fixed sand and fixed land.(3) In 1994, the biggest patch area accounts for a higher percentage of landscape, landscape was inclined to homogeneous and continuous distribution; in 2001, landscape fragmentation was most serious, strong heterogeneity and poor connectivity; in 2014, compared to the degree of landscape fragmentation in 2001, the sandy land showed a trend of gradual recovery.(4) In Otindag sandy land, during 1994-2001, the leading driving factors of degradation were temperature, wind speed, precipitation in natural factors and grazing intensity in human factors; the decrease of wetlands were impacted by precipitation and grazing intensity. From 2001 to 2014, the control of grazing intensity and governance played an major role in the recovery of sandy land, such as grain to green program, the treatment of sand and wind source from Tianjin and Beijing areas, nature reserve construction; wind speed and temperature in natural factors and human factors had a common influence on the decrease of wetlands.