Integrated Ecological Risk Assessment On Desert Steppe

Ecological Risk Assessment is developing rapidly in China. Many scholars take basin, mountain area, and urban development zone as study areas to study on ecological risk assessment. So far, a lot of practical experience has been accumulated, which is benefit for China to establish its own ecological risk assessment system. However, few researches can be located on the ecological risk assessment of desert grassland, which may influence the integrity of the establishment of the system. Thus, in this study, the desert grassland is taken as the research object and the Siziwang County in Inner Mongolia is considered to be the study area. According to the remote sensing data of Landsat TM and MODIS and field collected data, RS and GIS technology is applied and some representative indexes are selected. Moreover, the period from 2006 to 2015 is taken as the time scale, and what are conducted are the ecological risk assessment based on the changes of landscape pattern and the changes of NDVI and the combination of the two changes. The main conclusions of this study are demonstrated as follows:(1) During the decade from 2015 to 2016, the ecological risk index based on landscape pattern changes, the ecological risk index based on NDVI changes and the ecological risk index based on the combination of the two changes all showed that the ecological risk index of the study area in 2015 has increased compared with 2006.(2) Compared with 2006, the number of the areas with an increasing ecological risk index was significantly larger than that that of the areas with a decreasing ecological risk index in 2015. Among these areas, the area with a high ecological risk mainly distributed in the southern agro-pastoral ecotone where human activities are more frequent whereas the areas with a low ecological risk regional mainly distributed in the northern pastoral areas. In addition, the middle risk areas are at the surrounding of the high risk areas.(3) The determination coefficient of the power function model established by NDVI and dry weight is the highest, which can be used for the estimation of desert steppe.(4) From the year of 2006 to 2015, the overall landscape pattern changed little. Besides, what should be noted is the increase of the area of saline-alkali land+bare land+sandy land.