ANALYSIS OF HUMAN-INDUCED STEPPE DEGRADATION BASED ON REMOTE SENSING IN XILIN GOLE, INNER MONGOLIA, CHINA
基于遥感的草原退化人为因素影响趋势分析

Grassland degradation in arid and semi_arid steppe results from the integrated impacts of nature and human factors and is one of the most important ecological and economic issues in China. It is necessary to discriminate between natural and human_induced degradation for purposes of rehabilitation and restoration of degraded steppe regions. Based on existing research, we proposed a method that integrated regression analysis and residual analysis to discriminate between areas degraded by human activities and those caused naturally. We applied this method to the Xilin Gole Steppe in Inner Mongolia, China as a case study using Pathfinder NOAA/AVHRR NDVI data from 1983 to 1999 and meteorological data within the same time period. Firstly, we constructed a regression model using the first 6 years (1983_1988) of data for each pixel between annual maximal NDVI and meteorological data (precipitation and temperature) including a time lag for precipitation. Secondly, the difference or residuals between actual and predicted maximal NDVI were derived for the latter 11 years (1989-1999). The analysis of the trends in the residuals of the first data set over time indicated that pixels with negative trends were human_induced degradation. The results showed that the Xilin Gole Steppe experienced a heavier degree of human_induced degradation from 1989 to 1999 with larger areas being impacted. The results are in accord with the status quo of the study area.