内蒙古林草过渡区植被覆盖度时空变化及其驱动力研究──以呼伦贝尔市和兴安盟扎赉特旗为例

Spatial and Temporal Variation and Driving Force of Vegetation Coverage in Forest-grass Transition Area of Inner Mongolia:A Case Study of Hulunbuir City and Jalaid Banner of Hinggan League

以呼伦贝尔市、兴安盟扎赉特旗作为研究区,基于MODIS NDVI数据,利用像元二分模型反演得到研究区2001—2016年植被覆盖度数据,研究其草原退化整体变化趋势及影响因子。研究结果表明:极低覆盖和低覆盖植被面积不断增长扩大,年均增长分别率为12.29%和3.13%;中覆盖从面积增长转为面积减小,年均增长率为-4.63%;高覆盖和极高覆盖植被面积一直在减小,年均增长率分别为-5.99%和-4.8%;坡度≤5°的地区退化率较高。气象、海拔和坡向因子宏观上决定植被的分类和密集程度,但由于研究区人地关系复杂,草原退化主要以人口密度和牲畜密度较为集中的地区为主。

Hulunbuir City and Jalaid Banner of Hinggan League were taken as the study areas, based on the MODIS NDVI data, we used the dimidiate pixel model data from 2001 to 2016 to get the vegetation coverage data, studied the change trend of grassland degradation in these areas and the influencing factors. The results showed that the area of extremely low vegetation coverage and low vegetation coverage increased with the average annual growth rate of 12.29% and 3.13% , respectively, the area of middle vegetation coverage increased and then decreased, and the average annual growth rate was-4.63% ; that of high vegetation coverage and extremely high vegetation coverage reduced with the average annual growth rate of -5.99% and -4.8% , respectively. The degradation rate was high where the gradient was slope ≤5°. In general, meteorological condition, elevation and slope direction determine the classification and intensity of vegetation, but the relationship between man and land in the study area is complex, grassland degradation is mainly concentrated in the area where population density and livestock density are high.