八步沙林场防沙治沙区植被覆盖度时空演变分析

Spatio-temporal Evolution Analysis of Vegetation Coverage in Babusha Forest Farm Sand Control Area

以古浪县八步沙林场防沙治沙区域及其周边乡镇为研究区,基于Landsat影像,利用植被覆盖度遥感估算方法提取了1991-2019年研究区的植被覆盖度数据,并对区域内植被覆盖度变化的总体趋势、时空演变特征、影响因素等进行了深入分析。结果表明:(1) 1991-2019年区域内植被覆盖度明显向好发展,极低植被覆盖度区域逐年减少,2015年前低植被覆盖度区域逐年增加,2015年后逐渐转换为中植被覆盖度及以上等级;(2) 28 a间极低植被覆盖度区域减少了32%,同时低植被覆盖度及以上等级区域面积有不同程度的增加;(3) 2015年前区域内植被覆盖以向沙漠腹地的延伸为主,2015年后则以植被覆盖度等级的梯度递增为主;(4)区域内植被覆盖度的显著提高,受自然和人为双重因素影响,其中人为因素是主要影响因素。

We used the remote sensing vegetation coverage estimation method to extract the vegetation coverage data in the study area of Babusha forest farm and surrounding towns in Gulang County based on Landsat images from 1991 to 2019, and analyzed the overall trend, spatio-temporal evolution characteristics and influencing factors of vegetation coverage change in the research area. The results show that(1)the vegetation coverage in the research area obviously developed in a good direction from 1991 to 2019, the areas with extremely low vegetation coverage decreased year by year. The areas with low vegetation coverage increased year by year before 2015, and they gradually changed to medium vegetation coverage or above after 2015.(2) The areas with extremely low vegetation coverage decreased by 32% during the 28 years, and the areas with low vegetation coverage increased by more than 20%.(3) The vegetation coverage in the research area mainly extended to the desert hinterland before 2015, while the gradient of vegetation coverage grade mainly increased after 2015.(4) The significant improvement of vegetation coverage in the research area was affected by both natural factors and human factors, and human factors were the main factors.