Meng Qi, Wu Zhi-Tao, DU Zi-Qiang, Zhang Hong
Institute of Loess Plateau, Shanxi University, Taiyuan 030006, China.
College of Environment and Resource Science, Shanxi University, Taiyuan 030006, China.
Ying Yong Sheng Tai Xue Bao. 2021 Aug;32(8):2895-2905. doi: 10.13287/j.1001-9332.202108.018.
Based on the MODIS NDVI data from 2000 to 2018, we estimated the fractional vegetation cover (FVC) using the dimidiate pixel model and analyzed the spatiotemporal characteristics of FVC in the Beijing-Tianjin sand source region (BTSSR). The geographical detector model was used to estimate the impacts of natural and human factors on FVC spatial distribution at the regional scale. The results showed that the FVC of the BBTSR showed an increasing trend from 2000 to 2018, with an annual growth rate of 0.013·(10 a) and a vegetation increase rate of 8.2%. The area with high FVC was concentrated in the Yanshan Mountain water source protection area, followed by the pastoral transitional zone desertified land control area and the Otindag sandy land area. The area with poor FVC was concentrated in the northern arid grassland area. The explanatory power of driving factors to FVC varied across different regions. Among the natural factors, annual precipitation was the main driving factor for the spatial distribution of FVC in the northern arid grassland area, the Otindag sandy land area and the Yanshan Mountain water source protection area. Slope was the main driving factor for the spatial distribution of FVC in the pastoral transitional zone desertified land control area. Among different human activities, the number of large livestock at the year-end was the main driving factor controlling the spatial distribution of FVC in the northern arid grassland area and the pastoral transitional zone desertified land control area, while population density was the main driving factor controlling the spatial distribution of FVC in the Otindag sandy land area and the Yanshan Mountain water source protection area. There were regional differences in the influen-ce of other factors on FVC spatial distribution. The results of the interaction detector showed that the two-factor interactions were mainly the double-synergy and nonlinear synergy. The interaction of human activities with annual precipitation and slope could more fully explain the spatial variations of FVC. The range of suitable vegetation growth identified by the risk detector was the area with annual precipitation of 316.4-486.0 mm, average relative humidity of 48.4%-57.6%, and average annual temperature of 2.5-7.9 ℃, while other driving factors were different in different zones.
基于2000—2018年的MODIS NDVI数据，利用像元二分模型估算了植被覆盖度（FVC），并分析了京津风沙源治理工程区（BTSSR）FVC的时空特征。采用地理探测器模型估算自然和人为因素对区域尺度FVC空间分布的影响。结果表明，2000—2018年BTSSR的FVC呈增加趋势，年增长率为0.013·(10 a)，植被增加率为8.2%。高FVC区域集中在燕山山脉水源保护区，其次是农牧交错带荒漠化土地治理区和浑善达克沙地地区。低FVC区域集中在北部干旱草原区。不同区域驱动因素对FVC的解释力不同。在自然因素中，年降水量是北部干旱草原区、浑善达克沙地地区和燕山山脉水源保护区FVC空间分布的主要驱动因素。坡度是农牧交错带荒漠化土地治理区FVC空间分布的主要驱动因素。在不同的人类活动中，年末大牲畜存栏数是北部干旱草原区和农牧交错带荒漠化土地治理区FVC空间分布的主要控制因素，而人口密度是浑善达克沙地地区和燕山山脉水源保护区FVC空间分布的主要控制因素。其他因素对FVC空间分布的影响存在区域差异。交互探测器结果表明，双因素交互作用主要为双协同和非线性协同。人类活动与年降水量和坡度的交互作用能更充分地解释FVC的空间变异。风险探测器确定的适宜植被生长范围是年降水量316.4—486.0 mm、平均相对湿度48.4%—57.6%、年均气温2.5—7.9℃的区域，而其他驱动因素在不同区域有所不同。
