Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environmental Science, South-Central Minzu University, Wuhan, 430074, People's Republic of China.
School of Civil Engineering and Architecture, Wuhan Institute of Technology, Wuhan, 430074, China.
Environ Monit Assess. 2022 Nov 21;195(1):131. doi: 10.1007/s10661-022-10681-w.
The middle and lower reaches of Hanjiang River Basin (MLHB), areas that have an important ecological function in China, have experienced great changes in the vegetation ecosystem driven by natural environmental change and human activity. Here, we explored the spatio-temporal dynamics of fractional vegetation coverage (FVC) and quantitatively analyzed its driving factors to advance current understanding of how the ecological environment has changed. Specifically, we used the dimidiate pixel model to calculate the FVC of the MLHB from 2001 to 2018 based on Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data. We then used Theil-Sen median slope (Sen's slope) and coefficient of variation (CV) to explore spatial and temporal variations, as well as characteristics in fluctuations. Finally, we utilized a geographical detector model (with spatial scale effects and spatial data discretization tests) to quantify the influence of the detected natural and human factors. Results showed that average annual FVC was 0.30-0.75 for ~90% of the study area over the 19-year study period with a heterogeneous spatial distribution. FVC variation trend displayed stability and improvement. Areas with higher FVC displayed greater stability. All 10 detected natural and anthropogenic factors were responsible for changes in FVC. The primary factors causing FVC to change were precipitation (in 2001) and slope (in 2018), followed by landform type, distance to water, and nighttime light (NTL) (in 2018). Precipitation and slope consistently displayed the largest interaction across all years. The interaction between human and topographical factors had gradually increasing significance on changes in FVC over the research period. The range and type of factors suitable for promoting vegetation growth were detected in the study area. Results of this study can provide a scientific basis for developing effective strategies for local vegetation protection, restoration, and land resource management.
汉江中、下游流域（MLHB）是中国具有重要生态功能的地区，受自然环境变化和人类活动的驱动，其植被生态系统发生了巨大变化。在这里，我们探索了分维植被覆盖度（FVC）的时空动态，并定量分析了其驱动因素，以增进对生态环境变化方式的了解。具体而言，我们使用二分像元模型，根据中分辨率成像光谱仪（MODIS）增强植被指数（EVI）数据，计算了 2001 年至 2018 年期间 MLHB 的 FVC。然后，我们使用 Theil-Sen 中值斜率（Sen's slope）和变异系数（CV）来探索时空变化以及波动特征。最后，我们利用地理探测器模型（具有空间尺度效应和空间数据离散化测试）来量化检测到的自然和人为因素的影响。结果表明，在 19 年的研究期间，研究区域约 90%的平均年 FVC 在 0.30-0.75 之间，具有异质的空间分布。FVC 变化趋势表现出稳定性和改善。FVC 较高的地区表现出更大的稳定性。所有 10 种检测到的自然和人为因素都导致了 FVC 的变化。导致 FVC 变化的主要因素是降水（在 2001 年）和坡度（在 2018 年），其次是地形类型、距水体的距离和夜间灯光（NTL）（在 2018 年）。在所有年份中，降水和坡度一直表现出最大的相互作用。在研究期间，人类和地形因素之间的相互作用对 FVC 的变化具有逐渐增加的重要性。在研究区域内检测到适合促进植被生长的因素的范围和类型。本研究的结果可为制定当地植被保护、恢复和土地资源管理的有效策略提供科学依据。
