State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2024 Jan 10;907:168009. doi: 10.1016/j.scitotenv.2023.168009. Epub 2023 Oct 21.
Desertification caused by natural factors and human activities seriously threatens dryland biological communities. However, the impact of these factors on non-vascular plants in drylands has not been fully documented. This study proposed a framework to distinguish the natural and anthropogenic contributions to the distribution of the biological soil crust (BSC) coverage. The 20 model-simulated environmental datasets, including climate, soil characteristics and terrain, were selected to explore the internal relationship between these environmental drivers and BSC coverage. Random forest classification and regression models were developed to calculate the BSC coverage in the drylands of China under natural conditions. By subtracting the predicted natural BSC coverage from the observed BSC coverage, the spatial distribution of changes in BSC coverage attributed to human activities was mapped. The results showed that in the limited vegetation areas of China's drylands, human activities had a positive impact on BSC coverage in only 11.3 % of the regions while having a negative effect on 25.4 % of the regions. Moreover, human activities led to a 33 % reduction in BSC coverage in these regions. The positive impacts of large-scale ecological restoration projects on BSC coverage in the drylands of China were limited due to land use changes caused by human economic activities. This framework provides support for assessing regional variations in anthropogenic impacts on dryland BSC communities and contributes to the development of appropriate dryland management policies.
自然因素和人类活动导致的土地沙漠化严重威胁着旱地生物群落。然而，这些因素对旱地非维管束植物的影响尚未得到充分记录。本研究提出了一个框架，以区分自然和人为因素对生物土壤结皮（BSC）覆盖分布的贡献。选择了 20 个模型模拟的环境数据集，包括气候、土壤特征和地形，以探索这些环境驱动因素与 BSC 覆盖之间的内在关系。开发了随机森林分类和回归模型，以计算中国干旱地区自然条件下的 BSC 覆盖。通过从观测到的 BSC 覆盖中减去预测的自然 BSC 覆盖，可以绘制出归因于人类活动的 BSC 覆盖变化的空间分布。结果表明，在中国干旱地区有限的植被区域，人类活动仅对 11.3%的区域的 BSC 覆盖产生了积极影响，而对 25.4%的区域产生了消极影响。此外，人类活动导致这些区域的 BSC 覆盖减少了 33%。由于人类经济活动引起的土地利用变化，大规模生态恢复项目对中国干旱地区 BSC 覆盖的积极影响有限。该框架为评估人为因素对旱地 BSC 群落的区域变化的影响提供了支持，并有助于制定适当的旱地管理政策。
