Pei Jie, Wang Li, Huang Huabing, Wang Lei, Li Wang, Wang Xiaoyue, Yang Hui, Cao Jianhua, Fang Huajun, Niu Zheng
School of Geospatial Engineering and Science, Sun Yat-sen University, Zhuhai, China.
Key Laboratory of Natural Resources Monitoring in Tropical and Subtropical Area of South China, Ministry of Natural Resources, Zhuhai, China.
Front Plant Sci. 2022 Oct 27;13:1043389. doi: 10.3389/fpls.2022.1043389. eCollection 2022.
Plant growth and its changes over space and time are effective indicators for signifying ecosystem health. However, large uncertainties remain in characterizing and attributing vegetation changes in the ecologically fragile South China Karst region, since most existing studies were conducted at a coarse spatial resolution or covered limited time spans. Considering the highly fragmented landscapes in the region, this hinders their capability in detecting fine information of vegetation dynamics taking place at local scales and comprehending the influence of climate change usually over relatively long temporal ranges. Here, we explored the spatiotemporal variations in vegetation greenness for the entire South China Karst region (1.9 million km) at a resolution of 30m for the notably increased time span (1987-2018) using three decadal Landsat images and the cloud-based Google Earth Engine. Moreover, we spatially attributed the vegetation changes and quantified the relative contribution of driving factors. Our results revealed a widespread vegetation recovery in the South China Karst (74.80%) during the past three decades. Notably, the area of vegetation recovery tripled following the implementation of ecological engineering compared with the reference period (1987-1999). Meanwhile, the vegetation restoration trend was strongly sustainable beyond 2018 as demonstrated by the Hurst exponent. Furthermore, climate change contributed only one-fifth to vegetation restoration, whereas major vegetation recovery was highly attributable to afforestation projects, implying that anthropogenic influences accelerated vegetation greenness gains in karst areas since the start of the new millennium during which ecological engineering was continually established. Our study provides additional insights into ecological restoration and conservation in the highly heterogeneous karst landscapes and other similar ecologically fragile areas worldwide.
植物生长及其在空间和时间上的变化是表征生态系统健康状况的有效指标。然而，在生态脆弱的中国南方喀斯特地区，对植被变化进行特征描述和归因仍存在很大的不确定性，因为大多数现有研究是在粗略的空间分辨率下进行的，或者覆盖的时间跨度有限。考虑到该地区景观高度破碎，这阻碍了它们检测局部尺度上植被动态的精细信息以及理解通常在相对较长时间范围内气候变化影响的能力。在此，我们利用三期十年的陆地卫星图像和基于云计算的谷歌地球引擎，以30米的分辨率对整个中国南方喀斯特地区（190万平方公里）在显著增加的时间跨度（1987 - 2018年）内的植被绿度时空变化进行了探索。此外，我们对植被变化进行了空间归因，并量化了驱动因素的相对贡献。我们的结果显示，在过去三十年中，中国南方喀斯特地区（74.80%）出现了广泛的植被恢复。值得注意的是，与参考期（1987 - 1999年）相比，生态工程实施后植被恢复面积增加了两倍。同时，赫斯特指数表明，2018年之后植被恢复趋势具有很强的可持续性。此外，气候变化对植被恢复的贡献仅为五分之一，而主要的植被恢复高度归因于造林项目，这意味着自新千年开始生态工程不断建立以来，人为影响加速了喀斯特地区植被绿度的增加。我们的研究为全球高度异质的喀斯特地貌以及其他类似生态脆弱地区的生态恢复和保护提供了更多见解。
