State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China.
State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China.
Sci Total Environ. 2024 Oct 10;946:174256. doi: 10.1016/j.scitotenv.2024.174256. Epub 2024 Jun 25.
Since 2012, the "Mountain Excavation and City Construction" (MECC) project has been implemented extensively on the Loess Plateau of China, transforming gullies into flat land for urban sprawl by leveling loess hilltops to fill in valleys. However, this unprecedented human activity has caused widespread controversy over its unknown potential ecological impacts. Quantitative assessment of the impacts of the MECC project on the vegetation is key to ecological management and restoration. Taking the largest MECC project area on the Loess Plateau, Yan'an New District (YND), as the study area, this study investigated the spatiotemporal pattern of vegetation dynamics before and after the implementation of the MECC project using a multitemporal normalized difference vegetation index (NDVI) time series from 2009 to 2023 and explored the response of vegetation dynamics to the large-scale MECC project. The results showed that the vegetation dynamics in the YND exhibited significant spatial and temporal heterogeneity due to the MECC project, with the vegetation in the project-affected areas showing rapid damage followed by slow recovery. Vegetation damage occurred only in the project-affected area, and 84 % of these areas began recovery within 10 years, indicating the limited impact of the large-scale MECC project on the regional vegetation. The strong correlation between vegetation dynamics and the MECC project suggested that the destruction and recovery of vegetation in the project-affected areas was mainly under anthropogenic control, which highlights the importance of targeted ecological policies. Specifically, the MECC project induced local anthropogenic damage to the plant population structure during the land creation period, but regeneration and rational allocation of the vegetation were achieved through urbanization, gradually forming a new balanced ecological environment. These findings will contribute to a full understanding of the response of vegetation to such large-scale engineering activities and help local governments adopt projects or policies that facilitate vegetation recovery.
自 2012 年以来，“削山造地”（MECC）项目在中国黄土高原广泛实施，通过削平黄土山顶填平山谷，将沟壑变为城市扩张的平地。然而，这种前所未有的人类活动对其潜在生态影响引发了广泛争议。定量评估 MECC 项目对植被的影响是生态管理和恢复的关键。本研究以黄土高原最大的 MECC 项目区延安新区（YND）为研究区，利用 2009 年至 2023 年多时相归一化植被指数（NDVI）时间序列，调查了 MECC 项目实施前后植被动态的时空格局，并探讨了植被动态对大规模 MECC 项目的响应。结果表明，由于 MECC 项目，YND 的植被动态表现出显著的时空异质性，项目影响区的植被迅速受损，随后缓慢恢复。植被破坏仅发生在项目影响区，其中 84%的项目影响区在 10 年内开始恢复，表明大规模 MECC 项目对区域植被的影响有限。植被动态与 MECC 项目之间的强相关性表明，项目影响区植被的破坏和恢复主要受人为控制，这凸显了有针对性的生态政策的重要性。具体来说，MECC 项目在土地开垦期间对植物种群结构造成了局部人为破坏，但通过城市化实现了植被的再生和合理配置，逐渐形成了新的平衡生态环境。这些发现将有助于全面了解植被对这种大规模工程活动的响应，并有助于地方政府采取有利于植被恢复的项目或政策。
