2000—2019年四川省植被恢复成效与影响因素

Analyzing the Effect and Influencing Factors of Vegetation Restoration in Sichuan Province from 2000 to 2019

国家实施天然林资源保护工程与退耕还林等生态建设工程,为构筑长江上游生态屏障、促进长江流域经济可持续发展做出了突出贡献;评估退耕还林等生态工程实施后植被恢复成效及影响因素是促进区域植被恢复优化与生态环境改善的关键一步。基于MODIS MOD13Q1数据,应用Theil Sen斜率与Mann-Kendall趋势检验、“基线”评价方法、时空地理加权回归模型等量化不同时间尺度的植被时空变化、恢复成效和恢复机制。结果表明(1)植被覆盖状况良好,截止2019年底,四川省91%的区域植被出现增长,四川盆地东北部、四川省南部地区以及东南部乌蒙山、川西北高原地区植被覆盖较高;成都市内以及周围市区植被覆盖率较低。(2)植被恢复成效时空差异显著,占全省面积98.68%的区域植被恢复成效明显,高值区面积占比71.47%,集中于除成都平原外的四川省绝大部分区域。(3)气候变化对植被变化的影响以不显著为主,气温、降水对四川省植被恢复影响微弱,海拔和>35°坡度面积比等地理环境因子则以弱抑制作用为主。(4)在相对平稳的气候背景下,人均财政支出、耕地面积与人均GDP所代表的社会经济因素是植被恢复成效改善的重要影响因素。研究揭示的植被恢复效果及关键气候、地理环境和社会经济因子,可为植被恢复政策的优化提供一定理论支撑。

China has implemented natural forest resource protection projects and ecological construction projects such as returning farmland to forests, which have made outstanding contributions to building an ecological barrier in the upper reaches of the Yangtze River and to promoting sustainable economic development in the Yangtze River Basin. When evaluating the effectiveness and impacts of vegetation restoration after the implementation of ecological projects such as returning farmland to forests, assessments of the effects of various factors are key steps to promote optimization of regional vegetation restoration and improvement of the ecological environment. Based on MODIS MOD13Q1 data, this study used the Theil Sen slope and the Mann-Kendall trend test, the baseline evaluation method, and the spatiotemporal geographic weighted regression model to quantify the spatiotemporal changes, restoration effects, and restoration mechanisms of vegetation at different time scales. The results show that:(1) the vegetation coverage is in good condition. By the end of 2019, 91% of the regional vegetation in Sichuan Province had improved, and the vegetation coverage in the northeastern Sichuan Basin, southern Sichuan Province, southeastern Wumeng Mountains, and northwestern Sichuan Plateau was relatively high. However, the vegetation coverage in and around Chengdu was low.(2) The temporal and spatial differences in the effectiveness of vegetation restoration are significant. The vegetation restoration in regions accounting for 98.68% of the province′s area produced obvious results. High-value areas, which were concentrated in most areas of Sichuan Province, except for the Chengdu Plain, accounted for 71.47% of the area.(3) The influence of climate change on vegetation change is mainly insignificant. Temperature and precipitation have weak influence on vegetation restoration in Sichuan Province. Geographical environmental factors such as altitude and >35° slope area ratio are mainly weak inhibition.(4) Under the relatively stable climate background, the socioeconomic factors represented by per capita fiscal expenditure, cultivated land area and per capita GDP are important influencing factors for improvement of vegetation restoration. The vegetation restoration effect and key climate, geographical environment and socio-economic factors revealed by the study can provide certain theoretical support for the optimization of vegetation restoration policies.