基于土地利用变化的四川省凉山州移民生态效应研究

土地利用变化是自然演变与人类活动共同作用的结果,大量的人口流动一定程度上将影响土地利用方式,进而对区域生态环境质量产生影响作用。因此,研究人口流动对土地利用变化的影响及生态效应,能为合理调控区域人地关系,促进区域生态环境与经济的平衡发展提供理论支持。基于长时序高空间分辨率土地利用数据,以具有典型移民现象的四川省凉山州为研究区,针对移民驱动下的土地利用时空变化特征及其诱发的生态效应进行研究分析。结果表明:(1)2000-2020年间,受人口迁移影响,凉山州土地资源的利用结构和程度都发生了相应改变,以耕地、草地、林地及不透水面的面积变化最为显著。在人口迁入较多的西昌、冕宁和德昌等县市内,供人类生活、生存所需要的耕地和建筑用地的数量显著增加;相反,对于大量人口迁出的喜德、昭觉和美姑等地区,人类活动强度的降低为生态用地的恢复和重建提供了条件,生态用地面积不断上涨。(2)受土地利用类型、地形条件、人口分布等因素的影响,凉山州整体生态环境质量呈西高东低、北高南低的空间分布格局。2000-2020年,整体生态环境质量仅下降了0.36%,总体较为稳定。(3)生态环境质量改善区域集中于东部的越西、美姑及昭觉等县市,而生态环境质量降低的区域主要位于盐源、会里、西昌和德昌等县市。生态环境质量的改变与区域移民活动存在紧密联系,其中由移民迁入引发的耕地和不透水面对生态用地的挤占,对生态环境质量退化贡献比重达87.97%,而随着移民迁出为生态工程的实施提供条件,凉山州内生态用地面积共增加775.84 km²。

Ecological effects of resettlement based on land use change in Liangshan Yi Autonomous Prefecture of Sichuan Province

Land-use change is a consequence of human activities and climate change. It is heavily influenced by population migration, which further changes eco-environment. Therefore, investigating the impact of population migration on land-use change and its eco-environment implications can provide valuable theoretical support and reference for the rational land resource planning and utilization, as well as the sustainable development of the regional eco-environment and economy. In this study, we analyze the characteristics of regional land-use patterns and their changes in Liangshan Prefecture, Sichuan Province, which has experienced significant migration over the past decades. Using long-term and high-resolution land-use data, we examine the variations in eco-environment quality within the context of migration. The findings reveal the following: (1) From 2000 to 2020, the utilization pattern and intensity of land resources in Liangshan Prefecture underwent significant alterations due to population migration. The most prominent transformations were observed in the areas of cropland, grassland, forest, and impervious surfaces. In counties and cities such as Xichang, Mianning, and Dechang, which experienced a substantial population influx, there was a notable increase in the number of cropland and construction land required for human life and sustenance. In contrast, in regions like Xide, Zhaojue, and Meigu, where a sizeable number of people relocated, the decrease in human activity intensity created conditions conducive to the restoration and rehabilitation of ecological land, leading to a distinct expansion in ecological land area. (2) Influenced by variables such as land use patterns, topographical conditions, and population dispersion, the spatial distribution of overall eco-environment quality in Liangshan Prefecture exhibited a west-high, east-low, and north-high, south-low trend. Over the period from 2000 to 2020, a slight decline in quality was observed, yet the overall stability was maintained. (3) The eco-environment quality improvements were predominantly observed in the eastern region of the state, while declines were primarily centered in the western region. A clear correlation existed between variations in eco-environment quality and regional migration activities. Notably, the conversion of cropland and impervious induced by migrant inflows contributed to 87.97% of the overall eco-environment quality degradation. Concurrently, population migration has spurred the implementation of ecological projects, leading to the addition of 775.84 km² of ecological land within Liangshan Prefecture. Our study highlights the significant impacts of population migration on land-use change and eco-environment quality in Liangshan Prefecture. The findings emphasize the need for effective land resource management and ecological protection measures to mitigate potential ecological risks associated with ongoing migration trends. Furthermore, the investigation of regional land-use changes and eco-environment quality provides valuable insights for sustainable development strategies and decision-making processes in Liangshan Prefecture and other similar regions.