山地区域土地生态红线划定方法与实证研究——以重庆市涪陵区义和镇为例

无序和不合理的土地利用是引发生态问题的重要因素。合理划定土地生态红线,可协调土地利用和生态环境的关系,促进土地资源的合理配置,保障区域生态安全。山地区域地势起伏较大,水系密布,土地利用破碎化,作为重要的水土保持和水源涵养区域,是进行生态恢复和重建的关键地区。本文以山地区域村镇为例,运用GIS平台,基于生态敏感性和生态服务价值,对土地生态进行综合评价,据此划定刚性和弹性的土地生态红线。生态敏感性评价的指标包括坡度、植被覆盖度、水体、土壤类型和降水侵蚀力等5个指标;生态服务价值评价的指标包括食物生产、原料生产、气体调节、气候调节、水文调节、土壤保持、维持养分循环、生物多样性和美学景观9个指标。义和镇的刚性生态红线内所包含的刚性生态保护区面积为43.90 km²,占义和镇总面积的44.34%。弹性生态红线包含的弹性生态保护区面积为29.18 km²,占义和镇总面积的29.47%。义和镇的生态红线范围主要包含东北部山地区域和南部水系丰富地区,该区域的生态敏感性较高,同时也有较高的生态服务价值,因此生态红线的划定对于生态修复和生态保护具有指引作用,为生态系统健康发展提供基础保障,并可为构建生态文明安全格局提供科学支持。

Determination of ecological red line of mountainous areas: A case study of Yihe Town in Chongqing Municipality

Unsuitable land use is an important factor contributing to ecological problems. Determining ecological red line can coordinate the relationship between land use and the ecological environment, promote reasonable allocation of land resources, and improve regional ecological security. Research on methods to determine ecological red line has theoretical and practical values. Mountain areas have rugged terrain and dense water systems, where fragmentation of land use is often serious. They are also important areas with regard to soil and water conservation and key areas for ecological restoration and reconstruction. Taking a mountainous town—Yihe in Chongqing Municipality—as an example, this study used GIS tools and took into consideration ecological sensitivity and ecosystem services value to determine the rigid and flexible ecological red lines of the study area. This study chose slope, vegetation coverage, water and soil types, and erosive force of precipitation as indicators for ecological sensitivity assessment and food production, raw material production, gas regulation, climate regulation, hydrology regulation, soil retention, nutrient cycling maintenance, biodiversity, and aesthetic as indicators for ecological service assessment. The area within the rigid ecological red line is 43.90 km², 44.34% of the total area of Yihe Town; and the area within the elastic ecological read line is 29.18 km², 29.47% of the total area. Ecological red line encloses the northern and eastern mountainous area and southern area with dense water courses of the town. The ecological sensitivity and ecological services value are high is this area. The ecological red lines determined in this study identify key areas for ecological restoration and protection, and the methods and result can support policy-making for improving ecological security of the region.