四川省生态系统土壤保持功能空间特征及其影响因素

土壤保持是生态系统通过其结构与过程减少由于降水所导致的土壤侵蚀的作用,是生态系统重要调节服务之一。四川省位于长江上游,是我国重要的生态安全屏障区域,对其生态系统土壤保持功能的保护和土壤侵蚀的控制是维持长江中下游生态安全的重要保障。研究采用通用土壤流失方程(USLE)和统计学方法,对四川省生态系统土壤保持功能的空间特征以及影响因素展开分析,结果表明:(1) 2015年,四川省生态系统土壤保持总量为199.01亿t,平均土壤保持强度约409.43 t hm-2a-1,森林和灌丛生态系统是土壤保持功能的主体,农田生态系统仍发挥了相当数量的土壤保持作用,但农业活动中需注意采取水土保持措施;(2)空间上,土壤保持功能较强的区域主要位于地形起伏明显的盆周山地区(包括龙门山、邛崃山、大凉山和米仓山等),以巴中市、雅安市、达州市、广元市、攀枝花市、乐山市等地的平均土壤保持强度较高,以凉山州、阿坝州、甘孜州、雅安市、巴中市、达州市等地的土壤保持极重要区分布较广;(3)自然因素中,气候和地形是影响研究区生态系统土壤保持空间格局的主要因素,土壤因素在区域尺度上也表现出一定的影响,植被因素则可能在局域尺度上发挥作用。研究从土壤保持功能角度揭示了保障生态安全的重要区域,研究结果可为四川省的生态保护和侵蚀控制提供科学指导。

Spatial characteristics and effects of soil conservation service in Sichuan Province

Soil conservation, which is a fundamental regulating service, is defined as the reduction of water erosion by ecosystems through structures and processes. Sichuan Province, which is located in the upper reaches of the Yangtze River, is an important ecological security barrier in China. Protection of its soil conservation service and control of soil erosion are important safeguards for maintaining ecological security in the middle and lower reaches of the Yangtze River. This study used the Universal Soil Loss Equation (USLE) and statistical methods to analyze the spatial characteristics and influencing factors of ecosystem soil conservation service in Sichuan Province. The results showed that:(1) In 2015, the total soil conservation in Sichuan Province was 19.90 billion tons, and the average soil conservation intensity was approximately 409.43 t hm^-2 a^-1. Forests and shrubs were the main ecosystem components providing soil conservation service, whereas the cropland ecosystem still played a role, and soil and water conservation measures should be considered in agricultural activities. (2) From the spatial distribution, the areas with high soil retention capacity were mainly located in greatly undulating mountains surrounding the Sichuan Basin, such as Longmen Mountain, Qionglai Mountain, Daliang Mountain, and Micang Mountain. In terms of the cities at the prefectural level, Bazhong City, Ya''an City, Dazhou City, Guangyuan City, Panzhihua City, and Leshan City had relatively high soil conservation capacity, whereas the very important areas for soil conservation were widely distributed in the Liangshan Prefecture, Aba Prefecture, Ganzi Prefecture, Ya''an City, Bazhong City, and Dazhou City. (3) Among the natural factors, climate and terrain were the main factors affecting the spatial pattern of soil conservation service in the study area. The soil factor also exhibited some influence on the regional scale, whereas the vegetation factor may play a role on the local scale. The study revealed key areas for ensuring ecological security from the perspective of soil conservation service. Its results can provide scientific guidance for ecological protection and erosion control in Sichuan Province.