“三江并流”区生态系统土壤保持服务的空间分布特征

基于通用土壤流失方程(USLE)和地理信息系统(GIS)技术构建空间分析模型,作者对“三江并流”区土壤保持服务物质量的空间分布进行估算,揭示该服务在不同海拔高度和土地利用类型上的分布特征,明晰不同生态系统的土壤保持服务功能.结果显示本区年均土壤保持总量达5.10×109 t·a-1,单位面积土壤保持量为767.66 t·hm-2·a-1.土壤保持服务高值地区集中在泸水县中南部怒江沿岸、云龙县中部澜沧江沿岸、玉龙县东北部金沙江沿岸及宾川县东部;主要分布于2 000～3 500 m的有林地中.各类生态系统的土壤保持服务功能(单位面积土壤保持量)为半湿润常绿阔叶林＞中山湿性常绿阔叶林＞暖性针叶林＞季风常绿阔叶林＞干热河谷硬叶常绿栎林＞暖温性稀树灌木草丛,亚高山草甸生态系统最低.气候、地形、土地利用方式和植被覆盖及其综合作用是影响“三江并流”区土壤保持服务空间分布的主要因素.

The spatial pattern of soil retention ecosystem service in the Three Parallel Rivers Region

Using the Universal Soil Loss Equation (USLE) and GIS technique, this study ① modeled the spatial distribution of soil retention ecosystem service in the Three Parallel Rivers Region, ② analyzed the distribution of the service on different elevation zones, and land-use types, and ③ assessed the capacities of different ecosystem types in providing the service.The results showed that ① the annual total of soil retention in the Three Parallel Rivers Region was 5.10×10⁹ t·a^-1, averaged 767.66 t·hm^-2·a^-1;② the high-value regions of soil retention service were primarily located in the riverside areas of Nu River in south-central Lushui, Lancang River in central Yunlong, Jinsha River in northeast Yulong, and the east areas in Binchuan, mainly in the forest land ranged from 2 000 to 3 500 meters in elevation;③ semi-humid broad-leaf evergreen forest had the highest soil retention capability, followed by mid-montane humid broad-leaf evergreen forest, warm conifer forest, monsoon evergreen broad-leaf forest, hot-dry valley sclerophyllous evergreen oak forest, and warm temperate shrub-grassland, while sub-alpine meadow had the lowest soil retention capability.We concluded that climate, topography, land-use patterns and vegetation cover as well as the interactions among them are the main factors that affect the spatial pattern of soil retention ecosystem service in this region.