制定有空间差异的生态补偿标准是构建生态补偿机制的关键和难点。补偿标准的空间差异体现在提供的生态系统服务和付出的成本两个方面。其中，生态补偿保护成本因能准确反映某地关于生态系统保护的工作量和贡献程度而得到广泛关注。本研究针对山区自然因素和人文因素高度空间异质性的特点，以四川省雅安市宝兴县为例，利用 GIS 技术结合统计资料和实地调研， 核算了研究区的保护成本。同时使用面积内插法并从距离、 道路、 坡度和方向 4 个方面评价斑块可达性难易程度， 进行保护成本空间化研究。旨在为生态补偿标准的制定、 生态补偿空间选择以及生态补偿效果评价提供参考和依据。结果显示: ①通过考虑距离、 道路、 坡度和方向，计算得到宝兴县被管护林地的可达性系数，其范围在 0—1 之间，平均值为 0． 18，标准差为 0． 16。②2010 年，研究区流域生态补偿相关的保护成本为 4 590． 46 万元，其中不同保护对象的投入大小顺序为林地 ＞ 自然保护区 ＞ 水土保持地 ＞ 草地 ＞ 水源保护地。③研究区不同海拔带保护成本及其构成不同，林地保护成本在 1 000—4 000 m 范围内均较高，这与研究区林地的广泛分布有关; 草地保护成本集中在高海拔地区( 3 000—4 500 m) ; 而水源保护地保护成本集中在低海拔地区( 1 000—2 500 m) 。保护成本的核算准确性及空间化精度取决于对当地生态建设与保护措施的掌握程度和资料的收集、 获取情况。本研究使用的可达性难易程度来调整保护成本的空间差异，是一种基于地理环境要素空间化思路和尝试。主要考虑距离、 道路、 坡度和方向 4 个方面， 暂未考虑管护人员的交通工具、 视域范围、 办事效率等个体因素以及土地利用的限制。
 

Developing a scientific criterion with spatial difference of Payment for Ecosystem Service ( PES) is very important and difficult for the formation of PES mechanism． The spatial difference of the criterion of PES is dependent on the spatial difference of ecosystem services and the cost of PES． The protection cost calculation has been extensively applied in the current studies， because the protection cost can accurately reflect the workload and the contribution of ecosystem conservation． This study contraposes the
characteristics of the spatial heterogeneity of the natural and human factors in mountain regions of China， takes Baoxing County， Ya’ an City， Sichuan Province as an example， and estimates the protection cost of PES under the support of Geographic Information System ( GIS) and statistical data． Meanwhile， accessibility assessment of the protected patches and Areal Interpolation Method is applied to estimate the spatial difference of the protection cost． This study aims to provide reference for the spatial selection and quantitatively setting the criterion of PES． The results indicated that: ①the accessibility coefficient of forest lands is calculated with the road， slope and distance， and it is ranged between 0 and 1， with a mean of 0． 18 and the standard deviation of 0． 16． ② The protection cost of PES in Baoxing County is 459 046 yuan in 2010 and the magnitude order of the investment for protecting different objects is forest land ＞
nature reserve areas ＞ water and soil conservation areas ＞ grass land ＞ water source protected area． ③ The protection cost and its components are changed in diverse elevation． Protection cost of forest land is high in 1 000 － 4 000 m owing to the wide distribution of the forest in the study area． However， protection cost of grass land tends to occur at high elevation ( 3 000 － 4 500 m) and the protection cost of water source protected area tends to occur at low elevation ( 1 000 － 2 500 m) ． Accuracy of protection cost calculation and precision of protection cost spatialization depend on the data collection and acquisition of the local ecological construction and protection measures． It is an attempt based on the geographical environment factor for using the accessibility coefficient to adjust the protection cost． The distance， road， slope and direction are mainly considered in the accessibility assessment． However， the personnel factors ( such as the traffic tools， the range of vision， and efficiency) and the limit of land use are ignored．