秦岭森林生态系统服务价值的时空演变

以1984、2000、2005和2014年的Landsat TM影像为数据源,使用ERDAS软件中的监督分类方法获得秦岭土地利用类型分布图;从时间和空间角度对单位面积生态系统服务价值当量因子进行区域修正,并利用植被覆盖度进行逐像元二次修正后,运用RS和GIS技术计算1984—2014年秦岭森林生态系统服务价值,所得结果利用敏感性指数进行验证.结果表明: 1984—2014年,研究区森林面积约占总面积的77%,耕地和建设用地面积变化最明显;秦岭生态系统总服务价值逐年增长,研究期间共增长1.68×10¹⁷元,增长速率最快的森林生态系统服务价值的贡献率为93.8%,水域和草地的贡献率分别为1.6%和1.3%;生态系统服务价值在空间分布上呈现出随距研究区边界距离增大而增长的状态,且与秦岭土地利用类型的空间分布和单位面积价值基本一致;各项服务功能的年变化率相差不显著,4大生态系统功能中,调节服务价值对生态系统总服务价值的贡献最大(62.7%～65.8%),而气候调节服务价值变化最大,增加4.91×10¹⁶元;敏感性指数均小于1,表明修正后的服务价值指数较稳定,估算结果较可靠.秦岭森林生态系统服务价值巨大,加强森林生态系统的保护是维持秦岭生态系统稳定的有效措施.

Evaluation of the forest ecosystem service values in Qinling,China

Landsat TM images of Mt. Qinling in 1984, 2000, 2005, and 2014 were used to extract land use and land cover type by a supervised classification method in ERDAS software. Equivalent factor of ecosystem service value per unit area was revised regionally in temporal and spatial dimensions, and then was modified pixel by pixel using the vegetation coverage. Forest ecosystem service values from 1984 to 2014 were calculated with RS and GIS techniques, and the results were tested by the sensitivity index. The results showed that from 1984 to 2014, forest area accounted for 77% of the study area, and the area changes in cultivated land and construction land were the most obvious. The total ecosystem service value of Mt. Qinling increased annually and by a total of 1.68×10¹⁷ yuan during the study period. The forest ecosystem service value (its growth rate was the biggest) contributed 93.8% of the overall ecosystem service value, while water and grass ecosystem service value contributed 1.6% and 1.3%, respectively. The ecosystem service value tended to increase with increasing distance from the study area boundary, which was consistent with the spatial distribution and per-unit ecosystem service value of land use types in Mt. Qinling. The annual rate of change of each ecosystem service value was insignificant. Among the four ecosystem functions, the service value of regulation accounted for 62.7%-65.8% of the total ecosystem service value, and the service value of climate regulation showed the most dramatic increase by 4.91×10¹⁶ yuan over the study period. The sensitivity index was <1, which indicated that the modified service value index was stable and the calculated results were reliable. Overall, the forest ecosystem service value in Mt. Qinling was very large, and strengthening forest protection would be an effective measure for maintaining the stability of the Mt. Qinling ecosystem.