基于遥感技术的云南省生态系统水土保持价值测量

Value Evaluation of Conserving Water and Soil for Ecosystem Supported by Remote Sensed Technique in Yunnan Province

利用遥感影像数据进行生态系统净初级生产力、植被覆盖度等生态参数的采集,同时间接用于土壤保持量和水土保持价值的计算,结合修改过的U SLE模型,对云南省生态系统2001,2002,2003年水土保持价值进行了测算,利用NPP对估算结果进行调整,以考虑生态系统类型、结构与质量差异对水土保持价值的影响。结果表明:云南省生态系统2001,2002,2003年土壤保持量分别为131 798.92,117 845.5,104 176.71万t,对应的价值量分别为:1 933.351,1 707.579,1 566.783亿元。3年中林地(39.01%)、灌丛(23.02%)、草地(18.75%)3类生态系统平均土壤保持量占全省的80.77%,在水土保持中起着关键作用,因此一定要加强西部和南部的林地、灌丛和草地等生态系统的保护与管理。从水土保持价值的空间分布来看,基本保持西多东少,南多北少的格局,这与当地植被地带性分布基本一致。3年间云南省生态系统水土保持价值是逐年减少的,耕地和城市植被的水土保持价值主要受人为因素的影响,而林地、灌丛、草地的水土保持价值减少主要是由降水逐年减少造成的。

There were two purposes for it to use remote sensed data. The one was to collect the ecological parameter such as net primary productivity （NPP） and vegetation fraction and the other was to calculate the quantity of holding soil and the value of conserving water and soil indirectly. NPP and vegetation fraction were mainly used to illustrate the effect of ecosystems, their structures and quality differences on evaluating the value of conserving water and soil. Incorporating the modified USLE model, it evaluated the value of conserving water and soil for the ecosystem in Yunnan province from 2001 to 2003. The quantity of conserving soil of the ecosystem in the province was 1.31 × 10^9, 1.18 × 10^9 t and 1.04 × 10^9 t respectively for the year of 2001, 2002 and 2003, and its corresponding value was 1.93 × 10^11 RMB, 1.71 × 10^11 RMB and 1.57 × 10^11RMB. During the three years, the total average quantity of conserving soil of woodland （39.01%）, scrubland （23.02%） and grassland （18.75 %） was about 80.77% to that of the province, so the three ecosystems were on the key status to conserve water and soil in the provinces. For this reason, woodland, scrubland and grassland in south and west Yunnan Province must be protected and managed elaborately. From the spatial value distribution of conserving water and soil, the basic trend was that the west of the province was more than the east and the south was more than the north. The spatial pattern was consistent with zonal distribution of the vegetations. The value of conserving water and soil of the ecosystems was decreased gradually. Farmland and urban vegetation were affected by human factors and mainly decreasing precipitation caused the decreasing trend of that of woodland, scrubland and grassland.