三峡库区建坝前后森林生态系统服务动态

Dynamics of Forest Ecosystem Services Before and After Dam Construction in the Three Gorges Reservoir Area

基于六期Landsat TM/ETM+/OLI影像数据,利用生态系统服务功能评估规范及GIS空间统计方法,对三峡库区1990~2015年间森林生态系统服务价值动态变化进行分析。结果表明:三峡库区森林面积与森林覆盖率逐年增加,森林面积增长率71.04%,森林覆盖率由31.27%增加到53.48%。库区整体的森林类型结构比较稳定,表现为针叶林>混交林>灌木林>阔叶林。时间上,三峡库区森林生态系统服务价值呈上升趋势,具体表现为快-慢-快的增长特征。三峡库区单位面积森林生态系统服务价值在总体增长趋势下出现局部负增长趋势,各森林类型的单位面积价值与三峡库区整体的单位面积价值有着相同的变化趋势,均表现为增加-减少-增加的变化特征。三峡库区各类型服务价值的贡献表现为:涵养水源>固碳释氧>生物多样性保护>保育土壤>净化大气环境>积累营养物质>森林防护。空间上,1990~2015年,三峡库区森林生态系统服务价值的地域分布大致以巫溪至武隆一线为界,呈现出东南高、西北低的特征。1990~2015年三峡库区森林生态系统服务价值变化幅度呈现出'西增加快,东增趋缓'的格局特点。

Based on the six issues of Landsat TM/ETM+/OLI image data, the dynamic variations of forestry ecosystem service values in Three Gorges Reservoir Area(TGRA) from 1990 to 2015 was analyzed by using the ecosystem service function evaluation specification and GIS spatial statistical method. The results showed that the forest area and forest coverage rate of the TGRA increased annually. The forest area growth rate was 71.04%, and the forest coverage rate increased from 31.27% to 53.48%. The structure of overall forest type was relatively stable, which was characterized by coniferous forest > mixed forest > shrub forest > broad-leaved forest. The value of forest ecosystem services in the TGRA showed an upward trend on a timescale, growth characterized by "quick, slow, quick". The average forest ecosystem service value in the TRGA showed a local negative growth feature trend under the overall growth trend. Different types of forests had the value trend as that of the TRGA, which showed the variation characteristics of "increase, decrease, increase". Contribution of different ecosystem service in the TGRA ranked as follows: water conservation> carbon fixation and oxygen released > biodiversity conservation > soil conservation> atmosphere environmental purification > nutrient accumulation > action of forest against natural calamities. From 1990 to 2015, the geographical distribution of forest ecosystem service of the TGRA was along the Wuxi-Wulong line in a spatial scale, which was higher in the southeast and lower in the northwest. From 1990 to 2015, the variation range of forest ecosystem service value of the TGRA had grown rapidly in west while slowly in east.