国家自然科学基金项目"基于能值的纸坊沟流域生态资产与人类福祉变化动态模拟"(41271549); 国家科技支撑计划项目(2012BAD14B03); 中央高校基本科研业务费专项资金资助(2014KJJCB33)
[目的] 评估2000—2013年无定河流域水土保持和退耕还林(草)的成效,为评估无定河流域生态修复工程成效提供数据支撑. [方法] 采用线性回归、相关系数和偏相关系数等方法,分析无定河流域2000—2013年NDVI(归一化植被指数)与NPP(净初级生产力)的变化及影响因素. [结果] (1) 2000—2013年,无定河流域植被覆盖增长率3.39%/a,远高于1999—2008年黄土高原植被覆盖增长率0.99%/a,且植被覆盖呈现阶段性的变化特征,其中有2次持续增长期.(2) 无定河流域植被覆盖变化以明显增加趋势为主,集中分布于黄土丘陵沟壑区,退化区域仅占3.95%,"线状"分布于植被覆盖基数较好的河谷两岸.(3) 2000—2013年,无定河流域植被累计固碳增加量1.96×107 t,相当于2010年陕西省能源消费碳排放的22.82%,累计固碳价值增加量2.36×1010元,相当于2010年陕西省GDP的2.33%. [结论] 无定河流域植被覆盖与固碳持续增加,主要驱动因素为人类活动,尤其是水土保持和退耕还林(草)等工程的实施.
[Objective] The objective of this study is to evaluate the effects of "soil and water conservation project" and "grain for green project" in Wuding river basin during 2000—2013 in order to provide data support for ecological rehabilitation project in this region. [Methods] By using linear regression, correlation and partial correlation, this paper analyzed the variations of NDVI and NPP and its driving factors in Wuding river basin during 2000—2013. [Results] (1) From 2000 to 2013, the growth rate of vegetation cover was 3.39%/a in the study area, which was faster than that in Loess Plateau (0.99%/a) from 1999 to 2008. The vegetation cover showed periodical characteristics, with two sustainable growth periods. (2) The vegetation cover was significantly increased in most area, especially the area distributed in the loess hilly-gully region in the southeast of the study area. The degradation area only accounted for 3.95%, and distributed on the both sides of the valley. (3) From 2000 to 2013, the accumulative total carbon sequestration was 1.96×107 t, which equated to 22.82% of carbon emissions from energy consumption in Shaanxi Province in 2010. The value of accumulative carbon sequestration was 2.36×1010 CNY, which equated to 2.33% of GDP in Shaanxi Province in 2010. [Conclusion] Human activity was the main driving force that influence the changes of vegetation cover and carbon sequestration, especially the implementation of "soil and water conservation project" and "grain for green project".