甘肃省白龙江流域生态承载力的时空变化

Spatiotemporal Change of Ecological Carrying Capacity in Bailongjiang Watershed of Gansu Province

[目的]从土地利用角度开展甘肃省白龙江流域生态承载力时空变化研究,为该流域生态环境治理和可持续发展提供科学依据。[方法]基于生态足迹理论,利用1990,2002,2010,2014年4期土地利用数据与GIS空间分析技术,对近25a来该流域生态承载力时空变化进行空间可视化表达和定量分析。[结果](1)时间尺度上,25a来流域生态承载力呈现"降—升—降"的波动变化趋势,各地类生态承载力变化趋势不同。(2)空间尺度上,流域生态承载力总体呈现西北与西南部高,东北部低,随海拔和坡度增加而递增的不均匀分布格局;随时间推移,流域不同区域和坡度范围的生态承载力变化趋势各异。(3)1990—2002年,2002—2010年,2010—2014年间流域各地类生态承载力转换频繁,转变趋势明显,导致近25a来流域生态承载力及其内部组成变化较大。[结论]近25a来流域生态承载力在波动中上升,流域生态质量有所改善;受地形地貌和土地利用/覆被变化的影响,流域生态承载力具有明显的空间异质性。退耕还林还草政策是流域生态承载力变化的主要影响因素之一。

[Objective]Bailongjiang Watershed was selected as a case to study the spatiotemporal change of ecological carrying capacity（ECC）and its driving mechanism from the perspective of land use change for the purpose of the ecological environment management and sustainable development of the watershed.[Methods]Based on the theory of ecological footprint,the spatial and temporal changes of the ECC of the watershed during the latest 25 years were analyzed by the remote sensing data and transfer matrix analysis method from 1990 to 2014.[Results]（1） On the time scale,the ECC of watershed during the latest 25 years changed with a general trend of＂decrease-increase-decrease＂,but had different trend for different land use type.（2） On the spatial scale,the watershed ECC showed an uneven spatial distribution：the area with higher value located in the northwestern and southwestern parts,and the area with low value located in the northeastern parts;the higher of the altitude and gradient,the higher of ECC.（3） From 1990 to 2002,2002 to2010 and 2010 to 2014,the change of the watershed ECC varied frequently with apparent transfer,respectively.[Conclusion]The watershed ECC fluctuated increasingly while the ecological quality was improvedduring the latest 25 a.The spatial pattern of the watershed ECC changed with obvious spatial heterogeneity due to the landform characteristics and land use/cover change,the grain for green project also affected the change of watershed ECC.