黄土丘陵区的土地利用变化及其生态风险

Land Use Change and Ecological Risk Evolution in Loess Hilly Region

[目的]探讨土地利用方式对生态风险的影响,为黄土丘陵区生态保护与土地利用决策提供一定依据。[方法]通过构建土地利用方式决策分析模型及土地利用生态风险指数,分析了上黄试区不同时期土地利用方式决策模式及其生态风险演变特征。[结果]研究初期,上黄试区土地利用方式模式表现为耗损型,生态风险呈现较高风险态势。1982—2000年,上黄试区通过开展基本农田建设、加强农业生产管理、发展庭园经济等措施,提高了土地的生产能力,土地利用方式由耗损型逐步转变到半集约型,生态风险也由较高风险过渡到中风险态势。2000—2010年,在国家退耕还林还草政策的推动下,土地利用方式由半集约型转变为集约型,生态风险也由中风险转变为较低风险。[结论]科技因素是推动土地利用方式决策与生态风险转变的关键,而政策因素是必要的补充。

[Objective]This study was aimed to provide a basis for decision-making in terms of ecological protection and land use planning in the loess hilly region through exploring the effects of land use pattern on ecological risks.[Methods]Land use pattern model and land use ecological risk index were adopted to quantitatively analyze the land use patterns and ecological risk evolution characteristics.[Results]At the start point of the investigation,the land use pattern model showed a depletion pattern,and the ecological risk was higher in the Shanghuang experimental area.During 1982—2000,the production capacity of the land was improved by carrying out the construction of basic farmlands,strengthening the management of agricultural production,and developing the garden economy.The land use changed from depletion to semi-intensive pattern.Meanwhile,the ecological risk index declined from high-risk to middle-risk class.During 2000—2010,because of the policy conduct of returning farmlands to forests and grasslands,land use further changed from semi-intensive to intensive pattern,and the ecological risk index also reduced from middle-risk to lower-risk class.[Conclusion]Scientific and technological factors are the key that promote the changes of decisionmaking for land use patterns and ecological risks,whereas the policy factors are the necessary supplements.