黄土丘陵沟壑区县南沟流域景观的功能类型构成

Composition of Landscape and Function Types of Xiannangou Watershed in Loess Hilly-Gully Region

以陕北黄土丘陵沟壑区县南沟流域为研究对象,通过现地勾绘景观斑块类型分布图并建立流域景观斑块类型数据库,计算景观指数,分析景观构成,为流域景观格局优化和治理效果评价提供依据。研究结果表明:1)县南沟流域景观类型中,刺槐林(成熟刺槐林和幼龄刺槐林)面积最大(35.12%),白羊草-茭蒿+铁杆蒿群丛、农田、狼牙刺灌丛、铁杆蒿+茭蒿群丛次之,以上6种景观类型占流域面积的82.26%、占流域斑块数的60.23%,构成流域景观的主体。2)生态防护型、经济生产型、生活服务型三大景观功能类型面积比约为:3.63∶1∶0.08,生态防护型景观的斑块数量和总面积最多,占流域景观的3/4以上。3)流域内人类主导景观与自然景观面积比约为2∶1,其中约2/3人类主导景观面积由生态防护型景观组成。县南沟流域景观构成的特点可以概括为:景观类型多样,斑块数量丰富,景观整体粒级微小,景观破碎,人类活动对流域景观构成影响大。未来应提高生态防护型景观植被质量,防止经济生产型景观造成的污染,合理规划生活服务型景观,建立生态健康和经济持续发展的小流域模式。

The composition of landscape and function types of Xiannangou watershed in loess hilly-gully region was studied based on a field investigation on which the landscape patch type maps were drawn.After digitizing the maps with geographical information technology,the landscape classification system and patch type database of Xiannangou watershed were established.The relevant landscape indices were calculated in order to analyze the landscape composition of this watershed,which would provide evidence for optimizing landscape pattern and evaluating the watershed management effect.The result showed： 1） Robinia pseudoacacia （both mature and young） occupied the largest area of Xiannangou watershed,followed by Bothriochloa ischaemun-Artemisia giraldii＋Artemisia sacrorum association,farmland,Sophora viciifolia and Artemisia sacrorum＋Artemisia giraldii association.The 6 landscape types occupied 82.26% of landscape area and 60.23% of landscape patches,thus they constituted the main part of Xiannangou watershed.2） The eco-protection type occupied more than 3/4 of total patch number and area in Xiannangou watershed.The area ratio of three landscape function types （eco-protection type,pro-economics type and living-service type） was around 3.63∶1∶0.08.3） The area ratio of human directed landscape and natural landscape was almost 2∶1 and eco-protection type occupied about 2/3 area of human directed landscape.The landscape composition of Xiannangou watershed was characterized by diverse landscape types,abundant patches,tiny landscape granularity,landscape fragmentation and great human influence on landscape composition.In the future,the vegetation quality of eco-protection type should be improved and prevented from pollution caused by pro-economics type,meanwhile the living-service type should be planned reasonably,and all of these measures can favor establishing the small watershed model which is healthy in ecology and sustainable development in economy.