水是限制和维系生物活动的主要因子,水文连通性与诸多生态过程联系紧密。作为表征水循环过程中物质、能量和生物体在景观单元之间传输的过程,水文连通性建立了地表水循环过程中景观单元物质与能量流之间的相互联系。运用文献计量方法,以Web of Science数据库及CNKI数据库为数据源,检索国内外水文连通性相关研究文献,运用Bibexcel、Ucient和Citespace等软件分别得到高频词、关键词共现网络可视图,在此基础上梳理国内外水文连通性研究进展。研究结果表明:围绕水文连通性,国内外发文量均呈现上升趋势,自1990年以来,国外水文连通度方面的研究与国内相比起步较早,且增长幅度较大;从关键词频上看,国外多偏重于不同类型生态系统结构功能变化对水文连通性的研究,国内则多偏重于河湖生态系统水系连通演变的研究;爆发词词频分析显示水文连通性与气候变化、生物多样性以及生态系统服务一度成为该领域研究热点;根据共现网络可视图,梳理国内外研究方向,水文连通性与生态过程、不同类型生态系统水文连通性对物质传输的影响,生态系统结构和功能的变化对水文连通性的影响等方面是当前的研究热点。开展不同尺度水文连通性制图,地下水依赖型生态系统水文连通性表征,基于地理信息技术与长期野外监测资料开展多尺度水文连通性定量评估和模型模拟是未来水文连通性研究的趋势。
[Objective] The aim was to research the relationships among different e- valuation farmland units and conduct division-of farmland use in order to provide scientific references for protection and rational use of farml...
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[Objective] The aim was to research the relationships among different e- valuation farmland units and conduct division-of farmland use in order to provide scientific references for protection and rational use of farmland at county level. [Method] Using Pingdu City as a case, the research selected land use indices such as farmland use structure, output, geographical location, eta/., and then performed a cluster analysis for farmland use division. [Result] Farmlands in Pingdu can be classified into 4 groups. In groups 1 and 2, it is necessary to strengthen farmland protection, especially for highly-quality farmlands, to guarantee the quantity and quality of local crops. In groups 1 and 3, it is necessary to improve concentration degree and use rate of construction lands and control farmland pollution possibly caused by constructions. In group 4, priority should be given to maintaining diversity of land use patterns, and avoiding aimless farming expansion. [Conclusion] During urbanization process in eastern coastal agricultural regions, it is of importance to prevent fertile farmlands being occupied by construction lands to enhance use rate of construction lands. Furthermore, agricultural non-point pollution should be detected constantly in intensively used farmlands, especially in vegetable fields. Additionally, land use diversity should be well protected by avoiding farmland expansion and im- proving farmland environment.
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