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基于耕地连片度的高标准基本农田建设划区 被引量:20
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作者 杨建宇 赵龙 +3 位作者 徐凡 岳彦利 杜贞荣 朱德海 《农业机械学报》 EI CAS CSCD 北大核心 2017年第4期142-148,共7页
为提高高标准基本农田划定区域的耕地连片性,在耕地综合质量评价和耕地连片网络基础上,提出了局部耕地连片度计算公式来评价耕地的连片性,并采用四象限法空间耦合耕地质量和连片度2个时空属性。结果表明:献县高标准基本农田优先建设区... 为提高高标准基本农田划定区域的耕地连片性,在耕地综合质量评价和耕地连片网络基础上,提出了局部耕地连片度计算公式来评价耕地的连片性,并采用四象限法空间耦合耕地质量和连片度2个时空属性。结果表明:献县高标准基本农田优先建设区域面积为24 803.45 hm^2,重点建设区域面积为19 688.77 hm^2,有条件建设区域面积为19 538.64 hm^2,与面积累加方法相比,优先建设区域连片度提高了15.55%,而有条件建设区域连片度减小了37.82%,表明该方法明显提高了高标准基本农田建设划区的耕地连片度。 展开更多
关键词 高标准基本农田 网络 连片性 建设划区
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Reserve network planning for fishes in the middle and lower Yangtze River basin by systematic conservation approaches 被引量:1
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作者 Xinyi Huang Fan Li Jiakuan Chen 《Science China(Life Sciences)》 SCIE CAS CSCD 2016年第3期312-324,共13页
Although China has established more than 600 wetland nature reserves, conservation gaps still exist for many species, especially for freshwater fishes. Underlying this problem is the fact that top-level planning is mi... Although China has established more than 600 wetland nature reserves, conservation gaps still exist for many species, especially for freshwater fishes. Underlying this problem is the fact that top-level planning is missing in the construction of nature reserves. To promote the development of nature reserves for fishes, this study took the middle and lower reaches of the Yangtze River basin(MLYRB) as an example to carry out top-level reserve network planning for fishes using approaches of systematic conservation planning. Typical fish species living in freshwater habitats were defined and considered in the planning. Based on sample data collected from large quantities of literatures, continuous distribution patterns of 142 fishes were obtained with species distribution modeling and subsequent processing, and the distributions of another eleven species were artificially designated. With the distribution pattern of species, Marxan was used to carry out conservation planning. To obtain ideal solutions with representativeness, persistence, and efficiency, parameters were set with careful consideration regarding existing wetland reserves, human disturbances, hydrological connectivity, and representation targets of species. Marxan produced the selection frequency of planning units(PUs) and a best solution. Selection frequency indicates the relative protection importance of a PU. The best solution is a representative of ideal fish reserve networks. Both of the PUs with high selection frequency and those in the best solution have low proportions included in existing wetland nature reserves, suggesting that there are significant conservation gaps for fish species in MLYRB. The best solution could serve as a reference for establishing a fish reserve network in the MLYRB. There is great flexibility for replacing selected PUs in the solution, and such flexibility facilitates the implementation of the solution in reality in case of unexpected obstacles. Further, we suggested adopting a freshwater management framework in the implementation of such solution. 展开更多
关键词 middle and lower Yangtze River basin fish conservation systematic conservation planning reserve network MARXAN
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