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卧龙自然保护区三江珙桐群落种间关系的数量分析 被引量:14
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作者 朱利君 苏智先 +1 位作者 王伟伟 张亚爽 《生态学杂志》 CAS CSCD 北大核心 2005年第10期1167-1171,共5页
应用2×2列联表的Fisher精确检验、Pearson相关系数和Spearman秩相关系数检验研究了卧龙自然保护区三江珙桐(Davidia involucrata)群落种间关系。测定了83种植物,共3 403个种对的种间关联(或相关)。结果表明,2×2列联表的Fishe... 应用2×2列联表的Fisher精确检验、Pearson相关系数和Spearman秩相关系数检验研究了卧龙自然保护区三江珙桐(Davidia involucrata)群落种间关系。测定了83种植物,共3 403个种对的种间关联(或相关)。结果表明,2×2列联表的Fisher精确检验共186个种对为正关联,100个种对为负关联(P<0.05或P<0.01);Pearson相关系数有295个种对为正关联,129个种对为负关联;Spearman秩相关系数有448个种对为正关联,244个种对为负关联。用2×2列联表的Fisher精确检验不能反映两个种对的数量关系,应用Pearson相关系数和Spearman秩相关系数刻化种对间的数量变化关系;与Pearson相关系数检验相比,Spearman秩相关系数检验具有较高的灵敏度。种对的正关联和正相关,主要是由于它们具有相近的生物学特性,对生境具有相似的生态适应性和相互分离的生态位所致;而种对间的负关联和负相关,则主要是由于它们具有不同的生物学特性,对生境具有不同的生态适应性和相互重叠的生态位所致。 展开更多
关键词 珙桐群落 种问关系 FISHER精确检验 Pearson相关系 Spearrnan秩相关系
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COMPLEXITY ANALYSIS AND COMPUTATION OF THE OPTIMAL HARVESTING FOR ONE-SPECIES POPULATION RESOURCES 被引量:2
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作者 Haiying JING Zhaoyu YANG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2006年第4期517-526,共10页
The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly st... The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly study various complex relations appearing in the optimal exploitation process for renewable resources. First, we derive a sufficient condition on the existence of optimal harvesting policies for one-species population resources. Then we present every possible optimal harvesting pattern for such a modeh On the basis of this, we give a computing formula for estimating the optimal harvesting period, optimal transitional period, and optimal recruitment period. The main difference with respect to the previous works in literature is that our optimal harvesting policy is a piece-wise continuous function of time t, at the piecewise point to, which is called switching time. At the switching time we switch the harvesting rate from h to some transitional control u,, then to 0. Clearly this kind of harvesting policy is easier to carry out than those by others, provided that there exists a managing department which can highly supervise the resources. 展开更多
关键词 COMPLEXITY optimal harvesting patterns optimal harvesting period optimal switching time optimal transitional period.
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