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作 者 ：高昆,张峰

期 刊 ：生态学报 2008年 28卷 4期 页码：1601~1607

关键词：种间分离；最近邻体法；N×N最近邻体列联表；χ2检验；星座图；山核桃；历山；

Keywords:interspecific segregation, nearest-neighbor’s method, N×N nearest-neighbor contingency table, χ2-test, constellation diagram, Juglans mandshurica, Lishan Mountain,

摘 要 ：在野外样方调查的基础上，对山西历山山核桃群落35个样方内所有基径≥1cm的乔木和灌木绘制分布图。按照最近邻体法判定每个个体的最近邻体植株，然后用N×N最近邻体列联表及其2×2列联表截表的方法，应用Pielou的分离指数S和χ2检验研究山核桃群落所有乔木和灌木的种间分离规律。χ2检验结果表明：历山山核桃群落出现的25个物种共构成的300个种对中，存在显著分离的有294对，存在不显著分离的有6对。结合χ2值对S进行区间划分得出：正分离的112对占37.34%，负分离的28对，占9.33%；随机毗邻160对，占53.33%。负分离多出现在群落的优势种和一些伴生种之间，如山核桃、连翘与金花忍冬、灰栒子，伴生种相对个体少，盖度低，与优势种具有相似的生境要求，较激烈的竞争使得它们相互交错分布，充分利用资源，呈现负分离。较大的植株之间容易发生正分离，如茶条槭和杜梨，因为它们多是群落的建群种或优势种，具有较强的适应力和竞争力。从星座图上可清晰地看到种间分离在不同物种间存在一定差异。25×25最近邻体列联表的χ2检验结果表明：山核桃群落内25个物种是互相交错分布，全面不分离的。此外，种间分离的结果意味着该群落处于演替初期，与目前这一地区受人为和自然干扰严重，群落处于不稳定阶段的事实相符。

Abstract:Lishan Mountain，belonging to Zhongtiao Mountains，is situated in 35°16′30″-35°27′20″N, 111°51′10″-112°05′35 ″E in the southern Shanxi．It has a typical warm- temperate continental climate with abundant plant resources and high biodiversity. As an endemic to China, Juglans mandshurica is ranked the national third-class for protection of rare and endangered plants. Due to its multiple economic value, the species is shrinking and seriously influenced by human activities.
Interspecific segregation refers to extent of mosaic distributing among species, which is important to characterize community composition, structure and dynamics. In order to explore the pattern of the interspecific segregation in J. mandshurica communities, 35 quadratls were investigated in the field, and a distribution map was drawn for all trees and shrubs with an equal to or bigger than 1 cm basal diameter. The nearest neighbors of each individual were identified by using nearest neighbor method. The interspecific segregation for all species in these communities was studied by using χ2-test (including Fisher′s exact test for 2×2 contingency table), an N×N nearest-neighbor contingency table and a 2×2 nearest-neighbor contingency sub-table.
The results of χ2-test showed that there were 294 species-pair being significant segregation（P<0.05） and 6 species-pair being insignificant segregation（P>0.05）. Based on χ2 value to divide S, the interspecific segregation result indicated that there were 112 species-pair positive segregation, 28 species-pair negative and 160 species-pair random segregation accounting for 37.34%, 9.33%, and 53.33% respectively. Negative segregation appeared between dominant species and companioning species in the communities and companioning species had fewer individuals, lower coverage and similar habitat requirements with dominant species. Intensive interspecific competition resulted in mosaic distribution and fully exploiting competition for resources in speices such as J. mandshurica, Forsythia suspensa and Rhamnus davurica, Cotoneaster acutifolius. Therefore, they were apt to be negative segregation. The larger individuals being constructive or dominant species in the communities tended to be positive segregation with the other large trees and shrubs, due to their stronger capacity of adaptation and competition, such as Acer ginnala and Pyrus betulifolia. The constellation diagrams showed clearly the difference of interspecific segregation among the various species.
The result of χ2 test for N×N nearest-neighbor contingency table indicated that 25 species in the communities were mosaic distribution and overall non-segregation.
In addition, the results of species segregation suggested that the Juglans mandshurica communities in Lishan Mountain were in the early stage of succession, which was consistent with the fact that the communities were unstable due to the seriously disturbance of natural and human activities.

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