山西历山国家级自然保护区千金榆群落种间分离研究

对山西历山国家级自然保护区普通沟和西峡的千金榆(Carpinus cordata)群落进行野外调查,共记录了40个样方,44个物种,组成946个种对.利用最近邻体法构造N×N最近邻体列联表,以x2检验和种间分离指数S作为区分指标,研究了千金榆群落的种间分离情况.结果表明:(1)946个种对中呈现随机毗邻的最多,有507个种对,占总数的53.59％；呈现正分离的有349个种对,占总数的36.89％；而呈现负分离种对最少,只有90对,占总数的9.52％.(2)群落的建群种或优势种因为有较强的生存能力和竞争能力,往往表现出正分离,例如千金榆、小叶鹅耳枥(Carpinus turczaninowii)、五角枫(Acer mono)、葛罗槭(Acer grosseri)等有较强生存能力的物种与大多数的物种发生正分离；而六道木(Abelia biflora)、东北茶镳子(Ribes mandshuricum)、小花溲疏(Deutziaparviflora),美蔷薇(Rosa bella)和紫花卫矛(Euonymus porphyries)等群落中的伴生种或小灌木,与部分物种形成负分离.其余物种之间发生随机毗邻的较多.(3)对千金榆群落44×44列联表进行全面分离,结果表明群落内的44个物种相互交错分布,不是全面分离.此外,种间分离的结果也揭示该群落处于演替初期,受岩石风化崩塌的影响较严重,人为干扰因素较轻.

Interspecific Segregation in Carpinus cordataCommunities in Lishan Nature Reserve,Shanxi

Interspecific relationships are an important element affecting community structure and function.To explore the pattern of interspecific segregation in Carpinus cordata communities,40 quadrates were investigated in Lishan Nature Reserve,Shanxi,with a distribution map drawn for all trees and shrubs with the DBH≥5 cm for tree or basal diameter for shrubs.The nearest neighbors of each individual were identified using nearest neighbor method.The interspecific segregation for all species in these communities was studied by using the χ2-test,an N×N nearest-neighbor contingency table and a 2×2 nearest-neighbor contingency sub-table.Based on the value to divide S index,interspecific segregation indicated that there were 349 species-pair positive segregations,90 species-pair negative segregations,and 507 species-pair random segregations,accounting for 36.89%,9.52%,and 53.59%,respectively.The semi-matrix showed that the dominant species often showed positive segregation,and had a stronger viability and competitiveness,such as Carpinus cordata,Carpinus turczaninowii,Acer mono and Acer grosseri.The dominant and companion species usually showed negative segregation,with fewer individuals and lower coverage,such as Abelia biflora,Ribes mandshuricum and Rosa bella.The result of the χ2 test for the N×N nearest-neighbor contingency table indicated that 44 species in the communities demonstrated mosaic distribution and overall non-segregation.Moreover,the results of species segregation indicated that the Carpinus cordata communities were in the early stage of succession,which was consistent with the fact that the communities were unstable due to the disturbance of natural rock collapse and human activities.