太行山南麓锐齿槲栎-油松混交林竞争关系与空间格局

Spatial pattern and tree competition in the Quercus aliena var.acuteserrata-Pinus tabulaeformis mixed forest in the south of Taihang mountain

【目的】探究太行山南麓针阔混交林内植物的竞争关系及空间格局,以期更好地理解针阔混交林种内、种间相互作用,为生物多样性保护和森林生态系统管理提供一定的指导作用。【方法】在河南太行山猕猴国家级自然保护区内设置1 hm2锐齿槲栎-油松混交林固定监测样地,调查样地内所有木本植物(DBH≥2 cm)的物种名、胸径、坐标等。通过计算可知样地内锐齿槲栎和油松的重要值较高且平均胸径较大,进一步采用Hegyi单木竞争指数和g(r)函数分别研究混交林内优势种锐齿槲栎和油松的竞争强度和空间分布格局。【结果】1)混交林样地内所有木本植物径级结构呈倒“J”型曲线,且在小尺度上聚集分布,大尺度上随机分布;2)锐齿槲栎种群的径级结构呈“J”型曲线,不同径级个体在样地内都呈随机分布,平均种内竞争强度大于平均种间竞争强度,且小径级(DBH≤5 cm)个体所受竞争压力最大,平均种内、种间竞争指数CI分别为13.47和10.08;3)油松种群径级结构近似正态分布,全部个体在样地内呈聚集分布,油松的平均种内竞争强度大于平均种间竞争强度,小径级(DBH≤5 cm)个体所受竞争压力最大,其平均种内、种间竞争指数CI分别为18.95和1.01。【结论】样地内锐齿槲栎和油松的分布格局不同,锐齿槲栎呈随机分布,主要受种内竞争作用的影响;油松呈明显的聚集分布,可能是受环境异质性影响;两个种群的种内、种间竞争强度都随着径级的增加而降低,且种内竞争强度大于种间竞争。本研究通过对太行山南麓针阔混交林的竞争关系和空间格局进行相关研究,可以为当地的森林生态环境与生物多样性保护提供一定的理论依据。

【Objective】In order to better understand the intra-specific and inter-specific interactions and provide some guidance for forest ecosystem management and biodiversity conservation at the southern foot of Taihang Mountain,this study explored the spatial pattern and competition intensity in the mixed forest and coniferous broad-leaved mixed forest.【Method】In the southern Taihang Mountain macaque national nature reserve,one Quercus aliena var.acuteserrata-Pinus tabulaeformis forest plot(100 m×100 m)was selected,and species,DBH(diameter in breast height)and coordinates of all woody plants(DBH≥2 cm)in the plot were investigated and registered.It was calculated that the important values and average DBH of the Q.aliena var.acuteserrata and P.tabulaeformis population were higher than others in this plot.Then,Hegyi’s competition index and g(r)function were used to the study competition intensity and spatial distribution pattern of the Q.aliena var.acuteserrata and P.tabulaeformis population in the mixed forest.【Result】1)The DBH class of all individuals in the plot presented a reversed J-shape,and the distribution was clustered on the small scale and random on the large scale.2)The Q.aliena var.acuteserrata population exhibited a J-shape DBH class,and all individuals showed random distribution at different scales.The average intra-specific CI(competition intensity)was greater than the inter-specific CI,and the small individuals(DBH≤5 cm)suffered the greatest intra-specific and inter-specific competitive pressure of 13.47 and 10.08,respectively.3)The DBH class of the P.tabulaeformis population exhibited approximate normal distribution.The average intra-specific CI was much greater than the average inter-specific CI,and the smallest individuals(DBH≤5 cm)endured the most competitive intra-and inter-specific competitive pressure of 18.95 and 1.01,respectively.【Conclusion】The distribution patterns of Q.aliena var.acuteserrata and P.tabulaeformis are very different in the coniferous broad-leaved mixed forest plot.The Q.aliena var.acuteserrata population shows a random distribution pattern which may be mainly affected by the intra-specific competition effect.On the other hand,P.tabulaeformis presents an obvious aggregation distribution pattern that may be affected by the influence of environmental heterogeneity.The Q.aliena var.acuteserrata and P.tabulaeformis population has a similar competition intensity that their inter-species and intra-species CI decreases with increasing DBH classes,and their inter-species CI is greater than the intra-species CI.By exploring the spatial pattern and tree competition in the Q.aliena var.acuteserrata-P.tabulaeformis mixed forest in the south of Taihang Mountain,this study could provide a theoretical basis for the ecological system and biodiversity conservation of local forests.