两种不同起源华北落叶松林空间点格局及植物多样性

Spatial distributions and species diversity of two types of Larix principis-rupprechtii

【目的】分析山西省黑茶山国家级自然保护区两种不同起源类型落叶松人工林和天然林径级和林层特征,并对落叶松种群空间分布点格局特征和种群对邻域物种多样性的影响效应进行研究。【方法】采用g(r)函数点格局方法对优势种群落叶松不同生长阶段个体(小树、中树和大树)的空间分布点格局进行研究;用单物种-面积关系模型(m ISAR模型)分析样地中乔木树种对局域群落多样性的影响。【结果】两种不同起源的落叶松林内落叶松种群呈正态分布,根据林木胸径(DBH)将落叶松分为小(5 cm≤DBH<10 cm)、中(10 cm≤DBH<30cm)、大(DBH≥30 cm)3个阶段。人工林和天然林小、中、大3个不同阶段的株数比分别为10∶3∶4和10∶3∶6,树种多样性分别为0.96、0.54、0.52和1.27、0.94、0.63。两种起源落叶松林空间点格局分布总体均表现为小尺度上的聚集分布和中大尺度上的随机分布。此外,两种起源的落叶松林内物种在调查尺度范围内均表现为单物种所有个体对邻域全部树种的丰富度起到促进作用。【结论】研究区长期的干扰使两种起源类型的落叶松林具有较为相似的水平结构和垂直结构,中径级林木个体多但小径级和大径级较少,种群难以实现世代交替。

[ Objective] Based on investigation data on two types of Larix principis-rttpprechtii native to the Heicha Moun- tain, Shanxi Province, China, diameter and canopy structure of forests with the two types, spatial distribution of L. princi- pis-rupprechtii, and the effects of individual species on surrounding biodiversity were analyzed. [ Method ] Spatial point patterns were analyzed based on the g（r） function. The individual species-area relationship （mISAR） was used to evalu- ate the effects of individual species on surrounding biodiversity at different spatial scales. [ Result] The diameter structure of plantation and natural L. rupprechtii exhibited a unimodal distribution, the number ratios of the plants in small （5 cm ~〈 DBH〈IO cm）, middle （10 cm~〈DBH〈30 cm） ,and big（ DBH~〉30 cm） stages were 10：3：4 and 10：3：6 respectively, and the values of species diversity were 0.96, 0.54 and 0.52, and 1.27, 0.94 and 0.63. All trees exhibited clustered dis- tribution across a small range and random distribution with increase in spatial scale. Moreover, all tree species acted as diversity accumulators at all studied spatial scales in the forests with the two types. [ Conclusion ] The horizontal and verti- cal structure of the two types were the same for long-term continuous disturbance. Middle-aged trees were more frequent, while the number of young and old trees was less ,indicating that this popltiation could not achieve metagenesis by itself.