天宝岩竹阔混交林毛竹及其伴生树种生态位的研究

Niche characteristics of Phyllostachys edulis and its associated tree species in Tianbaoyan bamboo and broadleaved mixed forest

研究竹阔混交林中毛竹与伴生树种间生态关系,寻找适宜混交比例,从生态位角度为竹阔混交林优化经营提供依据。采用样方法对天宝岩自然保护区的竹阔混交林进行群落调查,以不同混交比的竹阔混交林作为不同资源位,运用Levins和Shannon生态位宽度指数、生态位重叠指数、生态位相似性比例指数,分别测定并分析竹阔混交林乔木层与更新层各树种间的生态位特征。结果表明:1)Levins和Shannon生态位宽度指数反映情况一致;栲树、米锥、拟赤杨作为毛竹优势伴生树种,其重要值和生态位宽度都很大,生态适应能力强,对群落结构的变化起着重要作用。2)各树种间生态位相似性比例不高,对毛竹的生态位重叠指数也不高,除了栲树生态位重叠指数Lhi值为0.509,其余树种Lhi值均小于0.5,说明毛竹与大多数树种存在较大的生态异质性与资源利用差异性,彼此间可形成稳定的共生关系。3)整体上常绿树种较落叶树种的生态位宽度大,对毛竹的生态位重叠也相对较大,当毛竹所利用的资源不足时,也更易对其造成潜在的竞争。4)竹阔混交林混交比在15%~20%时,毛竹的密度和地上生物量最大;当混交比过大时,毛竹逐渐失去群落中的优势地位,它与阔叶树形成的共生协同关系更多转变为了竞争关系。

By understanding the ecological relationship between Moso bamboo and the associated tree species in bamboo broadleaved mixed forest, this paper aims to find the appropriate proportion of cropping to provide basis for the optimization of the mixed forest from the niche level. A field plot sampling method was employed to investigate community niche of bamboo broadleaved mixed forest in Tianbaoyan of Fujian Province of Southern China. The Levins and Shaanon niche breadth index, niche overlap index, Schoener niche similarity index were used to study and analyze the niche characteristics of the tree layer and the regeneration layer with different mixing ratio of bamboo and broadleaved mixed forest as different resource niche. Results showed that： 1 ） the Levins and Shaanon niche breadth index showed that Castanopsis carlesii, Castanopsis fargesii and Alniphyllumfortunei were the dominant species of Moso bamboo, and their important value and niche breadth were strong, and the ecological adaptability was strong, and they play an important role in the change of community structure. 2） The ratio of niche similarity between tree species and the niche overlap index of Moso bamboo were not high. The Lhi value of Castanopsis fargesii was 0. 509, and the Lhl value of the other species was less than 0.5, indicating that there was a large ecological difference between Moso bamboo and most tree species and resource utilization differences, and a stable symbiotic relationship was formed between each other. 3） The niche breadth of the evergreen tree species was larger than that of the deciduous tree species, and the niche overlap of Moso bamboo was relatively large. When the resource used by Moso bamboo was insufficient, it was also more likely to cause potential competition. 4） The density and biomass of Moso bamboo were the largest when the mixed ratio of bamboo and broadleaved mixed forest was in the range of 15% - 20%. When the mixing ratio was too large, the bamboo gradually lost the dominant position in the community, and the symbiotic synergistic relationship with the broadleaved tree was more likely change to the competitive relationship.