川西北岷江冷杉种群的空间格局
Spatial Distribution Pattern of Abies faxoniana in Northwestern Sichuan
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摘要: 以四川王朗国家自然保护区岷江冷杉林1hm2样地的调查数据为基础,研究岷江冷杉的径级结构和重要值,运用Ripley’s K函数分析其空间格局和种内不同生长阶段的空间关联。结果表明:岷江冷杉在群落中占据绝对优势,中大径级林木较多。不同生长阶段的岷江冷杉主要呈聚集分布,可能与物种种子扩散方式有关;幼树和小树在所有空间尺度上均呈聚集分布,聚集强度随着尺度增大呈增大后减小的趋势,大树的空间格局随尺度增大,由随机(1~3m)趋于聚集分布(4~50m)。随着种群发育(幼树→小树→大树),岷江冷杉的聚集强度逐渐减小。幼树与小树在中小尺度上(1~25m)呈正向关联,不同生长阶段的岷江冷杉均与枯立木呈现出正向关联,随尺度变化而变化;岷江冷杉的聚集分布和种内的正向关联关系体现出了种群的生物学特性(耐荫)、干扰机制(林窗更新)和物种内部相互有利的生态关系。根据岷江冷杉的空间属性和更新机制,可以适当的进行人为干扰,以促进岷江冷杉林的发展。¬Abstract: A studied diameter distribution and importance value of Abies faxoniana was made based on the field survey in a plot with an area of a 1 hm2 of A. faxoniana forest in Wanglang Natural Reserve, Sichuan Province.In the study Ripley’s K function was used to analyze spatial pattern and spatial association of A. faxoniana at different growth stages. The result showed that: A. faxoniana was dominant species in the community with highest importance value, and there were many medium and big trees in the plot. A. faxoniana at different growth stages mainly showed aggregated distribution, indicating the way of seedling dispersal. Saplings and small trees were aggregated distributed at all scales, and aggregation intensity tended to increase first and then decreased as scale increased. While big trees tended to be clumped as scale increased.As age increase (sapling→small tree→big tree), aggregation intensity tended to reduce. Saplings and small trees showed positive association, while A. faxoniana at all growth stages were positively associated with standing dead trees, varied with spatial scale. The spatial pattern and association of A. faxoniana indicated the species′ shadetolerance characteristic, positive relationship among age classes, and mechanism of gap disturbance affecting regeneration. Based on its spatial character and regeneration mechanism,it is suggested that some measures can be taken to facilitate the development of A. faxoniana.