崖柏群落植物区系分析及其最优垂直结构搭配探究

崖柏(Thuja sutchuenensis Franch.)为中国特有珍稀濒危裸子植物。在多次调查的基础上,通过区系分析、聚类分析和热图分析等方法,对大巴山崖柏群落的区系特点、群落结构和搭配模式进行了研究,以明确群落区系的本质特征及伴生物种的成层结构对崖柏种群的影响。结果表明:(1)崖柏的伴生物种组成丰富,地理成分较为复杂,区系成分主要以温带成分为主;物种生活型以矮高位芽植物、地面芽植物和小高位芽植物占优势。(2)样地间聚类分析结果表明,海拔和空间地理位置是影响崖柏群落伴生植物区系组成的重要因素。(3)崖柏群落平均高度越矮越有利于崖柏种群的扩大和延续;其中,群落以灌木层、乔木下层类群为主时,崖柏种群内个体数量最多。(4)根据优势种热图结果分析,以崖柏为优势种的群落结构中,乔木层物种搭配以崖柏+多脉青冈+川陕鹅耳枥、崖柏+川柯+小叶青冈和崖柏+马尾松+高山栎最优,灌木层物种搭配以崖柏+球核荚蒾+豪猪刺、崖柏+粉背黄栌最优。(5)较为丰富的物种多样性和高大的伴生物种给崖柏种群造成较大威胁,结合崖柏群落的垂直结构构建适合崖柏种群延续和扩大的物种搭配模式对于崖柏的保护尤为重要。

Flora Analysis and Vertical Structure Optimization of the Community of Thuja sutchuenensis Franch.

Thuja sutchuenensis, a critically endangered gymnosperms restricted to a single population on the southern side of the Daba Shan (Chongqing, China), has received little attention so far. Based on investigation of many times, we used the floristic analysis, clustering analysis, heat analysis method and so on to studied floristic composition, community structure and collocation model of T. sutchuenensis community. The results showed that: (1) The community had high level of associated species richness and the life form of associated species is dominant of Nanophanerophyte, Hemicryptophyte, Microphanerophyte. Areal types are complex and temperate elements are more in the community. (2) The result of cluster analysis in the different sample plots showed that the altitude and spatial location were the important factors for influence the composition of the flora in the community. (3) When the community is dominated by shrub layer and lower tree layer, the number of individuals of T. sutchuenensis was more. We think that the average height of the community is the shorter, the better for expansion and regeneration of T. sutchuenensis populations. (4) According to the result of heatmap, we found that the following several patterns of the most conducive to the survival of the population of T. sutchuenensis which the T. sutchuenensis+Cyclobalanopsis multinervis+Carpinus fargesiana, T. sutchuenensis+Lithocarpus fangii+Cyclobalanopsis myrsinifolia and T. sutchuenensis+Pinus massoniana+Quercus semicarpifolia in the tree layer, and the T. sutchuenensis+Viburnum propinquum+Berberis julianae, T. sutchuenensis+Cotinus coggygria in the shrub layer. (5) T. sutchuenensis populations affected by high level of biodiversity and the higher associated species, so that it is particularly important to build a suitable model for the expansion and regeneration of the T. sutchuenensis populations by combined with the vertical structure of the community.