兴隆山自然保护区种子植物的垂直分布格局研究

该研究通过对甘肃省兴隆山自然保护区进行野外实地调查和相关文献资料收集,依据海拔梯度将保护区划分为6个植被垂直带草原带(1800~2000 m)、山地灌丛带(2000~2200 m)、亚高山针叶林带(2200~2900 m)、亚高山矮林带(2900~3000 m)、高山灌丛带(3000~3500 m)、高山草甸带(>3500 m)],在整理6个植被垂直带植物名录的基础上,以种子植物为研究对象,对各植被垂直带的种子植物丰富度、生活型、区系成分和系统发育结构进行分析,探讨植物多样性沿植被垂直带海拔升高的垂直变化规律,以揭示植物对环境的生态适应性,为山地植物多样性保护与开发利用提供理论依据。结果表明:(1)按最新的分类系统划分,兴隆山自然保护区种子植物隶属于87科387属889种,植物科、属、种丰富度随植被垂直带海拔升高呈单峰分布格局,在亚高山针叶林带达到峰值(81科304属661种);各植被垂直带间的Jaccard相似性系数呈中等不相似和极不相似水平,海拔越靠近的植被垂直带间相似性系数越高。(2)保护区内种子植物不同生活型的垂直变化格局存在差异,木本植物所占比例沿植被垂直带海拔升高呈先升后降的变化趋势,而草本植物呈相反的变化格局,且各植被垂直带中草本植物所占比例始终高于木本植物。(3)保护区植物在属水平上,热带成分所占比例随植被带海拔升高呈下降的变化趋势,而温带成分占比呈上升的变化趋势。(4)系统发育结构在中低海拔区域的亚高山针叶林带呈发散型,在高海拔区域(>2900 m)的3个植被带中呈聚集型,说明兴隆山自然保护区非随机分布格局在群落构建机制中发挥主要作用。

Vertical Distribution Pattern of Seed Plants in Xinglong Mountain Nature Reserve

The spatial distribution pattern of plant diversity is one of the important issues in phytogeography and macroecology research. In terms of phytogeographic zoning, Xinglong Mountain Nature Reserve is located at the intersection of Loess Plateau, Qinghai-Tibet Plateau and Mengxin Plateau, and possesses a rich mountainous plant diversity, whose vertical distribution pattern is not yet clear. Through field surveys and related literature collection, the nature reserve can be divided into six vegetation vertical zones: grassland zone (1 800~2 000 m), mountain scrub zone (2 000~2 200 m), subalpine coniferous forest zone (2 200~2 900 m), subalpine dwarf forest zone (2 900~3 000 m), alpine scrub zone (3 000~3 500 m) and alpine meadow zone (>3 500 m). In this paper, the plant richness, life type, zonal composition and phylogenetic structure of each vegetation vertical zone were analyzed with seed plants as the research object. The results showed that: (1) the plant family, genus and species richness showed a unimodal distribution pattern with the elevation of the vegetation vertical zone, reaching a peak in the subalpine coniferous forest zone; Jaccard similarity coefficient was moderately dissimilar and extremely dissimilar among the vegetation vertical zones. (2) The vertical variation pattern of different life types differed, with the proportion of woody plants showing an increasing trend followed by a decreasing trend, while the herbaceous plants showed the opposite pattern of variation. (3) At the genus level, the proportion of tropical components showed a decreasing trend with the elevation of the vegetation zone, while the proportion of temperate components showed an increasing trend. (4) The phylogenetic structure was dispersed in the subalpine coniferous forest zone in the middle and low elevation regions and aggregated in the three vegetation zones in the high elevation region (>2 900 m), indicating that the non-random distribution pattern plays a major role in the community construction mechanism. The results of this study are important for understanding the environmental characteristics and community building mechanism of this mountainous region, and provide a scientific and theoretical basis for plant diversity conservation and rational exploitation of resources.