茂兰喀斯特森林木本植物功能群研究

Karst forest in Maolan is a specific forest ecosystem at the same latitude in the world. The mixed evergreen and deciduous broadleaf forest is an climax community in the karst forest in Maolan. This forest has the specific habitat, complex community strueture and rich biodiversity, providing an ideal place for ecological study about primordial karst forest. By investigation on the communities, the woody plant species at three topography sites were as the object of research. Through the calculation of importance values, dominant species were selected in each communities. Overall association and interspecific association were used to analyze the interspecific association of these dominant species. Plant functional groups were defined according to interspecific associations of the dominant species. Non-parametric single factor analysis of variance (ANOVA) and multiple comparison analysis were used to analyze relative biomass of functional groups changing with different topography sites and the distribution of plant functional groups. Redundancy analysis (RDA) and correlation analysis were used to determine the main influencing factors to the  distribution and combination of plant functional groups. Dominance analysis was used to determine the potential keystone species in functional groups. The stability of forest communities at different topography sites was explained from the plant functional group diversity, species diversity, overall association and regeneration ability of plant functional group. These research results would provide scientific theoretical guide to conservation of karst forest in southwestern China.

茂兰喀斯特森林是同纬度地带上的一种特殊森林生态系统，常绿落叶阔叶混交林是其顶极群落。茂兰林区生境类型特殊，群落结构复杂，物种组成多样，是研究原生性喀斯特森林的理想区域。以林区内木本植物为研究对像，对区内槽谷、坡地、漏斗3种地形中的植被进行群落学调查，通过重要值计算结果在每个地形群落中选取优势种，应用多物种总体联结性，各物种间联结性等指数，对不同地形部位群落的种间联结性进行分析，并以此为依据，划分植物功能群。应用多重比较分析法(Post HocTests)和非参数单因素方差分析法(ANOVA)来研究各植物功能群随不同地形部位生境条件变化而产生的差异，以及功能群的分布格局；应用RDA分析和相关性分析来确定各植物功能群的分布、组合影响因子；应用优势度分析来确定各功能群的潜在关键种；并从功能群多样性、群落物种多样性、群落总体种间联结性和功能群更新能力四个方面对不同地形部位森林群落稳定性进行研究。

喀斯特森林生态系统是全球生态系统多样性的重要组成部分，在维持陆地生态系统的结构和功能方面扮演着重要的角色。茂兰喀斯特林区生境类型特殊，群落结构复杂，物种组成多样，是研究喀斯特森林木本植物功能群的理想场所。通过对茂兰槽谷、坡地、漏斗3种地形中的木本植物功能群分类、分布、更新类型、优势种群落特征及环境影响因子等进行研究，研究结果表明：（1）槽谷优势种共划分为七个功能群，坡地优势种共划分为六个功能群。（2）对槽谷、坡地森林群落同时出现的功能群优势种种群数量进行统计，灯台树、光皮梾木、圆果化香、柿树、樟叶槭5个种群在两个生境的径级结构由小到大为递减趋势，多为逆J字型或L字型，存活曲线接近DeeveyⅢ型，属增长型种群。而南酸枣、拐枣、白榉、狭叶润楠种群的径级结构大致呈钟型，存活曲线接近DeeveyⅡ型，属稳定型种群。（3）功能群优势种多以集群分布为主，随着龄级的增长，聚集程度逐渐降低，表现为大多数种群在幼苗、幼树甚至小树阶段呈集群分布，到中、大树阶段呈随机分布。（4）3种地形部位植物群落中，轮叶木姜子在乔木层占主导地位，为群落优势种，青冈栎、四照花、翅荚香槐是群落乔木层的亚优势种。皱叶海桐是灌木层的优势种，裂果卫矛、革叶铁榄和南天竹是群落灌木层的亚优势种。（5）影响三种地形部位中植物群落物种组成差异的主要环境因子为光照、水分和土壤。槽谷功能群土壤含水量、全氮、全钾、速效钾、碱解氮、有机质、土壤含水量、pH值、全磷含量总体上高于坡地；pH值在各地形部位无显著差异。坡地多个功能群与pH值、全磷、速效钾有较大的相关性。（6）优势种有5种更新类型：单峰型，单柱型，逆J字型，间歇型，L字型。（7）三种地形部位乔木层物种多样性指数为槽谷＞漏斗＞坡地，灌木层物种多样性指数则表现为槽谷＞坡地＞漏斗。槽谷森林稳定性>漏斗森林稳定性>坡地森林稳定性。为茂兰喀斯特森林的物种多样性维持机制和喀斯特森林生态系统的研究提供理论依据，发挥其在生态和生物多样性保护中的重要作用。