粤东农林交错区苔藓植物与生境的关联及指示种

Association of Bryophytes with Site Factors and Indicator Species in Agroforestry Ecotone of East Guangdong

苔藓植物作为最原始的高等植物,个体矮小,常呈大片垫状丛状群落,对环境变化极为敏感。为探讨亚热带森林地表苔藓植物与多种生境梯度的关联以及苔藓植物在不同生境中的指示作用,基于广东省东源县康禾省级自然保护区6 hm^2固定样地调查数据,采用随机森林分析方法,检验不同生境因子对苔藓植物影响的重要性,利用指示种分析方法揭示不同生境梯度下的苔藓植物指示种。结果表明:凹凸度和潜在直射光入射辐射对苔类植物和藓类植物的盖度、丰富度、Shannon-Wiener指数、均匀度指数和优势度指数的预测变量重要性均较高,说明凹凸度和潜在直射光入射辐射对苔藓植物的影响较大,是限制苔藓植物生长的重要环境因子。坡度、海拔高度等生境因子也对苔藓植物多样性指数具有不同程度的影响,说明苔藓植物多样性格局并不是受单一因素的影响,而是多个因素共同作用的结果。指示种分析发现,不同生境梯度下的苔藓植物指示种存在差异,有的苔藓植物能够同时指示不同的生境条件。东亚拟鳞叶藓(Pseudotaxiphyllum pohliaecarpum)对第2级海拔梯度、第3坡度级和第1凹凸度级均具有显著指示作用,能够适应3种不同的生境,生态幅较广;淡叶长喙藓(Rhynchostegium pallidifolium)对第1海拔梯度、阳坡和第2凹凸度级均具有显著指示作用,生态幅较高,适应性较强。

Bryophytes, as the most primitive higher plants, are small in individuals and often have large cushioned cluster communities, which are extremely sensitive to environment. In order to investigate the relationship between the surface bryophytes of subtropical forest and various habitats, and study the habitat-indicative role of bryophytes, data collected from 6 hm^2 permanent plots in Guangdong Kanghe Provincial Nature Reserve were analyzed. We used Random forest analysis was used to test the predictive importance of different habitat factors on bryophyte, and used indicator species analysis was used to reveal the indicative species under different habitat gradients. The results showed that convexity and potential direct incident radiation were of high importance to the cover, richness, Simpson Index, evenness and Berger-Parker dominance of Moss and Liverwort, which indicated that convexity and potential direct incident radiation had great influence on bryophytes and were important environmental factors to limit the growth of bryophytes. The habitat factors such as slope and elevation also had different effects on the diversity index of bryophytes, which showed that the diversity pattern of bryophytes was not affected by a single factor, but influenced by many factors. The indicator species analysis showed that there were differences in the indicative species of bryophytes under different habitat gradients, and some bryophytes were able to indicate different habitat conditions at the same time. Pseudotaxiphyllum pohliaecarpum had significant indicative effect on the 2nd elevational gradient, the 3rd slope calss and the 1th convexity gradient, with wide ecological amplitude. Rhynchostegium pallidifolium had significant indication effect on the 1th elevational gradient, sunny aspect and 2nd convexity gradient, with high ecological amplitude and strong adaptability.