青藏高原东部原始林下地表主要苔藓斑块特征及其影响因素

Major bryophyte patch structures and their relationships with environmental factors under a coniferous forest of eastern Tibetan plateau

引入并应用斑块概念对大渡河上游藓类-冷杉原始林下地表1 hm2面积的锦丝藓、大羽藓、赤茎藓、塔藓、锦丝-赤茎藓等五种地表苔藓斑块结构特征作了调查分析,并同时测定了斑块相关环境因子(空气温度、空气湿度、基质湿度、光照强度、乔木盖度、灌木盖度、草本盖度及生物量、凋落物盖度)。对数据进行综合分析发现,不同斑块类型在生物量、个体密度、层片厚度和物种丰富度上都表现出一定的差异性,所调查环境因素各个方面在五种斑块之间都表现出较强的差异性,且各类斑块的结构特征与环境因子间分别表现出很强的相关性。影响斑块结构特征的最主要因素是藓丛表面空气温度,空气湿度、光照强度和草本层盖度、灌木层的盖度等也对斑块特征产生重要影响,而草本层生物量、凋落物盖度及乔木层盖度仅对个别斑块的结构特征产生影响,基质湿度并未对斑块特征产生显著影响,可能是因为不同藓类生长基质不同所致。

Bryophyte distributed patchily on floor under primary coniferious forests in eastern Tibetan plateau, but the patch character hardly received any attention. The work conducted in a coniferious forest of the upper dadu River. Structural parameters （species richness, cover, thickness and shoot density） of five major bryophyte patches, including Actinothuidium hookeri, Thuidium cymbifolium, Pleurozium Schroberi, Hylocomium Splendens and Ach-Pls Patch, were investigated and environmental indexes （substrate humidity, light intensity, air humidity, air temperature, herb cover and biomass, scrub cover and litter cover） for each patch were measured. The relationships among the structural parameters and environmental factors were analyzed. By comprehensive analysis, we found that there was certain difference among five types of patches in environmental factors and community structural parameters, and there were very strong relationship between the bryophytes patches structural parameters and the environmental factors. Air temperature was the most important factor among all these factors, air humidity, sunshine intensity, scrub cover, herb cover, had also influenced patches＇ characteristics heavily, but some factors such as litter cover, arbor cover, herb biomass had only influenced specific patch type. Substrate humidity had not significant influenced patch characteristics. In a word, the characteristic of one patch was result of comprehensive influence of all the environmental factors.