Relationship among carnivorous macrophyte Utricularia foliosa L. and species composition and life forms of periphytic algae community

Abstract Aim Present study evaluated the life forms and taxonomic structure of the periphytic algae community on Utricularia foliosa L. (modified leaf and stem) and artificial substrate during the four seasons in a tropical shallow reservoir. Methods We evaluated the periphyton on natural and artificial substrate in order to evaluate the influence of substrate type on the taxonomic structure of algal community. Monospecific stands of U. foliosa were selected. Water and periphyton sampling were performed within U. foliosa stands in the autumn (April/2010), winter (July/2010), spring (November/2010) and summer (February/2011). Nylon thread was used as the artificial substrate. The community structure was evaluated through life forms, species richness, diversity and species composition. Results Species diversity was significantly different only among seasons. The life forms and species richness were different between substrate types and seasons. Entangled filamentous algae had higher biovolume in the periphyton on artificial substrate and unicellular flagellated algae had higher biovolume on natural substrate. Species composition changed among the seasons and species descriptors differed among substrates types. Species-level taxonomic classification responded clearly to the substrate type. Conclusions We concluded that the taxonomic structure and life forms of periphytic algae on artificial substrate poorly represented the natural periphyton on U. foliosa. The type of substrate strongly influenced the periphyton–Utricularia relationship.

摘要：本研究旨在评估热带浅水库中浮叶狸藻（Utricularia foliosa L.，其特化的叶与茎）及人工基质上附生藻类（periphytic algae）群落的生活型与分类学结构，采样覆盖全年四季。
方法：为探究基质类型对藻类群落分类学结构的影响，本研究对自然与人工基质上的附生藻类进行了调查。研究选取纯群丛分布的浮叶狸藻样地，分别于2010年4月（秋季）、2010年7月（冬季）、2010年11月（春季）及2011年2月（夏季）在浮叶狸藻群丛内开展水体与附生藻类采样。实验以尼龙丝线作为人工基质。通过生活型、物种丰富度、物种多样性及物种组成四个维度对群落结构进行分析。
结果：物种多样性仅在不同季节间存在显著差异；而生活型与物种丰富度在不同基质类型及季节间均存在显著差异。缠结丝状藻类在人工基质附生藻类群落中的生物体积更高，单细胞鞭毛藻类则在自然基质上具有更高的生物体积。物种组成随季节发生明显变化，且物种特征在不同基质类型间存在差异；物种水平的分类学分类对基质类型的响应极为显著。
结论：本研究表明，人工基质上附生藻类的分类学结构与生活型无法很好地反映浮叶狸藻上的自然附生藻类群落。基质类型对附生藻类与狸藻的互作关系具有强烈影响。