University of Applied Sciences Trier, Environmental Campus Birkenfeld, Post Box 1380, 55761 Birkenfeld, Germany; University of Duisburg-Essen, Faculty of Biology, Universitätsstrasse 5, D-45141 Essen, Germany.
Arbeitsgemeinschaft Biologischer Umweltschutz (ABU), Teichstraße 19, D-59505 Bad Sassendorf, Lohne, Germany.
Sci Total Environ. 2020 Jun 1;719:137169. doi: 10.1016/j.scitotenv.2020.137169. Epub 2020 Feb 11.
In river floodplains many conservation programs focus on the main river channel as the richest in species. Lateral floodplain waterbodies, which contribute largely to functional processes in river systems, often remain overlooked and exposed to anthropogenic pressures. Although the role of hydrological connectedness between lateral waterbodies and the main river on taxonomic composition of fish communities is well understood, effects on functional community composition is much less studied. Abundance data of fish communities were gathered from 152 electrofishing sites in the main channel and lateral floodplain waterbodies of the river Lippe (Germany), over 18 years. These data were used to compare taxonomic, functional, conservation and recreational fishing aspects along the floodplain lateral connectedness gradient. Fish species richness decreased along the lateral continuum from the main river channel to isolated floodplain waterbodies. In contrast, the relative abundance of endangered and also of non-native species increased along this gradient, highlighting the ecological and conservational importance of floodplain waterbodies. Species composition in floodplain waterbodies differed across the connectedness gradient showing distinct assemblages which were not merely subsets of the main channel. The variability of life-history and feeding strategists among classes of lateral connectedness confirmed the importance of each connectivity class in contributing to the overall floodplain functional diversity. This study highlights the need of preserving fish taxonomic and functional biodiversity across the floodplain as one integrated hydrosystem. Conservation and restoration measures should therefore extend to include the whole floodplain area and the complete spectrum of differently connected floodplain waterbodies in addition to the main channel of the river.
在河流泛滥平原上，许多保护项目都集中在物种最丰富的主河道上。侧向泛滥平原水体对河流系统的功能过程贡献很大，但往往被忽视，并受到人为压力的影响。尽管侧向水体与主河之间的连通性对鱼类群落的分类组成的作用已得到充分理解，但对功能群落组成的影响研究得较少。在 18 年的时间里，从德国利珀河的主河道和侧向泛滥平原水体中采集了 152 个电捕鱼点的鱼类群落丰度数据。这些数据用于比较沿泛滥平原侧向连通性梯度的分类学、功能、保护和娱乐性捕鱼方面。从主河道到孤立的泛滥平原水体，鱼类物种丰富度沿着侧向连续体逐渐减少。相比之下，濒危物种和非本地物种的相对丰度沿着这条梯度增加，突出了泛滥平原水体的生态和保护重要性。泛滥平原水体中的物种组成在连通性梯度上存在差异，表现出不同的集合，而不仅仅是主河道的子集。不同侧向连通性类别的生命史和摄食策略的多样性证实了每个连通性类在促进整个泛滥平原功能多样性方面的重要性。本研究强调了需要在整个泛滥平原作为一个综合水系统中保护鱼类的分类和功能多样性。因此，保护和恢复措施不仅应包括主河道，还应包括整个泛滥平原地区和不同连通的泛滥平原水体的完整范围。
