Data from: Habitat diversity and connectivity govern the conservation value of restored aquatic floodplain habitats

Floodplains have been strongly altered by human activities such as channelization and other river regulations. Globally, there is a growing interest in their restoration because of an increasing understanding of the ecological importance of these habitats for feeding, spawning, nursery or overwintering of aquatic species. In this study, a large floodplain restoration project of the upper Danube River was used to investigate colonization and succession patterns of fish, macroinvertebrates, macrophytes and periphyton in relation to abiotic habitat variables that can be restored through ecosystem management. Highest species diversity was detected near the contact zones of the floodplain channel to the main stem of the Danube, and in the transition zones of river sections (RS) and oxbow lakes (OS). The highest proportions of all taxa (82%) and of distinctive species (22%) were detected in RS, followed by OS (66% of all taxa, 8% distinctive species) and floodplain ponds (FP, 47% of all taxa, 5% distinctive species). The habitat types RS, OS and FP significantly differed in overall community composition and their colonization processes comprising fast colonization of current-adapted specialists in RS, and mostly generalist species in OS and FP. Our results indicate that restoration of floodplain habitats should not only consider the re-establishment of maximum connectivity, but also provide a mosaic of distinct habitat types with different degrees of connectivity and disturbance. Each habitat type in the floodplain supported a unique assemblage of species, which suggests that such habitat mosaics can facilitate exceptionally diverse ecosystems.

洪泛平原（floodplains）已因河道渠化及其他河流整治类人类活动而发生剧烈改变。随着学界对这类生境作为水生生物觅食、产卵、育幼或越冬关键栖息地的生态重要性认知不断加深，全球范围内对其开展修复的兴趣日益高涨。本研究以多瑙河上游一项大型洪泛平原修复工程为研究对象，旨在探究鱼类、大型无脊椎动物、大型水生植物以及周生生物（periphyton）的定殖与演替模式，并分析其与可通过生态系统管理手段实现修复的非生物生境变量之间的关联。研究发现，洪泛平原河道与多瑙河干流的交汇区域，以及河流区段（River Sections, RS）与牛轭湖（Oxbow Lakes, OS）的过渡区域，物种多样性最高。所有类群占比最高（82%）及特有物种占比最高（22%）的生境类型为河流区段（RS），其次为牛轭湖（OS，所有类群占比66%，特有物种占比8%）与洪泛池塘（Floodplain Ponds, FP，所有类群占比47%，特有物种占比5%）。河流区段（RS）、牛轭湖（OS）与洪泛池塘（FP）这三类生境类型的整体群落组成及定殖过程均存在显著差异：RS中为适应水流环境的特化类群快速定殖，而OS与FP中则以广适性物种为主。本研究结果表明，洪泛平原生境修复不应仅考虑重建最大连通性，还应构建具备不同连通程度与干扰强度的多样化生境镶嵌体。洪泛平原内的每一类生境均支撑着独特的物种组合，这意味着此类生境镶嵌体可助力形成极高多样性的生态系统。