Data underlying the publication: "Environmental requirements and heterogeneity of rheophilic fish nursery habitats in European lowland rivers: current insights and future challenges"

The large-scale degradation of riparian ecotones and of the connectivity between rivers and their floodplains has resulted in a drastic decline of rheophilic fish populations in European temperate lowland rivers. Recent river restoration projects have had variable success in effectively restoring these fish populations. Knowledge on nursery habitat requirements is considered essential for effective population restoration. However, a detailed understanding of the role of habitat heterogeneity in young-of-the-year (YOY) fish population development is limited. Therefore, we carried out a synthesis of the available knowledge on nursery habitat requirements of rheophilic fish species found in European temperate lowland rivers (<200 m elevation). From a total of 603 papers, 77 studies with primary information were selected, containing 390 associations between habitat features and YOY fish. As expected, most studies focused on static components of physical riparian habitat. Generally, YOY fish require habitats of shallow depth (<0.5 m), with slow-flowing water (<0.2 m·s-1), gentle bank slope (<20 degrees), variety in substratum types (fine sand to gravel), relatively warm water, and high food availability. Surprisingly, no clear ontogenetic habitat shifts between larvae and juveniles were found, which may be explained by the limited spatial-temporal resolution of most studies. Since 2011, studies on habitat heterogeneity have increased, but few have explicitly assessed its role in relation to movement patterns of YOY fish for nursery success. Therefore, we recommend that future research focuses on fish movement patterns between habitat patches in heterogeneous (river-floodplain) environments, to increase the knowledge base for effective recovery of rheophilic fish populations.欧洲温带低地河流中，河岸交错带（riparian ecotones）大规模退化以及河流与洪泛平原（floodplains）间的连通性丧失，导致嗜流性鱼类（rheophilic fish）种群数量急剧下降。近年来的河流修复项目在有效恢复此类鱼类种群方面成效参差不齐。育幼栖息地需求相关认知被认为是实现种群有效修复的核心前提。然而，学界对栖息地异质性（habitat heterogeneity）在当年幼鱼（young-of-the-year, YOY）种群动态中的作用机制仍缺乏深入认知。为此，本研究针对海拔低于200米的欧洲温带低地河流中嗜流性鱼类的育幼栖息地需求相关现有研究开展了系统性综述。研究共检索到603篇相关文献，最终筛选出77项包含一手数据的研究，涵盖390组栖息地特征与当年幼鱼的关联数据。正如预期，多数研究聚焦于河岸物理生境的静态组分。总体而言，当年幼鱼偏好的育幼栖息环境具备以下特征：水深较浅（<0.5 m）、水流平缓（<0.2 m·s⁻¹）、岸坡平缓（<20°）、底质类型多样（细沙至砾石）、水温相对较高，且食物资源充足。令人意外的是，研究未发现仔鱼与稚鱼间存在明确的发育性栖息地转移（ontogenetic habitat shifts）现象，这一结果或可归因于多数研究的时空分辨率不足。自2011年以来，针对栖息地异质性的研究数量有所增长，但鲜有研究明确探讨其与当年幼鱼移动模式的关联，进而阐明其对育幼成功的作用。因此，本研究建议未来研究应聚焦于异质性（河流-洪泛平原）环境中不同栖息地斑块间的鱼类移动模式，以夯实嗜流性鱼类种群有效恢复的科学基础。