Abstract：
River habitats are fragmented by barriers which impede the movement and dispersal of aquatic organisms. Restoring habitat connectivity is a primary objective of nature conservation plans with multiple efforts to strategically restore connectivity at local, regional, and global scales. However, current approaches to prioritize connectivity restoration do not typically consider how barriers spatially fragment species\' populations. Additionally, we lack knowledge on biodiversity baselines to predict which species would find suitable habitat after restoring connectivity. In this paper, we asked how neglecting these biodiversity baselines in river barrier removals impacts priority setting for conservation planning. We applied a novel modelling approach combining predictions of species distributions with network connectivity models to prioritize conservation actions in rivers of the Rhine-Aare system in Switzerland. Our results show that the high number and density of barriers has reduced structural and functional connectivity across representative catchments within the system. We show that fragmentation decreases habitat suitability for species and that using expected distributions as biodiversity baselines significantly affects priority settings for connectivity restorations compared to species-agnostic metrics based on river length. This indicates that priorities for barrier removals are ranked higher within the expected distributions of species to maximize functional connectivity while barriers in unsuitable regions are given lower importance scores. Our work highlights that the joint consideration of existing barriers and species past and current distributions are critical for restoration plans to ensure the recovery and persistence of riverine fish diversity.
摘要：
河流栖息地被阻碍水生生物运动和扩散的障碍所分割。恢复栖息地的连通性是自然保护计划的主要目标，并通过多种努力战略性地恢复当地的连通性，区域,和全球规模。然而,当前优先考虑连通性恢复的方法通常不考虑障碍如何在空间上分裂物种\'种群。此外,我们缺乏关于生物多样性基线的知识，无法预测哪些物种在恢复连通性后会找到合适的栖息地。在本文中,我们询问在河流屏障清除中忽略这些生物多样性基线如何影响保护规划的优先级设置。我们应用了一种新颖的建模方法，将物种分布的预测与网络连接模型相结合，以优先考虑瑞士莱茵-阿雷系统河流中的保护行动。我们的结果表明，高数量和密度的屏障减少了系统内代表性集水区的结构和功能连通性。我们表明，与基于河流长度的物种不可知指标相比，碎片化降低了物种的栖息地适宜性，并且使用预期分布作为生物多样性基线会显着影响连通性恢复的优先级设置。这表明，在物种的预期分布中，屏障清除的优先级较高，以最大程度地提高功能连通性，而不适合区域的屏障的重要性得分较低。我们的工作强调，对现有障碍和物种过去和当前分布的共同考虑对于恢复计划至关重要，以确保河流鱼类多样性的恢复和持久性。
