Rivers worldwide are fragmented by transportation infrastructure that blocks the movements of aquatic organisms. To assess the effects of road culverts on stream fishes in the Ozark and Ouachita Mountains regions of Oklahoma, we surveyed 39 free-flowing sites, 29 sites upstream and 29 sites downstream of culverts. We observed differences in species richness and abundance between free-flowing sites, sites upstream of a culvert, and downstream sites. We also found that the degree to which a culvert affected richness and abundance depended on culvert type and length. Furthermore, the culverts in the poorest condition had the greatest effects on abundance and richness. Replacement of these poor condition culverts is likely a high priority for both conservation groups and infrastructure agencies. Our findings enable conservation practitioners to identify structures that may be high priorities for aquatic organism passage projects, including those that may benefit from cost-sharing or collaboration with infrastructure agencies.

全世界的河流被阻碍水生生物运动的运输基础设施所分散。为了评估公路涵洞对俄克拉荷马州奥索卡克和瓦希塔山地区河流鱼类的影响，我们调查了涵洞的39个自由流站点，上游29个站点和下游29个站点。我们观察到自由流动的站点，涵洞上游的站点和下游站点之间物种丰富度和丰度的差异。我们还发现，涵洞影响丰富度和丰度的程度取决于涵洞的类型和长度。此外，最贫困的涵洞对丰度和丰富度的影响最大。对于保护团体和基础设施机构而言，更换这些条件恶劣的涵洞可能都是当务之急。