Fishes in the genus Nocomis function as keystone engineers via their mound-building spawning behavior. Furthermore, mound construction grants some Nocomis spp. resistance to excess sedimentation, as it concentrates gravel in an otherwise silty substrate. However, it is unclear whether silt-resistance is a general trait of Nocomis spp. or is instead more species-specific. The objectives of our research were to identify local- and watershed-scale environmental variables that could explain the distribution of hornyhead chub (Nocomis biguttatus) and redspot chub (Nocomis asper) in Kansas, with a particular focus on the impacts of sedimentation and agriculture. We accomplished these objectives by comparing physicochemical variables between sites where Nocomis spp. were present versus absent using analysis of deviance, and by constructing local- and watershed-scale environmental niche models (ENM) for the hornyhead chub using LASSO-regularized logistic regression. We found that streams where Nocomis spp. were present had less silt, clearer water, and more natural upstream watersheds compared to sites where absent. Furthermore, silt coverage was the only important predictor variable in the local-scale ENM, while the percentages of upstream watersheds that were agricultural or reservoirs were most important in the watershed-scale ENM. All three predictor variables exhibited negative relationships with chub occurrence. Our results suggested that neither species were silt-resistant, potentially meaning their ability to function as keystone engineers could be compromised in streams with excess sedimentation. As such, the implementation of land management practices that reduce soil erosion may be necessary to recover populations of these Nocomis spp., ultimately restoring their keystone functionality.

中文翻译：

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浑水：调查土墩建筑 Nocomis spp 抗淤泥的普遍性。使用 hornyhead chub (Nocomis biguttatus) 和 redspot chub (Nocomis asper)

Nocomis 属的鱼类通过它们的土墩产卵行为充当基石工程师。此外，土墩建设授予一些 Nocomis spp。抵抗过度沉降，因为它可以将砾石集中在粉质基质中。然而，尚不清楚抗淤泥是否是 Nocomis spp 的一般特征。或者更具有物种特异性。我们研究的目的是确定当地和流域尺度的环境变量，这些变量可以解释堪萨斯州角鲢 (Nocomis biguttatus) 和红斑鲢 (Nocomis asper) 的分布，特别关注沉积和农业的影响。我们通过比较 Nocomis spp 的站点之间的物理化学变量来实现这些目标。使用偏差分析存在与不存在，并通过使用 LASSO 正则化逻辑回归为 hornyhead chub 构建局部和流域规模的环境生态位模型 (ENM)。我们发现 Nocomis spp. 与不存在的地点相比，存在的地点有更少的淤泥、更清澈的水和更自然的上游流域。此外，淤泥覆盖率是局部尺度 ENM 中唯一重要的预测变量，而上游流域农业或水库的百分比在流域尺度 ENM 中最为重要。所有三个预测变量都与 chub 发生呈负相关。我们的结果表明，这两种物种都不是抗淤泥的，这可能意味着它们作为基石工程师的能力可能会在沉积过多的溪流中受到损害。因此，