Data from: Floodplains provide important amphibian habitat despite multiple ecological threats

Floodplain ponds and wetlands are productive and biodiverse ecosystems, yet they face multiple threats including altered hydrology, land use change, and non-native species. Protecting and restoring important floodplain ecosystems requires understanding how organisms use these habitats and respond to altered environmental conditions. We developed Bayesian models to evaluate occupancy of six amphibian species across 103 off-channel aquatic habitats in the Chehalis River floodplain, Washington State, USA. The basin has been altered by changes in land use, reduced river-wetland connections, and the establishment of non-native American bullfrogs (Rana catesbeiana = Lithobates catesbeianus) and centrarchid fishes, all of which we hypothesized could influence native amphibian occupancy. Despite potential threats, the floodplain habitats had relatively high rates of native amphibian occupancy, particularly when compared to studies from non-floodplain habitats within the species' native ranges. The biggest challenge for native amphibians appears to be non-native centrarchid fishes, which strongly reduced occupancy of two native amphibians: the northern red-legged frog (Rana aurora) and the northwestern salamander (Ambystoma gracile). Emergent vegetative cover increased occupancy probability for all five native amphibian species, indicating that plant-management may offer a strategy to counter the negative effect of centrarchids by providing refuge from predation. We found that temporary and permanent hydroperiod sites supported different species, hence both should be conserved on the landscape. Lastly, human-created and natural ponds had similar amphibian occupancy patterns, suggesting that pond construction offers a viable strategy for adding habitats to the floodplain landscape. Overall, floodplain ponds and wetlands provide important amphibian habitat, and we offer management strategies that will bolster amphibian occupancy in an altered floodplain landscape.漫滩池塘与湿地是兼具高生产力与丰富生物多样性的生态系统，但却面临多重威胁，包括水文格局改变、土地利用变化以及外来物种入侵。保护与修复重要的漫滩生态系统，需要厘清生物如何利用这些生境并对环境改变作出响应。我们构建了贝叶斯模型（Bayesian models），以评估美国华盛顿州切哈利斯河漫滩（Chehalis River floodplain）内103个河道外水生生境中6种两栖动物的栖息占有率。该流域因土地利用变化、河流-湿地连通性降低以及外来美洲牛蛙（non-native American bullfrogs，学名Rana catesbeiana = Lithobates catesbeianus）和太阳鱼科鱼类（centrarchid fishes）的种群定植而发生改变，我们推测上述所有因素均可能影响本土两栖动物的栖息占有率。尽管面临潜在威胁，该漫滩生境的本土两栖动物栖息占有率相对较高，尤其是与这些物种原生分布区内非漫滩生境的相关研究相比。本土两栖动物面临的最大威胁似乎为外来太阳鱼科鱼类，它们显著降低了两种本土两栖动物的栖息占有率：北红腿蛙（northern red-legged frog，学名Rana aurora）与西北钝口螈（northwestern salamander，学名Ambystoma gracile）。挺水植被覆盖度提升了所有5种本土两栖动物的栖息概率，这表明植被管理可通过为两栖动物提供捕食庇护所，成为抵消太阳鱼科鱼类负面影响的可行策略。我们发现，临时水文周期（hydroperiod）与永久水文周期的生境分别支持不同的物种，因此二者均需在景观尺度上得到保护。最后，人工营建池塘与自然池塘的两栖动物栖息格局相似，这表明池塘营建可为漫滩景观增添生境提供可行方案。总体而言，漫滩池塘与湿地是重要的两栖动物生境，我们提出的管理策略可在受干扰的漫滩景观中提升两栖动物的栖息占有率。