Abstract Managers often rely on species surveys and distribution models to evaluate species occurrence and develop management and conservation plans. However, these tools are rarely used in concert. We used a three-step framework to evaluate the distribution of a declining and elusive freshwater amphibian species, the hellbender salamander (Cryptobranchus alleganiensis). We used the Maximum Entropy (MaxEnt) algorithm to develop a habitat suitability model to guide sampling, environmental DNA (eDNA) surveys to ground truth the habitat suitability model, and multi-level occupancy modeling to assess species presence, while accounting for eDNA detection errors. Our suitability model (AUC = 0.941, True Skill Statistic = 0.7, sensitivity and specificity = 0.86) identified the greatest amount of high and very highly suitable habitat in the Interior Plateau and Blue Ridge ecoregions of the study area. We used eDNA survey results (n = 284 sites) to evaluate model fit and detected the species at 65 sites. Detection probability (p) was 0.692 (95% CRI: 0.547, 0.818) at the site level and 0.674 (95% CRI: 0.621, 0.721) at the quantitative PCR level. Ecoregion was the primary covariate that explained occupancy, with greatest estimates in the Blue Ridge ecoregion 0.695 (95% CRI, 0.390, 0.925). Although the MaxEnt output was not significantly correlated with occupancy probability, we established a relationship between habitat quality and the number of eDNA detections. This study highlights the use of a multi-level framework to optimize sampling, assess model fit, account for imperfect detection, and evaluate the distribution of rare species that have limited occurrence data available.

中文翻译：

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基于 eDNA 调查，整合物种分布和占有率模型以研究地狱弯曲者（Cryptobranchus alleganiensis）的发生

摘要 管理人员通常依靠物种调查和分布模型来评估物种发生并制定管理和保护计划。然而，这些工具很少一起使用。我们使用了一个三步框架来评估一种正在衰退且难以捉摸的淡水两栖动物物种的分布，即地狱火蝾螈（Cryptobranchus alleganiensis）。我们使用最大熵 (MaxEnt) 算法开发了栖息地适宜性模型来指导采样、环境 DNA (eDNA) 调查以确定栖息地适宜性模型的真实情况，并使用多级占用模型来评估物种存在，同时考虑 eDNA 检测错误. 我们的适用性模型（AUC = 0.941，真实技能统计 = 0.7，敏感性和特异性 = 0。86) 在研究区的内陆高原和蓝岭生态区中确定了最多的高度和非常适合的栖息地。我们使用 eDNA 调查结果（n = 284 个站点）来评估模型拟合并在 65 个站点检测到物种。检测概率 (p) 在位点水平为 0.692 (95% CRI: 0.547, 0.818)，在定量 PCR 水平为 0.674 (95% CRI: 0.621, 0.721)。生态区是解释入住率的主要协变量，蓝岭生态区的最大估计值为 0.695（95% CRI、0.390、0.925）。尽管 MaxEnt 输出与占用概率没有显着相关性，但我们建立了栖息地质量与 eDNA 检测数量之间的关系。这项研究强调了使用多级框架来优化抽样、评估模型拟合、解释不完美的检测、