Evaluating the predictors of habitat use and successful reproduction in a model bird species using a large scale automated acoustic array

The emergence of continental to global scale biodiversity data has led to growing understanding of patterns in species distributions, and the determinants of these distributions, at large spatial scales. However, identifying the specific mechanisms, including demographic processes, and determining species distributions remains difficult, as large-scale data are typically restricted to observations of only species presence. New remote automated approaches for collecting data, such as automated recording units (ARUs), provide a promising avenue towards direct measurement of demographic processes, such as reproduction, that cannot feasibly be measured at scale by traditional survey methods. In this study, we analyze data collected by ARUs from 452 survey points across an approximately 1500 km study region to compare patterns in adult and juvenile distributions in the Great Horned Owl (Bubo virginianus). We specifically examine whether habitat associated with successful reproduction is the same as that associated with adult presence. We postulated that congruence between these two distributions would suggest that all areas of the species’ range contribute equally to maintenance of the population, whereas significant differences would suggest more specificity in the species’ requirements for successful reproduction. We filtered adult and juvenile calls of the species for manual review using automated classification and constructed single season occupancy models to compare land cover and vegetation covariates which significantly predicted presence of each life stage. We found that habitat use by adults was significantly predicted by increasing amounts of forest cover, reduced forest basal area, and lower elevations whereas juvenile presence was significantly predicted only by decreasing amounts of forest cover, a pattern opposite that of adults. These results show that presence of adult Great Horned Owls is not a sufficient proxy for locations at which reproduction occurs, and also demonstrate a highly scalable workflow that could be used for similar analyses in other sound-producing species.从大陆到全球尺度的生物多样性数据不断涌现，使得学界对大空间尺度下的物种分布格局及其驱动因子的认知日益深入。然而，明确包括种群动态过程在内的具体机制、解析物种分布格局仍存在诸多挑战——这是因为大尺度生物多样性数据通常仅能获取物种出现的观测记录。新兴的远程自动化数据采集手段，例如自动记录单元（Automated Recording Units, ARUs），为直接测量传统调查方法难以规模化开展的种群动态过程（如繁殖活动）提供了极具前景的路径。本研究针对约1500公里研究区域内452个调查点的自动记录单元采集数据展开分析，对比大雕鸮（Bubo virginianus）成体与幼体的分布格局。研究专门探讨了与繁殖成功相关的栖息地是否与成体出现的栖息地保持一致。我们提出如下假设：若二者分布格局一致，则表明该物种分布范围内的所有区域对种群维持的贡献均等；若二者存在显著差异，则说明该物种成功繁殖的栖息地需求具有更强的特异性。本研究通过自动化分类筛选出该物种的成体与幼体鸣叫声用于人工复核，并构建单季占用模型，对比能够显著预测两个生命阶段物种出现的土地覆盖与植被协变量。研究结果显示，成体的栖息地使用可通过森林覆盖占比提升、森林断面积降低以及海拔更低得到显著预测；而幼体出现仅能通过森林覆盖占比下降得到显著预测，这一模式与成体的栖息地选择模式完全相反。上述结果表明，大雕鸮成体的出现不足以作为繁殖发生地点的有效替代指标，同时也展示了一套高度可扩展的工作流程，可应用于其他发声物种的类似分析研究。