Data from: Comparative demographics of a Hawaiian forest bird community

Estimates of demographic parameters such as survival and reproductive success are critical for guiding management efforts focused on species of conservation concern. Unfortunately, reliable demographic parameters are difficult to obtain for any species, but especially for rare or endangered species. Here we derived estimates of adult survival and recruitment in a community of Hawaiian forest birds, including eight native species (of which three are endangered) and two introduced species at Hakalau Forest National Wildlife Refuge, Hawaiʻi. Integrated population models (IPM) were used to link mark-recapture data (1994-1999) with long-term population surveys (1987-2008). To our knowledge, this is the first time that IPM have been used to characterize demographic parameters of a whole avian community, and provides important insights into the life history strategies of the community. The demographic data were used to test two hypotheses: (i) arthropod specialists, such as the ‘Akiapōlā‘au (Hemignathus munroi), are 'slower' species characterized by a greater relative contribution of adult survival to population growth, i.e. lower fecundity and increased adult survival; and (ii) a species’ susceptibility to environmental change, as reflected by its conservation status, can be predicted by its life history traits. We found that all species were characterized by a similar population growth rate around one, independently of conservation status, origin (native vs. non-native), feeding guild, or life history strategy (as measured by 'slowness'), which suggested that the community had reached an equilibrium. However, such stable dynamics were achieved differently across feeding guilds, as demonstrated by a significant increase of adult survival and a significant decrease of recruitment along a gradient of increased insectivory, in support of hypothesis (i). Supporting our second hypothesis, we found that slower species were more vulnerable species at the global scale than faster ones. The possible causes and conservation implications of these patterns are discussed.生存与繁殖成功率等种群统计参数的估算，对于指导受保育关注物种的管理工作至关重要。然而，获取可靠的种群统计参数对任何物种而言都颇具难度，对于珍稀或濒危物种更是如此。本研究于夏威夷哈卡拉森林国家野生动物保护区，针对夏威夷森林鸟类群落开展了成体存活率与种群补充率的估算工作，该群落包含8种本土鸟类（其中3种为濒危物种）与2种引入鸟类。研究采用集成种群模型（Integrated Population Models, IPM），将标记重捕数据（1994-1999年）与长期种群调查数据（1987-2008年）进行整合关联。据我们所知，本研究首次将集成种群模型应用于完整鸟类群落的种群统计参数表征，为该群落的生活史策略研究提供了重要见解。本研究利用种群统计数据检验了两项假说：其一，节肢动物专食类群（如‘Akiapōlā‘au（Hemignathus munroi））属于“慢节奏”物种，其成体存活率对种群增长的相对贡献更高，即繁殖力较低而成体存活率更高；其二，物种对环境变化的敏感性（可通过其保育等级体现）可通过其生活史特征进行预测。研究发现，所有物种的种群增长率均接近1，且不受保育等级、起源（本土与非本土）、取食功能群或生活史策略（以“慢节奏”衡量）的影响，这表明该群落已达到生态平衡。不过，不同取食功能群实现稳定种群动态的路径存在差异：随着食虫性梯度升高，成体存活率显著上升而种群补充率显著下降，这一结果支持了第一项假说。同时，研究结果也支持第二项假说：在全球尺度上，“慢节奏”物种相比“快节奏”物种的濒危风险更高。本研究还对上述格局的潜在成因及其保育启示进行了探讨。