Blood variation implicates respiratory limits on elevational ranges of Andean birds

The extent to which species ranges reflect intrinsic physiological tolerances is a major, unsolved question in evolutionary ecology. To date, consensus has been hindered by the limited tractability of experimental approaches across most of the tree of life. Here, we apply a macrophysiological approach to understand how hematological traits related to oxygen transport shape elevational ranges in a tropical biodiversity hotspot. Along Andean elevational gradients, we measured traits that affect blood oxygen-carrying capacity—total and cellular hemoglobin concentration and hematocrit—for 2,355 individuals of 136 bird species. We used these data to evaluate the influence of hematological traits on elevational ranges. First, we asked whether the sensitivity of hematological traits to elevation is predictive of elevational range breadth. Second, we asked whether variance in hematological traits changed as a function of distance to the nearest elevational range limit. We found that the correla..., From 2006 to 2020, we measured total blood hemoglobin concentration ([Hb]) and the percentage of hematocrit (Hct) for birds captured during collaborative fieldwork in Peru by the Museum of Southwestern Biology (MSB) in New Mexico, USA, and the Centro de Ornitología y Biodiversidad (CORBIDI) in Lima, Peru. As quickly as possible after capture, we punctured the brachial vein on the underside of each bird’s wing and collected whole blood using heparinized microcapillary tubes (for Hct) or spectrophotometer cuvettes (for [Hb]). We centrifuged microcapillary tubes for 5 minutes at 13,000 rpm to separate red blood cells from plasma and used digital calipers to quantify the relative volume of each, averaging two samples per bird to arrive at our final estimate of Hct as a percentage. We measured [Hb] (g/dL blood) for a ~5 μL blood sample with the Hemocue HB201 analyzer and associated hemoglobin photometer. As this proprietary method generates values approximately 1.0 g/dL higher than measures ..., Raw data are stored as comma-separated values (.csv) files. All data processing, analyses, and figures can be produced by sequentially running three R Markdown (.Rmd) notebooks found in the associated Zenodo repository (this procedure is documented in the README).Â物种分布范围在多大程度上反映其内在生理耐受能力，是进化生态学领域尚未解决的重大问题。迄今为止，由于对绝大多数生物类群而言实验方法的可操作性有限，学界始终未能达成共识。本研究采用宏观生理学（macrophysiological）研究方法，旨在解析热带生物多样性热点地区中，与氧转运相关的血液学性状（hematological traits）如何塑造鸟类的海拔分布范围。沿安第斯山脉海拔梯度，我们对136种鸟类的2355个个体开展了影响血液携氧能力的性状测定，包括总血红蛋白浓度、细胞血红蛋白浓度以及血细胞比容（hematocrit, Hct）。基于上述数据，我们评估了血液学性状对海拔分布范围的影响：其一，血液学性状对海拔的敏感性是否可预测海拔分布幅宽；其二，血液学性状的变异是否随与最近海拔分布边界的距离变化而改变。我们发现其相关性…… 2006年至2020年间，我们对秘鲁协作野外考察中捕获的鸟类进行了总血液血红蛋白浓度（[Hb]）与血细胞比容百分比的测定，该野外考察由美国新墨西哥州西南生物博物馆（Museum of Southwestern Biology, MSB）与秘鲁利马的鸟类学与生物多样性中心（Centro de Ornitología y Biodiversidad, CORBIDI）共同开展。捕获后尽快通过每只鸟翼下的臂静脉穿刺采血：使用肝素化微量毛细管采集全血以测定Hct，使用分光光度计比色杯采集全血以测定[Hb]。将微量毛细管以13000转/分钟离心5分钟，分离红细胞与血浆，使用数显卡尺分别测定二者的相对体积；每只鸟取两份样本取平均，最终得到以百分比计的Hct测定值。我们使用Hemocue HB201分析仪及配套的血红蛋白光度计，对约5微升的血液样本测定[Hb]（单位：g/dL血液）。由于该专有方法的测定值较其他方法约高1.0 g/dL…… 原始数据以逗号分隔值（.csv）格式文件存储。所有数据处理、分析与绘图流程均可通过依次运行关联Zenodo仓库中的三份R Markdown（.Rmd）笔记本文件完成（该流程已在README文件中说明）。