Spatial patterns in hydrogen isotope ratios in feathers of Burrowing Owls from western North America
Spatial patterns in hydrogen isotope ratios in feathers of Burrowing Owls from western North America
复制标题
北美西部穴居猫头鹰羽毛氢同位素比率的空间模式
DOI：
10.1642/auk-13-061.1
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发表时间：
2014
影响因子：
1.7
通讯作者：
C. Conway
中科院分区：
文献类型：
--
作者：
A. Macías;C. Conway
氘（2 H）被用来跟踪陆地鸟类的活动，假设降水中的δ 2 H（δ 2 Hp）和鸟类羽毛中的δ 2 H（δ 2 Hf）在广泛的地理梯度上是相关的。这种相关性的性质只在北美繁殖的一小部分鸟类中进行了评估。我们采样西部穴居猫头鹰（雅典娜cunicularia hypugaea）羽毛的已知来源（雏鸟羽毛）在36个地点在整个北美（从加拿大南部到墨西哥中部）。我们使用了Wassenaar和霍布森（2003）的“比较平衡”技术的修改版来测量羽毛样品中非交换性氢的δ 2 H。我们的特点之间的关系的强度δ 2 Hf和加权平均每年δ 2 Hp在整个北美西部干旱草原和沙漠中繁殖的猛禽。我们使用贝叶斯分层方法对δ 2 Hf-δ 2 Hp关系进行建模，考虑δ 2 Hf的内在和外在变化水平。我们发现了δ 2 Hf和δ 2 Hp之间的线性关系（δ 2 Hf = −13.48 + 0.78 δ 2 Hp; 95%可信区间（斜率）：0.55-1.01），并利用这种关系构建了羽毛氘同位素图。我们观察到不同地点的平均δ 2 Hf变化水平相对较高（SD = 11.01‰），部分原因是降水对当地食物网的贡献存在差异，以及地点内个体之间的显著差异（SD = 6.68‰）。我们的数据表明，幼年穴居猫头鹰的δ 2 Hf可以用来推断当地的加权平均年δ 2 Hp的起源位置。氘仍然是追踪大陆尺度猛禽运动的宝贵工具，但需要注意的是，研究人员必须在他们的推断中识别和建模δ 2 Hf-δ 2 Hp关系中的潜在不连续性。然而，同位素的不连续性，加上在这些地区的个体相对丰度高，可以严重阻碍氘的有用性，以确定个别鸟类的起源。
ABSTRACT Deuterium (2H) has been used to track movements of land birds, under the assumption that δ2H in precipitation (δ2Hp) and δ2H in bird feathers (δ2Hf) are correlated across broad geographic gradients. The nature of this correlation has been evaluated only in a small percentage of the birds that breed in North America. We sampled Western Burrowing Owl (Athene cunicularia hypugaea) feathers of known origin (nestling feathers) at 36 locations throughout North America (from southern Canada to central Mexico). We used a modification of the “comparative equilibrium” technique of Wassenaar and Hobson (2003) to measure the δ2H of nonexchangeable hydrogen in feather samples. We characterized the strength of the relationship between δ2Hf and amount-weighted mean annual δ2Hp in a raptor that breeds in arid grasslands and deserts throughout western North America. We used a Bayesian hierarchical approach to model the δ2Hf–δ2Hp relationship, accounting for levels of intrinsic and extrinsic variation in δ2Hf. We found a linear relationship between δ2Hf and δ2Hp (δ2Hf = −13.48 + 0.78 δ2Hp; 95% credible interval (slope): 0.55–1.01) and used this relationship to construct a feather deuterium isoscape map. We observed relatively high levels of variation in mean δ2Hf across locations (SD = 11.01‰), due in part to variation in the contribution of precipitation to local food webs, and substantial variation among individuals within locations (SD = 6.68‰). Our data demonstrate that δ2Hf of juvenile Burrowing Owls can be used to infer local amount-weighted mean annual δ2Hp from the location of origin. Deuterium remains a valuable tool for tracking continental-scale raptor movements, with the caveat that researchers must identify and model for potential discontinuities in the δ2Hf–δ2Hp relationship in their inferences. However, isotopic discontinuities, coupled with a high relative abundance of individuals in those areas, can seriously hinder the usefulness of deuterium for identifying the origin of individual birds.