Departamento de Ecologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil.
Department of Biology, University of Western Ontario, London, Ontario, Canada.
PLoS One. 2022 Aug 3;17(8):e0271573. doi: 10.1371/journal.pone.0271573. eCollection 2022.
Spatial patterns of stable isotopes in animal tissues or "isoscapes" can be used to investigate animal origins in a range of ecological and forensic investigations. Here, we developed a feather hydrogen isotope (δ2Hf) isoscape for Brazil based on 192 samples of feathers from the family Thraupidae from scientific collections. Raw values of δ2Hf ranged from -107.3 to +5.0‰, with higher values at the Caatinga biome (northeast Brazil) and lower values at the Amazon and Pantanal. A Random Forest (RF) method was used to model the spatial surface, using a range of environmental data as auxiliary variables. The RF model indicated a negative relationship between δ2Hf and Mean Annual Precipitation, Precipitation in the Warmest Quarter, and Annual Temperature Range and positive relationships for amount-weighted February-April precipitation δ2H (δ2Hp(Feb-April)) and Mean Annual Solar Radiation. Modelled δ2Hf values ranged from -85.7 to -13.6‰. Ours is the first δ2Hf isoscape for Brazil that can greatly assist our understanding of both ecological and biogeochemical processes controlling spatial variation in δ2H for this region. This isoscape can be used with caution, due to its poor predictive power (as found in other tropical regions) and can benefit from new sample input, new GNIP data, ecological and physiological studies, and keratin standard material better encompassing the range in feather samples from Brazil. So, we encourage new attempts to build more precise feather H isoscapes, as well as isoscapes based on other elements.
动物组织中稳定同位素的空间模式（即“同位素景观”）可用于研究一系列生态和法医学调查中的动物起源。在这里，我们基于科学收藏中的 192 个 Thraupidae 科的羽毛样本，为巴西开发了一个羽毛氢同位素（δ2Hf）同位素景观。δ2Hf 的原始值范围为-107.3 至+5.0‰，其中卡廷加生物群落（巴西东北部）的值较高，亚马逊和潘塔纳尔的值较低。我们使用随机森林（RF）方法，使用一系列环境数据作为辅助变量来对空间表面进行建模。RF 模型表明，δ2Hf 与平均年降水量、最暖季度降水量和年温度范围呈负相关，与加权 2 月至 4 月降水量的 δ2H（δ2Hp(Feb-April)）和平均年太阳辐射呈正相关。模拟的 δ2Hf 值范围从-85.7 到-13.6‰。这是巴西第一个 δ2Hf 同位素景观，可以极大地帮助我们理解控制该地区 δ2H 空间变化的生态和生物地球化学过程。由于其预测能力较差（在其他热带地区也发现了这种情况），因此该同位素景观的使用需要谨慎，并可以从新的样本输入、新的 GNIP 数据、生态和生理研究以及更好地涵盖巴西羽毛样本范围的角蛋白标准材料中受益。因此，我们鼓励新的尝试来构建更精确的羽毛 H 同位素景观，以及基于其他元素的同位素景观。
