Data from: Isotopic niches support the resource breadth hypothesis

Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges.
We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analyzed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology.
We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology.
Our study not only supports the resource breadth hypothesis, it highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies.

鉴于宽泛的资源利用策略可使物种在多样的生境类型中存续，进而得以占据广阔的地理分布范围；且广泛分布的物种能够接触到更多样化的资源基础，因此资源宽度假说（resource breadth hypothesis）提出：生物体所利用的资源多样性与其地理分布范围应呈正相关关系。
本研究针对Cinclodes属（灶雀属）的南美鸟类小型适应辐射类群展开调查，分析了该属12个物种的羽毛样本，以检验资源宽度假说的同位素版本，并探究同位素生态位宽度与形态特征之间的相关性。
研究结果显示，氢、氧同位素生态位宽度（用于估算物种的海拔分布范围）与碳、氮同位素生态位宽度（用于估算其摄食资源的多样性，亦即其所利用的生境多样性）呈显著正相关；同时，宽泛的同位素生态位与翼部形态特征亦存在正相关关系。
本研究不仅验证了资源宽度假说，同时凸显了稳定同位素分析作为生态位探索工具的应用价值；本研究亦是稳定同位素分析在宏生态学领域应用的典型案例，同时阐明了科学馆藏在生态学研究中的重要意义。