Analysis of enamel stable carbon isotopes (δ¹³C_enamel) of fossil herbivores is an important tool for making inferences about Plio-Pleistocene vegetation structure in Africa and the environmental context of hominin evolution. Many palaeoecological studies implicitly or explicitly assume that individual variation in C₃–C₄ plant consumption among fossil herbivores directly reflects the abundance of C₃ (trees, shrubs) or C₄ (low-altitude tropical grasses) vegetation. However, a strong link between δ¹³C_enamel of herbivores and ecosystem vegetation structure has not been rigorously established. Here we combine δ¹³C_enamel data from a large dataset (n = 1,643) with multidecadal Landsat estimates of C₃ woody cover across 30 African ecosystems to show that there is little relationship between intrataxonomic variation in δ¹³C_enamel and vegetation structure. This is especially true when removing forested ecosystems (>80% woody cover)—which numerous lines of evidence suggest are rare in the Plio-Pleistocene fossil record of eastern Africa—from our analyses. Our findings stand in contrast with the common assumption that variation in herbivore δ¹³C_enamel values reflects changes in the relative abundance of C₃–C₄ vegetation. We conclude that analyses using herbivore δ¹³C_enamel data to shed light on the environmental context of hominin evolution should look to explicitly community-level approaches for making vegetation inferences.

分析食草动物的珐琅质稳定碳同位素（δ ¹³ C_珐琅质）是推断非洲上更新世植被结构和人类进化环境背景的重要工具。许多古生态学研究暗示或明确假设化石食草动物中 C ₃ -C ₄植物消耗的个体差异直接反映了 C ₃（树木、灌木）或 C ₄（低海拔热带草）植被的丰度。然而，尚未严格建立食草动物的δ ¹³ C_{釉质与生态系统植被结构之间的密切联系。}这里我们结合 δ ¹³来自大型数据集 ( n  = 1,643) 的C_{珐琅质数据以及对 30 个非洲生态系统的 C 3木本覆盖的多年代际陆地卫星估计表明，δ} ¹³ C_珐琅质的分类内变异与植被结构之间几乎没有关系。在我们的分析中去除森林生态系统（>80% 的木本覆盖）时尤其如此——许多证据表明，在东非的上更新世化石记录中这种生态系统很少见。^{我们的研究结果与草食动物 δ 13} C_釉质值的变化反映了 C ₃ –C ₄相对丰度变化的普遍假设相反。植被。我们得出结论，使用食草动物 δ ¹³ C_釉质数据来阐明人类进化的环境背景的分析应该着眼于明确的社区级方法来进行植被推断。