资源环境科技发展态势分析平台

Closed-canopy rainforests are important for climate (influencing atmospheric circulation, albedo, carbon storage, etc.) and ecology (harboring the highest biodiversity of continental regions). Of all rainforests, Amazonia is the world’s most diverse, including the highest mammalian species richness. However, little is known about niche structure, ecological roles, and food resource partitioning of Amazonian mammalian communities over time. Through analyses of δ¹³C_bioapatite, δ¹³C_hair, and δ¹⁵N_hair, we isotopically characterized aspects of feeding ecology in a modern western Amazonian mammalian community in Peru, serving as a baseline for understanding the evolution of Neotropical rainforest ecosystems. By comparing these results with data from equatorial Africa, we evaluated the potential influences of distinct phylogenetic and biogeographic histories on the isotopic niches occupied by mammals in analogous tropical ecosystems. Our results indicate that, despite their geographical and taxonomic differences, median δ¹³C_diet values from closed-canopy rainforests in Amazonia (−27.4‰) and equatorial Africa (−26.9‰) are not significantly different, and that the median δ¹³C_diet expected for mammalian herbivores in any closed-canopy rainforest is −27.2‰. Amazonian mammals seem to exploit a narrower spectrum of dietary resources than equatorial African mammals, however, as depicted by the absence of highly negative δ¹³C_diet values previously proposed as indicative of rainforests (<−31‰). Finally, results of keratin and bioapatite δ¹³C indicate that the predictive power of trophic relationships, and traditional dietary ecological classifications in bioapatite-protein isotopic offset expectations, must be reconsidered.