A study explores dietary isotope signatures in Amazonian and African rainforests. Closed canopy rainforests influence Earth's climate and biodiversity. However, researchers lack comprehensive data about how these important ecosystems function, hampering attempts to identify closed canopy rainforests in the fossil record and to chart their evolution. Julia V. Tejada and colleagues used isotopic analysis to construct a model of feeding ecology in modern mammals from western Amazonia. The authors compared the results with similar analyses of extant mammals in equatorial Africa--a proxy used to identify past closed canopy rainforests on all continents. The comparison revealed the median value of dietary δ13C--a carbon isotope that tracks plant consumption--does not differ significantly between Amazonian and African closed canopy rainforests and may be representative of mammalian herbivores in any closed canopy rainforest. However, the Amazonian mammals in the study lacked the highly negative dietary δ13C values found in equatorial African mammals, suggesting that the former group exploits a narrower range of dietary resources than the latter. According to the authors, the study suggests that current assumptions about ecological niches, feeding habits, and isotopic signatures may need to be reassessed.
Article #20-07440: "Comparative isotope ecology of western Amazonian rainforest mammals," by Julia V. Tejada et al.
MEDIA CONTACT: Julia Tejada, Columbia University, NY; email: jtejada@ldeo.columbia.edu
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Journal
Proceedings of the National Academy of Sciences