Abstract
BackgroundCurrent global warming affects the composition and dynamics of mammalian communities and can increase extinction risk; however, long-term effects of warming on mammals are less understood. Dietary reconstructions inferred from stable isotopes of fossil herbivorous mammalian tooth enamel document environmental and climatic changes in ancient ecosystems, including C3/C4 transitions and relative seasonality.Methodology/Principal FindingsHere, we use stable carbon and oxygen isotopes preserved in fossil teeth to document the magnitude of mammalian dietary shifts and ancient floral change during geologically documented glacial and interglacial periods during the Pliocene (∼1.9 million years ago) and Pleistocene (∼1.3 million years ago) in Florida. Stable isotope data demonstrate increased aridity, increased C4 grass consumption, inter-faunal dietary partitioning, increased isotopic niche breadth of mixed feeders, niche partitioning of phylogenetically similar taxa, and differences in relative seasonality with warming.Conclusion/SignificanceOur data show that global warming resulted in dramatic vegetation and dietary changes even at lower latitudes (∼28°N). Our results also question the use of models that predict the long term decline and extinction of species based on the assumption that niches are conserved over time. These findings have immediate relevance to clarifying possible biotic responses to current global warming in modern ecosystems.
Highlights
Recent global warming alters species distributions, abundances, interactions, and the timing of seasonal activities [1,2,3]
Dietary reconstructions inferred from stable isotopes of mammalian tooth enamel yield minor to no changes between glacial and interglacial periods in both large and small mammals [8,9]
Equus is more enriched in 13C than all other taxa (p,0.0001), indicating a diet consisting mainly of C4 vegetation. This glacial site is dominated by C3 browsers, it is clear from the horse data that C4 grasses were present
Summary
Recent global warming alters species distributions, abundances, interactions, and the timing of seasonal activities [1,2,3]. Bioclimatic ‘envelope’ models examining current warming trends predict the long term decline and extinction of species. These models are based on an understanding of the modern ecological parameters of species, and often incorporate an assumption of niche conservatism, i.e. the idea that ecological niches are maintained over long time scales [4,5,6]. There is evidence that the niches of mammalian taxa, based on temperature and precipitation, that persisted during the last glacial to interglacial transition, are conserved [10] All of these studies suggest that mammalian responses to interglacial warming were generally minor. Dietary reconstructions inferred from stable isotopes of fossil herbivorous mammalian tooth enamel document environmental and climatic changes in ancient ecosystems, including C3/C4 transitions and relative seasonality
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
