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Communication Dans Un Congrès Année : 2020

Ground truthing dental ecological proxies on a modern alpine community of sympatric ruminants

Résumé

Ecological information from fossilized hard tissues is often difficult to interpret, because links between environment, diet, and hard tissue biology are insufficiently studied in modern communities. To address this dilemma, we investigate dietary proxies in a four-ruminant community from the French Alps, for which most of the vegetation cover is characterized on terrain up to 500 m from the very place where the animals were shot. Molar microwear textural analyses are applied to 82 specimens of roe deer (n = 18), red deer (n = 21), chamois (n = 21), and mouflons (n= 22). Intra-tooth serial enamel stable carbon and oxygen isotope analyses of the structurally bound carbonate were made on 11 specimens to assess the seasonality of diet and drinking water. Both inter-individual dispersion and heterogeneity of complexity together with the anisotropy track dietary differences. The red deer are likely more engaged in grazing than the two bovids, which both plot as mixed feeders. When combined, dental microwear and carbon stable isotope analyses accurately reflect known ecological separation between the chamois and the roe deer. Carbon and oxygen isotopes suggest niche separation by increasing enrichment from roe deer, to red deer, to chamois; mouflons appear to feed as generalists. In roe deer, which show the highest enamel oxygen isotope range (5.7‰), variation is nevertheless constrained compared to δ18O ranges observed in regional precipitation, where mean annual range reaches 9.9‰. However, through inverse modeling we estimate seasonal input ranges that average 9.7‰, a result strikingly similar to regional values. A preliminary analysis of correlation based on microwear textures with habitat type (open, mixed, and forested habitats) detect significant correlations. Dental microwear anisotropy is positively correlated with the mixed vegetation cover and negatively correlated with open vegetation cover. Given that anisotropy is expected to be higher for the most grazing species in open habitats, such results are at first glance surprising. Our results reflect the fact that the most open habitat dwelling species are not grazers but rather mixed feeders and that the cervids, both occupying the most forested zones, display contrasted feeding preferences. Altogether, our data demonstrate that given appropriate sampling strategies and modeling approaches, microwear and isotopic data can be effective tools for demonstrating niche separation among sympatric ungulates.
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Dates et versions

hal-03908565 , version 1 (20-12-2022)

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  • HAL Id : hal-03908565 , version 1

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Gildas Merceron, Emilie Berlioz, Hubert Vonhof, Daniel R Green, Mathieu Garel, et al.. Ground truthing dental ecological proxies on a modern alpine community of sympatric ruminants. The Society of Vertebrate Paleontology 80th Annual Meeting, The Society of Vertebrate Paleontology, Oct 2020, Online, France. ⟨hal-03908565⟩
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