Carnivoran resource and habitat use in the context of a Late Miocene faunal turnover episode

Abstract

We investigate resource and habitat use by apex predators through stable isotope analysis at two Spanish Late Miocene localities: Los Valles de Fuentidueña (~9.6 Ma, LVF) and Cerro de los Batallones (~9.1 Ma, BAT). The temporal window represented by LVF and BAT was crucial in the shaping of the current Iberian mammalian structure because it corresponds to the initial stages of a faunal turnover episode and regional environmental change at ~9.5–8.5 Ma (Vallesian–Turolian transition), associated with an increase in the seasonality of precipitation. Herbivore and carnivore δ13C and δ18O values do not point to significant changes in either the vegetation cover (a woodland to mesic C3 grassland) or the hydrological regime during the time lapse represented between LVF and BAT. This suggests that the environmental shift recorded around the Vallesian–Turolian boundary may have occurred later in time, since LVF and BAT ages are synchronic with the onset of the turnover event. From the standpoint of predator–prey evaluation by means of stable isotope analysis, statistical post hoc tests, mixing model output, and the assessment of niche occupation by LVF and BAT carnivores point to high levels of interspecific competition among large active carnivores, albeit some genera, such as the amphicyonid Magericyon and specially the hyaenid Lycyaena, seemed to avoid competition by taking prey from a more open habitat. Despite the drop in diversity and change in faunal components observed between the LVF and BAT assemblages, a high degree of resource and habitat competition is evident from stable isotope data.

Multi-scale interplays of biotic and abiotic drivers shape mammalian sub-continental diversity over millions of years

“…In times when open habitats were more widespread in Iberian ecosystems (higher δ 13 C), the diversity growth was substantially below that predicted by pure DD models. This is in agreement with very warm periods, associated with a severe evaporation of water bodies and higher δ 18 O values 34 , showing a negative effect on the diversity growth of the system when compared to pure DD models (Fig. 2E ).…”

Palaeoecological differences underlie rare co-occurrence of Miocene European primates

“…Stable carbon and oxygen isotope compositions (δ 13 C and δ 18 O) of mammalian tooth enamel reflect diet, primary production and animal and landscape water use, which permit to reconstruct palaeoecological preferences and, in turn, past environmental and climatic conditions [ 24 , 66 , 71 , 72 ]. For herbivorous terrestrial mammals, tooth enamel δ 13 C values are largely controlled by the photosynthetic pathway followed by the ingested plants, as well as by plant water economy, and inform about the vegetation cover present in an area [ 73 ].…”

“…The δ 18 O values of mammalian bioapatite—both the carbonate fraction (δ 18 O CO3 ) and the phosphate fraction (δ 18 O PO4 )—record the δ 18 O value of body water, which in turn reflects the fluxes and δ 18 O value of oxygen entering and exiting the body. Within an obligate-drinking taxon, variations in body water δ 18 O values can be interpreted as chiefly reflecting changes in the isotopic composition of ingested water, which varies with mean annual temperature and aridity [ 24 , 66 , 71 , 72 ].…”

Stable isotope paleoecology of the Baynunah Formation

“…The median oxygen isotope value for the Baynunah sivatheres (+ 4.3 ‰) is 9 ‰ more positive than the median value for all other Baynunah large mammals (−4.7 ‰; Fig. 18.7), which indicates a major difference in physiology or water-use strategy from the other Baynunah large mammals, a pattern observed at other late Miocene sites (Domingo et al 2017).…”