Resumen de Fate of cave bear in northeastern italy: Anthropic impact, extinction chronology, stable isotope and genetic evidence
Cave bears (Ursus spelaeus sensu lato) represent large extinct ursids with the most abundant fossil remains in Late Pleistocene caves in Europe. Since its recognition by the scientific community as an extinct species, this taxon has been extensively studied but some aspects contributing to their extinction are still a subject of intense debate. A better understanding of the mechanisms that led to the extinction of this species in Europe in a context of climate instability and changing human impact on the ecosystems will have implications for anticipating possible future extinctions. This research aims to revisit the debate about the extinction and paleoecology of cave bear through archaeozoological, taphonomic and chemical analysis of the bones of this species from Middle and Upper Palaeolithic of northeastern Italy. Key sites for this purpose are Rio Secco, Fumane, Buso doppio del Broion, Paina and Trene caves. Cave bear remains are very often found in these caves and, most of them are associated with evidence of human presence. We want to individuate the circumstances that led the disappearance of the cave bear in a Mediterranean area in Southern Alps, keeping not only a regional but a pan-European perspective. To be precise: what role does human impact play? Does the cave bear show divergences on ecology and diet in relation to dramatic climate change and in a context of territorial continuity and contemporary human occupation? When cave bears disappearance in northeastern Italy? Late disappearance? We intend to achieve this purpose through integrated methods of cave bear remains from layers dated 49 – 42 ky cal. BP (Rio Secco and Fumane) and 33 – 23 ky cal. BP (Buso doppio del Broion, Trene and Paina). In order to better understand the role of human impact on cave bear populations during a wide span of time, zooarchaeological and taphonomic analysis were performed on bones assemblage from Rio Secco Cave (layers 5top, 7, 5, and 8), Fumane Cave (layers A5-A6) and Buso doppio del Broion (layers 1-2), on more than 600 bear bones. Further techniques, such as a stable isotope, radiometric and ancient DNA analysis were applied to cave bear bones, selected from Buso doppio del Broion, Paina and Trene caves, in order to acquire a detailed picture of the ecology, diet, population dynamics and extinction chronology of cave bears.
The results indicate that in northeastern Italy the exploitation of cave bear starts with Neanderthals. This was determined at Rio Secco cave and Fumane cave, which can be considered rare cases of remain accumulations generated by the human predation of bears (mostly cave bear) of varied age classes during or near the end of hibernation. Human modification such a cut-marks on several skeletal elements of cave bear from Trene cave and Buso doppio del Brion, reveals a continuity in the hunting and subsistence strategies during a wide span of time. A situation that was probably not favourable to the survival of the species. The radiocarbon dates on cave bears from Berici Hills are an important contribution to extinction chronology and representing the most recent ones knows from Europe. The late cave bears from these sites belong to haplogroup of Ursus ingressus and represent the isolated and genetically impoverished relict of the much larger and more diverse cave bear population in Europe. The cave bear specimens with young radiocarbon dates are not outliers in terms of isotopic composition, suggesting that they had similar diets as earlier ones, an essential vegetarian diet. The δ13C and δ15N values do not show any obvious ecological change, despite climatic fluctuations, suggesting a strong niche conservatism for this species, leading to a possible lack of ecological flexibility in the LGM. Thanks to the application of this combined methods we were able to put “another brick in the wall” of our knowledge on the cave bear extinction.
