Retreat and extinction of the Late Pleistocene cave bear (Ursus spelaeus sensu lato)

Abstract

The cave bear (Ursus spelaeus sensu lato) is a typical representative of Pleistocene megafauna which became extinct at the end of the Last Glacial. Detailed knowledge of cave bear extinction could explain this spectacular ecological transformation. The paper provides a report on the youngest remains of the cave bear dated to 20,930 ± 140 14C years before present (BP). Ancient DNA analyses proved its affiliation to the Ursus ingressus haplotype. Using this record and 205 other dates, we determined, following eight approaches, the extinction time of this mammal at 26,100–24,300 cal. years BP. The time is only slightly earlier, i.e. 27,000–26,100 cal. years BP, when young dates without associated collagen data are excluded. The demise of cave bear falls within the coldest phase of the last glacial period, Greenland Stadial 3. This finding and the significant decrease in the cave bear records with cooling indicate that the drastic climatic changes were responsible for its extinction. Climate deterioration lowered vegetation productivity, on which the cave bear strongly depended as a strict herbivore. The distribution of the last cave bear records in Europe suggests that this animal was vanishing by fragmentation into subpopulations occupying small habitats. One of them was the Kraków-Częstochowa Upland in Poland, where we discovered the latest record of the cave bear and also two other, younger than 25,000 14C years BP. The relatively long survival of this bear in karst regions may result from suitable microclimate and continuous access to water provided by deep aquifers, indicating a refugial role of such regions in the Pleistocene for many species.

Additive effects of climate change and human hunting explain population decline and extinction in cave bears

“…; Baca et al . ). This period further coincides with the appearance of two rare taxa within the cave bear species complex in eastern Europe, that is U. kudarensis in the Caucasus (known from only four localities from 34 to 55 kya; Stiller et al .…”

“…We designed six possible extinction scenarios alternatively simulating the effect of climate change, H. sapiens presence and their combination over 52 thousand years of U. spelaeus evolution, up to the actual extinction record at 24 kya (Baca et al . ; Terlato et al . ).…”

“…We designed six possible extinction scenarios alternatively simulating the effect of climate change, H. sapiens presence and their combination over 52 thousand years of U. spelaeus evolution, up to the actual extinction record at 24 kya (Baca et al 2016;Terlato et al 2018). Each simulation was run with 10 000 iterations using starting demographic values and their standard deviations to account for parameter uncertainty.…”

“…Here, we applied for the first time PVA to an extinct species, the cave bear U. spelaeus. Our goal was to elucidate which combination of factors and parameters best explains its observed extinction date at 24 kya (Baca et al 2016;Terlato et al 2018), and to show that PVA is a powerful method helping to understand the determinants of extinction in fossil species.…”

Morphometry of upper cheek teeth of cave bears (Carnivora, Ursidae)

“…Cave bears from the Urals (Russia) are grouped, according to the genetic data, with cave bears from eastern Europe belonging to the haplogroup ‘ingressus’ (Baca et al. , ; Stiller et al. ); however, a craniometrical difference was detected between these two populations (Baryshnikov & Puzachenko ).…”