Can we Infer Humidity Gradients across the Ural Mountains during the Late Quaternary using Arvicoline Rodents as an Environmental Proxy?

The study aims to answer the question on the possibility of using the data on arvicoline rodent occurrence for revealing large-scale gradients of humidity in the central part of Northern Eurasia. We classify all arvicoline species known in the study area since the Late Pleistocene into 5 groups based on the vegetation type and moisture balance of breeding and survival habitats of their extant representatives and assign habitat moisture preference rates from 1 to 5 to the species associated with xero-, mesoxero-, meso- mesohygro- and hygrophytic vegetation. The obtained ordinal variable called relative humidity of arvicoline habitats (RH A ) is estimated for paleontological and neontological datasets subdivided into geographical segments. In the Southern, Middle and Northern segments of the Ural Mountains, the relative humidity of arvicoline habitats increased northwards and increased over time from the Late Pleistocene to the Late Holocene. During the Late Pleistocene—Holocene, the species of xeric habitats were less frequent on the western slope of the Ural Mointains than on the eastern slope. However, the differences between the slopes are not detected in the neontological dataset. The data on arvicoline habitat humidity reveal the increased gradual mesophytization of the communities in all geographical segments of the study area from the Late Pleistocene to the Late Holocene. Arvicolines associated with mesophytic vegetation predominate on the western slope of the Southern, Middle, and Northern Urals and on the eastern slope of the Middle Urals since the Early Holocene. On the eastern slope of the Southern Urals, the arvicolines of mesic habitats predominate since the Late Holocene. The results suggest that arvicoline rodents may be successfully used for reconstruction of spatiotemporal environmental gradients using the data on relative humidity of their habitats. Suggested approach may contribute to multi-proxy paleoenvironmental reconstructions for the Late Quaternary and appears to be important for paleoarchives comprising no reliable paleobotanic data (e.g., numerous karst caves of the Ural Mountains).