Highlighting the drastic body size decline in Cantabrian Brown Bear, Chamois and Wild Horse during the Holocene

During the Holocene, Iberian ecosystems have changed dramatically in response to different biotic and abiotic drivers. Typically, the impact of these changes on ecosystems is assessed in terms of the variation of diversity in the communities that compose them. However, there are a wide variety of population-specific parameters of vital importance for the maintenance of the structure and health of these ecosystems. In this study, we have focused on the drastic decrease in body size (body mass) during the Holocene in three large mammal species in the Cantabrian Mountains. Namely, the brown bear ( Ursus arctos ), the chamois ( Rupicapra pyrenaica parva ) and the wild horse ( Equus ferus ferus ). The research combines the analysis of new findings with an exhaustive compilation of previously published data to assess changes in the body size of these species at different geographical (European, Iberian and Cantabrian Regions) and chronological scales (during the Quaternary – i.e. Pleistocene and Holocene). We aim at assessing the impact of anthropogenic and climatic factors on macromammal populations in the Iberian Peninsula, using new data obtained from the new archaeo-palaeontological site of Cueva de Llamazares (León, Spain). The results show that, although the final decline in body size during the Holocene occurred in the three species, each of them seems to have been driven by different factors. Bear populations seem more influenced by their mobility versus the potential impact of changing in human hunting dynamics, while changes in vegetation cover would have been most important for chamois, and the gradual effect of climate changes for horse populations. Research covering broad chronological ranges in the past helps understanding the present and future dynamics of these species, thus contributing to their conservation and management.