Small mammals diversity of southern South America and western Europe during the climatic events of the Holocene (~8200 and 4200 years BP)

Abstract

The Holocene is considered a period of relative climatic stability although evidences for pervasive millennial-scale cycles have been detected. Amongst them, the 8.2 and 4.2 ka were considered in this work, which are two climate shifts that mark the boundary of Early/Middle and Middle/Late Holocene, respectively. So far, they have been better studied in Northern Hemisphere sites, based on botanic, sedimentological and isotopic data, than in South American sites. Micromammals (< 5 kg) have specific ecological requirements and are good palaeoecological indicators. The following sites have been selected (considering taxonomic representation, chronology and taphonomy): Cabeza de Buey, Arroyo Seco, Paso Otero 4, Epullán Grande, Cueva Traful I, Arroyo Malo 3, Cueva Salamanca, Cueva de Luna and Gruta del Indio (Argentina), and Valdavara-1, Atapuerca, Santimamiñe, El Mirón, Cova Colomera, Cova 120 and Cova del Frare (Spain). We here present preliminary results of a study of flow energy, β-diversity and Taxonomic Habitat Index (THI) at community level. Results do not show severe changes in any of these areas, although diversity values show greater differences in past communities than in recent ones. In spite of some minor changes, the absence of a greater influence of these events may be explained by ecosystems resilience or a low incidence in the study areas, without affecting the Thermo Neutral Zone (TNZ) of small mammals. However, the application of Bioclimatic model seems to reflect a slight reduction of temperatures for both study areas.