The end of the Last Glacial Maximum in the Iberian Peninsula characterized by the small-mammal assemblages

This paper presents a palaeoenvironmental and palaeoclimatic approach to the end of the Last Glacial Maximum (LGM) in the Iberian Peninsula on the basis of the small-mammal assemblages (insectivores, bats and rodents). The LGM is an important period in our climate history defined by the maximum extension of ice sheets between ca. 22 and 19 ka BP. In the Mediterranean region the LGM is characte­rized by humid conditions, which allow for the development of arboreal vegetation. The small-mammal remains described in this study were recovered from four different sites within the Iberian Peninsula: El Mirón cave (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), and Sala de las Chimeneas (Maltravieso, Cáceres). We found in these sites a non-analogue association represented by species associated with mid-European climatic conditions, such as the voles Chionomys nivalis, Microtus arvalis, Microtus agrestis and Microtus oeconomus, together with species associated with Mediterranean requirements, such as Microtus (Iberomys) cabrerae and Microtus (Terricola) duodecimcostatus. These assemblages reveal that the climate was harsher than today in the sites under study, though not as rigorous as elsewhere in Europe, with mean annual temperatures lower than present and an environment dominated by wet open meadows. All our data have been compared with other environmental and climatic proxies, global isotope curves and pollen data, providing a scenario for the palaeoclimatic and palaeoenvironmental conditions that occurred during the LGM in the Iberian Peninsula.Este artículo representa un enfoque paleoambiental y paleoclimático del final del Último Máximo Glacial (UMG), en la Península Ibérica a partir de las asociaciones de pequeños mamíferos (insectívoros, murciélagos y roedores). El UMG es un período importante en nuestra historia del clima definido por la máxima extensión de las capas de hielo entre ca. 22 y 19 ka BP. En la región del Mediterráneo, este UMG se caracteriza por condiciones de humedad, que permiten el desarrollo de la vegetación arbórea. Los restos de micromamíferos seleccio­nados para este estudio corresponden a cuatro yacimientos diferentes de la Península Ibérica: la cueva del Mirón (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), y la Sala de las Chimeneas (Maltravieso, Cáceres). En todos los yacimientos estudiados se ha encontrado una asociación representada por las especies relacionadas con las condiciones cli­máticas medio-europeas, como los topillos Chionomys nivalis, Microtus arvalis, Microtus agrestis o Microtus oeconomus, junto con las especies asociadas con los requerimientos mediterráneos, como Microtus (Iberomys) cabrerae o Microtus (terricola) duodecimcostatus. Estas asociaciones nos permiten observar que el clima era más frío que hoy en día en los diferentes yacimientos estudiados, pero no tan riguroso como en otros lugares de Europa, con temperaturas medias anuales más bajas que en la actualidad y un entorno dominado por pra­dos húmedos. Los resultados de este estudio han sido comparados con otros datos ambientales y climáticos, las curvas climáticas globales de isótopos y datos polínicos, proporcionando un escenario para las condiciones paleoclimáticas y paleoambientales que ocurrieron durante el UMG en la Península Ibérica

Diverse responses of common vole (Microtus arvalis) populations to Late Glacial and Early Holocene climate changes – Evidence from ancient DNA

The harsh climatic conditions during the Last Glacial Maximum (LGM) period have been considered the cause of local extinctions and major faunal reorganizations that took place at the end of the Pleistocene. Recent studies have shown, however, that in addition many of these ecological events were associated with abrupt climate changes during the so-called Late Glacial and the Pleistocene/Holocene transition. Here we used ancient DNA to investigate the impact of those changes on European populations of temperate vole species (Microtus arvalis). The genetic diversity of modern populations and the fossil record suggests that the species may have survived cold episodes, like LGM, not only in the traditional Mediterranean glacial refugia but also at higher latitudes in cryptic northern refugia located in Central France, the northern Alps as well as the Carpathians. However, the details of the post-glacial recolonization and the impact of the Late Glacial and Early Holocene climate changes on the evolutionary history of the common vole remains unclear. To address this issue, we analysed mtDNA cytochrome b sequences from more than one hundred common vole specimens from 36 paleontological and archaeological sites scattered across Europe. Our data suggest that populations from the European mid- and high latitudes suffered a local population extinction and contraction as a result of Late Glacial and Early Holocene climate and environmental changes. The recolonization of earlier abandoned areas took place in the Mid- to Late Holocene. In contrast, at low latitudes, in Northern Spain there was a continuity of common vole populations. This indicates different responses of common vole populations to climate and environmental changes across Europe and corroborates the hypothesis that abrupt changes, like those associated with Younger Dryas and the Pleistocene/Holocene transition, had a significant impact on populations at the mid- and high latitudes of Europe

Análisis de los cambios paleoambientales del Pleistoceno superior final-Holoceno a partir del estudio de micromamíferos en la cova Colomera (Sant Esteve de la Sarga, Lleida)

The sensitive adaptation of the small mammals to habitats and climates make them an optimum material for the study of palaeoenvironmental changes. Moreover, in the Cova Colomera’s case, that its records goes from Late Pleistocene to Bronze Age, it allows us to see the climatic and landscape evolution that happened during these periods in the occidental limit of northwestern Catalonia. We have achieved this by applying the Habitat Weigthings method in our sample. That is, the distribution of the species represented in relation to their optimum habitat as well as the distribution of these same species in each archaeological level. This has permitted us to observe the differences between the species of the Pleistocene and those of the Holocene, showing the change from rigorous climatic conditions at the end of the Pleistocene to more mild ones during the Holocene. Keywords: small mammals, Cova Colomera, palaeoenvironmental and Habitat Weigthings

palaeoenvironmental and palaeoclimatic approach to the heinrich event 1 from mirador cave (sierra de atapuerca, burgos, spain)

The Mirador cave is located in the Sierra de Atapuerca (Ibeas de Juarros, Burgos, Spain). This site represents an extensive archaeo-paleontological sequence extending from the latest Pleistocene to the ancient Holocene. In this paper we have studied the latest Pleistocene levels, MIR50 and MIR51. The palaeoenvironmental and palaeoclimatical data obtained with the small mammal assemblage show that the level MIR51 may be probably related with a cool moment from the end of the latest Pleistocene. Taking into account, the absolute dating for this level, this moment could be corresponds to the Heinrich Event 1 (H1). This event, dated between 14,000 to 16,000 years BP, is globally characterized for being a generally cold moment, as detected at the level MIR51, but with small peaks of climatic amelioration, as it is detected in the level MIR50

The end of the Last Glacial Maximum in the Iberian Peninsula characterized by the small-mammal assemblages

This paper presents a palaeoenvironmental and palaeoclimatic approach to the end of the Last Glacial Maximum (LGM) in the Iberian Peninsula on the basis of the small-mammal assemblages (insectivores, bats and rodents). The LGM is an important period in our climate history defined by the maximum extension of ice sheets between ca. 22 and 19 ka BP. In the Mediterranean region the LGM is characterized by humid conditions, which allow for the development of arboreal vegetation. The small-mammal remains described in this study were recovered from four different sites within the Iberian Peninsula: El Mirón cave (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), and Sala de las Chimeneas (Maltravieso, Cáceres). We found in these sites a non-analogue association represented by species associated with mid-European climatic conditions, such as the voles Chionomys nivalis, Microtus arvalis, Microtus agrestis and Microtus oeconomus, together with species associated with Mediterranean requirements, such as Microtus (Iberomys) cabrerae and Microtus (Terricola) duodecimcostatus. These assemblages reveal that the climate was harsher than today in the sites under study, though not as rigorous as elsewhere in Europe, with mean annual temperatures lower than present and an environment dominated by wet open meadows. All our data have been compared with other environmental and climatic proxies, global isotope curves and pollen data, providing a scenario for the palaeoclimatic and palaeoenvironmental conditions that occurred during the LGM in the Iberian Peninsula

Ancient DNA reveals interstadials as a driver of common vole population dynamics during the last glacial period

Aim: Many species experienced population turnover and local extinction during the Late Pleistocene. In the case of megafauna, it remains challenging to disentangle climate change and the activities of Palaeolithic hunter-gatherers as the main cause. In contrast, the impact of humans on rodent populations is likely to be negligible. This study investigated which climatic and/or environmental factors affect the population dynamics of the common vole. This temperate rodent is widespread across Europe and was one of the most abundant small mammal species throughout the Late Pleistocene. Location: Europe. Taxon: Common vole (Microtus arvalis). Methods: We generated a dataset comprised of 4.2 kb long fragment of mitochondrial DNA (mtDNA) from 148 ancient and 51 modern specimens sampled from multiple localities across Europe and covering the last 60 thousand years (ka). We used Bayesian inference to reconstruct their phylogenetic relationships and to estimate the age of the specimens that were not directly dated. Results: We estimated the time to the most recent common ancestor of all last glacial and extant common vole lineages to be 90 ka ago and the divergence of the main mtDNA lineages present in extant populations to between 55 and 40 ka ago, which is earlier than most previous estimates. We detected several lineage turnovers in Europe during the period of high climate variability at the end of Marine Isotope Stage 3 (MIS 3; 57–29 ka ago) in addition to those found previously around the Pleistocene/Holocene transition. In contrast, data from the Western Carpathians suggest continuity throughout the Last Glacial Maximum (LGM) even at high latitudes. Main Conclusions: The main factor affecting the common vole populations during the last glacial period was the decrease in open habitat during the interstadials, whereas climate deterioration during the LGM had little impact on population dynamics. This suggests that the rapid environmental change rather than other factors was the major force shaping the histories of the Late Pleistocene faunas