Mutual Climatic Range Method Research Articles

Subfossil Coleoptera from Eifel maar sediments as indicators of the environmental evolution in Central Europe over the last 60,000 years

A reconstruction of landscape and paleotemperatures is presented from a composite drill core from the Eifel maar lakes of Auel and Holzmaar, Germany. The compositecore is 112 m long and covers the last 60,000 years (Marine Isotope Stages MIS 3, 2, and 1) based on the new ELSA-20 stratigraphy. Findings are based on an analysis of arthropod remains, with moisture-dependent, riparian or (semi)aquatic Staphylinidae representing the majority of beetle sclerites in the assemblages, especially during cold intervals. Assemblages change corresponding to climate and vegetation, with a greater variety of taxa during the woodland phases (60,000–44,000 yr b2k, i.e. years before 2,000 CE) versus cold adapted taxa during late MIS 3 and early MIS 2 (28,500–23,500 yr b2k). Beetles that inhabit damp, moist or wet locations, as well as aquatic or riparian taxa are present throughout the record. The assemblage corresponding to a period of tundra-like vegetation (29,000–24,000 yr b2k), contained three taxa suitable for temperature calculation (Arpedium brachypterum, Bembidion fellmanni, and Boreaphilus henningianus), all of which are found only in cold phases (Greenland Stadial 2 and 4, and Heinrich Event 2). Paleotemperatures were reconstructed via the Mutual Climatic Range method giving the following results. Mean temperature for the early tundra phase (28,500–27,800 yr b2k) is −32 to −2 °C for the coldest month, and 6 to 9.5 °C for the warmest month. Mean temperature for the later tundra phase (27,000–24,000 yr b2k) is −30 to −20 °C for the coldest month and 6 to 9.5 °C for the warmest month. This shift indicates an increase in seasonality towards the Last Glacial Maximum. Paleotemperature calculations are in good agreement with other European records and indicate a major decline in median winter temperatures towards the Last Glacial Maximum, whereas the summer temperatures remained relatively stable throughout Europe, resulting in an increase in seasonality and continentality.

Late-Glacial palaeotemperatures and palaeoprecipitations in the Aubrac Mountains (French Massif Central) reconstructed from multiproxy analyses (Coleoptera, chironomids and pollen)

New investigations performed with a multi-proxy approach provide a robust climate reconstruction for the Late-Glacial in the Massif Central, France. The temperature reconstruction from Coleoptera is obtained from the Mutual Climatic Range Method, or “MCR” method, based on the range of climates corresponding to the area occupied today by the species identified in fossil assemblages. The Weighthed Averaging Partial Least Squared (WA-PLS) method is used to produce mean July temperature estimates from Chironomid assemblages. Climate reconstruction from pollen data is performed using an assemblage approach, the Modern Analogue Technique. During the Late-Glacial the July temperature (Tmax) reconstructed from beetles (Coleoptera) was lower than the current Tmax of 18.9 °C. Summer conditions were close to the present at the beginning of the Oldest Dryas (17400–14600 cal. BP), and during most of the Allerød (13900–12800 cal. BP). During the Younger Dryas (12800–11700 cal. BP) Tmax estimates ranged from 12 to 13 °C, much lower than today. The Tmax increased at the onset of the Holocene (11700 cal. BP), reaching values close to the modern conditions from the beginning of the period. Tmax reconstructed from chironomids shows an initial warming around 15000 cal. BP, with a Tmax rise from 7 °C to 11 °C. A maximum (13.5 °C) was reached around 13800 cal. BP. A second optimum of 16 °C occurred after 10800 cal. BP. The Late-Glacial Interstadial (LGI) is marked by temperature decreases (from 13 to 12 to 10–9 °C) around 13200–12900 cal. BP. A second climate minimum was reached around 12600 cal. BP, during the Younger Dryas (Tmax about 10 °C). The end of the Younger Dryas seems to have been warmer, with a Tmax of about 13 °C, just before the early Holocene climate improvement. Pollen-inferred results showed that the Late-Glacial climate at Roustières was characterized by colder and drier winter and summer seasons than today, and by conditions close to the modern ones around 11700 cal. BP, at the onset of the Holocene. Climate conditions comparable to the modern ones were also evidenced at the end of the Allerød, with colder than today conditions evidenced from both Tmax and Tmin (January temperature). During the Oldest and Younger Dryas the coldest month showed a temperature of −13 °C, while summers appeared more moderate (warmest month around 16 °C). Cold conditions were also reconstructed during the Bølling, while temperatures comparable to present-day values were reached during the Allerød. A cold oscillation occurred around 13400 cal. BP. Particularly dry conditions were reconstructed during the Oldest Dryas (17000–15800 cal. BP). From 15800 to the end of the Younger Dryas, the precipitation oscillated around 750 mm, but increased during the Allerød and the Holocene periods. These climatic trends reconstructed by the three proxies allowed identifying the temperate periods (LGI and the Holocene) and the cold events (Younger Dryas) of the Late-Glacial period. However, difficulties due to different sampling resolutions emerged, and several discrepancies linked to the proxy or the methods used are discussed.

Last glacial maximum ecology and climate from terrestrial gastropod assemblages in Peoria loess, western Kentucky

ABSTRACTThe Rocks loess section, in unglaciated western Kentucky, provides a high‐resolution environmental record during the last glacial maximum onset. The Peoria Silt (9 m thick) contains 26 terrestrial gastropod species, with up to 15 species within a single 5 cm interval. Thirteen radiocarbon ages, using shells or charcoal, range between 30 and 24.5 cal ka; younger loess has been leached or eroded. Stratigraphic shifts in gastropod assemblages imply significant cooling, particularly ~27 cal ka, as solar insolation was decreasing and the southern Laurentide Ice Sheet rapidly advancing. Midwestern to southern species (e.g. Anguispira kochi, Gastrocopta pentodon, Hawaii miniscula, Helicodiscus parallelus, Vallonia perspectiva) occur only in the lowermost Peoria Silt (~30–27 cal ka). In contrast, cold‐tolerant species (Columella alticola, Vertigo modesta, Vallonia gracilicosta) occur only in full glacial Peoria Silt (27–24.5 cal ka). Inferred mean July temperatures, from mutual climatic range methods, range from ~23 °C at 30 cal ka, cooling to ~18 °C by 26 cal ka; about 3–8 °C cooler than today (~26 °C). Superimposed on this cooling trend are multi‐centennial variations in detrital carbonate, fossil shell concentrations, palaeotemperature estimates, and oxygen isotope values (Vertigo, Discus, Helicodiscus). The finer‐scale variations imply relatively synchronous fluctuations in glacial sediment supply, loess sedimentation, and climate.

A sub-centennial, Little Ice Age climate reconstruction using beetle subfossil data from Nunalleq, southwestern Alaska

There is myriad evidence that global warming is exerting a profoundly disruptive influence on the lifeways of modern native (Yup'ik) communities living in the Yukon-Kuskokwim (Y-K) delta of southwestern Alaska. Yup'ik subsistence is intimately tied to seasonal change and the ability to accurately predict the availability of plant and animal resources. It therefore seems reasonable to suggest that periods of climatic instability such as the Little Ice Age (LIA) may have had a deleterious effect on Yup'ik communities in the past. However, at present there are no palaeotemperature records that document the localised climatic changes of the last millennium in the Y-K Delta region. This lack of data hinders our understanding of the archaeological record from the site of Nunalleq, which is situated at the heart of the delta and was occupied during the LIA. To address this oversight, this paper presents the results of a Coleoptera (beetle) based climate reconstruction from a peat profile in the vicinity of Nunalleq to investigate the magnitude of Late Holocene climatic changes. Using the Mutual Climatic Range (MCR) method, we reconstruct mean summer and winter temperatures from the mid-15th to late-19th centuries. The results indicate that the past environments of Nunalleq were characterised by a climate significantly cooler than the present. The earliest definitive evidence for Little Ice Age cooling dates from the late 16th century, when mean summer temperatures were at least 1.2ᵒC below the modern mean. Temperatures appear to have remained lower than modern until the early 19th century. The coolest Nunalleq record – 1.3ᵒC below the modern mean summer temperatures – is centred on AD 1815, after which there is evidence for climatic amelioration. These data present differences with observations from other regions of Alaska and underline the importance of more local palaeoclimate reconstructions, particularly when interrogating the relationships between past climatic and social change.

Identifying bias in cold season temperature reconstructions by beetle mutual climatic range methods in the Pliocene Canadian High Arctic

Well-preserved beetle elytra from the fossil and subfossil record are used by palaeoclimatologists to estimate past temperatures. Beetle-derived estimates of temperature across the Pliocene Arctic are consistently lower than those derived from other palaeoclimate proxies. Here we test if that pattern is attributable to either the modern dataset or specific mutual climatic range method (MCRM). We used a global dataset of observations (Global Biodiversity Information Facility) for modern beetles as opposed to a North American regional dataset, and a consistent MCRM for comparison to vegetation-derived estimates, termed CRACLE (Climate Reconstruction Analysis using Coexistence Likelihood Estimation), rather than different MCRM methods for each analysis. Beetle-derived estimates from one site, Beaver Pond, are consistently much lower than the vegetation-derived estimates, stable isotope results from flora and fauna, and summer temperatures from bacterial tetraethers. The reanalysis of beetle data produced a small reduction in proxy estimate mismatch overall. We found good agreement among proxy estimates of maximum temperature of the warmest month for two of the three sites in the Canadian Arctic, but increasingly poorer agreement for warmest quarter, coldest quarter and minimum temperature of the coldest month. This pattern may be due to beetles' avoidance mechanisms and a climate space different from modern calibration sets during the Pliocene. Beetle derived temperature estimates, especially cold season, should be interpreted with caution when reconstructing palaeoclimates.

Coleoptera from the middle-upper Eocene European ambers: generic composition, zoogeography and climatic implications

The paper contains a review of coleopteran genera known from Baltic, Bitterfeld and Rovno amber localities. Altogether 420 genera (191 extinct and 229 extant) from 78 families are listed from these three Lagerstätten (as of 7 March 2017). The listed beetles were analyzed zoogeographically and distributional maps for 72 genera were compiled. One-quarter (56) of the genera that have survived since the Eocene have cosmopolitan ranges at present; 35 extant genera have been extripated from the Palaearctic since the Eocene. Approximately 40% of beetle genera from the middle-upper Eocene European ambers can be encountered in the wild in present-day Europe, while 5 of these genera are supposed to be European relict endemics originating in Fennosarmatia. The general similarity of the Baltic amber (s.l.) beetle assemblage to modern south Palaearctic fauna is the strongest, the Nearctic elements are more numerous in the middle-upper Eocene European ambers than the Oriental taxa. The simplified Mutual Climatic Range (MCR) method was used for palaeoclimate reconstruction based on fossil beetles. The coleopteran assemblage of Baltic amber is interpreted as indicative of warm temperate, humid, equable climate with reduced thermal seasonality [annual average temperatures range from +10–20˚C; mean of the coldest month temperatures around +10˚C; mean of the hottest month temperature around +20–24˚C; annual precipitation around 750–1500 mm]. The primary importance of high humidity for existence of the Eocene biota is pointed out.

First Fossil Assemblage of Darkling Beetles (Coleoptera: Tenebrionidae) from Buenos Aires, Argentina: Evidence of Dry Climate During the Late Pleistocene in the Humid Pampas

Fil: Ramirez, Leonardo Cesar. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina

A review of the palaeoclimatic inference potential of Iberian Quaternary fossil batrachians

Ecological suitability analysis aims to model the potential or probable distribution of species using environmental variables and available species occurrence information as predictors. Most of the European fossil Quaternary amphibians belong to extant species, and being physiologically ectothermic animals, their current ecological niches could become a reliable inference tool to infer past environmental conditions. However, this expectation has never been properly verified. The validity and accuracy of palaeoclimatic inferences based on batrachian species ranges is tested on the Iberian Peninsula, using both palaeofaunistic and Recent distribution data, and an updated database of georeferenced species occurrences is provided. The difficulties of using current geographic information to represent the full spectrum of environmental conditions at which a species occurs are critically examined. A palaeofaunistic review of the role played by historical factors as dispersal limitations for present amphibian species ranges is presented using the available phylogeographical scenarios. Virtual hypothetical taxa can be devised by considering the distributions of several species together and relating their known joint presences with the environmental conditions in these locations. Species distribution models based on these virtual taxa provide the best advisable inferential procedure. For direct raw inferences of the mutual climatic range method, contrary to expectations, the combined taxa sets do not increase their accuracy with the number of species included. This preliminary review shows that Iberian amphibian palaeoclimatic inferences are both valid and reliable enough, a sufficient approximation to complement other techniques. The precision, however, is quite variable among taxa, reflecting the effect of non-climatic distributional constraints.

Predicting island beetle faunas by their climate ranges: thetabula rasa/refugia theory in the North Atlantic

AbstractAimThis paper addresses two opposing theories put forward for the origins of the beetle fauna of the North Atlantic islands. The first is that the biota of the isolated oceanic islands of the Faroes, Iceland and Greenland immigrated across a Palaeogene–Neogene land bridge from Europe, and survived Pleistocene glaciations in ameliorated refugia. The second argues for atabula rasain which the biota of the islands was exterminated during glaciations and is Holocene in origin. The crux of these theories lies in the ability of the flora and fauna to survive in a range of environmental extremes. This paper sets out to assess the viability of the refugia hypothesis using the climatic tolerances of one aspect of the biota: the beetle fauna.LocationThe paper focuses on Iceland, the Faroe Islands and Greenland.MethodsThe known temperature requirements of the recorded beetle faunas of the North Atlantic islands were compared with published proxy climate reconstructions for successive climate periods since the severing of a North Atlantic land bridge. We used theMCR(mutual climatic range) method available in the open access BugsCEPdatabase software.ResultsWe show that most of theMCRfaunas of the North Atlantic islands could not have survivedin situsince the Palaeogene–Neogene, and are likely to have been exterminated by the Pleistocene glaciations.Main conclusionsThe discrepancy between the climatic tolerances of the North Atlantic beetle fauna and the estimated climatic regimes since the severing of a land bridge strongly support thetabula rasatheory and suggests that the North Atlantic coleopteran fauna is Holocene in origin.

The continental record of Marine Isotope Stage 11 (Middle Pleistocene) on the Iberian Peninsula characterized by herpetofaunal assemblages

ABSTRACTMarine Isotope Stage (MIS) 11 in Iberia is documented at three main Acheulean archaeological sites: Gran Dolina (Burgos, Atapuerca), Áridos‐1 (Madrid) and Ambrona (Soria). As the amphibians and reptiles recovered as fossils from these sites are not extinct and their ecology can be directly studied, mutual climatic range and habitat weighting methods have been applied to the herpetofaunal assemblages to estimate climatic and environmental parameters during MIS 11. Compared with today, mean annual temperature varies from +2.7 to +0.3 °C and mean annual precipitation varies from +311.7 to +74.4 mm, suggesting, in accordance with the numerical dates for each locality, a progressive decrease in temperature and rainfall from the fully interglacial conditions of MIS 11c to the end of MIS 11. The presence of woodland areas is also well substantiated throughout the duration of MIS 11, at least during the interglacial and interstadial periods.

Paleoclimatic and paleoenvironmental context of the Early Pleistocene hominins from Dmanisi (Georgia, Lesser Caucasus) inferred from the herpetofaunal assemblage

Dmanisi is currently the oldest Early Palaeolithic site discovered out of Africa. It has produced over 40 hominin remains, including a set of very informative skulls, in direct association with faunal remains and numerous lithic artifacts. Given the relevance of this locality, every effort is being made to reconstruct the landscapes where these hominins once lived. Amphibian and reptile remains from Dmanisi are here described for the first time and used as paleoclimatic and paleoenvironmental proxies. They comprise at least six taxa: a green toad (Bufo gr. Bufo viridis), the Greek tortoise (Testudo graeca), a green lizard (Lacerta gr. Lacerta viridis), a four-lined snake (Elaphe gr. Elaphe quatuorlineata), an indeterminate colubrid and a water snake (Natrix sp.). As these taxa are not extinct and their ecology can be directly studied, they can contribute to the reconstruction of the landscape and climate. The application of the Mutual Climatic Range method provides quantitative data indicating that during the hominin presence at Dmanisi climate was warm and dry, similar to the present-day Mediterranean climate. In comparison with today climate of Dmanisi, estimated mean annual temperature was 3.1 °C higher, with a greater increase of temperature in summer (+7.1 °C) than in winter (+4.7 °C). The mean annual precipitation was slightly lower (−65 mm) than the current level, with precipitation higher than current one during winter (+104 mm) but strongly lower during the other seasons, suggesting a stronger contrast in the rainfall regime during the year. From a paleoenvironmental point of view, fossil amphibians and reptiles all suggest the predominance of arid environments, from steppe or semi-desert to open Mediterranean forest, with stony or rocky substrate and bushy areas. The presence of permanent aquatic environments is also documented. These results mainly agree with those for large mammals, small mammals and the archaeobotanical analysis that indicate an important water stress suggesting a period of increased aridity contemporaneous with human occupations of the site.

Palaeoenvironmental and palaeoclimatic reconstruction of the latest Pleistocene–Holocene sequence from Grotta del Romito (Calabria, southern Italy) using the small-mammal assemblages

The habitat weighting method, the Simpson diversity index and the mutual climatic range method are applied to the small-mammal assemblage of Grotta del Romito (southern Italy) in order to reconstruct the environmental and climatic fluctuations that occurred during the latest Pleistocene–Holocene sequence of the cave. The analysed strata have a discontinuous chronological range from the middle-late Gravettian (ca. 24ka uncal. BP) to the Mesolithic–Sauveterrian (still radiometrically undated). Gravettian and Epigravettian layers were excavated inside the cave, Mesolithic layers in the rockshelter outside the cave. The small-mammal assemblage shows significant differences along the sequence; a turning point is detected in strata D29-D11, coinciding with the end of Heinrich Event 1 (H1) and the beginning of the Bølling–Allerød interstadial (between ca. 14.9–14kacal. BP). These data are in accordance with the previously obtained environmental data for Grotta del Romito, as well as with other continental climatic and environmental changes detected at a regional scale.

Climate and environments during Marine Isotope Stage 11 in the central Iberian Peninsula: the herpetofaunal assemblage from the Acheulean site of Áridos-1, Madrid

The interglacial episodes of the Quaternary Period are currently the focus of a great deal of attention within the scientific community, primarily because they can help us to understand how the climate of the current interglacial may have evolved without human intervention and to assess the impact of these climate changes on ecological systems. In the central Iberian Peninsula, the archaeological site of Áridos-1 (Arganda, Madrid), with numeric dates of 379.7 ± 45 ka obtained by AAR for the upper part of the sedimentological unit of Arganda I, in combination with the evolved state of the small mammals, has been chronologically attributed to Marine Isotope Stage (MIS) 11. Given the diversified faunal assemblages delivered by the 1976 excavations, Áridos-1 is probably one of the best terrestrial candidates for an understanding of the climatic and environmental conditions that prevailed in central Spain during the MIS 11 interglacial. In consequence, the fossil amphibians and squamate reptiles stored in the collections of the Museo Arqueológico Nacional of Madrid have been newly described and quantified in order to apply the mutual climatic range and habitat weighting methods for estimating quantitative data. The Mediterranean climate is shown to have been warmer and wetter than today in central Spain during MIS 11, with the mean annual temperature 1.7 °C higher and mean annual precipitation 223.9 mm higher than at present. The monthly climatic reconstruction shows differences in the distribution of precipitation over the course of the year, with more abundant precipitation during the winter months, at the beginning of spring and at the end of fall (from October to March) and less precipitation than today during the summer months and at the end of spring (from May to August), suggesting stronger rainfall seasonality between winter and summer than currently occurs. Such climate reconstruction is consistent with other European MIS 11 paleoclimatic records. The paleoenvironmental reconstruction based on the herpetofaunal assemblage suggests a patchy landscape with a large representation of dry meadows, scrubland and rocky habitats together with well-evidenced aquatic habitats. Such open environments during a warm and humid forestal period are seen to be connected with the location of the site in a large river valley, where open vegetation would have been partly initiated and certainly maintained by the grazing, browsing, trampling and tree-felling activities of large mammals.

Environmental and climatic context of Neanderthal occupation in southwestern Europe during MIS3 inferred from the small-vertebrate assemblages

According to pollen analysis, Marine Isotope Stage 3 (MIS3, ca. 60–30 ka) is characterized in southern Europe by dynamic alternations of forest vs. semi-arid area expansion in accordance with the warming and cooling, respectively, of the sea-surface temperatures. It is in this context of rapid fluctuations that the Neanderthal occupation of the northeastern Iberian Peninsula took place. This paper sets forth a synthesis of the previously published environmental and climatic data obtained from the small vertebrates (herpetofauna and small mammals) of the Neanderthal localities of Cova del Gegant, Abric Romani, l'Arbreda cave, Canyars and Teixoneres. Using habitat weighting and mutual climatic range methods to reconstruct the environment, temperature and rainfall, the Middle Paleolithic occupations in northeastern Iberia are closely related to the presence of woodlands, irrespective of the climatic conditions. However, there are differences in the percentage of forest formations from the south to the northeast of Iberia. Southern Iberia (Gorham's cave) was much more forested than the northern parts (A. Romaní, l'Arbreda, Canyars, Teixoneres, C. Gegant). This observation coincides with the status of the southernmost Iberian Peninsula as a climatic refuge, where Neanderthals survived until ca. 28 ka BP.

Applying the Mutual Climatic Range method to the beetle assemblages in Japan using accurate data of climate and distribution of modern species

The Mutual Climatic Range method of Paleotemperature reconstruction is well suited to Japan, because the meteorological stations are densely located, and the modern distributions of beetles are well studied. Many of the cold adapted species which were in the Japanese lowlands during glacial periods still survive at higher elevations on the Japanese Archipelago, in high mountain refuges. A new way of drawing convex polygons as species envelopes is proposed here, make the method more accurate and objective. A test analysis using four beetle species from a stratum in the Nojiri-ko site, Nagano Prefecture is presented. The test shows a decline of temperatures, the first example of MCR from East Asia. The result agrees with the previous estimation based on modern range overlaps and on reconstructions based on vegetation.

Approche paléoenvironnementale et paléoclimatique de l’âge du bronze moyen (niveau MIR 4) de la grotte el mirador (Sierra de Atapuerca, Burgos, Espagne)

This article undertakes a palaeoenvironmental and palaeoclimatic reconstruction of the Middle Bronze Age on the basis of a study of the small mammals from level MIR 4 of El Mirador Cave. The chronology of the level under study is 3,720-3,140 cal. yr BP. The palaeoenvironmental analysis indicates that it represents the period of transition between the Subboreal and the Subatlantic, during which prevailed a very humid habitat, dominated by woodland and wet meadows. Otherwise, the palaeoclimatic analysis, carried out using the Mutual Climatic Range method (MCR), reveals that level MIR 4 falls within an interval in which the temperatures were very similar to present-day ones, while mean annual precipitation was notably higher than at present, i.e. 485 mm above the present level for Burgos.

Early Pleistocene palaeoenvironments at the time of the Homo antecessor settlement in the Gran Dolina cave (Atapuerca, Spain)

ABSTRACTHominin remains unearthed from level TD6‐2 of Gran Dolina have been dated to slightly more than 0.8 Ma. Owing to the importance of this discovery, every effort is being made to reconstruct the environment where these hominins once lived. In this paper, the mutual climatic range and habitat weighting methods are applied to the herpetofaunal assemblages in order to estimate climatic and environmental parameters. TD6‐2 is thus characterized by a warm and humid climate. Mean annual temperature is estimated at 2.1°C higher than at present in Burgos, with a greater increase in temperature during summer (+3.1°C) than during winter (+1.4°C). Rainfall was more abundant than at present (+407.2 mm), occurring as at present principally during spring and autumn. Humid meadows and riparian woody habitats were common. The association between warm climatic conditions and the not fully developed forest suggests that the several episodes of high‐intensity occupation in TD6‐2 may correspond to a recolonization by Homo antecessor of the high inland plateaus of the Iberian Peninsula from the Mediterranean seashore, using the Ebro valley as a savannah‐type corridor after a cold glacial period. Copyright © 2013 John Wiley & Sons, Ltd.

Climatic conditions for the last Neanderthals: Herpetofaunal record of Gorham's Cave, Gibraltar

Gorham's Cave is located in the British territory of Gibraltar in the southernmost end of the Iberian Peninsula. Recent excavations, which began in 1997, have exposed an 18 m archaeological sequence that covered the last evidence of Neanderthal occupation and the first evidence of modern human occupation in the cave. By applying the Mutual Climatic Range method on the amphibian and reptile assemblages, we propose here new quantitative data on the terrestrial climatic conditions throughout the latest Pleistocene sequence of Gorham's Cave. In comparison with current climatic data, all mean annual temperatures were about 1.6–1.8 °C lower in this region. Winters were colder and summers were similar to today. Mean annual precipitation was slightly lower, but according to the Aridity Index of Gaussen there were only four dry months during the latest Pleistocene as opposed to five dry months today during the summer. The climate was Mediterranean and semi-arid (according to the Aridity Index of Dantin–Revenga) or semi-humid (according to the Aridity Index of Martonne). The atmospheric temperature range was higher during the latest Pleistocene, mainly due to lower winter temperatures. Such data support recent bioclimatic models, which indicate that high rainfall levels may have been a significant factor in the late survival of Neanderthal populations in southern Iberia. The Solutrean levels of Gorham's Cave and climate records from cores in the Alboran Sea indicate increasing aridity from Marine Isotope Stage (MIS) 3-2. Because Neanderthals seem to have been associated with woodland habitats, we propose that lessening rainfall may have caused the degradation of large areas of forest and may have made late surviving Neanderthal populations more vulnerable outside southern refuges like the Rock of Gibraltar.

Characterization of a rapid climate shift at the MIS 8/7 transition in central Spain (Valdocarros II, Autonomous Region of Madrid) by means of the herpetological assemblages

Climate instability with high-amplitude and rapid shifts during the Middle Pleistocene is well known from pollen records and deep-ocean sediment cores. Although poorly correlatable with such long climate/environment records, the successive fossil amphibian and reptile assemblages from the Middle Pleistocene site of Valdocarros II (Autonomous Region of Madrid, central Spain) provide a unique opportunity to characterize the climatic and environmental features of such rapid (certainly less than 1000 years) shifts from cold to warm conditions in a terrestrial sequence. As the amphibians and reptiles do not differ at species level from the extant herpetofauna of the Iberian Peninsula, they can contribute to the reconstruction of the landscape and climate. In this paper, the mutual climatic range and habitat weighting methods are applied to the herpetofaunistic assemblages in order to estimate quantitative data. The difference in mean annual temperature between “cold” and “warm” periods is estimated at 3.2 °C, with a greater increase in temperature during winter (+3 °C) than during summer (+1 °C). During “cold” periods the climate was more Oceanic (although preserving some dryness during the summers), whereas during “warm” periods the climate became Mediterranean (with mild winters and a long period of dryness in the summer and early autumn). Though higher during cold periods, the continentality (or atmospheric temperature range) remained roughly similar, in accordance with the geographical location of the site in the centre of the Iberian Peninsula. A greater amount of open landscape occurred during “cold” periods, whereas during “warm” periods the wooded areas expanded from 20% to 40% of the landscape surface. Such climatic/environmental changes, together with the numeric datings of the site, suggest that this shift may correspond to the transition from MIS 8 to MIS 7, also called Termination III.

Paleoenvironmental and paleoclimatic proxies to the Early Pleistocene hominids of Barranco León D and Fuente Nueva 3 (Granada, Spain) by means of their amphibian and reptile assemblages

Because most amphibians are water dependent and most reptiles are temperature dependent, the climatic and/or environmental parameters in their immediate environment mark their distribution. Accordingly, they can contribute to an understanding of microhabitats and microclimates within a larger landscape, such as the Guadix-Baza Basin in south-eastern Spain. The Early Pleistocene archaeological and paleontological sites of Barranco León D and Fuente Nueva 3, which are localized in both space and time in the Guadix-Baza Basin, have together yielded a diversified accumulation of herpetofauna that comprises at least 20 taxa of amphibians, chelonians, lizards and snakes. With the exception of the bufonid Bufo sp. ( viridis group) and the anguid lizard Dopasia, these two assemblages do not specifically differ from the extant herpetofauna of the Iberian Peninsula, making them suitable for use in paleoclimatic and paleoenvironmental reconstructions without the ecological uncertainties of extinct taxa. In this paper, mutual climatic range and habitat weighting methods are applied to amphibian and reptile assemblages in order to estimate quantitative data. The results indicate that during the late Early Pleistocene mean annual temperature and mean annual precipitation were higher than they are now on the south-eastern Iberian Peninsula. The contrast between summer and winter temperatures (i.e. continentality) was less pronounced, mainly due to warmer conditions during winter. Rainfall distribution indicates a considerable increase in precipitation in every season but summer, which was drier and consistent with the Mediterranean climate pattern. The terrestrial landscape was composed of open environments (mainly dry meadows, rocky-stony areas and Mediterranean scrubland), although there were some wet wooded areas. Water-linked amphibians and reptiles suggest the existence of a sunny permanent aquatic environment with banks made up of a movable ground. These results are compared with those for large mammals, small mammals and pollen analyses, yielding a scenario for the paleoclimatic and paleoenvironmental conditions that were in place during the Early Pleistocene in the Guadix-Baza Basin.