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An environmental scenario for the earliest hominins in the Iberian Peninsula: Early Pleistocene palaeovegetation and palaeoclimate
Abstract
The Early Pleistocene deposits of the Iberian Peninsula provided some of the oldest hominin fossil sites of Western Europe. Evidence also shows that early Homo thrived in the Mediterranean peninsulas during the Early Pleistocene ‘interglacial’ phases. To assess the role of climatic conditions on early human environments, the present work features a quantitative palaeoclimatic analysis for a number of Early Pleistocene macroflora and pollen assemblages located at different geographical locations where hominin activity has been recorded. The results picture a cyclic climate with a possible latitudinal aridity gradient. Warm and humid (‘interglacial’) phases would have been wetter and slightly warmer than the modern climate. During cooler and drier (‘glacial’) phases, temperature and precipitation were comparatively milder and more similar to modern ones. The favourable conditions during the humid phases may have allowed for the earliest hominin communities arriving in Europe to rapidly thrive during ‘interglacial’ periods. The present climatic quantification suggests that hominins in Iberia may have survived these mild ‘glacial’ Early Pleistocene stages.
... The predominantly browse-dominated mesowear signals of ungulates suggests a palaeoenvironment where grasses were not a dominant element in the vegetation, but the browse-dominated mesowear does not further separate whether the browse was mainly obtained from trees, shrubs or non-grass herbs. The Palominas pollen core indicates a high variation in the vegetation in the GBB during the Early Pleistocene, ranging from open grass and Artemisia -dominated during dry phases to diverse deciduous/evergreen Quercus woodland and wetland during the humid phases (Altolaguirre et al., 2019). Pollen record from a sedimentary section in Palominas provides a reference to the vegetation cycles in the GBB during the Early Pleistocene roughly between the MIS 53 and MIS 34, suggesting that the levels indicating warm and humid conditions correspond with the conditions present in BL and FN3 (Altolaguirre et al., 2019). ...
... The Palominas pollen core indicates a high variation in the vegetation in the GBB during the Early Pleistocene, ranging from open grass and Artemisia -dominated during dry phases to diverse deciduous/evergreen Quercus woodland and wetland during the humid phases (Altolaguirre et al., 2019). Pollen record from a sedimentary section in Palominas provides a reference to the vegetation cycles in the GBB during the Early Pleistocene roughly between the MIS 53 and MIS 34, suggesting that the levels indicating warm and humid conditions correspond with the conditions present in BL and FN3 (Altolaguirre et al., 2019). The evidence from mammal ecometrics, herpetofauna and ungulate mesowear all point at relatively somewhat more humid than present conditions and non-grassy environments in BL and FN3, which would more likely correspond with the woodland-type vegetation in the Palominas core. ...
... The evidence from mammal ecometrics, herpetofauna and ungulate mesowear all point at relatively somewhat more humid than present conditions and non-grassy environments in BL and FN3, which would more likely correspond with the woodland-type vegetation in the Palominas core. The inferred vegetation of such phases of the Palominas core is generally forested with some degree of openness and dominated by deciduous and evergreen Quercus, with a diversity of mesophytes such as Carpinus, Acer, Juglans, Corylus, Populus, Salix, Ulmus, Castanea, Fagus and Buxus, and thermophytes such as Olea, Pistacia, Coriaria, Tamarix, Phlomis, Myrica, in addition to genera today extinct in the western Mediterranean such as Eucommia, Parrotia, Cathaya, Aralia, Zelkova, Pterocarya, Tsuga and Nyssa (Altolaguirre et al., 2019(Altolaguirre et al., , 2020. The sediments at BL and FN3 were deposited during a phase when the Baza Lake in the GBB was relatively large due to basin dynamics (Oms et al., 2011). ...
The Guadix-Baza Basin (GBB) in Andalucía, Spain, comprises palaeontological and archaeological sites dating from the Early Pliocene to the Middle Pleistocene, including some of the earliest sites with evidence for the presence of early humans (Homo sp.) in Europe. Thus, the history of climate and environments in this basin contributes significantly to our understanding of the conditions under which early humans spread into Europe during the Early Pleistocene. Here we present estimates of precipitation and primary productivity in the GBB from the Pliocene to the Middle Pleistocene based on dental ecometrics in fossil communities of large herbivorous mammals, and perform an ecometrics-based distribution modelling to analyse the environmental conditions of Early and Middle Pleistocene human sites in Europe. Our results show that Early Pleistocene humans generally occupied on average relatively diverse habitats with ecotones, such as woodlands and savannas, but avoided very open and harsh (cool or dry) environments. During the Middle Pleistocene in Europe, humans occupied a comparatively much broader range of environments than during the Early Pleistocene, but were on average more concentrated in environments where the dental ecometric of mammals indicate wooded palaeoenvironments. In the earliest human occupation sites of the GBB, Barranco León and Fuente Nueva 3, the mean annual precipitation and net primary production estimates indicate climatic conditions close to modern Mediterranean sclerophyllous woodland environments, but with slightly higher primary productivity, indicating some similarity with East African woodlands. On the other hand, the environments did not resemble African grassland savannas. The browse-dominated diets of ungulates from Barranco León and Fuente Nueva 3 further suggest palaeoenvironments where grasses were a minor component of the vegetation. In the slightly older site of Venta Micena that has no evidence for the presence of hominins, dental ecometric estimates indicate climate and environments similar to Mediterranean “forest steppe” environments existing in the surroundings of Baza today. Grasses were prevalent in the diet of some taxa, especially equids, in Venta Micena, but most of the species show browse-dominated diets even there.
... Recent pollen analysis (Altolaguirre et al., 2020) revealed that, throughout the Early Pleistocene, the vegetation of the area alternated between dry steppes and open forests or woodlands. This alternation was controlled by changes in precipitation and the Early Pleistocene orbital forcing (Altolaguirre et al., 2019(Altolaguirre et al., , 2020. Even during glacial periods, the temperatures were relatively mild thorough the Early Pleistocene, with mean winter temperatures steadily higher than 0 C (Altolaguirre et al., 2019), indicating that hominins could have survived the glacial periods in the southernmost latitudes of the Iberian Peninsula and expanded during the onset of the following interglacial periods. ...
... This alternation was controlled by changes in precipitation and the Early Pleistocene orbital forcing (Altolaguirre et al., 2019(Altolaguirre et al., , 2020. Even during glacial periods, the temperatures were relatively mild thorough the Early Pleistocene, with mean winter temperatures steadily higher than 0 C (Altolaguirre et al., 2019), indicating that hominins could have survived the glacial periods in the southernmost latitudes of the Iberian Peninsula and expanded during the onset of the following interglacial periods. ...
... Pollen-based climate reconstructions using the Coexistence Approach method (Altolaguirre et al., 2019(Altolaguirre et al., , 2020 report that MAP values during dry (glacial) periods were relatively similar to modern ones, whereas values during humid periods (interglacial) were higher than the modern average precipitation of the area. The Coexistence Approach method indicates that MAT values in the Baza Sub-basin remained within a range between 10 and 20 C through the Early Pleistocene, only slightly increasing during humid periods (interglacials) and decreasing during dry periods (glacials; Altolaguirre et al., 2019Altolaguirre et al., , 2020. ...
The Guadix-Baza Basin, in SE Spain, harbors hominin fossils and lithic artifacts dated to ca. 1.4–1.3 Ma, representing the first hominin habitat in the Iberian Peninsula and possibly in Western Europe. Recent palynological studies have described a high diversity of plant taxa and biomes existing in the basin at the time of hominin presence. However, the relationship between these hominins and their environment has not been fully explored. Two novel methodologies are developed. The first method maps the distribution of the Early Pleistocene vegetation units based on paleobotanical and paleogeographic data. The second method assesses the availability of edible plant parts using a combination of Early Pleistocene and modern taxa lists. The resulting vegetation maps reveal a great diversity of vegetation types. During dry (glacial) periods, the vegetation of the basin was represented mostly by steppes, with the appearance of forested vegetation only in the mountainous regions. During humid (interglacial) periods, Mediterranean woodlands represented the dominant vegetation, accompanied by deciduous and conifer forests in the areas of higher altitude. The lake system present in the basin also allowed for the presence of marshland vegetation. The assessment of the availability of edible plant parts reveals that early Homo could have found a high number of resources in marshland and riparian environments throughout the year. Mediterranean woodlands and deciduous forests also provided numerous edible plant parts. During dry periods, the availability of plant resources decreased heavily, but the prevalence of marshland and riparian vegetation and of forested vegetation in the areas of higher altitude could have sustained hominin communities during harsher climatic periods. However, the disappearance of the lake system and an increase of aridity after the Mid-Pleistocene Transition and during the Middle Pleistocene probably led to an impoverishment of plant resources available to early Homo in the Guadix-Baza Basin.
... In recent years multiple studies have outlined the general features, development and trends of the Early Pleistocene climate in the Mediterranean Basin using palynological records (Suc, 1984;Suc and Popescu, 2005;Joannin et al., 2007b;Combourieu-Nebout et al., 2015;Altolaguirre et al., 2019). The Pleistocene climate was characterized by the alternation of glacial and interglacial periods, during which the continental ice sheets in the northern hemisphere expanded and retreated (Ruddiman et al., 1989). ...
... Nine climatic parameters were calculated: mean annual temperature (MAT), mean temperature of the coldest month (MTCold), mean temperature of the warmest month (MTWarm), MART (temperature difference between of MTWarm and MTCold), mean annual precipitation (MAP), mean precipitation of the wettest month (MPWet), mean precipitation of the driest month (MPDry), mean precipitation of the warmest month (MPWarm), and MARP (precipitation difference between MPWet and MPDry). The present CA analysis represents an expansion of the analysis performed in Altolaguirre et al. (2019) where the method was used to obtain preliminary climatic data from 31 pollen samples from the upper half of the Palominas core. ...
... The Coexistence Approach has already been proven successful in outlining the changing palaeoclimatic conditions recorded in the upper part of the Palominas core (Altolaguirre et al., 2019). The application of the CA to the entire Palominas record offers new information on the climatic patterns during the Calabrian (Fig. 9). ...
The basin of Baza is located in the central area of the Betic Range (SE Spain) with a catchment area of over 4000 km2. It contains a continuous and well preserved lacustrine sedimentary record from the Late Miocene to the Middle Pleistocene. The basin encloses numerous Miocene to Pleistocene mammal fossil sites that include some of the oldest hominin occurrences in Western Europe, found at the Orce sites. The present work features the palynological analysis of sediment samples obtained from the Palominas drill core. The Palominas core cuts thorough fine grained sedimentary units located in the depocenter of the basin, which contain well preserved pollen grains. The palynoflora found in the core is rich in herbaceous pollen, as well as Quercus and Pinus, with other tree taxa appearing in lesser quantities. Spectral analysis reveals strong climatically controlled vegetation successions. The application of the Biomization method on these assemblages allows for a reconstruction of the biome succession. The Early Pleistocene landscape was dominated by a sequence of steppe, evergreen-bushland and mixed-forest biomes. The Coexistence Approach method shows that SE Spain experienced humid periods, during which precipitations were significantly higher than during the modern climate. These humid phases are correlated with warm interglacial periods which featured the development of open forests. Dryer phases and fully open environments are correlated with colder glacial periods. Based on the palynoflora a Calabrian age is suggested for the Palominas core. The flora and climatic patterns identified in Baza are similar to the ones identified in Calabrian records of Southern Italy and Greece.
... Putting our results within a broader palaeoenvironmental and palaeoclimatic context also reveals a knowledge gap in quantitative data for the end of the Early Pleistocene. Nevertheless, a recent pollen study is available from the Palominas core (Baza Basin; i.e. some 40 km from FN 3 and BL), casting light on the climatic conditions in the southeast of the Iberian Peninsula in the Early Pleistocene (Altolaguirre et al., 2019(Altolaguirre et al., , 2020. The quantitative results obtained by means of the coexistence approach show that the vegetation of the Iberian Peninsula during the Early Pleistocene was controlled by cyclical climate changes. ...
... They also reveal that the oscillations in precipitation recorded between the "interglacial" and "glacial" phases were not extreme, which could have facilitated the development of mosaic environments in the glacial phases of the Iberian Peninsula. In short, Altolaguirre et al. (2019Altolaguirre et al. ( , 2020 suggest that there were long warm, humid periods, interspersed with short periods of a more temperate and above all drier climate, visible in particular in the Upper and Lower Sections of Palominas, whereas in the Middle Section of Palominas the climate was cooler and humid during interglacials (Altolaguirre et al., 2020: Fig. 8). ...
The Early Pleistocene sites of Barranco León and Fuente Nueva 3 (Guadix-Baza Basin, SE Spain) have yielded abundant Oldowan lithic artifacts and one hominin tooth (Homo sp. in level D1 or D2 of Barranco León), today considered to be among the earliest evidence for a hominin presence in Western Europe, at ca. 1.4–1.2 Ma. Here, for the first time, the stratigraphic succession of these two sites are studied more precisely from a palaeoenvironmental point of view, taking into account the different levels of the depositional sequences to analyze the successive fossil assemblages of amphibians and reptiles. Palaeoenvironmental reconstructions are carried out by applying the “habitat weighting” method, which uses the modern distribution by habitat of amphibian and reptile species in order to interpret past landscapes. The successive herpetofaunal assemblages from Barranco León show a certain tendency towards more arid conditions from level D1 to level E, whereas in Fuente Nueva 3 environmental reconstructions reveal oscillating conditions, with a tendency towards more arid conditions in the basal part of the sequence, up to level 5, where the tendency shifts back to more humid conditions. Our results show that the layers included in this study with the highest density of anthropic evidence (such as level 5 in FN 3 and levels D1 and D2 in BL) are situated within the late Early Pleistocene climatic and environmental cyclicity, yielding different environmental conditions: a humid, wooded biotope for BL, and a more open and drier biotope in FN 3. This suggests that the hominins of the late Early Pleistocene, although conditioned to some extent by climatic factors, were able to cope with changing environmental conditions, both “interglacial” and “glacial”, in the southwestern extremity of the European continent.
... The Coexistence Approach (CA) method permits the quantification of temperature and precipitation values based on pollen and macroflora assemblages. Using this protocol, Altolaguirre et al. (2019) develop a climatic quantification for the Early Pleistocene in the Iberian Peninsula through the comparison of CA patterns in several hominin-bearing sites. The time period is one of the disputes in paleoclimatic terms, because despite its obvious variability (Lisiecki and Raymo, 2005;Leroy et al., 2011), and the impacts of climatic changes on vegetation and floristic extinctions (González-Sampériz et al., 2010), it seems there were no true, eccentricity-driven glacial phases like during the later stages of the Pleistocene (Ehlers and Gibbard, 2008). ...
... In Altolaguirre et al. (2019), a picture of climatic cyclicity with latitudinal aridity gradients is postulated. The wettest conditions may have allowed for the earliest hominin communities arriving in Europe to rapidly thrive during "interglacial" periods, while they would have survived the mild glacial Early Pleistocene stages. ...
... The transition between Pliocene and Pleistocene is well known for the abrupt climate change causing the onset of the major northern hemisphere glaciations at approximately 2.7 Ma (Lisiecki and Raymo, 2005). Also in the Iberian Peninsula, a cyclic climate regime with warm and humid interglacials and cold and dry glacials established during the early Pleistocene (Altolaguirre et al., 2019). The onset of glacial-interglacial oscillations might have produced latitudinal and elevational species-range shifts that brought into contact the once isolated Leucanthemopsis lineages. ...
Polyploidization is one of the most common speciation mechanisms in plants. This is particularly relevant in high mountain environments and/or in areas heavily affected by climatic oscillations. Although the role of polyploidy and the temporal and geographical frameworks of polyploidization have been intensively investigated in the alpine regions of the temperate and arctic biomes, fewer studies are available with a specific focus on the Mediterranean region. Leucanthemopsis (Asteraceae) consists of six to ten species with several infraspecific entities, mainly distributed in the western Mediterranean Basin. It is a polyploid complex including montane, subalpine, and strictly alpine lineages, which are locally distributed in different mountain ranges of Western Europe and North Africa. We used a mixed approach including Sanger sequencing and (Roche-454) high throughput sequencing of amplicons to gather information from single-copy nuclear markers and plastid regions. Nuclear regions were carefully tested for recombinants/PCR artifacts and for paralogy. Coalescent-based methods were used to infer the number of polyploidization events and the age of formation of polyploid lineages, and to reconstruct the reticulate evolution of the genus. Whereas the polyploids within the widespread Leucanthemopsis alpina are autopolyploids, the situation is more complex among the taxa endemic to the western Mediterranean. While the hexaploid, L. longipectinata, confined to the northern Moroccan mountain ranges (north-west Africa), is an autopolyploid, the Iberian polyploids are clearly of allopolyploid origins. At least two different polyploidization events gave rise to L. spathulifolia and to all other tetraploid Iberian taxa, respectively. The formation of the Iberian allopolyploids took place in the early Pleistocene and was probably caused by latitudinal and elevational range shifts that brought into contact previously isolated Leucanthemopsis lineages. Our study thus highlights the importance of the Pleistocene climatic oscillations and connected polyploidization events for the high plant diversity in the Mediterranean Basin.
... At this threshold, prior to the first major cold peak (Marine Isotope Stage, MIS 22) of the Early-Middle Pleistocene Transition, climate variability (i.e., the difference between the interglacial and glacial stages) was much more pronounced than that subsequently experienced. As Altolaguirre et al. (2019Altolaguirre et al. ( , 2020 recently determined based on the pollen record from the Palominas core (from the Guadix-Baza Basin, SE Spain), the interglacials were warmer and more humid than those today, while the glacials were characterised by more moderate temperature values (similar to those today) and were notably drier than the interglacials. As the temperature in the Guadix-Baza Basin region does not seem to have been the sole determining factor at around 1.2 Ma, other related eco-climatic agents, such as increased aridity, habitat fragmentation, decreased primary productivity, or a combination of these, may have been critical in contributing to the extirpation of the various herpetofauna, including the subtropical genus of legless lizards Ophisaurus, agamid lizards, and green toads (Blain et al., , 2014(Blain et al., , 2016aBlain and Bailon, 2019). ...
Amphibians are considered excellent indicators of ecological and climatic changes with a remarkable phenotypic plasticity. The study of such adaptative capacities is central to understanding the climate and environmental changes that occurred during the Early-Middle Pleistocene Transition, at around 1.2 Ma, when the persistence of subtropical ecosystems in Europe came to an end, and several reptile and tree taxa were extirpated. The SE Spain sites in the Guadix-Baza Basin offer an exceptional opportunity for studying this change, in addition to the significant findings made in this area in the field of human evolution.
We have analysed the body size of the most well-represented amphibian species in the sites, the Iberian waterfrog, Pelophylax perezi. In order to reconstruct past body sizes from fossil samples, a regression model from current osteological collections has been generated. Also, diversity of the herpetofauna community was studied at different levels as richness or species number. Finally, to study the relationships between body size, richness, climate and productivity, OLS regression models and Pearson correlations were applied. Also for this purpose, a productivity indicator was designed based on the addition of the two most productive ecosystems from previous habitat reconstruction.
Amphibian body size appears to be negatively associated with primary productivity, reaching minimum values during the interglacial stages, when species richness increased. In contrast, during glacial periods characterised by greater aridity and fewer resources, amphibian body size increased while species richness decreased. Main explanations proposed to justify this pattern are the “water-availability hypothesis” and a trade-off between somatic growth and reproductive opportunities for females. The study of herpetofaunal diversity shows a clear correlation to regional plant diversity and primary productivity. The results of this work indicate that species richness and amphibian body size are valuable proxies that can complement current environmental and climate reconstruction methods.
... In the Pliocene, the only confirmed occurrence is that of Parrotiapollenites, for which there is micro-and macrofossil evidence (Roiron 1983;Bessais and Cravatte 1988;Leroy 1997;Jiménez-Moreno et al. 2013). Parrotia persisted in the Iberian Peninsula until the Early Pleistocene (Julia Bruguès and Suc 1980;González-Sampériz et al. 2010;Postigo-Mijarra et al. 2010;Altolaguirre et al. 2019). Parrotia also seems to have become extinct in the Early Pleistocene (Calabrian) in other southern European regions (Italy and Greece) (Magri et al. 2017). ...
In this paper we review the fragmentary fossil pollen record of Hamamelidaceae which extends back to the middle Eocene until the Early Pleistocene in the Iberian Peninsula. Records of fossil palynomorphs related to Hamamelidaceae are very scarce in the European Cenozoic, in part due to difficulty in confident identification at a generic or even familial rank. The present review contributes to improving the accuracy of identification of Cenozoic Hamamelidaceae in standard palynological studies, which should help trace its poorly understood fossil and evolutionary history. The review of all published Iberian records indicates a considerable generic diversity. At least four genera can be confidently identified. The examination of new material from the Oligocene of north-west Spain has led to the formal description of three new fossil pollen genera that are related to extant genera currently restricted geographically to Asia: Disanthuspollenites, Embolantherapollenites and Parrotiapollenites. Based on SEM analysis, a new combination of the fossil species Tricolpopollenites indeterminatus, traditionally used to designate fossil pollen related to Hamamelidaceae in Europe, is proposed. Additionally, we discuss the occurrence of pollen forms that can be tentatively attributed to Corylopsis and Fothergilla.
... The most favorable areas for hominin settlement in the Iberian Peninsula appear to have been located in western and northern areas (regions of Galicia, the Basque Country, and northern Catalonia). During the Early Pleistocene, woodland flourished during the warm, humid phases, whereas during the cold, dry phases the landscape was dominated by steppes, savannahs, and open woods (Altolaguirre et al., 2019). On the basis of long pollen sequences, Agustí and Lordkipanidze (2019) show that 'interglacial' periods were much warmer than at present, whereas the 'glacial' periods were characterized by temperatures very similar to current ones. ...
Archaeological remains have highlighted the fact that the interglacial Marine Isotope Stage (MIS) 11 was a threshold from the perspective of hominin evolution in Europe. After the MIS 12 glaciation, considered one of the major climate-driven crises experienced by hominins, the archaeological records show an increasing number of occupations, evidence of new subsistence behaviors, and significant technical innovations. Here, we used statistical and geographic techniques to analyze the amphibian- and reptile-based paleoclimate and habitat reconstructions generated from a large data set of the Iberian Peninsula to (1) investigate if temperature, precipitation, and/or forest cover may have impacted the hominin occupation of the territory during the Early and Middle Pleistocene, (2) propose an ‘Iberian’ ecological model before and after the MIS 12/11 transition, and (3) evaluate, based on this model, the potential hominin occupation at a European scale. The results indicate the existence of climatic constraints on human settlement related to rainfall and environmental humidity. The Early Pleistocene and the first half of the Middle Pleistocene are dominated by the occupation of relatively humid wooded areas, whereas during the second part of the Middle Pleistocene, a broadening of the earlier ecological niche is clearly observed toward the occupation of more open arid areas. Based on the estimated occupational niche for hominins, a maximum potential distribution for early hominins is proposed in Europe before and after 426 ka. Results also indicate that parts of the Iberian Peninsula may not have been suitable for early hominin occupation. Our ecological model is consistent with the pattern of hominin occupation observed in northern and central Europe, where the earliest evidence reflects only pioneering populations merely extending their ranges in response to the expansion of their preferred habitats, as compared with a more sustained occupation by 400 ka.
... Until now, the palaeoclimatic reconstructions for the Iberian Peninsula have focused on the Neogene period and have been based on several different techniques derived from analyses of micromammals (López-Martínez et al., 1987;Cuenca-Bescós et al., 2011), sedimentological data (Hamer et al., 2007), squamata and amphibian assemblages (Blain et al., 2009(Blain et al., , 2018, pollen data, and fossil macroflora assemblages (Barrón et al., 2010;Barrón et al., 2016;Altolaguirre et al., 2019). Several quantitative and semi-quantitative methods, such as CA or Mutual Climatic Range, have also been used (Blain et al., 2009;Gaudant et al., 2015;Casas-Gallego et al., 2015;Casas-Gallego, 2018) and, very recently, CLAMP (Tosal et al., 2019(Tosal et al., , 2021. ...
In this paper, we reconstruct palaeoclimate for the late Oligocene (Chattian) La Val plant assemblage of Spain (NE Iberian Peninsula). Our study employs both CLAMP (Climate Leaf Analysis Multivariate Program) and LMA (Leaf Margin Analysis), the first time these two techniques have been directly compared, and is based on 25 morphotypes (representing 23 taxa) of woody dicot leaves from a single stratigraphic unit (layer LV6). Both methods have provided a similar result. Although the standard deviation of LMA is higher than CLAMP, the results of LMA are coherent with CLAMP. The palaeoclimatic variables obtained from CLAMP shows a marked contrast between WMMT and CMMT and between 3-WET (836.3 ± 145.4 mm) and 3-DRY (113 ± 33 mm). Meanwhile, the GROWSEAS (9.30 ± 0.7 months) points out that the growth season lasted almost all the year. These variations signal a seasonal contrast, showing the existence of a dry season. Results indicate a warm temperate climate with hot and dry summers. The palaeoclimatic variables obtained using CLAMP are: MAT 17.2 ± 1.7 °C, WMMT 25.5 ± 1.3 °C, CMMT 10 ± 1.8 °C and GSP 1480 ± 204 mm. The palaeoclimatic variables obtained using LMA are MAT 17.11 ± 4.61 °C (regression equation for data from East Asia) and 16.8 ± 4.7 °C (regression equation for data from Europe). The palaeoclimatic values estimated from La Val site match those obtained from other Oligocene sites from Iberia (e.g. As Pontes site) that rely on different palaeoclimate methods. These palaeoclimatic values obtained from La Val are also similar to those from several Oligocene localities (e.g. the Rot flora) in Europe and reflect peak temperature corresponding to the late Oligocene warming episode.
... In summary, Blain et al. (2018) interpret their results as indicating a temperate Mediterranean palaeoclimate with both summers and winters similar to or somewhat warmer than today; our interpretation of their results, on the other hand, would allow the additional possibility that summers and/or winters may have been significantly cooler. This is not to say that Blain et al. (2018) are wrong, however; a recent publication by Altolaguirre et al. (2019) has used an MPC approach (although they do not name it as such) to compare results from Blain et al. (2009) with new ones based on pollen and leaf assemblages using the Coexistence Approach (Mosbrugger and Utescher, 1997;Utescher et al., 2014;Alcalde-Olivares et al., 2004). They find that the two proxy methods give consistent results, thus validating them, but stop short of using them to determine narrower "mutual mutual" ranges in the way that we have done for HSB3. ...
Continuing coastal erosion in the vicinity of Happisburgh in north Norfolk has revealed archaeological sites documenting early human presence during at least two episodes in the Early and early Middle Pleistocene. At Happisburgh 3, the oldest archaeological site in northern Europe (approximately 900,000 years old) finds include at least 80 flint artefacts and human footprints associated with abundant, well-preserved organic remains. The deposits consist of gravels and estuarine sands and silts contained within a complex of channels, which accumulated in the estuary of a large river, probably the ancestral River Thames. The environmental remains reflect a slow-flowing tidal river, at the limit of tidal influence, and a grassland valley bordered by conifer-dominated woodland. Analyses of the pollen, wood, cones and leaves have identified a diversity of coniferous taxa, with some unexpected central and southern European elements (Pinus mugo ssp. mugo, Pinus mugo ssp. rotundata and Juniperus thurifera) indicating a type of coniferous woodland no longer present in Europe today. Here we present the conifer finds and their environmental implications. A new multi-proxy consensus palaeoclimate reconstruction, using conifer and beetle mutual climatic ranges, confirms and refines previous indications of a more continental climate than today, with significantly colder winters. These results provide a new perspective for understanding the climate and environment encountered by Early Pleistocene hominins at the northernmost limit of their range.
... Middle and Late Pleistocene pollen records suggest alternating phases of forested landscapes during interglacials and open landscapes during glacials, while millennial climate oscillations are usually recorded in high-resolution records as relatively abrupt shifts in the vegetation (e.g. Altolaguirre et al., 2019;Fletcher et al., 2010;Follieri et al., 1989;Kousis et al., 2018;Koutsodendris et al., 2019;Leroy, 2007;Panagiotopoulos et al., 2014;S anchez Goñi et al., 2002;Tzedakis et al., 2006). In order to constrain the amplitude and nature of obliquity-paced climate in the Mediterranean region and the Balkan peninsula in particular, there is a need to investigate the response of terrestrial ecosystems to climate oscillations in the 41-kyr world. ...
Mediterranean mid-altitude sites are critical for the survival of plant species allowing for elevational vegetation shifts in response to high-amplitude climate variability. Pollen records from the southern Balkans have underlined the importance of the region in preserving plant diversity over at least the last half a million years. So far, there are no records of vegetation and climate dynamics from Balkan refugia with an Early Pleistocene age. Here we present a unique palynological archive from such a refugium, the Lake Ohrid basin, recording continuously floristic diversity and vegetation succession under obliquity-paced climate oscillations. Palynological data are complemented by biomarker, diatom, carbonate isotope and sedimentological data to identify the mechanisms controlling shifts in the aquatic and terrestrial ecosystems within the lake and its catchment. The study interval encompasses four complete glacial-interglacial cycles (1365–1165 ka; MIS 43–35). Within the first 100 kyr of lake ontogeny, lake size and depth increase before the lake system enters a new equilibrium state as observed in a distinct shift in biotic communities and sediment composition. Several relict tree genera such as Cedrus, Tsuga, Carya, and Pterocarya played an important role in ecological succession cycles, while total relict abundance accounts for up to half of the total arboreal vegetation. The most prominent biome during interglacials is cool mixed evergreen needleleaf and deciduous broadleaf forests, while cool evergreen needleleaf forests dominate within glacials. A rather forested landscape with a remarkable plant diversity provide unique insights into Early Pleistocene ecosystem resilience and vegetation dynamics.
The early Pleistocene is the key period for understanding the evolutionary history and palaeobiogeography of rabbits (Genus Oryctolagus). In western Europe, many species were endemic, making them a reliable indicator of the evolution of the terrestrial ecosystems in which many species have evolved. However, the morphological variability of rabbit species is still poorly understood and their phylogeny remains a subject of debate. Through both qualitative (morphological description) and quantitative (linear measurements and two-dimensional geometric morphometrics) approaches, we address here the morphometric diversity of the third lower premolar (p3), a tooth commonly used to distinguish leporid species, in order to assess intra- and inter-regional morphological variations in several early Pleistocene rabbit populations. Our results suggest that the different approaches are complementary and allow, on different levels, a full characterization of the p3 variability of early Pleistocene rabbits and to imply relations between populations. The size and shape variations of this tooth reflect the taxonomic and phylogenetic signals of the different species but were probably also significantly impacted by geographical position and local climatic conditions. In view of the great morphometric variability highlighted in this work, we suggest a careful reconsideration of certain dental criteria previously considered ‘diagnostic’ in the characterization of these species. However, the overall results allowed us to discuss the phylogeny of the genus Oryctolagus and to hypothesize the ecological requirements and different phases of the dispersal of taxa in western Europe, probably associated with global climate changes.
Early Pleistocene terrestrial climate conditions in the Mediterranean region, especially between 1.3 and 1.7 Ma, are poorly understood. Here, the amphibian and reptile fossil record from 24 fissures (Cava Pirro) of the Pirro Nord karstic complex (southern Italy) is used to infer quantitative paleoclimatic and paleoenvironmental reconstructions. These numerical data indicate that the mean annual temperature may have been somewhat lower (–1.6 to –3.6 °C compared to modern temperatures) than that of today, and the mean annual precipitation slightly higher (+90 to +240 mm) than modern values. Seasonality was more pronounced, with cooler summers (–0.4 to –2.0 °C) and much colder winters (–1.2 to –6.0 °C). Rainfall distribution patterns during the year show more precipitation during the winter (+14 to +43 mm), with quantities of summer rainfall (–1.7 to +6.6 mm) being similar to modern values. The associated landscape comprised an open dry environment with scattered patches of woodland, locally along water courses or around swamps. This ecological scenario fits with early Pleistocene cold conditions, where the first occurrence of some eastern emigrants suggests a scenario of trans-Adriatic dispersal, as may have also occurred for the earliest European hominins.
The Coexistence Approach has been used to infer palaeoclimates for many Eurasian fossil plant assemblages. However, the theory that underpins the method has never been examined in detail. Here we discuss acknowledged and implicit assumptions and assess the statistical nature and pseudo-logic of the method. We also compare the Coexistence Approach theory with the active field of species distribution modelling. We argue that the assumptions will inevitably be violated to some degree and that the method lacks any substantive means to identify or quantify these violations. The absence of a statistical framework makes the method highly vulnerable to the vagaries of statistical outliers and exotic elements. In addition, we find numerous logical inconsistencies, such as how climate shifts are quantified (the use of a "centre value" of a coexistence interval) and the ability to reconstruct "extinct" climates from modern plant distributions. Given the problems that have surfaced in species distribution modelling, accurate and precise quantitative reconstructions of palaeoclimates (or even climate shifts) using the nearest-living-relative principle and rectilinear niches (the basis of the method) will not be possible. The Coexistence Approach can be summarised as an exercise that shoehorns a plant fossil assemblage into coexistence and then assumes that this must be the climate. Given the theoretical issues and methodological issues highlighted elsewhere, we suggest that the method be discontinued and that all past reconstructions be disregarded and revisited using less fallacious methods. We outline six steps for (further) validation of available and future taxon-based methods and advocate developing (semi-quantitative) methods that prioritise robustness over precision.
For several decades, conventional pollen analyses have been supplemented with information provided by Non-Pollen Palynomorphs (NPP). Generally, the taxa included in this group are microalgae, fungi, insects and arachnid's chitinous remains, as well as plant debris and other organic palynomorphs of undetermined origin, that are valuable tools with which to characterise the original strata as well as the local environmental features that influence deposit formation processes. In this work, we present the results of the NPP analysis of the archaeological and palaeontological deposits of Sima del Elefante, Gran Dolina and Galería, all of which are located in the Trinchera area (Sierra de Atapuerca, Burgos), spanning a period from 200 ka to almost 1.5 million years ago. The NPP analysis of the three deposits has provided information about the presence of decayed organic matter accumulations, erosion processes and moisture conditions. Knowledge of palynomorphs contributes to the understanding of the biological, physical and chemical dynamics that resulted in different sedimentary sequences. In almost all cases, there is a clear connection between the major stratigraphic trends established for the three deposits and the NPP assemblages identified. However, the eminently local character of the dispersion of most of the palynomorphs identified has prevented the interrelation between the three sequences analysed.
a b s t r a c t We carry out a new paleomagnetic study across stratigraphic layer TD7 of Gran Dolina Site, Atapuerca, and reassess the existing absolute ages (thermoluminescence, electron spin resonance) obtained at this site. The new and more detailed magnetostratigraphic record of the Matuyama-Brunhes boundary, combined with absolute ages, enables further constraint on the age of the underlying human-bearing level or Aurora Stratum. Paleomagnetism of the studied silts and sandstones reveals stable, dual polar-ity Characteristic Remanent Magnetization directions. A new normal magnetic polarity short interval is found at several consecutive sampling localities in the upper part of TD7, providing a new ante quem date for the human-bearing sediments of 0.9 Ma, possibly formed during MIS 25. Ó 2013 Published by Elsevier Ltd.
Recent discoveries of evidence for hominin activity in Britain before MIS 13 challenge previous understanding of the nature of the earliest colonization of NW Europe. Insights into the nature of colonization in this region may be obtained by examining the much richer fossil and archaeological record from Iberia. It has generally been assumed that southern Europe was permanently occupied after the first appearance of hominins in the region, and that it provided a reliable source for populations re-colonizing areas further north. However, continuity of occupation in these southern areas is still to be demonstrated. This paper provides an outline of the palaeoenvironmental, archaeological and fossil evidence from Iberia during the Early Pleistocene and early Middle Pleistocene. This evidence is used to argue that hominin occupation in this region and time period was discontinuous. This may help to address a number of questions about the earliest occupation history of NW Europe: who were the colonists and where did they come from? Were they strongly limited by climatic conditions? Were source populations always available in nearby areas, and did this influence the permanency of occupation in this region?
The vegetation response to cyclic climatic changes has been investigated by means of pollen analysis carried out on marine deposits outcropping in the Lamone valley (Northern Italy). The deposits consist of grey–blue silty–clays of the “Argille Azzurre” Formation. Three sedimentary successions, which form the Lamone section, have been analysed. These successions, according to previous studies, have been referred to the first two substages of the lower Pleistocene, the Santernian and the Emilian.
Excavated between 2005 and 2007, the site of Vallparadís (Terrassa, Spain) has given an abundant and diversified fauna associated with a rich Mode 1 industry. In order to complete the chronostratigraphic framework, we performed ESR and combined US-ESR dating applied to quartz grains extracted from sediments and fossil teeth, respectively. The results obtained are very significant, giving a weighted mean ESR age of 0.83 +/- 0.13 Ma for the reference archaeological level of the site (level 10) and another of 0.79 +/- 0.23 Ma for the archaeological level 12 of the Vallparadís sequence. These ESR results are in total agreement with the ones derived from biochronology and paleomagnetism. This whole dataset allows the elaboration of a reliable and consistent chronostratigraphic framework which chronologically places Vallparadís site in the late Early Pleistocene period, i.e. within a time range comprised between Jaramillo and Brunhes geomagnetic events. Consequently, as well as Gran Dolina-TD6 and Sima del Elefante- TE9 sites, in Atapuerca, Burgos, Vallparadís can be therefore considered as a key site for the study of early hominid settlements in Europe.
Aim To generate maps of potential refugia for summer-green trees during the Last Glacial Maximum (LGM).
Locations Southern Europe and south-western Asia.
Methods Time-slice simulations of the atmospheric climate with the ECHAM3 model are used for the LGM. Limiting factors beyond which cool and warm groups of deciduous trees cannot grow (such as temperature in growing degree days, minimum monthly temperature and precipitation in summer) are chosen. A limited validation by fossil pollen and charcoal records from LGM sites was done.
Results Two sets of maps extending from Europe to the Caspian region for cool and warm summer-green trees are presented. Three criteria are combined using contour lines to indicate confidence levels. Small areas within the three southern peninsulas of Europe (Spain, Italy and Greece) are highlighted as possible refugia for summer-green trees. Further, areas that have remained poorly known are now proposed as refugia, including the Sakarya–Kerempe region in northern Turkey, the east coast of the Black Sea and the area south of the Caspian Sea.
Main conclusions The maps produced in this study could be used to facilitate better long-term management for the protection of European and south-western Asian biodiversity.
We propose a population model for Middle Pleistocene Europe that is based on demographic “sources” and “sinks”. The former were a small number of “core” or populations in glacial refugia in southern Europe from which hominins expanded northwards in interstadial and interglacial periods; occupation outside glacial refugia would have been restricted to warm or temperate periods, and populations at the northern limit of the Middle Pleistocene range would have been “sink” populations in that they depended upon recruitment from source populations further south. Southwest Asia would also have been a likely source of immigrant, source populations. We argue as an alternative to an “ebb and flow” model in which groups retreated to refugia when conditions worsened that local extinction outside refugia would have been frequent. In extreme situations, Europe may have been a population “sink” (i.e. unpopulated) that was replenished from source populations in Southwest Asia. We suggest that this pattern of repeated colonisation and extinction may help explain the morphological variability of European Middle Pleistocene hominins, particularly Homo heidelbergensis and its apparent non-lineal evolution towards Homo neanderthalensis.
Evaluation of the first early human settlement of northern Europe is closely bound up with issues of climate change, human social and technical capability, and sampling visibility. The finds from Dmanisi (1.7 Ma) suggest that small-brained early Homo with simple technologies was able to colonise temperate regions, and it is unlikely that Europe presented insuperable problems compared with Georgia; or that hominids who colonised the South of Europe in favourable conditions could not advance to the north within a few thousand years. Consideration of the geological record, however, shows how much has been lost: apart from large areas currently under sea, evidence of past rivers such as the proto-Thames and Bytham helps measure the extent of erosion, much of it caused by glacial planing. Fire history, in terms of controlled fire use, appears in northern Europe by isotope stage 11, when it is widespread across the continent. Beeches Pit is a prime example indicating fire control, and social activity around fires and in fire management. Fire is however puzzlingly absent from many sites, including those of OIS13. The paper considers the alternative possibilities: that fire use was introduced through an increase in human social/intellectual capability around OIS 11, and that sampling limitations greatly reduce our chances of seeing it on earlier sites. To cite this article: J.A.J. Gowlett, C. R. Palevol 5 (2006).
The pattern of the varying climatic conditions in southern Europe over the last million years is well known from isotope studies on deep-ocean sediment cores and the long pollen records that have been produced for lacustrine and marine sedimentary sequences from Greece, Italy and the Iberian margin. However, although relative glacial and interglacial intensities are well studied, there are still few proxies that permit quantitative terrestrial temperature and precipitation reconstruction. In this context, fauna-based climate reconstructions based on evidence preserved in archaeological or palaeontological sites are of great interest, even if they only document short windows of that climate variability, because (a) they provide a range of temperature and precipitation estimates that are understandable in comparison with present climate; (b) they may allow the testing of predicted temperature changes under scenarios of future climate change; and (c) quantitative temperature and precipitation estimates for past glacials and interglacials for specific regions/latitudes can help to understand their effects on flora, fauna and hominids, as they are directly associated with those cultural and/or biological events. Moreover such reconstructions can bring further arguments to the discussion about important climatic events like the Mid-Bruhnes Event, a climatic transition between moderate warmths and greater warmths during interglacials. In this paper we review a decade of amphibian- and reptile-based climate reconstructions carried out for the Iberian Peninsula using the Mutual Ecogeographic Range method in order to present a regional synthesis from MIS 22 to MIS 6, discuss the climate pattern in relation to the Mid-Bruhnes Event and the thermal amplitude suggested by these estimates and finally to identify the chronological gaps that have still to be investigated.
Marine Isotope Stage 31 (MIS 31) is an important analogue for ongoing and projected global warming, yet key questions remain about the regional signature of its extreme orbital forcing and intra-interglacial variability. Based on a new direct land-sea comparison in SW Iberian margin IODP Site U1385 we examine the climatic variability between 1100 and 1050 ka including the " super interglacial " MIS 31, a period dominated by the 41-ky obliquity periodicity. Pollen and biomarker analyses at centennial-scale-resolution provide new insights into the regional vegetation, precipitation regime and atmospheric and oceanic temperature variability on orbital and suborbital timescales. Our study reveals that atmospheric and SST warmth during MIS 31 was not exceptional in this region highly sensitive to precession. Unexpectedly , this warm stage stands out as a prolonged interval of a temperate and humid climate regime with reduced seasonality, despite the high insolation (precession minima values) forcing. We find that the dominant forcing on the long-term temperate forest development was obliquity, which may have induced a decrease in summer dryness and associated reduction in seasonal precipitation contrast. Moreover, this study provides the first evidence for persistent atmospheric millennial-scale variability during this interval with multiple forest decline events reflecting repeated cooling and drying episodes in SW Iberia. Our direct land-sea comparison shows that the expression of the suborbital cooling events on SW Iberian ecosystems is modulated by the predominance of high or low-latitude forcing depending on the glacial/interglacial baseline climate states. Severe dryness and air-sea cooling is detected under the larger ice volume during glacial MIS 32 and MIS 30. The extreme episodes, which in their climatic imprint are similar to the Heinrich events, are likely related to northern latitude ice-sheet instability and a disruption of the Atlantic Meridional Overturning Circulation (AMOC). In contrast, forest declines during MIS 31 are associated to neither SST cooling nor high-latitude freshwater forcing. Time-series analysis reveals a dominant cyclicity of about 6 ky in the temperate forest record, which points to a potential link with the fourth harmonic of precession and thus low-latitude insolation forcing.
1. It has been suggested that the habitats which a species occupies can be divided into sources and sinks, depending on whether or not local reproduction is sufficient to balance mortality. Source populations are those where reproduction exceeds mortality, surplus individuals dispersing to sink populations where mortality exceeds local reproduction. Sink populations would not be viable in the absence of immigration. 2. A difference equation model is constructed to show that sources and sinks cannot be identified from a simple comparison of the demographic rates between populations, as measured by the numbers of births and deaths. 3. Viable populations may appear to be non-viable simply because the dispersal of individuals into them depresses fecundity or increases mortality as a result of density-dependence. The consequence is that local recruitment appears insufficient to balance local mortality. 4. Viable populations that appear as sinks, as a result of the dispersal of individuals into them, are termed here as `pseudo-sinks'. They will clearly be difficult to distinguish from genuine sinks on the basis of a simple comparison of the numbers of births and deaths in different populations. 5. Examples of source and genuine sink populations and the data required to establish them are discussed.
Pleistocene level TD6-2 of the Gran Dolina site (Sierra de Atapuerca, Spain) is the result of anthropogenic accumulation. Hominin groups occupied the cave as a home base, where they brought in, butchered and consumed the carcasses of ungulates and other hominins. In this paper, we reassess the role of carnivores in the formation and/or modification of the assemblage. We employed different methods to explore the scenario in which the TD6-2 assemblage was formed: (1) identifying the actor responsible for tooth marks; (2) determining the frequency of carnivore tooth marks and their distribution; (3) identifying the co-occurrence of modifications (butchering marks and carnivore tooth marks); (4) calculating the percentage of change and the epiphysis to shaft ratio. Carnivore tooth marks are scarce, as is the co-occurrence of hominin and carnivore modifications. However, not all tooth marks have been attributed to a particular agent due to the high equifinality between human and carnivore tooth marks. For these reasons, the frequency of tooth marks and the co-occurrence of modifications have been of little help in interpreting the role of carnivores.
Axial skeletal remains and the epiphyses of the long bones are in large part missing. The percentage of change and the epiphysis to shaft ratio suggest moderate carnivore ravaging activity. Our data indicate that the role of carnivores in TD6-2 seems to have had an impact on the original assemblage after hominins had extracted a large amount of nutrients from the carcasses. Cannibalized hominin remains showed no carnivore tooth marks and have a greater presence of low survival bones compared to ungulate remains. These findings point to a different taphonomic history suggesting that TD6-2 represents a succession of settlements having different characteristics.
The combined U-series/electron spin resonance (ESR) dating method was applied to nine teeth from two Early Pleistocene archaeological sites located in the Orce area (Guadix-Baza Basin, Southern Spain): Fuente Nueva-3 (FN-3) and Barranco León (BL). The combination of biostratigraphy and magnetostratigraphy places both sites between the Olduvai and Jaramillo subchrons (1.78–1.07 Ma).
Our results highlight the difficulty of dating such old sites and point out the limits of the combined U-series/ESR dating method based on the US model. We identified several sources of uncertainties that may lead to inaccurate age estimates. Seven samples could not be dated because the dental tissues had (230Th/234U) activity ratios higher than equilibrium, indicating that uranium had probably leached from these tissues. It was however possible to calculate numerical estimates for two of the teeth, both from FN-3. One yielded a Middle Pleistocene age that seems to be strongly underestimated; the other provided an age of 1.19 ± 0.21 Ma, in agreement with data obtained from independent methods. The latter result gives encouragement that there are samples that can be used for routine dating of old sites.
Hominid remains found in 1994 from the stratified Gran Dolina karst-filling at the Atapuerca site in NE Spain were dated to somewhat greater than 780 ka based on palaeomagnetic measurements, making these the oldest known hominids in Europe (sensu stricto). We report new ESR and U-series results on teeth from four levels of the Gran Dolina deposit which confirm the palaeomagnetic evidence, and indicate that TD6 (from which the human remains have been recovered) dates to the end of the Early Pleistocene. The results for the other levels are consistent with estimates based mainly on microfaunal evidence, and suggest that TD8, TD10 and TD11 date to the Middle Pleistocene.
This paper proposes a new theoretical model to explain the evolution of the genus Homo in Europe during the Early and the Middle Pleistocene in the light of the latest human discoveries in Europe. This model is contextualized within a biogeographical framework in order to assess its environmental feasibility. After the first Out of Africa hominin dispersal, the colonization of Europe may be the result of several hominin migrations originated from a central area of dispersals of Eurasia (CADE), located in the Levantine Corridor and continuously inhabited by a “source population”. Evolutionary changes occur in the source population and are reflected in the demes that migrate to the east and the west of the vast Eurasian continent, but can also occur in their “descendants” and not always at a species level. Populations in the central (CADE) and peripheral areas are intermittently connected, due to the existence of geographic and climatic barriers, possibly with climate being the driving force of the populations expansions, contractions and local extinctions. Populations with a recent common origin and that occupied the same territory might have interbred. During most of the Pleistocene, the human occupation of Europe depended upon the non-linear recruitment of populations from the CADE.
Aim The aim of this work was to identify the main changes in the flora
and vegetation of the Iberian Peninsula over the Cenozoic Era, to record the
disappearance of taxa associated with these changes and to determine the
influence of climate and human activity on these events.
Location The Iberian Peninsula and Balearic Islands.
Methods A critical review was made of the palaeobotanical literature with the
aims of detecting patterns of floristic change and extracting information on the
disappearance of different taxa over the Cenozoic. These data are viewed
alongside the most recent data for the climate of this period. A critical analysis is
made of the role of Palaeotropical and Arctotertiary taxa in the forest
communities of the Iberian Peninsula throughout the Cenozoic.
Results Although the Eocene–Oligocene transition was a time when many taxa
disappeared, the most outstanding events occurred between the end of the
Oligocene and throughout the Miocene. Substantial floristic changes took place
over this period, including the disappearance of 177 Palaeotropical taxa. This was
probably related to acute cooling and aridification; no evidence exists that the
Messinian Salinity Crisis had any important effect in the Iberian Peninsula. The
last great disappearance of Palaeotropical taxa (36 in total) ended in the Middle–
Late Piacenzian; Arctotertiary taxa were most affected during the Pleistocene. The
Lower–Middle Pleistocene transition, best represented by marine isotopic stages
(MIS) 36–34 and 20–18 and characterized by a change in glacial cyclicity, was the
time of the last notable disappearance of taxa.
Main conclusions This work provides the first chronogram of extinctions for
the Iberian flora, and records the disappearance of 277 taxa during the Cenozoic.
A clear relationship was detected between the main climatic events and the latest
appearances of the different taxa.
The coexistence approach (CA) is widely used to reconstruct palaeoclimates for the Cenozoic. Most published CA analyses relied on climate data for nearest living relatives (NLRs) stored in the Palaeoflora database (PFDB). Here, we used more than two-hundred modern relevés (taxon lists of forest stands) from North American, Caucasian and East Asian forest regions in order to test the ability of CA/PFDB to estimate palaeoclimate. Since only data for mean annual temperature (MAT) are publicly available from the PFDB, we concentrated on this climate parameter. Two criteria were tested: ‘resolution’ and ‘reliability’ of CA/PFDB analyses. The CA assumes that for a given climate parameter (e.g. MAT; mean annual precipitation; coldest month mean temperature etc.) the interval shared by all or nearly all NLRs for a fossil assemblage is best describing the past climatic conditions. Narrow, i.e. well-resolved, intervals are desirable, since they describe most precisely the climate. Our results show that CA/PFDB is unable to reliably reconstruct the actual climates of most of the relevés analysed. CA/PFDB performed best for lowland and mid-altitude stands with MAT of ca. 13–16 °C, while producing remarkably incorrect results for warmer lowland stands and cooler stands at higher elevations. This is mainly due to generally incorrect entries of MAT ranges of NLRs in the PFDB. Using corrected MAT tolerances, the reconstructed, low-resolved intervals (3 °C in exceptional cases, typically 5–10 °C) fall within the actual climates. Hence, only dramatic climate changes are likely to be captured in a CA analysis. This renders the coexistence approach useless for the quantitative reconstruction of palaeoclimate and calls for alternative approaches of investigating past climates by means of fossil plants.
The temperature evolution during the Praetiglian and Tiglian (Plio–Pleistocene) of northern Germany and the southern North Sea area is reconstructed based on the pollen record from Lieth, northern Germany. The examined record covers the time span from approximately 2.6 to 1.7 Ma. Calculations of the temperatures of the warmest (MTW) and coldest (MTC) months are presented utilizing the mutual climatic range principle. The thermal resolution of the reconstruction is increased through the calculation of most likely intervals for actual temperature ranges. For the analyzed pollen record, the MTW and MTC resolution reaches up to 1.5 °C using 100% most likely intervals and up to 1 °C using 70% most likely intervals. A seasonality index is calculated as a further tool for evaluating the climate development.
Une étude approfondie de la flore de Crespià a permis de revoir sa composition et de signaler en particulier sept taxons jusque là inconnus pour ce gisement. Dans ce travail, on envisage la reconstitution de la végétation et du climat grâce à une analyse quantitative des échantillons. L'étude paléoécologique et la comparaison avec d'autres macroflores montrent que cette végétation était de type interglaciaire. Compte tenu des renseignements chronologiques obtenus à pactir des faunes de mammifères et des informations floristiques fournies par les analyses polliniques réalisées sur des sites du Pliocène et du Pléistocène inférieur, il est possible d'attribuer au gisement de Crespià un âge compris entre-2,1 et -1,6 MA.
This paper summarizes the latest studies on lithic raw material raising that are currently undertaken within the Sierra de Atapuerca research project. During the past two years, several works have provided new petrographical and technological data, contributing to the knowledge of the kinds of materials exploited by the Atapuerca hominids, as well as the areas where those materials were raised. The sites yielding this information are Gran Dolina (Lower and Middle Pleistocene) and Galeria (Middle Pleistocene), both located in the Trinchera del Ferrocarril archeopaleontological complex.
A new pollen-derived method of climatic quantification, based on the mutual climatic range of plant taxa, has been applied to 17 Pliocene pollen sequences in the West Mediterranean area. The latitudinal gradient observed in the pollen data was confirmed by the climatic reconstructions: there is a gradient from north to south both for temperatures and precipitation. At the beginning of the Pliocene (5.32–5 Ma), the climate in the North Mediterranean area was, on average, warmer and more humid than today (respectively 1–4°C and 400–700 mm). In the South Mediterranean region, the climate was both warmer and drier than today (respectively equal to or 5°C higher and drier or equal humidity). The pollen-based climate estimates were then used to reconstruct biomes for the region. The results show the occurrence of three biomes: the broad-leaved evergreen/warm mixed forest, the xerophytic woods/scrub biome and the warm grass/shrub biome. These biomes are still represented today in the Mediterranean region despite different thermic and water conditions.
The first detailed reconstruction of the continental paleoclimate evolution of the Northwest German Tertiary (Late Oligocene to Pliocene) is presented. The paleoclimate data are derived from the paleobotanical record using the coexistence approach, a method recently introduced that employs climatic requirements of the Nearest Living Relatives of a fossil flora. Twenty six megafloras (fruits and seeds, leaves, woods) from the Tertiary succession of the Lower Rhine Basin. and neighboring areas are analyzed with respect to ten meteorological parameters. Additionally two sample sets from Late Miocene to Early Pliocene sediments comprising 396 palynofloras are analyzed by the same method providing a higher temporal resolution. The temperature curves show a comparatively cooler phase in the Late Oligocene, a warm interval the Middle Miocene, and a cooling starting at 14 Ma. The cooling trend persisted until Late Pliocene with a few higher frequency temperature variations observed. From the beginning of Late Miocene to the present, the seasonality increases and climate appears to have been less stable. As indicated by the precipitation data, a Cfa climate with wet summers persisted in NW Germany from Late Oligocene to Late Pliocene. The results obtained are well in accordance with regional and global isotope curves derived from the marine record, and allow for a refined correlation of the Tertiary succession in the Lower Rhine Basin with the international standard. It is shown that the reconstructed data are largely consistent with the continental climate record for the Northern Hemisphere, as reported by various authors. Discrepancies with previous reconstructions are discussed in detail.
Hominin 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.
The native or allochthonous nature of certain extant species of the Iberian Peninsula is a matter of some controversy given our lack of knowledge regarding the survival and extinction processes to which they have been subject. The aim of the present work is to provide a review of the current knowledge regarding these processes during the Quaternary. The Middle Pleistocene Transition was a period of noticeable disappearance of Arctotertiary taxa in the Iberian Peninsula, related to the alteration in glacial cyclicity and climate change, including an increase in the severity of glaciations, a reduction in the length of the interglacial periods, and increased dryness during the coldest times. It is difficult to maintain that human activities played any important part in the complete or near-complete disappearance of some taxa during the Quaternary. In the Late Pleistocene and Holocene, however, the extinction of Cedrus, Picea and Carpinus might be related to climate change, competition with other taxa, and anthropogenic disturbances. In contrast, the extreme reduction or even complete disappearance of Platanus or Syringa seems to be due to natural causes alone. The available geological, molecular and palaeobotanical data suggest that some Arctotertiary taxa persisted over long periods of time during the Quaternary in the Iberian Peninsula. Indeed, the fossil record of one important group of taxa, including Castanea, Ceratonia, Carpinus and Juglans, shows its continued presence throughout the Quaternary.
In a recent INQUA project the extent of Pleistocene glaciations has been digitally mapped and the chronology of events reviewed. The onset of the present Ice Age in both hemispheres dates back to the Palaeogene. In Greenland, Iceland, North America and southernmost South America sizeable ice sheets formed well before 2.6 ka BP. In Alaska and on Tierra del Fuego the ice advanced further than in any later glaciations. Evidence for Early Pleistocene glaciation (2.6–0.78 Ma) has been reported from many parts of the world, but in most cases dating remains problematic, and the size of the glaciers and ice sheets is unknown. A number of Middle Pleisto-cene glaciations (0.78–0.13 Ma) have been identified, mostly correlated with MIS 16, 12 and 6, including the Donian, Elsterian and Saalian of Europe. The extent of the MIS 6 glaciations is well known. Especially in Eura-sia the extent of the Late Pleistocene (0.13 Ma to present) glaciations had to be revised. Major ice advances are reported for 80–100 ka BP, c. 70–80 ka BP and c. 20 ka BP, with the earlier glaciations being most extensive in the east. The very different shapes of the ice sheets—Donian vs Elsterian, Early vs Late Weichselian —are as yet difficult to explain and remain a challenge for climatic modellers.
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.
The recent discovery of a site at Vallparadís (Terrassa), dated to the upper boundary of
the Jaramillo sub-chron (0.98 Ma), allows us to close the archaeological gap in the Late
Lower Pleistocene of the Iberian Peninsula and to propose the hypothesis that western
Mediterranean Europe may have been continuously inhabited by humans from 1.4-1.2Ma
until the early Middle Pleistocene. Early hominid groups present in the area were capable of
successfully withstanding the changing climatic conditions that they encountered, thanks
to their specific adaptive strategies based on a Mode 1 lithic technology, and probably also
on well developed social cohesion. These strategies enabled them to obtain meat by gaining
primary access to herbivore carcasses and thus to successfully compete with other large
carnivores. These first hominids in the western Mediterranean Europe succeeded in raising
themselves to the top of the food chain, and in doing so guaranteed the continuity of human
settlement.
In this paper we review a number of scenarios which have been proposed to explain the first hominin “out of Africa” at the base of the Pleistocene. These are the brain expansion scenario, the cultural exclusion scenario, the migratory wave scenario and the common African home scenario. These scenarios are checked against the current evidence provided by the Georgian site of Dmanisi, which contains the oldest Eurasian hominins. Therefore, it is concluded that none of these scenarios fits with the existing evidence, and that the only real African influence in Dmanisi is restricted to early Homo itself. In order to explain the presence of early Homo at Dmanisi, it is concluded that the expansion out of Africa should have happened before the actual datum of Dmanisi, most probably linked to the spread of Mode 1 tools in Africa.
This review presents the themes of a special issue dealing with environmental scenarios of human evolution during the Early Pleistocene (2.6–0.78 Ma; MIS 103-MIS 19) and early Middle Pleistocene (0.78–0.47 Ma; MIS 19-base of MIS 12) within the western Palaearctic. This period is one of dramatic changes in the climates and the distribution of Palaearctic biota. These changes have played their role in generating adaptive and phyletic patterns within the human ancestry, involving several species such as Homo habilis, “Homo georgicus”, Homo erectus, Homo antecessor and Homo heidelbergensis. In the archaeological record, these species include the Oldowan (Mode 1) and Acheulian (Mode 2) lithic technologies. Taphonomic considerations of palaeoecological research in hominin-bearing sites are provided and evaluated. Syntheses are provided for north Africa, western Asia, the Mediterranean Basin, Britain, and continental Europe. Palaeoenvironmental reconstructions based on multidisciplinary data are given for Ain Boucherit, Ain Hanech and El-Kherba in Algeria, Dmanisi in Georgia, Atapuerca, Cueva Negra, and the Orce Basin in Spain, Monte Poggiolo and Pirro Nord in Italy, Pont-de-Lavaud in France, and Mauer in Germany. The state of the art with the Out of Africa 1 dispersal model is reviewed. A source-sink dynamics model for Palaeolithic Europe is described to explain the morphological disparity of H. heidelbergensis (we will sometimes use the informal name “Heidelbergs”) and early Neanderthals. Other aspects debated here are the selective value of habitat mosaics including reconstructions based on mammal and avian databases, and the role of geological instability combined with topographic complexity. This review is completed by addressing the question of whether the appearance of evolutionary trends within hominins is concentrated in regions of highest worldwide biological diversity (biodiversity hotspots). It is concluded that the keys for the activation of evolutionary change in hominins may have been geological instabilities, and a shifting physiographical heterogeneity combined with high biodiversity and ecological interaction.
The Cal Guardiola site, discovered during the construction of an office building in the centre of Terrassa (Province of Barcelona, NE Spain), is home to one of the richest deposits of lower–middle Pleistocene flora in the Iberian Peninsula. The site contains a large quantity of plant macroremains, including non-carbonised wood, in an exceptional state of preservation. In this work, 100 wood fragments were analysed along with 25 pollen samples and 2 coprolites, all from the same horizon. These remains revealed the presence of a mixed deciduous forest with significant numbers of Quercus (Quercetum mixtum). Thermophilous, meso-hygrothermophilous and river forest species were also present, including some taxa rarely recorded for the Pleistocene, e.g., the mesocratic group of species represented by Juglans, Carya and Platanus. Fossil wood of Aesculus was also identified; this is the first Pleistocene reference of this species in Iberia. In this open Mediterranean forest, several remarkable gymnosperms were present. For example, Pinus haploxylon-type pollen was identified, demonstrating the survival of this group of conifers during the lower Pleistocene in the Iberian Peninsula. Pollen of Taxodiaceae was also found — the first reference of this family for the Iberian Pleistocene-showing these taxa survived on the Peninsula until the lower–middle Pleistocene transition. Warm-temperate and humid conditions prevailed during this interval; clear indications of an interstadial episode were observed.