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Unravelling the Late Pleistocene habitat of the southernmost woolly mammoths in Europe
Abstract
The southernmost record of woolly mammoths (Mammuthus primigenius) in
Europe has been found in Late Pleistocene sediments from 'El Padul'
peat-bog, in the Granada Basin (southern Spain). In this paper we
discuss a plausible habitat based on stable isotopic analyses of these
specimens, dated ˜40-30 cal ky BP, probably corresponding with the
beginning of Heinrich Stadial 4 (HS4) and the end of Heinrich Stadial 3
(HS3). Woolly mammoth remains preserve an accurate isotopic register of
past climatic conditions because they needed to ingest large amount of
resources daily (water and fresh food), whose isotopic signature,
influenced by the environmental conditions, was recorded in their
tissues. The δ18Ow values of the past
meteoric waters (-5.4‰ to -6.7‰ vs V-SMOW),
calculated from the isotopic composition of teeth enamel, suggest
moderate temperatures in comparison with those of similar age recovered
in central and northern Europe. Due to its geographic position in
southern Europe, our samples recorded the highest
δ18Ow values of past meteoric waters deduced
from mammoth remains in Europe. The difference between these values and
those of δ18Ow of current mean annual
precipitation are minimal, contrasting with those of higher latitudes
during the end of the last glaciation (˜50 to ˜20 cal ky
BP). The isotopic values of nitrogen (10.1‰ to 13.2‰ vs
AIR) and carbon (-20.7 to -21.8‰ vs V-PDB) of
collagen show a dry habitat, which occasionally could have been extreme.
Taken as a whole, the isotopic results suggest that the studied
specimens lived in a very dry steppic area, with moderately cold
conditions, contrasting with the wet environment of 'El Padul' peat-bog,
and its colder temperatures, due to the influence of glacial conditions
of the Sierra Nevada, the highest peninsular mountain range. The
described habitat may be sited in a more westerly position than the 'El
Padul' peat-bog, and it was warmer and drier than those of
contemporaneous European woolly mammoths.
... It was analyzed in a XL Thermo Finnigan mass spectrometer. For a detailed procedure description consult García-Alix et al. (2012). Results are expressed in δ notation, using the standard V-SMOW for oxygen. ...
... Traditionally, temperatures for continental past environments have been estimated on the basis of oxygen isotopes from fossil mammals (Grimes et al., 2003;Amniot et al., 2004;Arppe and Karhu, 2010;Herán et al., 2010;García-Alix et al., 2012;and references therein). In mammals there is a direct relationship between isotopic composition of the ingested meteoric waters and body water, and the carbonates and phosphates in hydroxylapatite (Longinelli, 1984;Luz and Kolodny, 1985;Delgado Huertas et al., 1995;Iacumin et al., 1996;Royer et al., 2013;among others). ...
... During the last years various authors used these equations relating mean air temperatures and δ 18 O values of meteoric waters in order to obtain mean annual past temperatures by means of the deduced past meteoric δ 18 O w values (Delgado Huertas et al., 1997;Grimes et al., 2003;Amniot et al., 2004;Arppe and Karhu, 2010;Herán et al., 2010;García-Alix et al., 2012;among others). However this approach has serious inconveniences and may lead to erroneous results: ...
Tropical conditions during the late Miocene in southwestern Europe influenced the continental environments. Although there are previous qualitative environmental interpretations of these continental landscapes during the late Miocene, quantitative environmental and paleohydrological data are scarce. A very long sequence of small mammals allowed to date the different continental drainage stages of the Granada Basin from latest Tortonian to the Holocene and to reconstruct qualitatively its environmental evolution. The study of the isotopic record of these fossil small mammals and sediments in the stratigraphic sequence of a latest Messinian paleo-lake in the Granada Basin has provided quantitative environmental and paleohydrological data, in order to know if the fluctuations in the faunal distribution were mainly influenced by the paleogeographic configuration, such as changes in the landscape of the basin, or by the climatic conditions. Open habitats with C3 plants predominated. Estimated quantitative data suggest an oxygen isotopic composition of meteoric waters ranging from − 4.9 to − 3.9‰, past temperatures from ~ 2.5 °C to 4.7 °C higher than the current ones, and summer relative paleohumidity from ~ 60% to ~ 70%. In this context, changes in the landscape, such as the reduction of the lacustrine system caused by tectonic activity, would affect taxa with high dependence on humid conditions.
... The mammoth sample from Zók (Hungary) provides the lowest (9.8), while the one from the Slaninova Cave (Slovakia) the highest (16.7) d 18 O P composition. The d 18 O signature of the ECE samples presented in this study are amongst the highest values (Fig. 4) reported to date for woolly mammoth from the European Late Pleistocene (Ayliffe et al., 1992; Genoni et al., 1998; Tütken et al., 2008; Arppe and Karhu, 2010; García-Alix et al., 2012), except for the Z1 (Zók) sample from Hungary (9.8&). The oxygen isotopic signal of pre-LGM mammoth samples correlates well with those values of fossil finds from the North Sea and Rhine River sediments (Tütken et al., 2008) Zók sample (age 18 ka BP) is w3.5& lower than the Danish sample. ...
... Based on d 18 O P of the enamel and dentin samples, the oxygen isotope composition of the mean annual Late Pleistocene precipitation in East Central Europe varied from À13.4& to À4.6&, with an average value of À9& (Fig. 5 ). Based on the relationship of Equations (9)e(11), this would correspond to a surface air temperature of Ayliffe et al. (1992); Genoni et al. (1998); Arppe and Karhu (2006); Tütken et al. (2007, 2008); Ukkonen et al. (2007); Arppe and Karhu (2010); García-Alix et al. (2012); Pryor et al. (in press). 10 C. The oxygen isotope composition of present-day precipitation in ECE ranges from À9& to À10.5& (Deák et al., 1996; Sanda et al., 2009; Jiráková et al., 2011; Varsányi et al., 2011), while the d 18 O composition of Late Pleistocene groundwater varies from À11.2& and À10.6& for the western part ( Silar and Silar, 1995; Kadlec et al., 2000; Jiráková et al., 2010 Jiráková et al., , 2011), and from À11& and À14& for the eastern part of the study region (Stute and Deák, 1989; Deák et al., 1996; Varsányi et al., 2011). ...
... The mammoth dentin d 13 C C values are typical for herbivores found in pure C 3 ecosystems. These values are in accordance with values measured in Siberian, Ukrainian and Russian mammoth remains by Iacumin et al. (2000) and in samples from Finland (Arppe and Karhu, 2006; Arppe et al., 2011) as well as from Poland (Pryor et al., in press) and Spain (García-Alix et al., 2012). The Polish, Swedish, Lithuanian and Estonian specimens provide intermediate regional mean values of À11.3 AE 0.4&, À11.4 AE 0.4&, À11.5 AE 0.3& and À11.6 AE 0.4, respectively (Arppe et al., 2011). ...
Stable carbon and oxygen isotope values (δ13C, δ18O) of structural carbonate were determined in the bioapatite component of fossil teeth from the Czech Republic, Slovakia and Hungary. Oxygen isotope compositions of enamel and dentin samples provide new quantitative records of the Late Pleistocene climate in East Central Europe (ECE). These δ18O data were combined with records of oxygen isotope values of recent and paleogroundwaters to study the spatial patterns and temporal variations in the oxygen isotope composition of precipitation and the thermal climate over ECE. The new isotopic data suggest that surface air temperatures in the study region between 33 and 12 ka were 2–9 °C colder than present. Specimens of woolly mammoth, rhino and horse from the Late Pleistocene were primarily C3 grazers.
... Although the Quaternary mammalian fossil record is well represented in the Iberian Peninsula García, 2010, 2011a,b), its biogeochemical characterization and subsequent paleoclimatic, paleoecological and paleoenvironmental reconstruction remain scarce and fragmentary (e.g., Palmqvist et al., 2003Palmqvist et al., , 2008Feranec et al., 2010;García-Alix et al., 2012;Stevens et al., 2014). The Iberian Peninsula is a key region in the paleobiogeographical distribution of the coldadapted Eurasian megafauna, as it constitutes the southernmost limit of expansion of some of those taxa, such as the woolly mammoth Mammuthus primigenius, the woolly rhinoceros Coelodonta antiquitatis, the reindeer Rangifer tarandus or the muskox Ovibos moschatus (Álvarez-Lao et al., 2009;Álvarez-Lao and García, 2011a,b;García-Alix et al., 2012). ...
... Although the Quaternary mammalian fossil record is well represented in the Iberian Peninsula García, 2010, 2011a,b), its biogeochemical characterization and subsequent paleoclimatic, paleoecological and paleoenvironmental reconstruction remain scarce and fragmentary (e.g., Palmqvist et al., 2003Palmqvist et al., , 2008Feranec et al., 2010;García-Alix et al., 2012;Stevens et al., 2014). The Iberian Peninsula is a key region in the paleobiogeographical distribution of the coldadapted Eurasian megafauna, as it constitutes the southernmost limit of expansion of some of those taxa, such as the woolly mammoth Mammuthus primigenius, the woolly rhinoceros Coelodonta antiquitatis, the reindeer Rangifer tarandus or the muskox Ovibos moschatus (Álvarez-Lao et al., 2009;Álvarez-Lao and García, 2011a,b;García-Alix et al., 2012). Pollen analyses and phylogeographic models have revealed that a mosaic-like landscape of forests, woodlands, savannahs and steppes may have been present in the Iberian Peninsula even during the harshest climatic episodes of the Quaternary González-Sampériz et al., 2010;Rodríguez-Sánchez et al., 2010). ...
La Paloma cave (Asturias, northern Spain) stands out as one of the most notable prehistoric sites of the northern Iberian sector due to the richness of its archaeo-paleontological material, spanning a complete Magdalenian-Azilian sequence (~20,300-12,900calyears BP). The abundance, diversity and good preservation of mammalian remains make of La Paloma site an excellent location to characterize paleoclimatic, paleoecological and paleoenvironmental conditions from a biogeochemical standpoint. Stable isotope analyses performed on tooth enamel (δ13Cen, δ18OCO3, δ18OPO4) and bone collagen (δ13Ccoll, δ15N) of a suite of herbivore, carnivore and omnivore species did not yield significant variations across the stratigraphic sequence, likely pointing to prevalent and stable local conditions, with i) no major vegetation turnover, ii) maintenance of hydrological conditions, and iii) relatively constant soil activity, in spite of the synchrony of the La Paloma temporal context with global events, such as the end of the Last Glacial Maximum, the Heinrich Event 1 and the Bølling-Allerød oscillation. La Paloma δ13Cen and δ13Ccoll values are within the expected range for C3 mixed woodland-mesic C3 grassland conditions. Overall, bovids (large Bovidae, ibex and chamois) show higher δ13Cen, δ13Ccoll and δ15N values than cervids (red deer and roe deer), indicating a preference for more open environments in the former. Horse δ13C values are undistinguishable from those of red deer and point to a mixed-feeding behavior. Horse low δ15N values may be indicative of a diet with a low protein content. Bayesian mixing model results yielded differences in carnivore resource use, with wolf preying on all ungulates and red fox preferentially incorporating roe deer. Stable paleoenviromental conditions during the latest Pleistocene at the La Paloma area may have favored the persistence of a stable mammalian community structure, supporting the idea of the existence of refuge areas in the northern Iberian sector throughout the late Quaternary glacial-interglacial dynamics.
... It was analysed in a XL Thermo Finnigan Mass Spectrometer at the Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR). For a detailed procedure description, consult Alix et al. (2012). Results are expressed in δ notation, using the standard SMOW for oxygen. ...
... account (see García-Alix et al., 2013; Royer et al., 2013). However, knowing these restrictions as well as the difference between the current and the past mean isotopic composition of oceanic waters (Lear et al., 2000; Zachos et al., 2001), allow a broad approach to be carried out, as Alix et al. (2012Alix et al. ( , 2013 ) suggested. The oxygen isotopic composition of the seawater, source of the precipitation at low/middle latitudes, was impoverished between ~0.4‰ and ~0.8‰ SMOW during the latest Miocene–early Pliocene (Δδ 18 O prsw-pasw ‰) (Lear et al., 2000; Zachos et al., 2001), and so was the rainwater originated from that (Table 1). ...
... It was analysed in a XL Thermo Finnigan Mass Spectrometer at the Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR). For a detailed procedure description, consult García-Alix et al. (2012). Results are expressed in δ notation, using the standard SMOW for oxygen. ...
... A preliminary approach can be expressed by the following equation obtained by means of the Ordinary Least Squared Regression (OLS): account (see García-Alix et al., 2013;Royer et al., 2013). However, knowing these restrictions as well as the difference between the current and the past mean isotopic composition of oceanic waters (Lear et al., 2000;Zachos et al., 2001), allow a broad approach to be carried out, as García-Alix et al. (2012 suggested. The oxygen isotopic composition of the seawater, source of the precipitation at low/middle latitudes, was impoverished between~0.4‰ ...
Paleoenvironmental reconstructions from fossil mammals are based on the straightforward relationship between the environment and the mammal assemblage living in the area. However, in some cases the environmental variables estimated from mammals are biased by local influences. The paleoenvironmental reconstruction of the Granada Basin (southern Spain) based on carbon and oxygen isotopes from enamel rodent teeth is compared with the paleoenvironmental data from small mammal assemblages. Estimated temperatures from both proxies coincide, in general terms: cold-temperate conditions during the latest Tortonian (~ 16°C; cold-temperate climate), dry sub-tropical conditions during the Messinian (16.6°C-22°C), and dry sub-tropical conditions during the early Pliocene (16.6°C-17.2°C). Reconstructed humidity trends from both proxies only agree in the first part of the record, showing dry conditions during the Tortonian-Messinian boundary and an increase in humidity at the beginning of the Messinian. During the Messinian and earliest Pliocene, humidity trends in each proxy are frequently opposed: small mammal assemblages suggest a huge increase in humidity at the beginning of the Messinian, and a decreasing trend towards the Pliocene, whereas carbon isotopes from rodent teeth suggest moderate humidity conditions during the Messinian. It can be concluded that physical changes in the landscape would affect taxa with high dependence on humid conditions, and they are more likely to record local environmental humidity changes rather than regional or global humidity ones. However, the past reconstructions of temperatures are not biased by this effect, as the general temperature trends deduced from the faunal assemblages as well as those deduced from the isotopic approaches coincide. The general climatic trends reconstructed from isotopic analyses in small mammals teeth agree with the general environmental change in the western Mediterranean region as well as with the global evolution of sea temperatures.
... Terrestrial paleoclimatic reconstructions based on δ 18 O PO4 values have been attempted by many studies (e.g., Longinelli, 1984;Sharp and Cerling, 1998;Tütken et al., 2007;García-Alix et al., 2012). Assuming that similar water sources were ingested by animals of the same species in the same area, then the precipitation of apatite in teeth and bones should have occurred under the same conditions, and there is thus a linear relationship between the δ 18 O values recorded in tooth enamel and those of the meteoric water (δ 18 O H2O ; Longinelli, 1984). ...
... The warmest paleotemperatures during MIS3 were recorded in young sites in the French Jura (Gigny,~33 ka, Fabre et al., 2011;Fig. 5) and in Spain (El Padul, 40-30 cal ka BP, García-Alix et al., 2012;Fig. 5) with MAT of 12 and 10°C, respectively. ...
Fossils of megaherbivores from eight late Pleistocene 14 C-and OSL-dated doline infillings of Ajoie (NW Switzerland) were discovered along the Transjurane highway in the Swiss Jura. Carbon and oxygen analyses of enamel were performed on forty-six teeth of large mammals (Equus germanicus, Mammuthus primigenius, Coelodonta antiquitatis, and Bison priscus), coming from one doline in Boncourt (~80 ka, marine oxygen isotope stage MIS5a) and seven in Courtedoux (51–27 ka, late MIS3), in order to reconstruct the paleoclimatic and paleoenvironmental conditions of the region. Similar enamel δ 13 C values for both periods, ranging from −14.5 to −9.2‰, indicate that the megaherbivores lived in a C 3 plant-dominated environment. Enamel δ 18 O PO4 values range from 10.9 to 16.3‰ with a mean of 13.5 ± 1.0‰ (n = 46). Mean air temperatures (MATs) were inferred using species-specific δ 18 O PO4 –δ 18 O H2O -calibrations for modern mammals and a present-day precipitation δ 18 O H2O -MAT relation for Switzerland. Similar average MATs of 6.6 ± 3.6°C for the deposits dated to ~80 ka and 6.5 ± 3.3°C for those dated to the interval 51–27 ka were estimated. This suggests that these mammals in the Ajoie area lived in mild periods of the late Pleistocene with MATs only about 2.5°C lower than modern-day temperatures.
... On the other hand, where pH is buffered by chemical species other than CO2, the availability of CO2 together with the presence of alkaline earth metals leads to the precipitation of carbonate phases (i.e., mainly calcite and dolomite). This mineral precipitation is common in sedimentary environments such as peat bog with anoxic conditions, which contributes to the preservation of the bones up to the present day [19]. These compositional changes may involve the dissolution and recrystallization of bone tissue or its replacement by other mineral phases characteristic of sedimentary environments [54,56]. ...
Elephants are currently the largest terrestrial mammals, along with their extinct ancestor the mammoth. These species are of great interest due to their geographic distribution and ecological importance. However, the bone mineral characteristics of their skeleton as well as their alteration during burial processes over millions of years have been poorly investigated. In the current research, we analyzed the compositional and structural mineral properties of different types (i.e., long and flat bones) of elephant and mammoth bones. For this purpose, we performed a comparative study between these bone types using complementary analytical techniques based on X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma spectroscopic analysis. The chemical composition of the samples shows a relative loss of a considerable percentage of water and organic matter components for the fossilized bone, accompanied by a higher bone mineralization degree and the presence of other crystalline phases (i.e., calcite and pyrite) related to a certain degree of diagenesis alteration. Our results also show a variation in the crystalline properties of mammoth bone related to the recrystallization process during the dissolution–precipitation transformation through diagenetic burial. This research provides relevant information for understanding the mineral properties of different types of bones and their possible changes during diagenesis.
... These extreme environmental conditions had a direct impact on faunal distribution in the Iberian Peninsula, forcing replacements between different Homo populations (Jiménez-Espejo et al., 2007;Ludwig et al., 2018) and inducing southward migrations of faunal assemblages. This was the case of the southernmost displacement of European woolly mammoths, documented in the Padul wetland during the HS4 and HS3 (southern Iberia) (Álvarez-Lao et al., 2009;García-Alix et al., 2012). This highlights the complex feedbacks this transitional region is experiencing and the direct environmental impacts of these abrupt climate changes. ...
The transitional regions between the low and high latitudes of the Northern Hemisphere are highly vulnerable to future climate change yet most of the current climate models usually diverge in their projections. To better understand the dynamics in these regions, the reconstruction of past hydrological fluctuations and precipitation patterns is of paramount importance to accurately constrain present and future climate scenarios. In this study, we investigated paleohydrological dynamics in the western Mediterranean region, a transitional zone between low-mid latitudes and Atlantic - Mediterranean realms. We reconstruct precipitation and moisture source changes during the last ~35 ka in order to propose the potential mechanisms driving these oscillations. To do so, we use hydrogen isotopes from sedimentary leaf waxes, more specifically the C31 n-alkane homologue, and a precipitation proxy based on previously published pollen data from a sedimentary core (Padul-15-05) in southern Iberia (Padul wetland ~37° N). With this combination we disentangle the coupled effect of precipitation amount and source on the hydrogen isotopic signature of the studied C31 n-alkane record. Our results show three main periods characterized by different precipitation patterns. Low precipitation, mainly linked to a significant contribution from an isotopically-enriched Mediterranean precipitation source, occurred from ~30 to ~15.5 ka BP and during the last ~5 ka, whereas enhanced precipitation with a predominant isotopically-depleted Atlantic precipitation source prevailed from ~15.5 to ~5 ka BP. This latter stage is here defined as the Western Mediterranean Humid Period (WMHP). In addition, some occasional millennial-scale opposite precipitation patterns can be observed during these climatically distinct periods. These changes in the source of precipitation were likely coupled to a shift in the main rainy season from winter, when Atlantic precipitation prevailed, to late winter-early spring, when the contribution of Mediterranean moisture is higher. Comparison between the studied mid-latitude terrestrial Padul-15-05 core and a low-latitude marine record offshore of northwestern Africa shows clear long-term synchronous responses of both western Mediterranean precipitation and western African monsoon systems to northern Hemisphere atmospheric dynamics, ultimately controlled by orbital forcing and ice-sheets fluctuations.
... Alberta also contained similar fauna, including the woolly mammoth, as traditionally defined mammoth steppe regions (Burns, 1991(Burns, , 2010Burns and Young, 1994;Heintzman et al., 2016;Jass et al., 2011;Jass and Barr on-Ortiz, 2017;Kahlke, 2015;Mandryk, 1996). Further, the southernmost woolly mammoth remains in Europe occurred on the Iberian peninsula where mammoths lived during periods of dry, steppe conditions and in association with other mammoth steppe herbivores ( Alvarez-Lao and García, 2011;García-Alix et al., 2012;Kahlke, 2015). Such areas are consistent with current definitions of the mammoth steppe during those times. ...
Woolly mammoth (Mammuthus primigenius), horse (Equus spp.) and bison (Bison spp.) coexisted with a variety of mammalian megafauna across the Pleistocene mammoth steppe – a megacontinental ecosystem that spanned northern Eurasia and northwestern North America. Previous research has suggested that highly conserved niches with minimal niche overlap allowed high levels of species diversity on the mammoth steppe. Here we evaluate previously published and some new collagen carbon and nitrogen isotope data (δ13C, δ15N) for mammoth steppe megaherbivores using Stable Isotope Bayesian Ellipses in R (SIBER) and linear regression models to determine isotopic niches for individual species during broad time intervals (pre-, during and post-Last Glacial Maximum (LGM)) at multiple geographic regions across the mammoth steppe. Individual species maintained relatively consistent isotopic niche positions at different geographic locations and during different times. Diet and habitat niches for any given species appear to have been similar across the mammoth steppe. Between some regions and times, however, species' isotopic niches changed, suggesting adaptation to local climatic conditions and/or changes in the nitrogen isotope patterns at the base of the food web. Isotopic niche overlap, including at the level of core niche overlap (>60% overlap), was observed in at least one time and region for most species. This overlap suggests high levels of functional redundancy in the ecosystem, whereby one species could fulfil another's ecological role in the latter's absence. Despite spatial and temporal environmental variation, species' adaptability and functional redundancy within the ecosystem would have made the mammoth steppe a highly resilient ecosystem.
... Framboidal pyrite (FeS 2 ) and barite (BaSO 4 ) with Sr have been found covering exceptionally preserved mammals remains from 40 to 30 ka at the Padul Peat bog ( García-Alix et al., 2012) pointing towards a peat-bog environment with enhanced anoxic conditions. The presence of pyrite and organic-sulfur compounds is common in peat bogs (Wieder and Lang, 1988;Feijtel et al., 1989;Chapman, 2001) and other organic rich sediments under anoxic conditions ( López-Buendía et al., 2007). ...
... Stable isotope data on Pleistocene Iberian fauna remain scarce when compared to other areas of Europe (e.g.,Bocherens and Drucker, 2003;Stevens and Hedges, 2004;Tütken et al., 2007;Stevens et al., 2008;Drucker et al., 2011;Ecker et al., 2013;Domingo et al., 2015). Some of these isotopic studies on Pleistocene Iberian fauna have considered a single taxon (e.g.,García-Alix et al., 2012;Stevens et al., 2014) or provide information on the ungulates, but lack information about carnivores (Casta~ nos et al., 2014). Studies of multi-taxon fossil assemblages are key to unveil resource and habitat use, and trophic interactions, since each species record their specific stable isotope imprint, ultimately related to their particular lifestyle. ...
The northern coastal area of the Iberian Peninsula shows an excellent archaeo-paleontological record with a unique representation of Pleistocene mammalian fossils. While the Late Pleistocene is better recorded, the Middle Pleistocene record remains more fragmentary. The Punta Lucero site (Biscay) has yielded the most important fossil assemblage of the middle Middle Pleistocene for the northern Iberian Peninsula in both, number of identified specimens and taxonomic diversity. Punta Lucero constitutes a unique opportunity to evaluate Middle Pleistocene mammalian resource and habitat use, and trophic dynamics employing a combined approach: biogeochemical analysis and mathematical modeling. Stable isotope analysis points to resource partitioning between Punta Lucero cervids and bovids. Stable isotope analysis and trophic modeling evidence resource overlap and interspecific competition among predators, especially between the scimitar-toothed cat Homotherium latidens and the European jaguar Panthera gombaszoegensis. The trophic resource availability modeling assumes that Canis mosbachensis consumed a 20% of preys of more than 10 kg, mainly as carrion. Thus, while there would be a taxonomic overlap with those preys consumed by the large felids, the different strategy would have facilitated the coexistence of these canids with larger carnivores. Trophic modeling indicates a high competition among the predator guild. The potential presence of hominins in the area would have reached to an unsustainable situation. However, the potential presence of other prey species, such as Equus sp., would have made the ecosystem more sustainable. The methodology followed in this study highlights the potential of multidisciplinary approaches in the assessment of Pleistocene faunal dynamics.
... It was later analyzed in a XL Thermo Finnigan Mass Spectrometer with a coupled TC/EA device. The details of the protocol are provided by García-Alix et al. (2012). Results were expressed in δ notation, using the standard mean ocean water (SMOW) for oxygen. ...
Fossil gathering by humans has been rarely documented in the Iberian Peninsula. In the present paper, a multidisciplinary approach has been taken to analyze a straight-tusked elephant (Elephas antiquus) molar retrieved in a Magdalenian deposit at the rock shelter of El Pirulejo in southern Spain. The taphonomical analyses revealed a multifarious use of a tooth that had not only been worked into an anvil-sort-of-tool but also used as a core and partly tainted with a composite pigment. The dating and geochemical analyses further evidenced that the molar derived from an animal that had lived in a rather arid landscape with a temperature range between 12.3 and 14.3 °C coincident with a cold episode within marine isotope stage (MIS) 6.6 and probably fed on herbaceous plants. These analyses evidence the potential fossils from archaeological sites bear for addressing a wide range of issues that include both the cultural and paleoenvironmental realms.
... At the same time, subtropical and tropical southern Asia were earlier, more permanently, and more densely colonized by archaic humans [24] and may thus be relatively similar to sub-Saharan Africa, with low late Quaternary extinctions because of either coevolution and/or pre-Late Pleistocene extinctions [28,64]. Such a scenario fits the extinction pattern for Mammuthus primigenius in Eurasia, with a range contraction towards high latitudes despite earlier temperate occurrences [65], and late survival in the high north beyond the range of modern humans, followed by sudden extinction with human arrival to these regions [60,63]. Eurasia experienced the most prolonged extinction during the Late Pleistocene with species lost before and after the LGM [3]. ...
The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial-interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary.
... Marine sediment cores of this age have been studied in the western Mediterranean area and warm and humid conditions were reconstructed (Barcena et al., 2001;Jiménez-Espejo et al., 2008;Rodrigo-Gámiz et al., 2011. However, continental records describing the latest Pleistocene/earliest Holocene climate evolution, although frequent in Northern Iberia, are very rare in the South (Moreno et al., 2010Muñoz Sobrino et al., 2013, and references therein), which is an especially arid and very sensitive area to climate variations (García-Alix et al., 2012a,b, 2013. In this area, the Bølling-Allerød period is only well-recognized in the sequences from El Padul peat-bog (Ortiz et al., 2004) and Alicún travertines (Prado, 2012) and other less detailed records including the cave sequence from the Carihuela cave (Fernández et al., 2007), the site of Navarrés (Carrión and Dupré, 1996;Carrión and van Geel, 1999) and the montane site of Siles (Carrión, 2002). ...
The Bølling–Allerød interstadial is the closest warm time period to the Holocene. The study of the climate variability during this most recent warm scenario provides a natural record of potential environmental changes related with global temperature variations. Little is known about this interstadial in the Southern Iberian Peninsula. Therefore, the exceptional climatic record of the Otiñar paleo-lake (ca. 14.5–14.0 cal ka BP), provides environmental information about the first part of this interstadial (Bølling) in this key region. Although the studied high-resolution isotopic record point to almost invariant hydrological conditions in the paleo-lake, with little change in the carbon budget and important limestone dissolution, the pollen record shows an increase in forest species that can be interpreted as a warming trend and an increase in humidity during the Bølling in the area. This record is one of the few continental archives that show this climatic trend in Southern Iberia, agreeing with many other regional records from the western Mediterranean. This does not agree with higher latitude records that show an opposite trend. This opposite pattern in precipitation between the western Mediterranean and more northern latitudes could be explained by a persistent and increasing negative NAO mode during the Bølling in this area.
... Oxygen of phosphates (δ 18 O p ) was precipitated as Ag 3 PO 4 (O'Neil et al., 1994) and analyzed in a XL Thermo Finnigan Mass Spectrometer with a coupled TC/EA device, following the procedure of Vennemann et al. (2002). For a detailed procedure description consult García-Alix et al. (2012). Results are expressed in δ notation, using the standard SMOW for oxygen. ...
Paleoecology of fossil rodents is frequently inferred from the dental pattern of the teeth, attributing the habitat conditions of extant rodents to fossil species with similar dental pattern. This technique is common practice and has been in use for several decades. A relatively new technique is based on the carbon and oxygen isotope composition of the incisor enamel of fossil rodents to reconstruct paleoenvironmental scenarios. We combine these two methods, studying material from two Early Miocene Spanish sections, one in the Mediterranean coastal area and one in Northcentral inland Spain. Comparison of the humidity values obtained by means of these two proxies reveals discrepancies. Therefore, we analyzed the habitat preferences, especially humidity, of extant rodents and found that dental pattern is not very reliable to reconstruct the humidity preferences of fossil rodents and this kind of interpretation has to be taken with caution. We conclude that the isotopic composition of enamel of fossil teeth is a more reliable proxy in the studied sections.
... The fluctuating environmental conditions during the stadial and interstadials though the MIS 3 and MIS 2 were also accompanied by changes in fauna. In contrast to the southern France and the Cantabrian-Catalonian regions, the south of the Iberian Peninsula was far from the favorite migration route of large mammals (e.g., Finlayson and Carrión, 2007;Álvarez-Lao et al., 2009;García-Alix et al., 2012), nevertheless, after 25.5 cal. kyr BP, cold-adapted mammals spread along the northern Iberian Peninsula García, 2010, 2011). ...
This study utilizes geomorphology, marine sediment data, environmental reconstructions and the Gorham's Cave occupational record during the Middle to Upper Paleolithic transition to illustrate the impacts of climate changes on human population dynamics in the Western Mediterranean. Geomorphologic evolution has been dated and appears to be driven primarily by coastal dune systems, sea-level changes and seismo-tectonic evolution. Continental and marine records are well correlated and used to interpret the Gorham's Cave sequence. Specific focus is given to the three hiatus sections found in Gorham's Cave during Heinrich periods 4, 3 and 2. These time intervals are compared with a wide range of regional geomorphologic, climatic, paleoseismic, faunal and archeological records. Our data compilations indicate that climatic and local geomorphologic changes explain the Homo sapiens spp. occupational hiatuses during Heinrich periods 4 and 3. The last hiatus corresponds to the replacement of Homo neanderthalensis by H. sapiens. Records of dated cave openings, slope breccias and stalactite falls suggest that marked geomorphologic changes, seismic activity and ecological perturbations occurred during the period when Homo replacement took place.
Circular structures made from woolly mammoth bones are found across Ukraine and west Russia, yet the origin of the bones remains uncertain. We present ten new mammoth radiocarbon dates from the largest circular structure at Kostenki 11-Ia, identifying two mammoth mandibles ∼200-1,200 years older than the other dated materials from the site, suggesting skeletal material from long-dead individuals was scavenged and used in the site construction. Biomolecular sexing of 30 individuals showed a predominance of females, suggesting the Kostenki mammoths are primarily from herds. We identify six mitochondrial lineages across 16 samples, showing they are not all from the same matriline. Integrating biomolecular sexing with stable δ ¹³ C and δ ¹⁵ N isotope analysis, we find no isotopically-differentiated resource use by females and males, providing the first analysis of foraging differences between sexes in any Late Pleistocene megafauna. Our study highlights the significance of integrating ancient biomolecular approaches in archaeological inference.
Teaser
Integrating ¹⁴ C dating, ancient DNA, palaeoproteomics, and stable isotopes improves our understanding of Kostenki 11-Ia
Alpine regions of the Mediterranean realm are among the most climatically sensitive areas in the world. Thus, alpine wetlands from the southern Iberian Peninsula, in the westernmost part of the Mediterranean region, are highly sensitive sensors of environmental changes. Difficulties have surfaced in separating controls by temperature and/or precipitation in previous paleoenvironmental studies from alpine environments in this area. We present a Holocene biomarker record (n-alkanes and long-chain diols) from a high elevation lake, Laguna de Río Seco (LdRS), in the south of the Iberian Peninsula, which contributes to the identification of these forcing mechanisms. The hydrological history of the area, primarily water availability and evapotranspiration, is reconstructed by means of the n-alkane record, including the indices of average chain length, portion aquatic, and carbon preference index, as well as hydrogen isotopes (δD) of aquatic (δDaq) and terrestrial (δDwax) n-alkanes. Temperatures are also estimated using the algae derived long-chain diols. We interpret δDaq and δDwax fluctuations as showing changes in the source and amount of precipitation throughout the LdRS record. An Atlantic precipitation source appears to have predominated during the early-middle Holocene, but an occasional Mediterranean influence with an isotopic enrichment in precipitation is detected in the middle-late Holocene that is likely related to the setting of the current atmospheric pattern in southeastern Iberia under the joint control of the North Atlantic Oscillation (NAO) and the Western Mediterranean dynamics, such as the Western Mediterranean Oscillation (WeMO). Our new record from LdRS is consistent with a generalized trend of a humid early-middle Holocene with low temperature variability, evolving towards an arid middle-late Holocene with abrupt temperature changes. In addition to these long-term trends during the last ∼10,500 years, two phases of climate instability, evidenced by abrupt depletions in δDaq, have been identified at the end of these periods, one between ∼6500 and 5500 cal yr BP and another in the last ∼500 years. These episodes would represent strengthened winter cold conditions that favoured the persistence of snowpack and frozen soil in the catchment, causing reduced terrestrial plant growth and low lake evaporation. According to the long-chain diol record, temperatures during these phases were relatively low, but experienced abrupt increases at the end of each period.
Los humedales y turberas de la cuenca de El Padul (provincia de Granada) constituyen un enclave natural singular y único, en el que encuentran cobijo una gran variedad de especies de flora y fauna, algunas de ellas amenazadas o en riesgo de extinción. En esta depresión, los sedimentos llegan a alcanzar un espesor de más de 100 metros y hasta 1 millón de años de antigüedad, lo que permite considerar el registro paleoambiental de El Padul como uno de los más importantes de Europa occidental y de todo el Mediterráneo.
Isotopic analyses of proboscidean remains (e.g., mammoth, mastodon, gompothere, elephant) can provide significant insights into past environmental conditions and animal behaviour. Because they are associated with humans over a broad geographical and temporal scale, proboscidean remains can also be used to understand the activities and environmental contexts of ancient humans. This paper reviews the isotopic literature on proboscideans, including (1) bulk tissue approaches to understanding past climate, vegetation patterns, and migrations, (2) serial sampling approaches to understanding seasonal variations, and (3) direct uses of proboscidean isotopic compositions to investigate human lifeways, including Neandertal and Upper Paleolithic humans in Europe and Paleoindian/Clovis people in North America.
Studies using measurements of deltaN-15 to delineate diet or trophic level in natural ecosystems are based on the premise that deltaN-15 values in consumer tissues can be reliably correlated with those in the diet. However, juvenile Japanese Quail (Coturnix japonica) fed a rationed diet designed to maintain, but not increase, body mass showed significantly enriched tissue deltaN-15 values over a control group fed the same diet ad libitum. We tested the hypothesis that fasting or nutritional stress can also cause elevated deltaN-15 values in tissues of wild birds by examining tissues of Arctic-nesting female Ross' Geese (Chen rossii) before and after their period of fasting during egg laying and incubation. Significant declines in body, pectoral muscle, liver and abdominal fat mass occurred from arrival through incubation. Post-incubating geese showed significantly higher pectoral muscle and liver deltaN-15 values compared to geese taken before clutch initiation but deltaC-13 values in these tissues were unchanged. We hypothesize a mechanism of tissue deltaN-15 enrichment due to reduced nutrient intake and discuss the implications of these results to ecosystem studies using stable-nitrogen isotope analysis.
This text focuses on the principles and methods of using growth layers formed in teeth and bones of mammals to make a judgement on essential traits of the animal's life history. In nearly all mammalian species, including man, the age of individuals can be determined from the number of growth layers and, at least in some of them, it is possible to estimate the season of an animal's birth and death, age of sexual maturation, periodicity of reproduction, certain feeding habits and other aspects of the individual's biology. It is also possible, from tooth-enamel analysis, to assess doses of radiation accumulated by animals and human beings during their lifetime.;This book is intended for zoologists, wild-game biologists and zoo archaeologists, but some of the sections could also be of interest for anthropologists, radioecologists and conservation biologists.
Mammoth evolution in Eurasia represents one of the best-studied examples of evolutionary pattern and process in the terrestrial fossil record. A pervasive belief in the gradual transformation of chronospecies in Europe is giving way to a more complex model incorporating geographical variation across the whole of northern Eurasia. This in turn casts doubt on biostratigraphic deductions which assume gradual transformation of molar morphology, simultaneous across the species’ range. The earliest European elephantids, Mammuthus rumanus, occur in the interval 3.5–2.5 Ma, and are distinctly more primitive than the better-known M. meridionalis. The species ‘M. gromovi’, identified in the interval c. 2.6–2.2 Ma, appears to be a junior synonym of M. meridionalis. M. meridionalis dispersed widely and, in the interval 2.0–1.5 Ma, gave rise to M. trogontherii in eastern Asia, probably in China, spreading to NE Siberia by 1.2 Ma. Between that date and c. 600 ka, flow of genes and/or individuals westwards produced an interaction with European M. meridionalis which led to a network of populations in time and space and the eventual supplanting of that species by M. trogontherii. This conclusion is based principally on the earlier appearance of M. trogontherii morphology in eastern Asia, supplemented by complex morphological patterns in Europe during the time of transition. Subsequently, M. trogontherii did not undergo a gradual transformation into M. primigenius (woolly mammoth) in Europe, but remained in stasis (apart from size reduction) until 200 ka. In NE Siberia, however, M. trogontherii began a transformation into primitive M. primigenius morphology as early as 700 ka, and that species continued its evolution in the same region through the Middle and Late Pleistocene. The incursion of M. primigenius into Europe appears to have occurred soon after 200 ka, and its ‘replacement’ of M. trogontherii there probably included some introgression from the latter species.
The Late Quaternary, and more particularly the Last Glacial (Marine Isotope Stages 4, 3 and 2, defined here as 73,500–14,700 calendar years, 73.5–14.7 ka; ka is used solely for calendar years and kyr BP refers to 14 C ages), was characterised by millennial-scale climate oscillations of irregular periodicity. The onset of these oscilla-tions was abrupt, with most of the change in climate accomplished within 10–200 years (Steffensen et al., 2008) and the magnitude of the change was large (of the order of 8–15 C in Greenland) (Huber et al., 2006). Two types of rapid climate changes have been described: Dansgaard–Oeschger (D-O) cycles (Dansgaard et al.,1984), associated with abrupt warming and subsequent cooling in Greenland, and cold phases associated with the formation of ice-rafted debris (IRD) deposits (Heinrich layers) (Heinrich, 1988) in the North Atlantic. Dansgaard–Oeschger cycles are clearly registered in the Greenland ice-core record (e.g. Johnsen et al., 1992; North GRIP Members, 2004) and the traces of both of these climate oscillations are recorded in a variety of marine and terrestrial records worldwide (e.g. Bond et al., 1993; Allen et al., 1999; Wang et al., 2001; Gonzalez et al., 2008). The geographic pattern of registration of individual oscillations (Sanchez Goñ i et al., 2008), and the magnitude, nature and length of the component phases of each recorded oscillation, appear to vary (Johnsen et al., 1992). However, documentation of regional changes has been hampered by problems of the synchronisation of individual chronologies, and our understanding of the mechanisms underlying these climate oscillations is still far from complete. Analysis of the mechanisms and impacts of large and rapid climate changes in the past is given additional impetus by the possibility that such events might occur in the future. Although the precise causes are different, investigation of the impact of the warming events at the beginning of D-O cycles or of iceberg melting during Heinrich intervals on the Meridional Overturning Circula-tion (MOC) in the North Atlantic speaks directly to the impact of future changes in the MOC on regional climate. Coupled ocean– atmosphere model simulations show a reduction of the MOC during the 21st century, in some cases by up to 50%, as a conse-quence of greenhouse-gas-induced polar warming (Gregory et al., 2005). Simulations with simpler climate models have shown that complete shutdown of the MOC can occur if the slowdown reaches a crucial threshold (which differs in different models) (Stocker and Schmittner, 1997; Stouffer and Manabe, 2003; Stouffer et al., 2006). Clearly, the coupled models do not reach the critical threshold as a result of the gradual change in greenhouse-gas forcing during the 21st century but might do so if the additional forcing due to even partial melting of the Greenland ice sheet were taken into account. There have been several recent attempts to synthesise millen-nial-scale climate change during the glacial (e.g. Broecker and Hemming, 2001; Alley et al., 2002; van Andel, 2002; Voelker, 2002), but most focus on marine and ice-core records. In this issue, we focus on documenting regional changes in vegetation indicated by pollen records from both marine and terrestrial cores (Fletcher et al., in this issue; Takahara et al., in this issue; Jimé nez-Moreno et al., in this issue; Heßler et al., in this issue). There are multiple reasons why this is timely. First, there has been a very rapid increase during the last decade in the number of pollen records with high temporal resolution. However, there is no global compi-lation of the pollen data, nor a synthesis of vegetation reconstruc-tions based on these data. Second, the development of a new and coherent ice-core reference chronology (GICC05: Svensson et al., 2006, 2008; see also Wolff et al., in this issue) makes it possible to achieve a better synchronisation between documented changes in Greenland and the pollen records. Third, a regional synthesis of charcoal records from North America (Marlon et al., 2009) shows that fire regimes respond to abrupt climate changes during the last deglaciation – but little is known about the response of fire globally to millennial-scale climate variability and associated vege-tation changes during earlier intervals (Daniau et al., in this issue). Fourth, investigation of the impact of changes in vegetation cover, including wetland extent, and in fire regimes is important for understanding the rapid and extremely large (up to ca 200 ppb) changes in methane during D-O cycles (Blunier and Brook, 2001; Flü ckiger et al., 2004) and the potential climate feedback. Finally, modelling groups have recently begun to explore the impact of, e.g., changes in freshwater forcing under glacial conditions on regional climates (e.g. Crucifix et al., 2001; Ganopolski and Rahm-storf, 2001; Claussen et al., 2003; Knutti et al., 2004; Flü ckiger et al., 2006, 2008; see also Kageyama et al., in this issue) but more detailed documentation of observed changes is required for the evaluation of these experiments. A multiplicity of terms is used in discussing rapid climate changes and millennial-scale climate variability during the glacial, and this has led to some confusion particularly in relating records from different regions. Alley et al. (2002), in a definition adopted by the IPCC (Meehl et al., 2007), define abrupt climate change as one that takes place more rapidly than the underlying forcing, pointing out that this kind of behaviour can only occur when the climate system crosses a critical threshold defining the limit between two different climate states. This definition provides a theoretical basis for understanding abrupt climate changes (e.g. Kageyama et al., in this issue) but the rapidity of the climate change
Variations in the strontium isotope ratio (87Sr/86Sr) of tooth enamel are used to examine the migration patterns of late Pleistocene mammoths and mastodons from Florida. An animal's 87Sr/86Sr ratio tracks the ratios of its environment, which vary with differences in bedrock and soil. Consequently, the environmentally controlled differences in 87Sr/86Sr ratio recorded in mineralized tissue, such as tooth enamel, may be used to reconstruct the movement patterns of an individual. We map variations in local 87Sr/86Sr ratios across modern Florida and Georgia through analysis of rodent teeth, plants, and surface water, then use this map to interpret the movement patterns of extinct mammals. Mastodons from northern and central Florida have higher 87Sr/86Sr ratios than both modern environmental samples from Florida and fossils from nonmigratory species, suggesting that mastodons migrated north into Georgia. Mammoths display ratios similar to those of environmental samples and resident species, suggesting that they did not migrate outside Florida.
The sensitivity to temperature of Mg/Ca ratios in the shallow-infaunal benthic foraminifera Uvigerina spp. has been assessed. Core-top calibrations over ∼1–20°C show a range in sensitivity of 0.065–0.084mmol/mol/°C but few data are available spanning the temperature range anticipated in deep-sea records over glacial–interglacial cycles. In contrast to epibenthic foraminiferal species, carbonate ion saturation appears not to affect Mg/Ca significantly. A method based on estimating the ratio of the temperature sensitivity of foraminiferal Mg/Ca to that of δ18Ocalcite shows that sensitivity for Mg/Ca at the high end of the observed core-top range (∼0.1mmol/mol/°C) is required for consistency with LGM–Holocene differences in each property as constrained by independent proxy data. This is supported by a Mg/Ca record for Uvigerina spp. generated for the Southern Ocean over the past 440,000 years from Ocean Drilling Program Site 1123 (Chatham Rise, New Zealand). The record shows variability that correlates with climate oscillations. The LGM deep ocean temperature derived from the Mg/Ca record is −1.1±0.3°C. Transformation to temperature allows estimates to be made of changes in bottom water temperature and seawater δ18O and comparison made with literature records. Analysis reveals a ∼2.5-kyr lead in the record of temperature over calcite δ18O and a longer lead over seawater δ18O. This is a reflection of larger phase offsets at eccentricity periods; phase offsets at tilt and precession are within error zero.
High-resolution clay mineralogical analyses were performed on sediment deposited during the last 50,000yr in the Alboran sea (ODP Site 976). The clay mineral record is compared with pollen assemblages and with annual precipitation (Pann) and mean temperatures of the coldest month (MTCO) reconstructed with the modern analog technique (MAT). Enhanced contribution of palygorskite, a typical wind-blown clay mineral, characterizes the North Atlantic cold climatic events. Coeval development of the semi-arid vegetation (Artemisia rich) associated with a drastic fall of reconstructed precipitations and temperatures, suggest cold and arid continental conditions in the West Mediterranean area during North Atlantic cold events. The clay mineral association, especially the palygorskite content and the illite-to-kaolinite ratio, indicate western Morocco as one of the major source of the clay-size fraction during the North Atlantic cold events. The maximum abundance of Artemisia associated with the presence of Argania pollen both indicate Morocco as the main origin for pollen during these cold periods. The comparison of these pollen and clay mineral-specific features allows us to pinpoint western Morocco as the dominant source of wind-blown particles during North Atlantic cold events. These specific mineralogical composition and palynological assemblages reveal enhanced aridity over North Africa and intensification of winds favouring dust erosion and transport from North Africa toward the Alboran Sea during the North Atlantic cold events. According to atmospheric models, such a meridian transport (1) likely results from the development of strong and stable anticyclonic conditions over the tropical Atlantic and North Africa, similar to today's summer meteorological configuration and (2) implies a northward position of the westerly winds during North Atlantic cold events. Finally the synoptic situation over the West Mediterranean during the North Atlantic cold events is compared with the North Atlantic Oscillation (NAO), suggesting that during the cold Atlantic events, weather regimes over Europe and North Africa may have been systematically shifted towards a positive NAO situation.
Multiproxy paleoenvironmental records (pollen and planktonic isotope) from Ocean Drilling Program Site 976 (Alboran Sea) document rapid ocean and climate variations during the last glacial that follow the Dansgaard-Oeschger climate oscillations seen in the Greenland ice core records, thus suggesting a close link of the Mediterranean climate swings with North Atlantic climates. Continental conditions rapidly oscillated through cold-arid and warm-wet conditions in the course of stadial-interstadial climate jumps. At
the time of Heinrich events, i.e., maximum meltwater flux to the North Atlantic, western Mediterranean marine microflora and microfauna show rapid cooling correlated with increasing continental dryness. Enhanced aridity conceivably points to prolonged winter time stability of atmospheric high-pressure systems over the southwestern Mediterranean in conjunction with cooling of the North Atlantic.
The n-alkane components of sediments were measured in 530 samples taken from a 107m-long core in the Padul Basin (Andalusia, Spain) covering from the Lower Pleistocene (ca. 1Ma) to the mid-Holocene (ca. 4.5kaB.P.). We show that the relative percentages of the high molecular weight n-alkanes (C27, C29 and C31) are useful tools to reconstruct the ancient vegetation and palaeoclimatological evolution of this basin. On the basis of these proxies, we distinguished twelve long-term climatic periods linked to alternating dry/humid scenarios: 6 Dry Episodes alternating with 5 Humid Episodes were interpreted in the Pleistocene record, together with a final Episode covering the Holocene. Dry scenarios produced the recession of forests and the development of grasses, whereas the inverse pattern was interpreted during humid phases. The good correlation with the Guadix-Baza Basin record showed that, in most cases, dry periods coexisted with warm conditions, while humid ones were linked to temperate-colder conditions. Only during the last long-term Dry Episode of the Pleistocene, which coincided with the end of the Last Glacial Period, did low temperatures concur. The relative percentages of the high molecular weight n-alkanes also indicate rapid changes in vegetation produced by short-scale arid cycles during the last Glacial Period (
A detailed stable-isotope record is presented for the full length of the Greenland Ice-core Project Summit ice core covering the last 250,000 years according to a graduated timescale. It appears that the climatic stability of the Holocene is the exception rather than the rule; the last interglacial is also noted to have lasted longer than is implied by the deep-sea SPECMAP record. This discrepancy may be accounted for if the climate instability at the outset of the last interglacial delayed the melting of the Saalean ice sheets in America and Eurasia.
Isotopic biogeochemistry ( ¹³ C, ¹⁵ N) of fossil collagen is nowadays currently used to infer extinct animals and prehistoric man diet, and a wide developement of this technic is expected in the near future. In prehistoric specimens, only parts of bones and teeth are usually available and we have to be sure that isotopic values from any part of a single skeleton do not differ significantly before comparing isotopic values from different specimens.
Isotopic investigations on recent lower jaws from several mammal species show that δ ¹³ C values do not differ significantly between bone and teeth collagen but that δ ¹⁵ N values present an enrichment (up to 2–3 ±) in teeth collagen compared to bone in species with teeth that stop growing (reindeer Rangifer tarandus , sheep Ovis aries , bear Ursus americanus , wolf Canis lupus ). On the contrary, species with continuously growing teeth (horse Equus caballus ) present almost identical δ ¹³ C and δ ¹⁵ N values in bone and teeth collagen. Such δ ¹⁵ N values variations are very probably linked to teeth replacement chronology and time of weaning in the different species and for each tooth. Species with continuously growing teeth show similar evolution of isotopic variations in teeth and bone collagen during their lifetime.
Quaternary mammals almost 45 000 years old from France present a similar variation pattern for isotopic values in bone and teeth collagen. Cave bears ( Ursus spelaeus ) from Aldene and Mialet caves present slightly more negative δ ¹³ C values (-0.3 to -1.1 ±) and significantly more positive δ ¹⁵ N values (1.5 to 2.2 ±) in teeth than bone collagen from same fossil individuals. On the site as a whole, collagen δ ¹³ C values for definitive teeth are on average 0.7 and 1.1 ± more negative than for bone and δ ¹⁵ N values for definitive teeth are on average 3.1 and 1.9 ± heavier than for bone in Aldene and Mialet caves respectively. In Aldene cave, collagen δ ¹³ C values for deciduous teeth are on average 1.5 ± more negative than for bone and collagen δ ¹⁵ N values for deciduous teeth are on average 4.4 ± heavier than for bone. In Marillac, reindeers ( Rangifer tarandus ) present collagen δ ¹³ C values for definitive teeth almost identical than for bone and collagen δ ¹⁵ N values for definitive teeth are on average 1.8 ± heavier than for bone. On the contrary, there is no significant difference between δ ¹³ C and δ ¹⁵ N values from horses ( Equus caballus ) bone and teeth collagen, for a single individual as well as on average of several specimens.
δ ¹³ C and δ ¹⁵ N values seem to be equivalent between teeth and bone collagen only for species where teeth grow continously during the whole lifetime. In species where teeth stop growing in adult life, teeth collagen δ ¹⁵ N values seem to be significatly enriched in comparison with bone collagen δ ¹⁵ N values (1 to 3 ±), probably because of an ¹⁵ N-enriched diet (milk) during the first stages of growing and no subsequent renewal of teeth collagen. The enrichment seems to be even more important for deciduous teeth.
Further investigations on recent mammals teeth and bones are thus urged to obtain a more accurate estimate of intra-individual isotopic variations according to individual age in the most studied species, including man.
Teeth of mammals including man, are common finds on archaeological sites, and scientific study yields remarkable information about the animals themselves and about the health, hygiene and diet of ancient communities. This book draws together a mass of information on dental studies in archaeology and related disciplines and provides descriptions and specially designed line-drawings to assist the identification of teeth from 150 different genera. -from Publisher
The isotopic ratios of common light elements often provide useful information about past geologic, environmental, or biologic history. Bender’s (1968) clear identification of two distinct isotopic values for carbon from C3 and C4 plant organic matter led to the experiments which showed that animal δ13C values were closely related to dietary values (DeNiro and Epstein 1978a; Tieszen et al. 1983). Results from field applications (DeNiro and Epstein 1978b; Vogel 1978; Tieszen et al. 1979; Tieszen and Imbamba 1980) established the usefulness of these tracers and soon led to numerous archaeological studies. C and N, both present in bone collagen, have been most useful to suggest marine versus terrestrial dependence, to establish maize utilization or dependence on legumes, and to identify relative trophic-level positions or carnivory versus herbivory. Recently, attention has been focused on the use of bioapatite CO3 (Lee-Thorp et al. 1989a, 1989b; Lee-Thorp and van der Merwe 1991) as a supplement to collagen, especially in bones older than 10000 years, and as an adjunct to collagen for estimates of carnivory. The 180 signal in bioapatite also has the potential to provide information on the water status of the individual or the environment. Sulfur isotopes δ
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S), when present in sufficient quantities, as in hair or skin, are also useful and in some cases can distinguish clearly between marine and terrestrial dietary sources (Krouse and Herbert 1988).
The new method requires only a simple vacuum extraction line and a high-temperature furnace. It is much quicker, safer, and less expensive than the conventional fluorination method. The phosphate radical is isolated as Ag3PO4 without employing separate purification steps. A key aspect of the method is that Ag3PO4, when heated to temperatures above 1000°C, liberates O2 in 25% yield. -Authors
The use of stable carbon isotopes for diet reconstruction is predicated on the assumption that you are what you eat. In other words, the carbon isotopic composition of animal tissues is assumed to be a direct and constant function of the diet. Is this assumption valid? Precise dietary reconstruction requires as accurate knowledge of the isotopic composition of locally available dietary resources, as well as an adequate understanding of the effects of nutrition, environment, and physiology on the diet-tissue function (van der Merwe 1982, 1989; Chisholm 1989; Norr 1990; Matson and Chisholm 1991; Tieszen 1991; Ambrose 1992). There is a systematic but poorly defined difference between the isotopic composition of the consumer tissues and that of the diet (an enrichment factor, expressed as Δ diet-tissue). Given the isotopic composition of a specific tissue, that of the diet or of other tissues may be calculated if the Δ diet-tissue difference factors are known. The dietary proportions of isotopically distinct food resources (e.g., C3 vs C4, or C3 vs marine) have thus been calculated from the δ
13C value of bone collagen (Δ13Cd-co) and bone apatite carbonate (Δ13Cd-ca). Deviations from actual or assumed average δ
13C values for dietary endmembers, and incorrect values for diet-to-tissue isotopic relationships, will lead to errors in the estimation of consumption of specific classes of resources. Experiments and observations designed to determine the diet-to-collagen stable isotope functions (Δ13Cd-co) however, have provided widely different values.
Dietary evaluation using isotopic analyses of carbon in collagen from bone is an exciting new area of archaeological chemistry. Analyses of bone from herbivores, carnivores, and omnivores (including humans) suggest that a simple isotopic fractionation between dietary carbon and carbon in bone collagen may be an inadequate model for interpretation of results. Dietary carbohydrates are primarily metabolized for energy and their carbon is reflected mainly in the hydroxyapatite of bone. Dietary lipids are also important energy components of the diet. Dietary proteins, on the other hand, are utilized for protein (e.g. bone collagen) synthesis as needed and only excess amino acids are metabolized for energy. Herbivores, carnivores, and omnivores thus might have different isotopic fractionation models, each of which is presented. Biochemical evidence in support of these models is discussed.
Plants metabolize carbon dioxide photosynthetically either through a 3-carbon (Calvin) or 4-carbon pathway. Most plants are of the C-3 type; C-4 plants are primarily grasses adapted to hot, arid environments. Since C-4 plants have a higher 13C/12C ratio than C-3 plants, animals and humans with a significant C-4 plant food-intake will have higher 13C/12C ratios as well. Maize is a C-4 plant, hence maize cultivators living in predominantly C-3 plant environments should show significant isotopic differences from local hunter-gatherers in their skeletal remains; the importance of maize in their diet should also be measurable. The practicability of this method is demonstrated for New York State archaeological materials and wider implications are mentioned.
The most puzzling feature of the mammoth steppe is its great diversity of large mammals. The reasons for their diversity, their dietary specializations and their gigantism are examined here, in conjunction with other information, as clues to an investigation of the general paleoenvironment.
The mammalian evidence suggests a specific vegetational mosaic with certain seasonal characteristics. Mammalian growth patterns indicate a long growing season, requiring diets high in available energy and nutrients. These features would require a seasonally rich Pleistocene vegetation in comparatively fertile soil that utilizes antiherbivory defenses quite different from those used by the dominant plant forms now present in the North.
The annual seasonal cycle reconstructed here is characterized by cold, but perhaps variable, winters with very little snowfall. Most of the annual moisture would have fallen during spring and little to none during summer. Summer soils generally were warm, dry, and had a deep thaw. This intraannual variability in the growth season produced hydric, mesic, and xeric plants within the same local communities. Windy conditions were most common.
A new model is presented to explain the high species diversity of Pleistocene mammals, their large social organs and gigantism, as well as the converse: Holocene dwarfing, shrinking social organs, range contractions and extinction with the demise of the mammoth steppe.
The influence of diet on the distribution of carbon isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant carbon isotopic composition. The isotopic composition of the whole body of an animal reflects the isotopic composition of its diet, but the animal is on average enriched in delta/sup 13/C by about 1/sup 0///sub 00/ relative to the diet. In three of the four cases examined, the /sup 13/C enrichment of the whole body relative to the diet is balanced by a /sup 13/C depletion of the respired CO/sub 2/. The isotopic relationships between the whole bodies of animals and their diets are similar for different species raised on the same diet and for the same species raised on different diets. However, the delta /sup 13/C values of whole bodies of individuals of a species raised on the same diet may differ by up to 2/sup 0///sub 00/. The relationship between the /sup 13/C//sup 12/C ratio of a tissue and the /sup 13/C//sup 12/C ratio of the diet depends both on the type of tissue and on the nature of the diet. Many of the isotopic relationships among the major biochemical fractions, namely the lipid, carbohydrate, and protein fractions, are qualitatively preserved as diet carbon is incorporated into the animal. However, the difference between the delta/sup 13/C values of a biochemical fraction in an animal and in its diet may be as large as 3/sup 0///sub 00/. The delta /sup 13/C values of the biochemical components collagen, chitin, and the insoluble organic fraction of shells, all of which are often preserved in fossil material, are related to the isotopic composition of the diet. These results indicate that it will be possible to perform dietary analysis based on the determination of the /sup 13/C//sup 12/C ratio of animal carbon. Analysis of the total animal carbon will in most cases provide a better measure of diet than the analysis of individual tissues, biochemical fractions, or biochemical components.
The record of oxygen isotopic variations in foraminifer shells from deep-sea cores preserves a continuous record of ice volume and sea level oscillations. To extract the ice volume record, however, it is necessary to remove the temperature and local hydrological influence on δ18O. We employ the strategy of estimating calcification temperatures from Mg/Ca and removing this signal from an observed δ18O record of planktonic foraminifera from a core on the Cocos Ridge, eastern equatorial Pacific. The residual, δ18Owater, reveals a pattern of changes that appears to be consistent with known ice volume and sea level variations. Over the last four glacial terminations, δ18Owater decreases by 1.2±0.1‰. The magnitude of high stands appears to be consistent with modern sea level during MIS 5.5 (5e), 7.1 and 7.5 but somewhat lower during MIS 9.1. The magnitude of low stands is similar (∼-120m) for MIS 2.2 (LGM), 6.2, 8.2 and 10.2. The Cocos Ridge record also shows a period of intermediate sea level (∼−30m) during MIS 6.5. At present it is not possible to validate these estimates for those periods of time in which coral reef based estimates of sea level are unavailable.
The quality of bone collagen extracts is central to the14C dating and isotope palaeodietary analysis of bone. The intactness and purity of the extracted gelatin (“collagen”) is strongly dependent on the extent of diagenetic degradation, contamination and the type of extraction method. Possible chemical, elemental and isotopic parameters for the assessment of “collagen” quality are discussed. The most important distinction that can be made is the one between contaminated bone (mostly from temperate zones), and bone low in collagen content (mostly from arid and tropical zones). The latter shows more variability in all quality parameters than the former. The natural level of contamination is mostly so low that stable isotopic measurements are not impaired, although14C measurements can be. It is concluded that there is no unequivocal way to detect natural levels of contamination with the discussed parameters, although their use can identify many cases. In low “collagen” bone, the parameters can identify the great majority of problematic samples: although deviations in these parameters do not necessarily mean isotopic alterations, the increased background found in these samples makes most samples unusable.
Nineteen Late Pleistocene samples of fossil mammoth and four of horse and bison from the Leptev Sea area were studied for their C, N and O stable isotope composition. The majority of the samples have interstadial (MIS 3) ages and only two have late-glacial ages. The carbon and nitrogen isotope values are in good agreement with those previously measured on other mammoths from the same area. They seem to indicate, for the interstadial period, a stability of the climate conditions characterised by low and constant rainfall with only few oscillations. Only after the LGM are more humid conditions apparent.The calculated oxygen isotope composition of water are several per mill more positive than those of modern meteoric water in the area. They do not seem to correlate with well-established Late Pleistocene temperature changes but rather with aridity. The temporal pattern indicates a rapid increase of dry conditions after around 34ka BP. Only the two samples dated after the LGM might indicate an effective increase in temperature.
Isotopic strontium composition of several bones, for which 14C data are available, retrieved from latest Pleistocene deposits of the Yakutian region has been analysed. Three different groups have been detected, corresponding to samples from great maritime (Yana-Indigirka interfluve, Kolymian lowland) lowlands covered by thick Pleistocene sediments, from areas where Palaeozoic and Precambrian complex and Mesozoic granites crop out, and from Arctic coasts and Siberian Islands. Preliminary results highlight the difficulty in discriminating among resident, temporary migrant or long-distance newcomers if the sampling is not consistent. Taking into account global changes of sea level, the Laptev Sea shelf was mainly drained during the sea level lowering in the Late Pleistocene. Herbivores, and especially mammoths, did not utilise this shelf pastures. Therefore, the results pose several questions: what is the reason for herbivores not visiting the shelf? Was the shelf occupied by other mammal populations whose remains lie on the sea bottom? Was the territory too boggy for large animals? Why did mammals prefer vegetation from inland over shelf landscapes? The ongoing research might clarify some issues.
Seventy-seven specimens of fossil (Upper Pleistocene–Early Holocene) woolly mammoth, reindeer, deer and bison from 17 different locations in Eurasia have been measured for the nitrogen and carbon stable isotope composition of their collagen and for the carbon stable isotope composition of bioapatite. The aim was: (1) to check the existence of differences in N and C isotope ratios between and within different herbivore species (mainly between mammoth and reindeer); (2) to discuss these data in terms of animal physiology, temporal and spatial distribution of animals and effects of climatic changes; and (3) to obtain further information about the environmental changes that occurred in that area during the period considered.A geographical variation from south-west to north-east in the δ15N and/or δ13C values of collagen and bioapatite for all the herbivore species is apparent, the most negative δ13C values and the most positive δ15N values being located in the north-eastern area. This was probably due to a different temperature and water stress on animals and plants and to a different plant availability.The differences in 13C/12C and 15N/14N isotope ratios among species are mainly related to different food intake and different metabolic pathways. It seems also that the diet of mammoths from north-eastern Siberia was higher in protein content compared with that of mammoths from the Russian Plain.From this study, it is clear that there was a rapid and important change in the amount of precipitation soon after the last glacial maximum; the rainfall conditions around 40000 and 30000yearsBP were probably similar to those existing around 10000yearsBP, though lower than those existing after the glacial maximum.
The carbon isotope composition (δ13C) of tooth enamel of woolly mammoth molars from Estonia, Latvia, Lithuania, Denmark and southern Poland was analysed and the data were complemented with previously published δ13C values from Sweden, Finland and northwestern Russia, Switzerland and Britain. The δ13C values display a NE- to SW-trending geographical pattern, with more depleted compositions in the northeast, suggesting differences in the diet consumed by mammoths in the northeastern parts of the study area relative to mammoths in the southwesterly regions. While the pattern is probably a reflection of a number of controlling environmental parameters, with possible additional contribution from physiological factors, statistically significant correlations of the δ13C values to δ18O data from the same specimens and to palaeotemperature estimates imply a strong influence of climate over the δ13C values. The δ13C data do not provide convincing evidence of any temporal changes in diet.
The Siwalik Sequence of northern Pakistan contains a 16-Ma record of paleosol carbonate and fossil teeth from which a record of paleovegetation can potentially be reconstructed and compared. The carbon isotopic composition of paleosol carbonate and organic matter from Siwalik strata reflects a major paleoecological change on the floodplains of major rivers beginning ∼ 7.3 Ma ago. By 6 Ma C3-dominated plant communities, probably composed of mostly trees and shrubs, were displaced by nearly continuous C4 grassland. We find that the carbon isotopic ratios in herbivore tooth enamel reflect this dramatic ecologic shift. Carbonate in enamel older than 7 Ma averages −11‰ in δ13CPDB, consistent with a largely C3 diet. Enamel from the Plio-Pleistocene averages +1.9‰ in δ13C, similar to the value displayed by modern C4 grazers. Analysis of post-burial carbonate cements, and the concordance with isotopic evidence from paleosols argues strongly against major isotopic alteration of the enamel, while coexisting bone may have been altered early in burial. This study confirms that enamel apatite is useful for paleodietary reconstruction much further back in the geologic record than was previously thought.
TheC/Nratio and amino acid composition of organic matter extracted from fossil mammal bones from the Paleolithic site at Marillac (Charentes, France) shown that this organic matter comes from collagen.δ13Candδ15Nvalues of known-diet fossil species demonstrate that these values have been preserved through fossilization processes, and that these fossil mammals can be used as ecological references to determine the Neandertal position in the past food web. Initial Neandertalδ13Candδ15N values suggest that he was mostly carnivorous.RésuméLes rapportsC/N et le spectre d'accides amine´s de la matie`re organique extraite des ossements de mammife`res fossiles du site de Marillac (Charentes, France) montrent que cette matie`re organique provient du collage`ne. Les valeurs deδ13Cet deδ15N de mammaife`res fossiles dont le re´gime alimentaire est connu de´montrent que ces valeurs n'ont pase´te´alte´re´es par la fossilisation et donc ces mammifr`es fossiles peuvent servir de standardse´cologiques pour replacer l'Homme de Ne´anderthal dans son re´seau trophique. Les premie`res valeurs deδ13C et deδ15N mesure´es pour cet homme sugge`rent qu'ile´tait essentiellement carnivore.
This book highlights new and emerging uses of stable isotope analysis in a variety of ecological disciplines. While the use of natural abundance isotopes in ecological research is now relatively standard, new techniques and ways of interpreting patterns are developing rapidly. The second edition of this book provides a thorough, up-to-date examination of these methods of research. As part of the Ecological Methods and Concepts series which provides the latest information on experimental techniques in ecology, this book looks at a wide range of techniques that use natural abundance isotopes to: Follow whole ecosystem element cycling understand processes of soil organic matter formation follow the movement of water in whole watersheds understand the effects of pollution in both terrestrial and aquatic environments study extreme systems such as hydrothermal vents follow migrating organisms. In each case, the book explains the background to the methodology, looks at the underlying principles and assumptions, and outlines the potential limitations and pitfalls. Stable Isotopes in Ecology and Environmental Science is an ideal resource for both ecologists who are new to isotopic analysis, and more experienced isotope ecologists interested in innovative techniques and pioneering new uses.
We used analyses of the strontium isotope (87Sr/86Sr) ratios of tooth enamel to reconstruct the migration patterns of fossil mammals collected along the Aucilla River in northern Florida. Specimens date to the late-glacial period and before the last glacial maximum (pre-LGM). Deer and tapir displayed low 87Sr/86Sr ratios that were similar to the ratios of Florida environments, which suggest that these taxa did not migrate long distance outside of the Florida region. Mastodons, mammoths, and equids all displayed a wide range of 87Sr/86Sr ratios. Some individuals in each taxon displayed low 87Sr/86Sr ratios that suggest they ranged locally, while other animals had high 87Sr/86Sr ratios that suggest they migrated long distances (>150 km) outside of the Florida region. Mastodons were the only taxa from this region that provided enough well-dated specimens to compare changes in migration patterns over time. Pre-LGM mastodons displayed significantly lower 87Sr/86Sr ratios than late-glacial mastodons, which suggests that late-glacial mastodons from Florida migrated longer distances than their earlier counterparts. This change in movement patterns reflects temporal changes in regional vegetation patterns.
Composite monthly samples of atmospheric precipitation were collected over different periods of time ranging from one to seven years at 77 different locations throughout Italy. These samples were measured for their oxygen and hydrogen isotopic composition to obtain basic information for hydrological and meteorological studies in this area. On the basis of the results obtained a first map of the isotopic composition of precipitations in Italy has been drawn up. The main features of this map are the following: (1) no isotopic latitudinal gradient has been found along the Tyrrhenian coast from Sicily to the Italian–French border, despite the considerable range of latitude; (2) a minor latitudinal gradient is found in the southeasternmost section of the country (Apulia), partially favored by the local morphology; (3) a marked ‘shadow effect’ of the Apennines is apparent along the southern section of the Po valley and along the central section of the Adriatic coast; (4) the contribution of water vapor from the northernmost section of the Adriatic sea affects the eastern and central sections of the Po plain; (5) the shadow effect of the Alps is considerably smaller than expected; (6) the isotopic vertical gradients calculated in nine different areas and based on groups of two to five different stations vary but are essentially close to about −0.2‰/100m; (7) when mean monthly temperature values were available, their relationship with the isotopic composition of precipitation was found to be, on average, very poor; (8) the relationship between mean δ18O and mean δD calculated for the collection locations shows shifts of both the slope and the deuterium excess when compared to the global meteoric water line. These shifts are different for northern, central, and southern Italy; (9) in a few cases anomalously low monthly δ values suggest the existence of pronounced ‘amount effects’.
About eighty specimens from ten different species of mammals, collected from different areas under different climatic and environmental conditions, were measured for the oxygen isotopic composition of their bone and tooth phosphate. The equations relating these values to the mean oxygen isotopic composition of local meteoric water were also derived. The same equation can be used for goats, roe-bucks, and mouflons, despite the biological differences among these species. Measurements were made on about fourty different specimens of rabbit and hare from Europe, Africa, and Canada, but in this case the data obtained clearly show no direct relationship between the oxygen isotopic composition of local meteoric water and the isotopic composition of the skeletal phosphate. However, there seems to be an inverse relationship between the relative humidity of the studied areas and the delta(18)O(PO43-) of the skeletal phosphate, thus suggesting the use of fossil bones of these mammal species as recorders of palaeoenvironmental relative humidity. Finally, a new equation was derived for the isotopic scale for horses, on the basis of all the previous data and of a few newly obtained results
Carbon isotopic abundances in Alaskan, Albertan and Russian mammoths indicate a diet of C3‐plants. The relatively high nitrogen isotopic abundances suggest arid conditions in Alberta and Alaska during the last ice age, and similar conditions in Russia. Nitrogen isotopic abundances are higher in mammoths relative to coeval herbivores, which may be due to differences in protein content of their diet. Oxygen isotopic abundances are similar in mammoths and in modern mammals from the same areas. The characteristic isotopic signature of mammoth ivory allows distinction from elephant or marine mammal ivory.
The 13C/12C isotope ratios in animal1 and human2 bone can be used as indicators of diet, more recently it was shown that the 15N/14N ratios of animals and humans are similarly determined by the food they eat3–5. Specifically, the stable carbon isotope composition reflects the proportion of C3 and C4 plants at the base of the food chain1,2, while both 15N and 13C reveal the difference between a marine and terrestrial diet in modern as well as archaeological contexts5–7. Here we present data for human and animal bones from southern Africa which only partly conform to previously recognized patterns for 15N/14N ratios. Prehistoric human bones from a particular coastal region of South Africa show 15N/14N ratios consistent with the marine and terrestrial diets indicated by the 13C/12C ratios, but bones of both prehistoric humans and modern wild animals from a larger part of the subcontinent show variations in 15N/14N ratios which cannot be ascribed to known variations in diet. It appears that, in some environments, nitrogen isotope studies must also take into account the possible influence of the climate.
Since its introduction in 19771, stable isotope analysis of bone collagen has been widely used to reconstruct aspects of prehistoric human and animal diets2–11. This method of dietary analysis is based on two well-established observations, and on an assumption that has never been tested. The first observation is that bone collagen 13C/12C and 15N/14N ratios reflect the corresponding isotope ratio of an animal's diet1–5,12. The second is that groups of foods have characteristically different 13C/12C and/or 15N/14N ratios13,14. Taken together, the two observations indicate that the isotope ratios of collagen in the bones of a living animal reflect the amounts of these groups of foods that the animal ate. Thus, it has been possible to use fresh bone collagen 13C/12C ratios to determine the relative consumption of C3 and C4 plants15–17, while 13C/12C and 15N/14N ratios have been used to distinguish between the use of marine and terrestrial foods14. The 15N/14N ratios of fresh bone collagen probably also reflect the use of leguminous and non-leguminous plants as food5, but this has not yet been demonstrated. Prehistoric consumption of these same groups of foods has been reconstructed from isotope ratios of collagen extracted from fossil bone1–11. Implicit in the application of the isotopic method to prehistoric material is the assumption that bone collagen isotope ratios have not been modified by postmortem processes. Here I present the first examination of the validity of this assumption. The results show that postmortem alteration of bone collagen isotope ratios does occur, but that it is possible to identify prehistoric bones whose collagen has not undergone such alteration.
Oxygen and carbon isotope compositions of well-preserved mammoth teeth from the Middle Würmian (40–70 ka) peat layer of Niederweningen, the most important mammoth site in Switzerland, were analysed to reconstruct Late Pleistocene palaeoclimatic and palaeoenvironmental conditions. Drinking water δ18O values of approximately −12.3±0.9‰ were calculated from oxygen isotope compositions of mammoth tooth enamel apatite using a species-specific calibration for modern elephants. These δ18OH2O values reflect the mean oxygen isotope composition of the palaeo-precipitation and are similar to those directly measured for Late Pleistocene groundwater from aquifers in northern Switzerland and southern Germany. Using a present-day δ18OH2O-precipitation–air temperature relation for Switzerland, a mean annual air temperature (MAT) of around 4.3±2.1 °C can be calculated for the Middle Würmian at this site. This MAT is in good agreement with palaeotemperature estimates on the basis of Middle Würmian groundwater recharge temperatures and beetle assemblages. Hence, the climatic conditions in this region were around 4 °C cooler during the Middle Würmian interstadial phase, around 45–50 ka BP, than they are today.During this period the mammoths from Niederweningen lived in an open tundra-like, C3 plant-dominated environment as indicated by enamel δ13C values of −11.5±0.3‰ and pollen and macroplant fossils found in the embedding peat. The low variability of enamel δ13C and δ18O values from different mammoth teeth reflects similar environmental conditions and supports a relatively small time frame for the fossil assemblage.