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1.
MethodsGenetic diversity and structure were examined using 20 microsatellite markers in 37 populations of C. japonica. The locations of glacial refugia were assessed using STRUCTURE analysis, and potential habitats under current and past climate conditions were predicted using SDM. The process of genetic divergence was also examined using the approximate Bayesian computation procedure (ABC) in DIY ABC to test the divergence time between the gene pools detected by the STRUCTURE analysis.ConclusionsThe combined evidence from microsatellites and SDM clearly indicates that climatic changes have shaped the genetic structure of C. japonica. The gene pool detected in northern Tohoku district is likely to have been established by cryptic northern refugia on the coast of the Japan Sea to the west of the Archipelago. The gene pool in Yakushima Island can probably be explained simply by long-term isolation from the other gene pools since the LGM. These results are supported by those of SDM and the predicted divergence time determined using ABC analysis.  相似文献   

2.
The article presents a dendrochronological investigation of subfossil oaks from the riverine sediments of the Seda River in the Lake Burtnieki Undulating Plain, northern Latvia. Thirty-nine oak trunks were investigated for our study. Cross-dating of samples resulted in six floating chronologies spanning 141–636 years. The longest chronology was absolutely dated to AD 652–1287 against regional oak chronologies from Lithuania, Latvia, Belarus and central European Russia. 14C dating revealed that oaks grew on the site from the last century of the third millennium cal BC to the first half of the second millennium cal AD. We assessed the depositional anomalies from two best-replicated chronologies. The germination of oaks occurred during climate warming, and dying-off phases were triggered by climate cooling and increased precipitation throughout Europe. Our results give new insights into the forest history in northern Latvia and provide a potential to construct absolute-dated millennial oak chronologies in the Baltic countries.  相似文献   

3.
The late Pleistocene site of Oerel which represents the Eemian and the Weichselian interstadials Brörup, Odderade, Oerel and Glinde as well as parts of the stadials Herning and Rederstall was investigated for botanical remains such as fruits, seeds, wood, leaves and mosses, as well as insect remains. A large number of taxa were identified. They show the different environmental conditions, in particular several changes of water level leading to the formation of lakes and diverse forms of mires up to raised bogs. The trophic conditions, too, changed several times. The macrofossil record supports the pollen evidence of dense forests during the two early Weichselian interstadials and tundra vegetation during the later ones. Several indicator species show comparably warm summers but very cold winters during the Brörup and Odderade while the climate during Oerel and Glinde was generally cool. Climatic reconstructions using the MCR method were performed on the basis of the beetle finds.  相似文献   

4.
5.
Geographical and temporal variations in the start dates of grass pollen seasons are described for selected sites of the European Pollen Information Service. Daily average grass pollen counts are derived from Network sites in Finland, the Netherlands, Denmark, United Kingdom, Austria, Italy and Spain, giving a broad longitudinal transect over Western Europe. The study is part of a larger project that also examines annual and regional variations in the severity, timing of the peak and duration of the grass pollen seasons. For several sites, data are available for over twenty years enabling long term trends to be discerned. The analyses show notable contrasts in the progression of the seasons annually with differing lag times occurring between southern and northern sites in various years depending on the weather conditions. The patterns identified provide some insight into geographical differences and temporal trends in the incidence of pollinosis. The paper discusses the main difficulties involved in this type of analysis and notes possibilities for using data from the European Pollen Information service to construct pan European predictive models for pollen seasons. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

6.
Local and regional vegetation since the last glacial period was reconstructed on the basis of a palynological study of sediment at Iwaya, in the Sea of Japan area, western Japan. During the interstade (before about 30 000 years BP), forests were composed predominantly ofCryptomeria japonica withTsuga sieboldii and cool-temperate deciduous broad-leaved trees. In the pre-full-glacial, the full-glacial and the early late-glacial (30 000-12 000 years BP), forests were dominated by temperate (montane) and boreal (subalpine) Pinaceae andBetula. During the early full-glacial, the pinaceous forests were mixed with cool-temperate trees such asFagus crenata. In the late full-glacial (18 000-16 000 years BP), the maximum development of pinaceous conifer forests was recognized. Cool-temperate broad-leaved forests composed mainly ofF. crenata andQuercus (Lepidobalanus) replaced the pinaceous forests at about 12 000 years BP and were maintained to the early postglacial.Cryptomeria japonica was distributed around the Mikata lowland during the last glacial.Cryptomeria japonica, which began to increase at 16 000 years BP, increased abruptly in the early postglacial and spread throughout the postglacial in the lowlands. After 6300 years BP, lucidophyllous forests composed mainly ofQuercus (Cyclobalanopsis) andCastanopsis were established in the Mikata district; this was later than in the inland and the Pacific Ocean areas in the Kinki region, western Japan. In historic times (afterca 2000 years BP), secondary forest ofPinus densiflora, which can grow as a pioneer in disturbed habitats, spread.  相似文献   

7.
The spectacular art of the Grotte Chauvet stands out among all other examples of Aurignacian art, which are restricted to a handful of sites in other regions of western and Central Europe, which take the form of sophisticated carvings on organic materials and of simple engravings on rockshelter walls. Given its sophistication, Chauvet has understandably come to feature prominently in debates as to the nature of human symbolic origins, the behavioral capacities of Homo sapiens, the nature of the dispersal of modern humans across Europe, and the possibly contemporary extinction of Homo neanderthalensis. Significant objections to such an antiquity have, however, been made in recent years on the grounds of the style, themes, and technical practice of the art itself, and on the grounds of the AMS radiocarbon dating program that was first seen to suggest an early Upper Paleolithic age. To date, no attention has been paid to claims for an Aurignacian age on specifically archaeological grounds. Here, I undertake a critical examination of the archaeology of the cave and its wider region, as well as attempts to verify the antiquity of the art on the basis of comparison with well-dated Aurignacian art elsewhere. I conclude that none of the archaeological arguments withstand scrutiny and that many can be rejected as they are either incorrect or tautologous. By contrast, hypotheses that the art is of Gravettian-Magdalenian age have not been successfully eliminated. The age of the art of the Grotte Chauvet should be seen as a scientific problem, not an established fact. While it may prove impossible to prove an Aurignacian age for some of the Chauvet art I suggest a set of expectations that would, in combination, strengthen the robusticity of the ‘long chronology’ argument. The onus is upon Chauvet long chronologists to do this, and until they do, we must conclude that the art of the Grotte Chauvet is not dated, and very possibly much younger than claimed.  相似文献   

8.
Pleistocene climate fluctuations shaped the patterns of genetic diversity observed in extant species. In contrast to Europe and North America where the effects of recent glacial cycles on genetic diversity have been well studied, the genetic legacy of the Late Pleistocene for East Asia, a region of great topographical complexity and presumably milder historical climate, remains poorly understood. We analysed 3.86 kb of the mitochondrial genome of 186 Chinese Hwamei birds, Leucodioptron canorum canorum , and found that contrary to the conventional expectation of population decline during cold periods (stadials), the demographic history of this species shows continuous population growth since the penultimate glacial period (about 170 000 years ago). Refugia were identified in the south, coastal regions, and northern inland areas, implying that topographic complexity played a substantial role in providing suitable habitats for the Chinese Hwamei during cold periods. Intermittent gene flow between these refugia during the warmer periods (interstadials) might have resulted in a large effective population of this bird through the last glacial period.  相似文献   

9.
Measuring trends in the size of prehistoric populations is fundamental to our understanding of the demography of ancient people and their responses to environmental change. Archaeologists commonly use the temporal distribution of radiocarbon dates to reconstruct population trends, but this can give a false picture of population growth because of the loss of evidence from older sites. We demonstrate a method for quantifying this bias, and we use it to test for population growth through the Holocene of Australia. We used model simulations to show how turnover of site occupation across an archaeological landscape, interacting with erasure of evidence at abandoned sites, can create an increase in apparent site occupation towards the present when occupation density is actually constant. By estimating the probabilities of abandonment and erasure from archaeological data, we then used the model to show that this effect does not account for the observed increase in occupation through the Holocene in Australia. This is best explained by population growth, which was low for the first part of the Holocene but accelerated about 5000 years ago. Our results provide new evidence for the dynamism of non-agricultural populations through the Holocene.  相似文献   

10.
In this paper we reconstruct the location of the last glacial refugia and postglacial spread of Abies throughout Europe based on combined pollen and macrofossil data. More than 208 pollen sequences available in the European Pollen Database (EPD) and 38 macrofossil sites are used to produce distribution maps encompassing a time span between 38000 and 5500 years B.P. The investigation excludes more recent periods, because these could be strongly influenced by human impact. The pollen data presented here confirm long-lasting refugial areas such as southern Italy and Greece already described in previous studies. The combined pollen/macrofossil dataset identifies the Pyrenees as a further important refugium. In addition the pollen data indicate potential refugia in south-east France and north-west Italy. Possible migration tracks of Abies are discussed by comparing the palaeobotanical evidence with isozyme studies on gene markers of recent fir populations.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00334-004-0049-4.  相似文献   

11.
Abstract. The results of pollen analysis and radiocarbon dating are presented from three northern Apennine sequences; Lago Padule in northern Tuscany and Lago Pratignano and Ospitale in the Emilia-Romagnan Apennines. This is the first detailed pollen stratigraphic information from sites in Emilia-Romagna and north Tuscany and extends eastwards the area from which information on vegetational history is available. The sequence from Lago Padule is one of the most complete Holocene records known from the northern Apennine region. Lago Pratignano has the deepest sequence of organic sediments (1544 cm) and the fastest rates of sediment accumulation (up to 28 cm per 100 years) providing the highest resolution record for the mid to late Holocene periods in the region. High rates of sedimentation have also occurred at Ospitale where organic sediments are 780 cm deep and began to form at approximately 5500 bp. The record from Lago Padule is compared with Holocene records from two nearby sites and a series of Regional Pollen Assemblage Zones is defined for the eastern area of the northern Apennines. The main features of vegetational change identified are: (i) a‘pioneer’phase of rapid forest development during the early Holocene followed by the establishment of an upper forest belt dominated by Abies, and a belt of mixed deciduous forest at lower altitudes; (ii) the appearance and rapid expansion of Fagus between approximately 5200 bp and 2900 bp forming a mixed Abies-Fagus association in the upper forest belt; and (iii) the overall reduction of forest cover, and dominance of Fagus in the arboreal vegetation from around 2900 bp. The scheme of Regional PAZs for the eastern area is used as a framework for the review of pollen stratigraphic information and radiocarbon dates from other sites in the northern Apennine region. Characteristics of pollen records which can be identified in sequences from across the region are identified and the chronology of similar changes in pollen stratigraphy is examined. The scheme of four regional PAZs for the Holocene period is shown to be valid for the entire northern Apennine region. The examination of a series of pollen records shows that Fagus appeared earlier in the western than the eastern part of the region during the mid Holocene and became dominant in the northern Apennine forests post 3000 bp. The impact of anthropogenic activity and climatic change on the spread and development of Fagus are discussed. The palynological evidence which is now available from the northern Apennines is compared with information for the region shown in the‘European pollen maps’of Huntley & Birks (1983). This study provides an updated review of the representation of different tree taxa in Holocene pollen records from the northern Apennines and illustrates the role of the northern Apennines as a refugium for trees during the Wurmian Lateglacial.  相似文献   

12.
郝丽霞  程智慧  孟焕文  孙金利  韩玲 《生态学报》2010,30(19):5316-5326
为探讨利用大蒜的生物和生态效应克服设施番茄连作障碍并同时生产促成大蒜,试验选用4个大蒜品种,设置3个套播期,重点分析不同套播时期不同大蒜品种的生长发育和产量。结果表明:S1(8月25日)套播比S2(9月9日)和S3(9月24日)套播大蒜出苗时间长,但出苗日期早;S1的大蒜最大叶长、叶宽、假茎高、假茎粗、株高、根数和叶片数均比后两个套播时期有优势,品种间最大叶长、叶宽、假茎粗、株高、根数都以G64大于其他3个品种;早播促进大蒜鳞茎膨大,鳞茎最大直径、最小直径、纵径和周长以G64最大,其次是G87;G64的单头重极显著大于其他3个品种,产量最高。以S1套播时,G64比露地大蒜提早上市30—35d,价格提高60%,产值为32614元/hm2。所以,G64和8月25日是试验推荐的设施番茄套作大蒜适宜品种和套播时期。  相似文献   

13.
《L'Anthropologie》2018,122(3):348-373
Here we present an overview of the personal ornaments of the Swabian Aurignacian and the Early Aurignacian sites of south-western France made from mammoth ivory. The production sequences for the serial manufacture of beads from these sites are quite similar. While the Swabian sites have yielded numerous different types of beads with a focus of the double-perforated bead, the nearly exclusive use of one bead-type, the perle en forme de panier, is striking at the sites of south-western France. Following the presentation of major inventories of ivory ornaments in the two regions concerned, we discuss potential factors underlying both the differences and the similarities we observe in these assemblages.  相似文献   

14.
We describe a new palaeobotanical site at Bubano quarry on the easternmost Po plain, northern Italy. Pollen and macrofossils from river and marsh sediments demonstrate the occurrence of Picea in a Pinus sylvestris forest growing in a radius of some tens of kilometres south of the sedimentation place, at the beginning of the Late-glacial interstadial. The Late-glacial and Holocene history of Picea in the northern Apennines is reconstructed on the basis of the palaeobotanical record. The sharp climatic continentality increase eastwards across the northern Apennines from the Tyrrhenian to the Adriatic coast is considered significant for the survival of Picea during the Late-glacial. The most critical phase of survival is related to the moisture changes and consequent Abies competition associated with the last glacial-interglacial transition and the early Holocene. The residual spruce populations expanded during the middle Holocene. The history of Picea in the northern Apennines is a case of ineffective interglacial spread of tree populations from pre-existing stands of LGM (Last Glacial Maximum) and Late-glacial age.  相似文献   

15.
In this paper we describe fossil remains of an indeterminate species of the genus Paracamelus (Artiodactyla, Camelidae) from the Messinian post-evaporitic deposits (5.55–5.40 Ma) of Verduno (Piedmont, NW Italy). Camelins dispersed into Eurasia from North America in the late Miocene and almost instantaneously spread in western Europe and Africa. The size and morphology of the fossils found at Verduno are consistent in with those of Paracamelus, the earliest Old World camelin. Up to now, the only fossil camels recovered in the Neogene of Western Europe have been found at Venta del Moro and Librilla in Spain at 6.2 Ma. The remains from Verduno represent the first evidence of a camelin in the Neogene of Italy and they considerably expand the paleobiogeographic range of the Old World early camelins. The presence of a camelid at Verduno reinforces and confirms the importance of the fossiliferous deposits of NW Italy in defining the complex paleobiogeographic patterns of Europe during the Messinian, at the end of the Messinian salinity crisis.  相似文献   

16.
A new hadrosaurid dinosaur, Arenysaurus ardevoli gen. et sp. nov., from the Late Maastrichtian of Aren (Huesca, South-central Pyrenees) is described on the basis of a partial, articulated skull, mandibular remains and postcranial elements, including vertebrae, girdle and limb bones. Arenysaurus is characterized by having a very prominent frontal dome; nearly vertical prequadratic (squamosal) and jugal (postorbital) processes, and deltopectoral crest of the humerus oriented anteriorly. Moreover, it possesses a unique combination of characters: short frontal (length/width approximately 0.5); midline ridge of parietal at level of the postorbital-squamosal bar; parietal excluded from the occiput; squamosal low above the cotyloid cavity. A phylogenetical analysis indicates that Arenysaurus is a rather basal member of Lambeosaurinae and the sister-taxon to Amurosaurus and the Corythosaurini-Parasaurolophini clade. The phylogenetic and biogeographical relationships of Arenysaurus and other lambeosaurines suggest a palaeogeographical connection between Asia and Europe during the Late Cretaceous.  相似文献   

17.
18.
Isolation of Mediterranean species in the southern European peninsulas during the cold glacial phases often resulted in differentiation of several genetic lineages confined to the respective peninsulas. However, whilst there is good genetic evidence for multiple refugia in Iberia, there are only limited data available for the Balkans. Therefore, we wish to examine the hypothesis of a strong genetic structuring within southeastern Europe for the existence of multiple Balkan differentiation centres and/or several leading edges. As a model we use the marbled white butterfly, Melanargia galathea. We studied 18 allozyme loci of 564 individuals from 16 populations distributed over a large part of southeastern Europe. The single populations showed moderately high genetic diversity and no northward decline of genetic diversity was detected. The overall genetic differentiation between populations was considerable (F(ST) 7.0%). Cluster analysis discriminated three genetic groups: (i) a western flank in the former Yugoslavia, parts of eastern Austria and Hungary; (ii) an eastern flank with populations from Bulgaria and Romania (south of the southern Carpathians and eastern Carpathians); and (iii) the eastern Carpathian Basin. Hierarchical variance analysis distributed 53% of the variance among populations between these three groups. One sample from the Greek-Bulgarian border clustered within the eastern flank, but showed some tendency towards the eastern Carpathian Basin populations. Two populations from Carinthia clustered together with the eastern Carpathian Basin ones and a population from Styria showed an intermediate genetic composition between the three groups. Most probably, the eastern and the western flank groups are due to postglacial range expansion from the northeastern and the northwestern edges of the glacial differentiation centre (so-called leading edges). The eastern Carpathian Basin group may have resulted from postglacial expansion from northern Greece through valley systems of the central Balkan peninsula, maybe even expanding westwards north of the Balkan mountains reaching some parts of eastern Austria (e.g. Carinthia). Therefore, the Balkanic refugium of M. galathea may or may not have been continuous along the coastal areas of the Mediterranean, but must have been strongly genetically structured.  相似文献   

19.
European lobster populations in Norway and Sweden are severely reduced as a result of intense harvesting over a long time. Various alternative management options have been proposed or endorsed to both facilitate recovery and increase yield. Accordingly, Minimum Landing Size (MLS) regulations are widely used for the European lobster. We developed an individual-based population model which integrates biological knowledge about lobsters’ population dynamics to explore how available harvesting strategies and management options influence abundance and yield. The model reproduced basic features of a real lobster population in Sweden. Even for a relatively large MLS high fishing effort may still be detrimental to the long term production of the stock, while increasing the MLS further prevents this recruitment overfishing. A moratorium on berried females, in combination with the MLS appears to stabilize population fluctuations and yield, leading to higher yield for all MLS's considered. The female moratorium harvesting strategy also performed better than a maximum size limit. Yield per recruit calculations gave similar quantitative results, and also shows that a larger MLS reduce the risk of growth overfishing. A smaller MLS enables the harvest of many individuals but is very sensitive to increase in effort which easily promotes overfishing.  相似文献   

20.
Aim Shells of fossil molluscs are important for palaeoecological reconstructions. However, the habitat requirements of snail species typical of central European full‐glacial loess sediments are poorly known because most of them became very rare or extinct in Europe. The recent discovery of an almost complete extant assemblage of such species in mountainous regions of central Asia enables more precise characterization of their habitats, which may significantly improve reconstructions of Pleistocene environments. Location Altai Mountains, Russia. Methods Terrestrial snail assemblages, vegetation composition and selected environmental variables were recorded at 118 sites along a gradient of climatic continentality in the Russian Altai. Habitat characteristics of sites where species typical of the full‐glacial period occurred were described using a classification tree. Results Seven of the eight species that are typical of central European full‐glacial loess sediments were found in the study area. They were confined to cool areas with January mean temperatures below ?17 °C, but occurred mainly in sheltered habitats with a warmer microclimate, such as scrub or open woodland. Pupilla loessica and Vallonia tenuilabris had the broadest habitat range, occurring from woodland to dry steppe. Unexpectedly, Columella columella, Pupilla alpicola, Vertigo genesii, V. parcedentata and V. pseudosubstriata were found mainly in wooded fens and shrubby tundra rather than in open steppe. Most of these seven species were recorded in base‐rich wooded fens. Very dry open steppe habitats usually supported no snails. Main conclusions Habitat ranges of the studied snails in the Altai indicate that the full‐glacial landscapes of central European lowlands that harboured these species were not completely dominated by open and dry loess steppe. Most probably they contained a significant component of shrubby vegetation, patches of wet habitats, and probably also areas of woodland at sites with a favourable mesoclimate.  相似文献   

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