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1.
Pollen analytical results from a littoral profile taken in Lake Constance compared with pollen profiles from small kettle holes nearby form the basis for conclusions concerning human population density, the economy and environment from the Neolithic period to the Middle Ages. Early Neolithic human impact is implicated in a lime decline and also the expansion of beech. The late Neolithic lakeshore settlements caused a decline of elm, beech and lime and, by shifting cultivation, considerably changed the forest cover. The settlements were abandoned after less than 100 years. There were long periods without distinct human impact in the middle and towards the end of the late Neolithic period. Since at least the Late Bronze Age there has been permanent habitation in the region. Human impact was greatest in the High Medieval period and later, and was also substantial in the late La Tène and Roman periods. Distinct declines in human impact can be observed between the La Tène and Roman periods and in the Migration and Merovingian periods. In these intervals, open land and grazed oak forest were replaced by birch and later on by beech forests. The decreases in human impact are not of the same intensity in all diagrams.  相似文献   

2.
There are five major hypotheses to explain the apparently synchronous, widespread, spectacular, specific, and sudden elm decline in north-west Europe — climatic change, soil change, competition, human impact, and pathogenic attack. The first four hypotheses predict slow declines (ca. 50–250 years), whereas the pathogen hypothesis predicts a rapid decline (ca. 10–20 years). Pollen analyses of annually laminated sediments from Diss Mere across the elm fall show that the Ulmus decline occurred within 7 years but that there was human impact in the surrounding forest for at least 160 years, including local cereal cultivation for at least 120 years, prior to the elm fall. At the time of the elm decline, there is no evidence for particularly warm or cold seasons or for any additional human interference. The magnitude and rate of the elm pollen decline are consistent with O. Rackham's hypothesis of a pathogenic attack taking place within woodland where the elm trees were already damaged as a result of human activity.A contribution to the 8th IPC, Aix-en-Provence, Sept. 1992  相似文献   

3.
Sections of two pollarded parkelms (Ulmus glabra) from Damsgaard, Bergen, west Norway have been studied. Changes in annual ring-width are attributed partly to management, namely pollarding, and partly to pathogenic attacks, probably by Ceratocystis ulmi. The oldest attack on the trees dates back to 1826: so far the oldest known record of Dutch elm disease in Norway. Pollarding may be an important factor in attacks by the pathogen within parkelms. A possible relationship between pollarding, the pathogen and the Neolithic elmfall is suggested.  相似文献   

4.
榆树疏林是中国东北松嫩草原沙地植被演替的顶极群落,其对维持物种多样性,保持水土,涵养水源等都发挥着重要的功能。过去20a间,榆树疏林在人为干扰(农耕和放牧)下,其群落结构和物种组成发生了巨大变化。在1983年和2004年,对松嫩草原不同人为干扰下榆树疏林群落结构和物种组成等进行调查,结果显示:农耕和放牧一方面使松嫩草原榆树疏林群落多物种消失、生物量和多样性显著下降、植被结构简单化;另一方面,也是导致建群种——家榆低矮化,灌木化的主要因素。  相似文献   

5.
Pollen, plant macrofossils and charcoal were analysed from a lake-sediment sequence, including a refuse layer, from the Late Mesolithic settlement at Bökeberg III, southern Sweden. The chronology was established by means of AMS-dated plant macroremains. The results of the biostratigraphical studies indicate two settlement phases (A and B), at ca. 6650-6400 B.P. (5560-5320 cal. B.C.) and ca. 6150-5800 B.P. (5200-4680 cal. B.C.), respectively. The two settlement phases are associated with periods of low lake-level contemporaneous with the second major period of low lake levels during the Holocene in southern Sweden, and thus with a period of generally drier climate. The pollen analytical data suggest only minor human impact on the local vegetation during the two settlement phases. Three elm declines at ca. (1) 6200 B.P. (5200-5100 cal. B.C.), (2) 5450 B.P. (4340 cal. B.C.), and (3) 5150 B.P. (3980 cal. B.C.) are discussed. Elm decline 3 is synchronous with the classical north-west European elm decline. Elm declines 2 and 3 may be due to outbreaks of elm disease rather than to strong human impact or climate change. The charcoal analyses show that wood of a wide range of species was collected for fuel or other purposes. During phase A, plants used included acorns, hazelnuts and, possibly, Cornus sanguinea, and also Prunus spinosa, Sorbus aucuparia and Rubus idaeus. There is convincing evidence that Cladium mariscus was used for thatching. The second occupation phase, B, is characterised by the use of hazelnuts for food. The possible use of several other identified species is discussed.  相似文献   

6.
The investigated area near Flintbek (Schleswig–Holstein, Northern Germany) was used as a burial ground from the Neolithic until the Iron Age. Due to modern agriculture, the above-ground funerary monuments have been destroyed. Rescue excavations from 1976 to 1996 recovered the archaeological remains. In addition to the archaeological reassessment of the findings, further scientific analyses were carried out. The results of the charcoal analyses are presented in this paper. The overall spectrum of wood species represents the typical species composition of mixed oak forests. Over the whole investigated time span (Neolithic–Iron Age) these species alternate with a second group of taxa: species benefiting from better light conditions. In times of intensive human impact, these light-demanding taxa gained considerable importance, showing the opening of the wooded landscape. In phases with less human impact, a regeneration of mixed oak forest is detectable. For the Neolithic it was possible to develop a more detailed picture of wood usage based on 162 radiocarbon dates of 106 samples. These illustrate considerable changes during the Neolithic, which resulted in a varied pattern of open land and closed forest influenced by human presence and land use. Another important aspect of the Flintbek area is the handling of samples deriving from different contexts. While charcoal samples related to fire usage or grave constructions contain only slight contamination, samples from fillings (pits, burial layers) are characterized by charcoal dating being either too old or even too young for the archaeological context.  相似文献   

7.
身高、体重、颅容量等是反映人类身体大小,探讨人类体质特征、生长发育水平及营养健康状况的重要指标。本文采用公式推算法,对2011年在福建漳平奇和洞遗址出土的、距今约9500年的奇和洞II号女性个体的身高、体重、颅容量等身体大小特征进行了研究。结果显示,奇和洞II号的身高和体重约为160.3cm和59.9kg,在新石器时代成年女性个体中属于较高水平,同时高于福建地区现代成年女性的平均水平;颅容量约为1369m L,在新石器时代成年女性个体中处于中间水平。奇和洞II号较好的身体特征发育,提示处于更新世晚期向全新世过渡这一时期的奇和洞人可能具有较好的营养状况;与新、旧石器时代各组的比较显示,这一时期我国华南地区古人类身体大小、形状特征已经形成;我国南、北方地区人群身高、体重差异已经出现。  相似文献   

8.
《Comptes Rendus Palevol》2013,12(2):115-126
Vallone Inferno rock-shelter is an archaeological site located in the Madonie mountain range in Sicily. Archaeological excavation and research have provided a long prehistoric and historic sequence from the Neolithic to the medieval period, this being the most complete work in this area at present. In this paper we present the preliminary data provided by a multidisciplinary study based on pottery, lithic, human, faunal and plant remains. Stratigraphic studies have identified four complexes, of which complex 3 has provided almost all the archaeological remains. 14C AMS dates, obtained from four samples, place the human activities between 2601 cal BC and 644 cal AD. These dates are coherent with the cultural attribution of the ceramic and lithic remains. Macrofaunal and plant remains show a persistent use of the shelter for pastoral activities. Environmental data, obtained from microvertebrate and archaeobotanical remains, show the aridification and opening of the landscape from the base to the top of the sequence as a consequence of the human impact.  相似文献   

9.
A stratified profile of the Zhuangbianshan (ZBS) archaeological site (Fuzhou Basin, Fujian) was studied to investigate Neolithic era anthropogenic influence and associated environmental changes. Analysis of the archaeological sediments focused on phytoliths, palynomorphs and microcharcoal. Until now, a lack of direct evidence for agriculture has made it difficult to know if Neolithic cultures of this area relied on the exploitation of wild plants such as nuts and sago palm, or a combination of farming and foraging. Three types of rice phytoliths were found in ZBS archaeological deposits, providing robust evidence for rice farming as part of a broad-spectrum Neolithic subsistence economy centered on fishing and hunting. Chronologies based on AMS 14C dates and artifact typology place the earliest rice during the Tanshishan (TSS) Period (5,000–4,300 cal bp) followed by a shift to economic dependency on rice in the Huangguashan (HGS) Period (4,300–3,500 cal bp). The ZBS phytolith assemblage contains high frequencies of rice husk (peaked-shape glume cells) phytoliths, with far fewer leaf and stem types. This indicates late stage processing activities such as dehusking, implying a focus on consumption rather than rice production. High concentrations of charcoal in the Neolithic ZBS deposits indicate local human settlement and peaks in fire use. The ZBS pollen record also reflects human settlement and peaks in local forest clearance during the Neolithic. Forest cover was renewed when the site was temporarily abandoned following the Neolithic. Rapid formation of the Min River floodplain began ~2,000 cal bp in association with retreating sea level and intensifying anthropogenic influence. Prior to that, rice farming in the Fuzhou Basin was limited by the scarcity of wetlands suitable for agriculture.  相似文献   

10.
Forest pest epidemics are responsible for many population declines reported in forest trees. While forest tree populations tend to be genetically diverse, in principle mortality resulting from disease could diminish that genetic diversity and alter the genetic structure of the remnant populations with consequences for the ability of a species to adapt to changing environments. Slippery elm (Ulmus rubra Muhl.) is a long-lived, wind-pollinated forest tree with a native range covering essentially all of eastern North America. Dutch elm disease (DED) caused by an introduced fungal pathogen (Ophiostoma ulmi) devastated North American elm populations, including slippery elm, beginning in the 1930s. Estimates of the numbers of elms lost to DED are unknown but range into the hundreds of millions of trees given their former abundance. In this study, the genotypes of 77 herbarium specimens collected between 1890 and 2004 in Wisconsin, and of 100 slippery elm trees from five wild Wisconsin populations, were characterized using 13 microsatellite loci. Levels of genetic diversity were compared between the herbarium specimens collected pre- and post-DED spread in Wisconsin. In addition, the levels of genetic diversity and degree of genetic differentiation were quantified in the five wild populations. The allelic diversity and expected levels of heterozygosity were similar between the pre- and post-DED herbarium specimens. The five wild populations were only slightly differentiated and no genetic bottleneck was detected for any population. At least in Wisconsin, slippery elm apparently has maintained levels of genetic diversity that could facilitate adaptation to future climatic and environmental changes.  相似文献   

11.
中国西北地区史前人类活动与生存环境变化的关系是学术界关注的热点科学问题。本文通过总结分析西北地区新石器至青铜时代遗址14C测年、动植物遗存以及人骨碳同位素数据,梳理了不同降水量区域人与环境相互作用的时空特征和变化过程,以及可能的影响因素。研究结果表明,10000-6000 BP,人类活动强度较弱且多分布在降水量大于400 mm的区域,人类活动与气候的关系尚不清楚;6000-4000 BP,粟黍农业的强化促进了人类活动空间向西扩散,显著的气候事件导致人类活动强度下降,人类活动对自然环境的影响开始显现;4000-2200 BP,史前跨大陆文化交流带来的农牧业元素促使不同降水量区域生存资料多样化,人类适应和影响环境的能力进一步加强,但该时期人类活动强度存在时空差异性,对环境的影响仅在区域尺度上呈现。  相似文献   

12.
Demographic change of human populations is one of the central questions for delving into the past of human beings. To identify major population expansions related to male lineages, we sequenced 78 East Asian Y chromosomes at 3.9 Mbp of the non-recombining region, discovered >4,000 new SNPs, and identified many new clades. The relative divergence dates can be estimated much more precisely using a molecular clock. We found that all the Paleolithic divergences were binary; however, three strong star-like Neolithic expansions at ∼6 kya (thousand years ago) (assuming a constant substitution rate of 1×10−9/bp/year) indicates that ∼40% of modern Chinese are patrilineal descendants of only three super-grandfathers at that time. This observation suggests that the main patrilineal expansion in China occurred in the Neolithic Era and might be related to the development of agriculture.  相似文献   

13.
This paper compares the dentition of two samples of populations which lived in the same sites of Western Liguria (Italy) during the late phases of a hunting and gathering economy and at the beginning of agriculture respectively. The characteristics considered include metrics, pathology and wear. The older sample dates back to the Late Epigravettian (X-IX millennium B.C.), while the group of early farmers belongs mostly to the Middle Neolithic (IV millennium B.C.).The Neolithic group, conforming to the trend generally observed in human populations after the development of agriculture, shows reduction in crown size, spread of caries, increase in enamel hypoplasia, slower rates of wear on posterior teeth and less use of the anterior part of the dentition. Economic, technological, and dietary differences can provide a coherent explanatory model for the observed results. The possibility of biological relationships between the two samples is discussed with reference to archeological data.  相似文献   

14.
The commonly held belief that the emergence and establishment of farming communities in the Levant was a smooth socio-economic continuum during the Pre-Pottery Neolithic (ca. 12,000-9,000 cal BP) with only rare minor disruptions is challenged by recently obtained evidence from this region. Using a database of archaeological radiocarbon dates and diagnostic material culture records from a series of key sites in the northern Levant we show that the hitherto apparent long-term continuity interpreted as the origins and consolidation of agricultural systems was not linear and uninterrupted. A major cultural discontinuity is observed in the archaeological record around 10,000 cal BP in synchrony with a Holocene Rapid Climate Change (RCC), a short period of climatic instability recorded in the Northern Hemisphere. This study demonstrates the interconnectedness of the first agricultural economies and the ecosystems they inhabited, and emphasizes the complex nature of human responses to environmental change during the Neolithic period in the Levant. Moreover, it provides a new environmental-cultural scenario that needs to be incorporated in the models reconstructing both the establishment of agricultural economy in southwestern Asia and the impact of environmental changes on human populations.  相似文献   

15.
Elms containing narrow and scattered vessels have been reported to be more resistant to Ophiostoma novo-ulmi (Dutch elm disease pathogen) than elms with large and contiguous vessels. However, recent measurements in Ulmus pumila and U. minor showed a contrary trend. The pin method was applied to 4-yr-old branches of eight clones planted in Madrid. During 2002, radial growth increments and vessel diameters were measured monthly, and beetle trapping was undertaken weekly. U. minor formed larger vessels at the beginning of the season, coinciding with a peak of captured beetles, but, up to June 15, vessels were larger for U. pumila. The number of vessels per group, the transversal area per vessel group, and the mean theoretical hydraulic conductances were significantly higher for U. minor on most dates. Researchers should take into consideration the seasonal changes in vessel size. The results highlight that seasonal variation of vessel diameters and hydraulic parameters, in combination with beetle abundance, are the main factors that could explain the different susceptibility of both elm species to O. novo-ulmi.  相似文献   

16.
Dietary hardness and abrasiveness are inferred from human dental microwear at Ohalo II, a late Upper Palaeolithic site (22,500-23,500 cal BP) in the southern Levant. Casts of molar grinding facets from two human skeletons were examined with a scanning electron microscope. The size and frequency of microwear was measured, counted, and compared to four prehistoric human groups from successive chronological periods in the same region: pre-pottery Neolithic A, Chalcolithic (this study); Natufian, pre-pottery Neolithic B (Mahoney: Am J Phys Anthropol 130 (2006) 308-319). The Ohalo molars had a high frequency of long narrow scratches, and a few small pits, suggesting a tough abrasive diet that required more shearing rather than compressive force while chewing. These results imply that the diet of the two late Upper Palaeolithic hunter-gatherers did not focus on very hard foods. Aquatic foods with adherent contaminants, as well as grit from plant grinding tools seemed likely causal agents. The size of the pits and scratches on the Ohalo molars were most similar to microwear from the pre-pottery Neolithic A period, though they also compared well to the Chalcolithic period. These results contrasted with the larger pits and scratches from the Natufian hunter-gatherers and pre-pottery Neolithic B farmers, implying that there is no simple increase or decrease in dietary hardness and abrasiveness across the late Upper Palaeolithic to Chalcolithic development in the Southern Levant.  相似文献   

17.
Air temperature is one of the most frequent parameters for the application of pheno-climatic models which can give information for the forecasting of the beginning of pollination of various species. For the present study 12 years of aerobiological monitoring data concerning the pollination of hazel, alder, elm, poplar, and willow have been employed to forecast the beginning of their pollination assuming that the beginning of pollination of one species corresponds to a specific moment of phenological development for another species with later pollination. The difference expressed in days between the pollination of two winter taxa with successive flowering is very variable. If this interval is expressed in terms of heat (summation of mean daily temperature above a certain threshold) the differences are smaller. The delay between the pollination of alder and elm varies between 3 and 21 days depending on the climatic trend, but during this period elm on average accumulates 26 degree-days (base temperature 4°C) with a lesser variability. In this way we can begin to calculate the heat requirement for elm from the beginning of alder flowering. This application can be used for other couples obtaining statistical values which are more significant than those obtained with the phenological model, with the exception of willow. The results indicate that for the majority of the species with winter flowering there is a linear relation between the flowering dates and air temperature.  相似文献   

18.
Summary The appearance of pollen grains ofPlantago maior andPlantago lanceolata in the pollen diagrams before and contemporary with the elm decline is, unless accompanied by pollen of Cerealia and archaeological material, not necessarily an indication of the presence of Neolithic man in the immediate vicinity, because of the occurrence of the Agropyro-Rumicion crispi alliance, order Plantaginetalia maioris in naturally unstable contact zones.Translated by Dr.J. J. Butler.  相似文献   

19.
Developmental success on 47 species of plant and reproductive compatibility were studied for four strains of the European red mite,Panonychus ulmi (Koch), collected from dwarf bamboo, elm and apple trees. The host range was variable in those strains and there was no plant species on which all four strains were able to reach maturity.Intra-populational crosses in the dwarf-bamboo strain and the two apple strains of mites, as well as crosses between the two apple strains, gave both female and male progeny. Inter-populational crosses between the dwarf-bamboo and apple strains produced only male progeny, as in the case where females of each strain were kept virgin, indicating that these two were reproductively incompatible and had an arrhenotokous reproductive system. When females of the elm strain were crossed with males of the elm, dwarf-bamboo or apple strain, no males were produced, as in the case for virgin females of the elm strain which had a thelytokous reproductive system. It is thus concluded that the strains derived from different host species were reproductively incompatible with one another.  相似文献   

20.
We evaluated elm leaf beetle, Pyrhalta luteola (Müller) (Coleoptera: Chrysomelidae), defoliation of 32 elm species or hybrids (taxa) established under field conditions in Holbrook, AZ. Percentage of defoliation, number of eggs, and number of larvae were estimated on randomly selected 15-cm shoot lengths annually in July, from 1996 to 2001. The following nine taxa consistently sustained 15-46% mean overall defoliation: 1) Siberian elm, U. pumila L.; 2) 'Dropmore' elm, U. pumila; 3) 'Camperdownii' elm, U. glabra Huds.; 4) 'Regal' elm, U. glabra x U. carpinifolia Gledisch x U. pumila); 5) 'Sapporo Autumn Gold' elm (U. pumila x U. japonica Sang.); 6) 'New Horizon' elm (U. pumila x U. japonica); 7) 'Charisma' elm [(U. japonica x U. wilsoniana Schneid.) x (U. japonica x U. pumila)]; 8) 'W2115-1' elm (U. parvifolia Jacq. x U. procera Salisb.); and 9) 'Homestead' elm [(U. hollandica Mill. x U. carpinifolia) x (U. pumila-racemosa Dieck x U. carpinifolia)]. Percentage of defoliation was significantly low on four Chinese elm (U. parvifolia) cultivars ('Allee', 'Athena', 'Glory'/lace bark, and 'Kings Choice'). Percentage of defoliation was also low on seven Asian elms (including U. chemnoui Cheng, U. bergmaniana Sneid., U. szechuanica Fang, and species of the U. davidiana Planch. complex [U. davidiana, U. japonica, U. wilsoniana, and U. propinqua Koidz.]) and the American elm (U. americana L.) 'Valley Forge'. Percentage of defoliation and the number of eggs or larvae per plant were highly correlated. The results of this study are generally consistent with results of past laboratory screening trials.  相似文献   

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