Human impact during the Bronze Age on the vegetation at Lago Lucone (northern Italy)

Lake-sediment records were used to reconstruct human impact on the landscape around Lago Lucone (45°33′N, 10°29′E, 249 m a.s.l.), a former lake in the western amphitheatre system of the Lago di Garda. Presence of prehistoric human populations is attested by pile-dwelling settlements from the Early-Middle Bronze Age, with one settlement at a distance of only 100 m from the coring site. Pollen, plant-macrofossil and microscopic charcoal analyses were applied to a 250 cm sediment core with four dates providing the time control. A mixed oak forest that was important during the Early-Middle Holocene was cleared and replaced by open vegetation during the Bronze Age (∼2000–1100 b.c.) when open lands were estimated to have covered more than 60% of the total relevant pollen-source area. During a phase of high human impact, independent climatic proxies suggest warm and dry climatic conditions. Later, ca. 1100 b.c., palaeobotanical evidence indicates a sharp decrease in human pressure in the Lago Lucone area. The comparison with other sedimentary palaeocultural records shows that the period 1300–1100 b.c. was characterised by general declines of agricultural activities both south and north of the Alps. These declines have been previously attributed to a change towards wetter and colder climatic conditions in and around the Alps. However, the decline in human impact around Lago Lucone cannot be exclusively attributed to climatic variation. Therefore other forcing factors independent of climatic changes, such as cultural crises or changes in spatial organisation of the habitats, cannot be ruled out under the present state of knowledge.     

基于中高分辨率遥感的植被覆盖度时相变换方法

植被覆盖度是衡量地表植被状况、指示生态环境变化的一个重要指标,也是许多学科的重要参数。传统的测量方法难以获取时间连续的面状数据,且耗时、耗力,很难大范围推广。遥感估算方法虽然可以弥补传统方法的不足,但由于云覆盖等天气条件的影响,获得同一时相覆盖整个研究区的遥感影像非常困难,时相的差异必然导致研究结果产生误差。针对植被覆盖度这一重要生态参数,结合低分辨率遥感数据的时间优势和中高分辨率遥感数据的空间优势,提出一种时相变换方法,将源于中高分辨率影像的植被覆盖度变换到研究需要的时相上。首先,利用像元二分模型计算MODIS尺度的时间序列植被覆盖度,并利用已经获得的SPOT影像计算其获取时相上的植被覆盖度;其次,利用土地利用图划分植被覆盖类型,并利用MODIS数据和土地利用数据之间的空间对应关系制作MODIS像元内各类植被覆盖的面积百分比数据;再次,利用面积百分比数据提取各类植被覆盖的纯像元,结合MODIS植被覆盖度时间序列,从而提取各类植被覆盖纯像元的植被覆盖度时间序列曲线;最后利用像元分解的方法提取MODIS像元内各类植被覆盖组分的植被覆盖度的变化规律,将其应用到该组分对应位置上SPOT像元的植被覆盖度上,从而将其变换到所需要的时相上。在密云水库上游进行试验,将覆盖研究区的10景SPOT5多光谱影像计算的植被覆盖度统一变换到7月上旬,结果显示:视觉效果上明显好转,且空间上连续一致;变换前后植被覆盖度的统计量对比结果也符合植被生长规律;利用外业样点数据与对应位置的植被覆盖度变换结果进行回归分析,结果发现各植被覆盖类型的R2均在0.8左右,表明变换结果与实测值非常接近,时相变换的效果较好,从而可以很好地促进相关研究精度的提高。     

Determining the responses of vegetation to natural processes and human impacts in north-eastern Poland during the last millennium: combined pollen,geochemical and historical data

Pollen, charcoal and geochemical investigations were carried out on annually laminated sediments of Lake ?abińskie (54°07′54.5″N; 21°59′01.1″E) and the results were combined with historical and climate data to better understand the mechanism behind plant cover transformations. A millennium-long record of environmental history at 6-years time resolution permitted an assessment of vegetation responses to past human impact and climate fluctuations. Our results show that the history of the region with repeated periods of warfare, epidemics, famine and crop failures is well reflected by environmental proxies. Before the Teutonic Order crusade (ad 1230–1283), agricultural activities of the Prussian tribes were conducted at a distance from the studied lake and caused slight disturbances of local forests. A stronger human impact was registered after ca ad 1460. We confirm that co-domination of pine forests with spruce and oak-hornbeam forests on drier habitats as well as the presence of birch and alder woods on wet surfaces near the lake lasted until ad 1610. We identified a transition period of 20 years between ad 1590 and 1610, when forest cover was significantly reduced and the area was partly transformed into open land used for farming activities. The comparison of our data with other pollen datasets from the region confirms significant spatio-temporal differences in the initiation of large-scale woodland clearings in the Great Masurian Lake District. A strong increase in local cultivation was noted after ad 1750 and became even stronger in the period ad 1810–1940. The last 60 years experienced a succession from arable fields and open grasslands to more tree-covered habitats overgrown by birch and alder.     

Analyzing microbial disease at high resolution: following the fate of the bacterium during infection

The study of bacterial pathogens has historically been viewed with a wide lens, providing a picture of how bacterial populations act as groups, but with insufficient resolution to see how microorganisms act as individuals. For most bacterial pathogens, we do not know the minimal number of microbes that initiate infection in a particular organ site, the number that spread outside the site of initial colonization, and how many persist over time. Recent studies have begun to shed light on these points, and the development of new techniques has dramatically increased the ability of researchers to interrogate these problems. With new approaches, the field of bacterial pathogenesis is on the verge of understanding the role and fate of individual bacteria during infection.     

Gender and ethnicity at the millennium: from margin to centre

Three decades of feminist academic work have led to claims about its maturity and “coming of age”. This article offers a critical evaluation of feminism’s success, particularly in the context of “race” and ethnicity awareness. Feminism has challenged mainstream thought by making women and gender central concerns, by opening up new fields for study and by breaking down disciplinary barriers. However, the global hegemony of Western feminism means that the range of women’s issues tends to be narrowly and parochially conceived. Women of different ethnicities have had an uphill struggle to redefine feminist terms, benchmarks and understandings. One particular difficulty involves the use of ideas and concepts which are not easily translated into English. Drawing on debates between Western women and Islamist feminists, the article explores some of the problems in understanding terminologies and deciphering definitions about cultures and languages. It argues that the views of non-Western and ethnic minority women must be moved from margin to centre stage.     

Selection on age at first and at last reproduction in the long‐lived Alpine Swift Apus melba

The way an organism spreads its reproduction over time is defined as a life‐history trait, and selection is expected to favour life‐history traits associated with the highest fitness return. We use a long‐term dataset of 277 life histories to investigate the shape and strength of selection acting on the age at first reproduction and at last reproduction in the long‐lived Alpine Swift. Both traits were under strong directional selection, but in opposite directions, with selection favouring birds starting their reproductive career early and being able to reproduce for longer. There was also evidence for stabilising selection acting on both traits, suggesting that individuals should nonetheless refrain from reproducing in their first 2 years of life (i.e. when inexperienced), and that reproducing after 7 years of age had little effect on lifetime fitness, probably due to senescence.     

Middle Holocene vegetation and human impact in central Sudan: charcoal from the neolithic site at Kadero

Charcoal recovered from middens and graves in the neolithic site of Kadero, north of Khartoum, Sudan was analysed. The site lies within the semi-desert vegetation zone at present. During the occupation period (5960-5030 uncal B.P.), a scrub and thorn savanna grew around the site. It is further suggested that the vegetation during the neolithic period at Kadero was already under strong human impact through controlled fires, felling and grazing.     

Mid- and late-Holocene vegetation history,climate and human impact in the forest-steppe ecotone of European Russia: new data and a regional synthesis

Appropriate management of contemporary environments requires knowledge of their long-term history. We use palaeoecological data to explore how contemporary forest-steppe environments have been shaped by climate change and human impacts through the Holocene using the western Mid-Russian Upland as a case-study. Our paper presents new reconstructions of Mid- and Late Holocene climate, vegetation dynamics and local environmental change based on pollen, plant macrofossil and testate amoeba records from a site at Selikhovo (Mid-Russian Upland, Russia). Eutrophic fen vegetation dominated by Phragmites australis developed around 6800 cal year BP and has been resilient to episodes of local burning and variable input of mineral material through the Holocene. New and previously-published data show that the boundary between broadleaf forest and steppe occupied a similar position to present during the period 7000–4800 cal year BP, despite a warmer and drier climate, but shifted to the south following climate cooling and an increase in precipitation from 4800–2500 cal year BP. A subsequent decline in woodland cover was caused by both climate change and human impacts, with human activity becoming increasingly significant over the last two millennia. Prior to major human disturbance (about 1700 cal year BP) the landscape was dominated by mixed broadleaf-pine forests with some spruce covering about 60 % of the study area. Our results emphasize the variability of steppe-forest habitats over long time periods and the need to consider human impacts and climate change when setting targets for habitat conservation.     

The vegetation and climate at the last glaciation on the emerged continental shelf of the South China Sea

Studies on the dispersal mechanism and source areas of pollen from hemipelagic sediments recovered from the continental slopes of the South China Sea (SCS) reveal that vegetation existed on the exposed shelves at the Last Glacial Maximum (LGM) and the latter part of the Marine Isotope Stage 3. At the low sea level stand, Artemisia-dominated grassland covered the northern continental shelf and tropical lowland rainforest and mangroves grew on the southern shelf ‘Sunda Land’. Consequently, the climate in the northern SCS must have been much colder and drier during the last glacial period compared to the present. Sunda Land experienced only a marginally lower temperature but was not drier than today. The enhanced contrast between the northern and southern parts of the SCS in vegetation and climate during the LGM may be ascribed, at least partly, to the strengthening of Winter Monsoon during the last glacial period.     

Silent chromatin at the middle and ends: lessons from yeasts

Eukaryotic centromeres and telomeres are specialized chromosomal regions that share one common characteristic: their underlying DNA sequences are assembled into heritably repressed chromatin. Silent chromatin in budding and fission yeast is composed of fundamentally divergent proteins tat assemble very different chromatin structures. However, the ultimate behaviour of silent chromatin and the pathways that assemble it seem strikingly similar among Saccharomyces cerevisiae (S. cerevisiae), Schizosaccharomyces pombe (S. pombe) and other eukaryotes. Thus, studies in both yeasts have been instrumental in dissecting the mechanisms that establish and maintain silent chromatin in eukaryotes, contributing substantially to our understanding of epigenetic processes. In this review, we discuss current models for the generation of heterochromatic domains at centromeres and telomeres in the two yeast species.     

Local vegetation dynamics and human habitation from the last interglacial to the early Holocene at Theopetra cave,central Greece: the evidence from wood charcoal analysis

This paper presents the results of wood charcoal analysis carried out on material from Theopetra cave in central Greece. The sequence dates from prior to 130–8 ka bp and is made up of layers of both anthropogenic and geogenic origins. The study of the wood charcoal samples from these layers sets out to distinguish changes in the local vegetation through time, to correlate these with broader environmental conditions and to discuss how they may relate to differences in the frequency and intensity of human occupation of the cave from shortly before the last interglacial to the Holocene. Changes in the presence and frequency of Prunus sp., Juniperus sp. as well as taxa needing temperate, thermophilous or riverine conditions in successive layers reflect a pattern of vegetation succession that can be correlated with the pollen and marine isotope stage (MIS) records. The earliest human occupation took place in an open park-woodland environment dominated by Prunus during the late MIS 6–6/5 transition. This was followed by a succession of temperate woodlands with deciduous Quercus, Carpinus and Fraxinus, reflecting the optimal conditions of the last interglacial (MIS 5e), followed by more open vegetation during subsequent cooling events. Middle Palaeolithic hunter-gatherers visited the cave repeatedly during the last interglacial, in contrast to more sporadic human presence during the following climatic deterioration. This was characterized by Juniperus dominated steppe and open vegetation and/or riparian woods, reflecting the harsh and unstable climatic conditions of the pleniglacial. Finally, the expansion of Pistacia and re-establishment of temperate woodland points to climatic amelioration during the Holocene from which there is evidence of regular use of the cave by Mesolithic and Neolithic people. The dominant role of Prunus observed in several periods provides important complementary information to the pollen evidence from the late Pleistocene.     

The influences of climatic variation and vegetation on stream biota: lessons from the Big Dry in southeastern Australia

Aquatic biodiversity faces increasing threats from climate change, escalating exploitation of water and land use intensification. Loss of vegetation in catchments (= watersheds) has been identified as a substantial problem for many river basins, and there is an urgent need to better understand how climate change may interact with changes in catchment vegetation to influence the ecological condition of freshwater ecosystems. We used 20 years of biological monitoring data from Victoria, southeastern Australia, to explore the influences of catchment vegetation and climate on stream macroinvertebrate assemblages. Southeastern Australia experienced a severe drought from 1997 to 2009, with reductions of stream flows >50% in some areas. The prolonged drying substantially altered macroinvertebrate assemblages, with reduced prevalence of many flow‐dependent taxa and increased prevalence of taxa that are tolerant of low‐flow conditions and poor water quality. Stream condition, as assessed by several commonly used macroinvertebrate indices, was consistently better in reaches with extensive native tree cover in upstream catchments. Prolonged drought apparently caused similar absolute declines in macroinvertebrate condition indices regardless of vegetation cover, but streams with intact catchment and riparian vegetation started in better condition and remained so throughout the drought. The largest positive effects of catchment tree cover on both water quality and macroinvertebrate assemblages occurred above a threshold of ca. 60% areal tree cover in upstream catchments and in higher rainfall areas. Riparian tree cover also had positive effects on macroinvertebrate assemblages, especially in warmer catchments. Our results suggest that the benefits of extensive tree cover via improved water quality and in‐channel habitat persist during drought and show the potential for vegetation management to reduce negative impacts of climatic extremes for aquatic ecosystems.     

Prehistoric impact on landscape and vegetation at high altitudes: An integrated palaeoecological and archaeological approach in the eastern Pyrenees (Perafita valley,Andorra)

Abstract

A multi-proxy palaeoenvironmental study (pollen, non-pollen palynomorphs-NPP, macrocharcoal particles) of a small fen located in the Perafita valley (2240 m a.s.l, eastern Pyrenees, Andorra) was undertaken to trace prehistoric human activities related to woodland clearance and past land-uses at high altitudes. The results of this study constrained by 9 AMS radiocarbon measurements are combined with archaeological data and compared with similar research carried out at the same altitude in the adjacent Madriu valley (Andorra). The overall objectives of this article are, first, to formulate different chronological patterns and spatial land-use distribution at a micro-regional scale during prehistory and, second, to discuss different drivers of prehistoric occupation models in the eastern Pyrenean highlands. The palaeoecological study of the Planells de Perafita fen was performed at high temporal resolution, allowing us to focus on detailed prehistoric (mainly Mesolithic and Neolithic) and Bronze Age human activity. It demonstrates that the shaping of this cultural landscape is the result of a long-term land-use history, which began at the late Mesolithic/early Neolithic transition onwards (ca 6400–6100 cal BC). The existence of three main phases of “inter-valley” land-use variability has also been highlighted, thus testifying a complex and heterogeneous upland land-use model during the Neolithic and Bronze Age. These land-use variabilities between the two adjacent Andorran valleys provide the basis for a discussion of the way in which environmental constraints influenced prehistoric land-use spatial organisation and of how the interaction between environmental (including climatic parameters), socio-economic and cultural conditions affected the temporal and spatial dynamics of landscape shaping in the eastern Pyrenean highlands.     

Man and the last great wilderness: human impact on the deep sea

The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life--SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO(2) and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO(2) and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods.     

Mid-Holocene local vegetation dynamics and human impact at Los Castillejos,Andalusia, Spain: evidence from charcoal analysis

From the anthracological study of considerable quantities of charcoal recovered from the excavation of the settlement at Los Castillejos de Montefrío, a synthesis was made of the vegetation dynamics during Recent Prehistory of the area, from the middle of the sixth millennium bc to the beginning of the second millennium bc. The vegetation dynamics mark four anthracological phases over this sequence. From the Late Neolithic (end of the fifth millennium bc) the influence of different activities such as livestock raising, burning and agriculture become evident in the development of the natural vegetation, altering species composition and appearance frequency. The last anthracological phase, MF4, spanning the second half of the third millennium bc, saw the regeneration of the tree vegetation as certain former activities ceased, indicating the environmental singularity of this enclave within the context of the southern Iberian Peninsula.     

Temporal and spatial changes of vegetation cover on the Chinese Loess Plateau through the last glacial cycle: evidence from spore-pollen records

To reconstruct the palaeovegetation cover of the Chinese Loess Plateau over different time intervals of the last glacial–interglacial cycle, the spore-pollen representation of loess-soil samples in six loess sections along a north–south transect is analyzed and previously published pollen data reviewed. Results show that the temporal changes in the vegetation cover of the Plateau are controlled essentially by the history of the East-Asian summer monsoon; there is a general pattern that the pollen components indicating relatively humid climatic conditions are better represented during interglacial and interstadial periods than during glacial and stadial periods. The herbaceous pollen concentrations show a general increase from south to north with the decrease of monsoonal precipitation over the Loess Plateau. Through the last 130 ka or so, the main body of the Loess Plateau has been covered by an Artemisia-dominated grassland vegetation, suggesting that future rehabilitation of the landscape that aims for soil–water preservation on the Loess Plateau should focus on the planting of herbs.     

The impact of sex and sex hormones on lung physiology and disease: lessons from animal studies

Numerous animal studies have revealed significant effects of sex and sex hormones on normal lung development, lung physiology, and various lung diseases. The primary goal of this review is to summarize knowledge to date on the effects of sex and sex hormones on lung development, physiology, and disease in animals. Specific emphasis will be placed on fibrosis, allergic airway disease, acute lung injury models, respiratory infection, and lung toxicology studies.