A high‐resolution record of mire development and climatic change spanning the Late‐glacial–Holocene boundary at Church Moss,Davenham (Cheshire,England)

Excavations of deposits filling a closed basin within glacial drift at Church Moss, Davenham, near Northwich (Cheshire, England) revealed a sequence of Late‐glacial and Early Holocene sediments. Analyses of pollen and plant and invertebrate macrofossils were undertaken, together with loss‐on‐ignition analyses and a programme of AMS radiocarbon dating, to provide a record of changing biostratigraphy and climatic and ecological regimes. The infilling of features identified as frost‐cracks in the till flooring the basin gave remains that reflected conditions of extreme cold towards the end of the Devensian. The pollen record from a 3.5 m sequence of peat towards the deepest part of the basin, supported by radiocarbon dates, shows that organic deposition was initiated during the Late‐glacial Interstadial and continued into the early part of the Holocene. There was some evidence for a cool episode during the interstadial, with amelioration prior to the rapid onset of the tundra conditions of the Loch Lomond Stadial. Following the stadial, amelioration was rapid. There was evidence from both central and marginal sequences for a mosaic of fen dominated by sedges and often also mosses, with short‐lived small pools through much of the succession. Change to terrestrial conditions proceeded intermittently, probably as a result of subsidence caused by solution of underlying salt‐bearing strata. Copyright © 2000 John Wiley & Sons, Ltd.     

Middle Devensian (Weichselian) coleopteran assemblages from Earith,Cambridgeshire (UK) and their bearing on the interpretation of ‘Full glacial’ floras and faunas

Macroscopic plant remains from middle Devensian organic lenses, exposed in a gravel pit near Earith in the valley of the River Great Ouse in Cambridgeshire, were the object of an extensive study by Frances Bell in the late 1960s, which has been much referred to in the subsequent literature. The floras from each sampling site have been taken to be characteristic of Full‐glacial conditions in general. Coleopteran assemblages taken at the same time from exactly the same sampling sites show that at least two periods of markedly different climatic regimes were involved. The first of these (? the older) was characterised by a cold and continental climate with mean July temperatures at or below 10d°C and mean January/February temperatures about −23°C. The second climatic regime was characterised by warm summers with mean July temperatures about 16°C and mean January/February temperatures close to −5°C. In spite of this temperate climate, pollen analysis shows that no trees grew in Britain at that time. This treeless but temperate episode in the middle of the Devensian (Weichselian) is discussed in the context of coleopteran assemblages from other sites in southern England that probably date from the same period. Copyright © 2000 John Wiley & Sons, Ltd.     

青岛市海岸带野生的堇菜属植物

青岛市海岸带野生的堇菜属植物有７种。本文简要介绍了每种植物的外部形态、分布状况、用途、开花结果日期。为变野生为家养,满足沿海城市医药、园林部门需求,提供科学依据。     

Impact of climate change on dynamic of plant communities, lakes and swamps in Beijing area during Holocene period

IntroductionInPAGESofIGBPcoreprojectstudy',pollenanalysisinsbeenoneoftheimportantmethodstoreco~ctQuaternarypaleoclilnate.Recently,tviththedeepeningofglobalchangeresearches,manyresearchersactounderstandindetaildiechangeofclimatebystUdyingpollenrecordsoflandsoilsandlakesandswamps.Foralongbine,theChinesescienhstshavepaidgreatattenhontotheStUdyofthehistoricalclinistcandenvironmentchangesinNorthChina.particularlyinBedingarea.Daingthepastthreedecades,thescienhstShavemadesurveysandstUdiesonth…     

城市垃圾堆埋对地质环境的影响

本文介绍了国内外城市垃圾的处置方法,阐明了垃圾埋场对地质环境的影响以及对垃圾堆埋场场址的选择要求。     

郴州金船塘锡铋矿选厂工业流程的调整建议

本文通过对金船塘锡铋矿１００ｔ／ｄ选厂的流程考察,找出了存在的主要问题,提出了改进工业流程的有益建议。     

Distribution of the aphid Hyalopterus pruni Geoffr. within and between habitats of Common Reed Phragmites australis (Cav.) Trin. ex Steudel as a result of migration and population growth

The aphid Hyalopterus pruni migrates to its secondary host Common Reed in late spring and early summer. Reed fields are known to be more heavily infested at the edges compared to the centre, as the migrants are attracted to the colour of the reed. There is also evidence that reeds growing at wet sites are more heavily infested than at dry sites. This paper shows that both proceses interact in determining the distribution of aphids in different habitats.The observations were carried out in the vast reed field of the Zuidelijk Flevoland polder (The Netherlands) during a number of years after its reclamation in 1968. In the period of migration flying aphids were caught with sticky traps situated in and around the reed field. The distribution of aphids on the reed was determined at different times during the season along transects through the centre of the polder. The existence early in the season (June) of a higher infestation at the edges than in the centre of the field was confirmed. The density of winged aphids in this early period was higher in wet than in dry habitats, which may have been a result of a preference of the settling migrants for reed standing in water. Later in the season (August) the dry habitat still had a relatively low infestation in the centre, but at the wet sites the infestation was high everywhere. This could be attributed to the much quicker population growth that was found in the wet habitat and subsequent short range movement of newly born winged aphids.     

气候变化对福建冬种小麦生产的影响

使用福建省３１个县小麦产量资料及相应各地的气象资料,通过气象产量与经膨胀处理后的气象因子进行相关分析,得知影响福建冬种小麦产量的关键气象因子是３月份的降水量和上年１１月中旬至１２月上旬的平均气温。分析了冬种小麦生长期气候资源变化及关键气象因子的年代变化,得出近年气候变化不利于福建冬种小麦的生产。最后对福建冬种小麦种植区重新进行了划分,对福建冬种小麦生产布局提出了建议。     

干旱地区植被影响沙地水分传输机理及其参数化

从植物生长与水分平衡的关系入手,在土壤水分动力学和近地面空气动力学等学科的研究基础上,依据植物生理生态学原理,探讨了干旱地区植被影响沙地水分传输的机理,初步建立了植被参数化模型和土壤-植物-大气连续体(SPAC)水分传输综合模型。主要研究结果如下:①分析了荒漠植物的生长及其动态变化特征,对沙生植物地上部与根系生长,尤其是根系在土壤中的分布进行了量化。②分析了荒漠植物的蒸腾特性及其气孔调节作用机制,指出了土壤水分亏缺是叶片气孔关闭、蒸腾作用降低的主要原因,探讨了植物蒸腾作用与气孔调节之间的复杂关系及其今后的研究重点。③揭示了沙地植被蒸发蒸腾的变化规律;分析了影响沙地植被蒸发蒸腾的生物因素和环境因素的作用。④初步建立了植被参数化和SPAC水分传输综合模型,模拟了植被结构影响冠层能量平衡过程,探讨了植物状态参数、生理参数与蒸发蒸腾的相互关系。     

甘肃金昌市引种植物抗旱性的比较研究

对金昌市新引进的30种植物进行了PV曲线主要水分状况参数的测定,以抗旱性指数大小为基础,结合束缚水与自由水的比值,分析了引种植物的抗旱性,通过植物叶水势、相对水分亏缺及细胞弹性模量的分析,提出了初步种植建议。