北极Barrow地区几种冻原植物的花粉形态

根据中一美合作协议,研究北极巴罗地区2000年以来气候和环境变化史,张青松和唐领余于1998年5—6月到阿拉斯加巴罗地区进行了为期4周的野外考察。除湖泊打钻外,还在巴罗地区采集了表土花粉和植物标本。本文是研究北极巴罗(Barrow)地区12种冻原植物的花粉形态,它们的形状有球形、近球形、扁球形、茧形和四面体形,其萌发孔有三孔沟,三沟,二合沟以及散孔等类型。花粉具辐射对称和两侧对称两种类型。这些花粉的植物体是北极地区常见的植物,分属于10个科,除三种为小灌木外,大多数为多年生或一年生草本植物。这些冻原植物花粉形态的研究为恢复北极地区古植被和古气候的研究,提供了有价值的对比资料和依据。     

重庆喀斯特地区现代花粉组合与植被的关系

重庆喀斯特地区4种不同地貌单元的81份表土和苔藓样品的孢粉分析结果表明:(1)研究区植物孢粉组合共由109科属组成。除金佛山外,其他植被退化严重地区样点均以草本和蕨类植物占据优势(剔除石漠化治理大量引种的马尾松、柳杉和侧柏等乔木花粉),其次是乔木植物花粉(主要为马尾松),灌木植物花粉含量很低,显示该区植被退化严重;(2)孢粉组合的PCA分析能够很好地将研究区的现代孢粉组合区分开来,较好地反映了重庆喀斯特地区不同地貌单元的植被特征,特别是石漠化区植被退化严重的孢粉组合特征。生态保护较好、自然植被发育的金佛山地区具有106科属的乔木、灌木与草本孢粉类型,以及高含量的乔木花粉,而喀斯特石漠化地区的鸡公山(46科属)、青木关镇(56科属)和南平镇(50科属)则表现为乔灌木孢粉类型较少;(3)银杉作为金佛山特有的孑遗植物,其花粉含量明显低于松属花粉,说明其花粉不利于远距离传播;(4)随着土地利用强度的增加,现代孢粉组合中乔灌木花粉含量和种类越少,草本和蕨类植物孢粉含量越多,且以耕地杂草为主。因此,土地利用方式的变化是喀斯特石漠化区次生植被及其现代孢粉组合变化的主要影响因素。研究可为重庆喀斯特地区土地利用策略的制定,重庆及其周边地区第四纪古植被、古气候和古环境重建研究,以及中国孢粉数据库建设提供基本数据和科学依据。     

中全新世以来福建东北地区植被与环境变化

本文提供了福建宁德市霞浦县沿海平原XPZK3钻孔的年代和孢粉记录用于研究中全新世以来福建东北地区的植被与环境变化。中全新世以来,研究区植被中亚热带木本成分逐步降低而落叶阔叶成分逐渐增多,反映气温逐步降低,与东亚季风和北半球温度变化的趋势相同,反映在轨道尺度上北半球夏季太阳辐射对东亚季风的影响。DCA分析显示,中全新世以来,人类活动是影响研究区植被变化的最主要因素,5 000 cal. yr BP以来,松属、草本植物花粉和蕨类孢子的逐步增加反映人类活动对植被的干扰逐步加重,尤其是1 370 cal. yr BP(南北朝)以来,反映人类活动的孢粉占主要地位,人类活动对植被产生了重要影响。     

黄土高原西部4万多年以来植被与环境变化的孢粉记录

采集甘肃静宁、定西、秦安等地晚更新世晚期以来几个黄土剖面的孢粉样品,分别以晚更新世每个样品分辨率200—300年,全新世20—200年,揭示了黄土高原西部4万多年以来古植被曾经历过草原、森林草原(或疏林草原)、针叶林以及荒漠草原或荒漠几种植被的多次快速变化。在44.2—11kaBP期间,静宁地区植被主要表现为森林和草原成分的相互消长,其中44—29kaBP期间(MIS3)气候以湿润为主,发育针叶林,温度低于现在;23kaBP之后,气候冷干,以稀疏草原为主,在末次盛冰期植被甚至演化为荒漠草原。全新世大部分时间内是以草原或森林草原(或疏林草原)植被为主。在全新世中期,约7.6—5.8kaBP有近1700年时间发育有森林植被,在这个时期当地自然植被覆盖度较高,而草原或疏林草原发育时期植被往往较稀疏,反映气候相对干冷。根据出现的不同类型植物的孢粉浓度及其生态环境特性,研究区早、中全新世,约8.8—5.8kaBP沉积环境较湿润;自3.8kaBP以后气候环境总的变化趋势是逐渐变干,植被开始向草原荒漠化演变。然而,研究区整个全新世气候环境存在多次干湿交替现象,据孢粉记录,其中可能存在11次气候干寒事件。     

新疆车排子地区孢粉植物群与古气候

通过对新疆准噶尔盆地西北缘车排子地区多口探井样品分析,见丰富的孢粉化石,建立了PiceapollisPodocarpidites-Tsugaepollenites,Parajunggarsporites-Piceaepollenites,Protohaploxypinus-Striatoabieites-Hamiapollenites三个孢粉组合。根据孢粉母体植物形态和生态特征、干湿度环境和气候环境,对其孢粉植物群反映的植被类型、干湿度类型和气候带类型进行了划分,认为晚中新世孢粉植被类型为针叶林,所处的气候环境为湿润的暖温带;早白垩世孢粉植被类型为混交林,所处的气候环境为湿润的亚热带-暖温带;晚石炭世时期其植被面貌是以阔叶植物为主,所处的气候环境为半干旱的暖温带。     

云南亚热带南部表土孢粉组合与植被间的定量关系

以云南亚热带南部沿温度带分布的35个表土孢粉样品和7个植被样方调查为基础,计算了代表性孢粉类型的百分比和孢粉浓度,及常见孢粉的R值,并分析了影响R值的因素;同时,研究了植物群落和样方内孢粉组合的相似度。结果表明,云南亚热带南部表土样品孢粉产量丰富,蕨类植物孢子产量较高,具有典型的亚热带特征,且山地垂直分异显著;木本、草本植物花粉基本代表了区域内乔木和草本植物特征,蕨类植物孢子则具有超代表性;表土孢粉组合与植物群落间的相似系数绝大部分都在70％以上,表土孢粉组合基本上可以反映植物群落面貌;表明云南亚热带地区表土孢粉与现代植被之间具有较好的对应关系,这对在该区利用化石孢粉资料定量恢复古植被和重建古气候有重要意义。     

中国西南喀斯特地区植被变化时空特征及其成因

2000年以来,国家在中国西南喀斯特地区开展一系列生态治理工程,该地区退化生态系统得到一定程度的恢复,而2008年开展石漠化综合治理工程以来该地区的植被覆盖和生产力如何变化尚不清楚。本研究利用遥感增强型植被指数(EVI)和总初级生产力(GPP)数据,研究2000—2015年西南喀斯特地区植被EVI年均值和GPP年总量的时空变化特征,重点探讨2008年以来石漠化综合治理工程、气候变化等因素对植被覆盖及生长的影响,进而评估石漠化综合治理工程的成效。结果表明,2000—2015年西南喀斯特地区植被EVI总体显著增加,其中2008—2015年植被EVI均值和变化率分别比2000—2007年高6.9%和85.7%,EVI显著增加的区域占西南喀斯特地区的13.4%;该区域GPP年总量亦呈显著增加趋势(20.58 g C m-2a-1)。2008—2015年气温和降水对植被EVI变化趋势的贡献仅占28.3%,退耕还林还草等生态恢复措施、大气CO2浓度、大气氮沉降的增加可能是该区域植被覆盖显著增加的主要贡献因子。在100个首批石漠化综合治理试点县中,大部分试点县植被EVI的变化趋势受非气候因子的影响,其中治理面积大的县受非气候因子的影响显著高于治理面积小的县,表明石漠化综合治理工程的实施有效地促进了试点县植被覆盖的增加。     

福建泉州湾西部晚全新世孢粉组合特征及其古环境意义

通过对泉州湾西部QZDSZK02孔的沉积孢粉及AMS14 C进行分析,对泉州地区晚全新世古植被和古环境演化历史进行了恢复。其中,共鉴定出60种孢粉类型,主要以木本植物花粉和蕨类孢子为主,含草本植物花粉。根据孢粉特征及测年结果,划分出了4个孢粉组合带,恢复了本区植被演化和气候波动的4个阶段。探讨了孢粉来源,通过研究松属与温度的关系,得出泉州地区松属树种的兴衰与温度关系比较密切的结论。泉州湾晚全新世的海侵,可能是沉积物供给的减少或沿海地区构造的下降,不一定是海面上升的结果。     

辽西义县组孢粉植物群指示的古气候条件

迄今为止,在辽西北票义县地区的下白垩统义县组二段沉积层中,已发现孢粉化石62属,82种,藻类化石3种。本文对产于不同地点沉积层中的孢粉化石进行了系统研究和总结。根据孢粉母体植物形态和生态特征、生长的气候环境和干湿度环境,对义县组二段的孢粉植物群进行了植被类型、气候带类型和干湿度类型的统计和划分,认为义县组二段沉积时期,其孢粉植被类型为针叶林,所处的气候环境为湿润的亚热带一暖温带。由于植被成分中存在落叶阔叶植物和旱生植物,推测气候环境存在季节性变化,间有干旱一半干旱气候条件。     

西藏和北极巴罗地区菊科植物几个属的花粉

对西藏和北极巴罗地区菊科4个属(蒿属、飞蓬属、风毛菊属和千里光属)17个种的花粉形态进行了光学和扫描电子显微镜的观察、比较。结果表明这两个地区菊科4个属的花粉粒大多为球形或近球形,少数是扁球形或长球形。萌发孔的类型均为三孔沟。但在花粉大小、萌发孔形状、外壁厚度以及表面纹饰等方面存在差异。通过对这两个地区菊科植物花粉形态的观察有可能为菊科分化、迁移,以及化石孢粉的研究提供参考资料。     

Vegetation and climate reconstructions on different time scales in China: a review of Chinese palynological research

This paper reviews vegetation and climate reconstructions for different time scales based on palynological studies in China. It discusses examples of significant developments in palynological research topics within China: (1) Modern pollen—a modern pollen database (East Asia Surface Pollen Database) has been established through the collaboration of Chinese palynologists. Based on these data, modern pollen distributions and their quantitative relationship with vegetation and climate have been thoroughly studied. (2) Pre-Quaternary vegetation and climate dynamics—scientists have mapped pollen and palaeobotanical data from the Palaeogene. The vegetation distributions confirm a north–south zonal pattern during the Palaeogene that changed to an east–west monsoonal pattern during the Miocene and Pliocene. These results provide key evidence for understanding monsoon evolution. (3) Late-Quaternary vegetation—biome reconstructions based on fossil pollen data show spatial and temporal changes in vegetation since the Last Glacial Maximum, permitting a better understanding of climate change across China. (4) Quantitative climate reconstructions—some reconstructions have successfully detected Holocene climate variability thereby providing insights into monsoon history. At present, there are no comprehensive spatial reconstructions. Major possible future developments should focus on: (1) long-term vegetation reconstructions from lakes to study Asian monsoon dynamics at orbital scales; (2) quantitative reconstructions of vegetation and climate change to help stronger integration with palaeoclimate models and dynamic vegetation models; (3) land-cover and land-use change across China over the last 6,000 years to understand human impacts and provide empirical data for climate modellers; and (4) integration of pollen data with vegetation and climate modelling to understand the CO₂-vegetation relationship and climate dynamics.     

Differentiating vegetation types from eastern South American ecosystems based on modern and subfossil pollen samples: evaluating modern analogues

In south and southeast Brazil land use caused profound changes in natural vegetation and consequently the value of the pollen composition in surface samples as modern analogues. In order to test the capability of modern pollen to represent the natural vegetation, three different time slices of pollen assemblages from 27 sites spread over southern and south-eastern Brazil and the Misiones Province in Argentina were collated. Pollen samples from the pre-colonization period, selected from the moment just before abrupt changes evidenced on pollen diagrams caused by the colonization process throughout the last 500 years, were assumed to represent the natural vegetation conditions once the climate remained stable within this period. Thus we used pre-colonization assemblages to compare with modern samples to explore to what extent surface pollen may be biased in representing the natural vegetation types. Furthermore, to compare man made vegetation change to climate driven vegetation change we also compared to these 20 out of 27 samples dated to 3,000 years bp. Guided by ordination and cluster analysis, but using abundance thresholds of indicator taxa we classified the pollen spectra of pre-colonization time into seven groups consistent with the main vegetation types in the area. Ordination analyses capture the differentiation between grassland and forested vegetation and between tropical and subtropical vegetation types. Comparing the pre-colonization with other time slices we observed that based on Poaceae abundance, 70 and 85 % respectively of sites from 3,000 bp and modern assemblages maintained their classification. Based on finer classification criteria these values decreased to 40 and 52 % respectively. Square chord dissimilarity indicates that colonization impact altered the pollen composition as strongly as 3,000 years of climate induced vegetation change. The surface samples still represent important environmental gradients; however, their use as modern analogue requires careful treatment and eventual exclusion of highly impacted sites.     

陕西中部黄土高原地区空气花粉组成及其与气候因子的关系——以洛川县下黑木沟村为例

空气花粉研究是现代孢粉学、植被变迁与预测的重要内容之一.陕西省黄土高原地区洛川县2007-2009连续2a的空气花粉分析表明:空气花粉组成与区域植被分布特征和植物花期一致.与2007—2008年相比,2008-2009年的花粉总通量及蒿属花粉通量明显增加,但木本植物花粉通量降低,这主要与2008-2009年降水明显偏少密切相关.2007-2008年降雨量高于500 mm,花粉组合中乔木花粉百分比高于30％,表现出森林植被特点;2008-2009年降雨量少于450 mm,花粉组合中草本花粉高于80％,乔木花粉低于10％,更多表现出草原植被特点.但从植被观测来看并没有明显的变化,表明花粉组合较植被对气候变化更为敏感.主要花粉类型与气候因子的相关分析表明:气候因子影响空气花粉的组成及数量.栎属、松属、蔷薇科花粉数量主要受春季温度影响,温度越高花粉数量越多;其他季节花粉数量主要受相对湿度影响,湿度越低,花粉数量越大.榆属花粉数量主要与冬季温度有关,温度越高,花粉数量越高.杨属只受春季温度影响,春季温度越低,花粉数量越多.胡颓子科花粉含量主要受春季相对湿度、风速影响,相对湿度越低,风速越大,花粉数量越多.绝大多数草本花粉数量均主要受春、冬季相对湿度及风速影响,相对湿度越低,风速越大,花粉数量越高;此外,禾本科花粉数量还受春季温度影响,温度越高,花粉数量越多;菊科花粉数量在夏秋季节还受温度、湿度和风速的共同影响,温度越低,湿度越低,风速越大,花粉数量越多.这些结果表明,黄土高原中部地区的空气花粉特征能反映区域植被组成,且对气候变化非常敏感,对认识和预测当地气候变化与植被动态等具有重要意义.     

Holocene vegetation history of the Sahel: pollen, sedimentological and geochemical data from Jikariya Lake, north-eastern Nigeria

Aim This study aims to separate regional and local controls on Holocene vegetation development and examine how well pollen records reflect climate change in a semi‐arid region. The relative importance of climate and human activity as agents of vegetation change in the Sahel during the late Holocene is also considered. Location Jikariya Lake, an inter‐dune depression in the Manga Grasslands of north‐eastern Nigeria. Methods Pollen and charcoal were used to provide a record of Holocene vegetation history. Palaeoclimate and hydrological changes were reconstructed from sedimentary and geochemical data. Regional and local influences were separated by comparing the evidence obtained from Jikariya Lake with previously published data from the Manga Grasslands. Results The Manga Grasslands experienced a prolonged wet period during the early and mid‐Holocene, during which swamp forest vegetation with Guinean affinities (Alchornea, Syzygium, Uapaca) occupied the inter‐dune depressions. However, variation in the pollen records between sites suggests that their establishment was dependent on conditions being locally favourable, rather than being directly coupled to regional climate. The pollen records from the Manga Grasslands are more consistent in suggesting the colonization of the dunefields by trees associated with Sudanian savanna (Combretaceae, Detarium) c. 8700 cal. yr bp . The Jikariya Lake pollen data are in accordance with the sedimentological and geochemical data from the region in indicating that the onset of arid conditions occurred progressively during the late Holocene (from c. 4700 cal. yr bp ). Abrupt changes in pollen stratigraphy, recorded at other Manga Grasslands sites 3500 cal. yr bp , appear to be the product of the local passing of ecological thresholds. The dunefield vegetation (Sahelian savanna) appears to have been resilient to (or at least palynologically silent regarding) to the climatic variability of the late Holocene. Main conclusions While climate appears to have been the primary control on vegetation development in the Manga Grasslands during the Holocene, local conditions (particularly depression size and sand influx) had a strong influence on the timing of pollen stratigraphic changes. Anthropogenic influences are difficult to detect, even during the late Holocene.     

末次盛冰期以来沙漠-黄土过渡带植被演替及其对气候变化的响应

末次盛冰期(LGM)以来的增温期和全新世高温期是人类古文化进步的重要时期。黄土高原北部沙漠-黄土过渡带两个自然剖面高分辨率花粉分析结果显示,该区LGM以来为草原植被景观,但优势群落和伴生植物随气候变化而有所不同,温度和降水变化对植被演替有着重要的控制作用。气候干冷时,以耐干旱的草本植物种属为主,群落成分单一,植被盖度低;增温期和高温期,出现少量暖温带乔木植物如胡桃科、栎属等,植被盖度高,群落发育良好。全新世暖期是植被发育良好、植被盖度高的适宜期。本研究为黄土高原地区未来增温下植被响应的分析提供了历史相似型。     

Climate-related changes during the Late Glacial and early Holocene in northern Poland, as derived from the sediments of Lake Sierzywk

Reconstruction of past climate change and ecosystem response is important to correctly assess the impacts of global warming. In this study, we provide a paleoenvironmental record of in-lake and catchment changes in northern Poland during the Late Glacial and early Holocene using various biotic proxies (pollen, macrofossils and Cladocera) preserved in the lake sedimentary record. Chronology was derived from palynological correlation with a well-dated pollen sequence from nearby-lying Lake Ostrowite and some well-dated events of vegetation history in Central Europe. Pollen analysis provided information on regional climate change affecting vegetation dynamics, whereas macrofossils supplied substantial information on the response of local flora and fauna to climatic, geomorphological and limnological changes. Data were supplemented by analysis of Cladocera remains, which are of special importance because of their quick response to changes in trophic conditions and climate (especially temperature). The bottom of the sediment core reflects an initial stage of the lake formed during the late Aller?d. The Younger Dryas cooling apparently resulted in forest recession and presence of cold tolerant Cladocera species. Due to amelioration of climate at the end of the Younger Dryas and melting of ice, the lake deepened. The beginning of the Holocene was characterised by forest shrinkage and induced clear changes in local flora and fauna communities. The regional vegetation development deduced from the lake’s core is generally consistent with the vegetation history of central Europe. Due to the location of the site near the seashore (oceanic climate and western wind), signals of warming came earlier than inland and in eastern Poland.     

Climatic impacts on the vegetation of eastern North America during the past 2000 years

Pollen diagrams from seven lakes with annually laminated sediments sampled at 40-year intervals are analyzed to isolate the climatic effects from other effects on the long-term dynamics of vegetation during the past 1000–2000 years along a transect from Maine to Minnesota. Principal components analysis is used to reduce the dimensionality of the pollen data. The pollen records from all lakes show long-term trends, medium frequency oscillations, and higher frequency fluctuations. The long-term trend is associated with the neoglacial expansion of the boreal forest. The mechanism causing this replacement is a change in frequency of air masses in the area. The medium-frequency oscillations are also associated with climate changes, the most recent of which is the ‘Little Ice Age’. The climate-related mechanism causing the medium-frequency changes may be changes in disturbance frequency. The higher frequency fluctuations may also be related to disturbance. This analysis of pollen diagrams into time scales of variation has enabled the separation of climate from other factors affecting vegetation dynamics. By comparing the principal components across a transect of sites it proved possible to interpret the climatic effects on vegetation at most sites and not only at range boundaries and ‘sensitive’ sites.     

A Preliminary Study on Vegetation and Climate Changes in Dianchi Lake Area in the Last 40000 Years

This paper presents results of pollen analysis on sediments of core Cao 2 from Dianchi Lake. Four pollen zones are defined, namely zone I, which is further divided into four subzones, zone Ⅱ, zone Ⅲ and zone Ⅳ. Zone Ⅰ(ca. 47600–11800 yrs B. P.) is characterized by low land pollen sedimentation rates and constant presence of Abies pollen. In zone Ⅱ (ca. 11800–6900 yrs B. P.) broad-leaved tree pollen increases and Abies pollen gradually disappears. In zone Ⅲ (ca. 6900–3800 yrs B. P.) evergreen broad-leaved-tree pollen and total land pollen influx reach their maximum values while, Tsuga pollen decreases. Zone Ⅳ shows a great decreases in pollen influx of various pollen types and a increase in Monolete psilate spores. In the past 40000 years vegetation in this area trend changes from a dominantion of coniferous tree to an evergreen broad-leaved forest, co-existing or mixing deciduous broadleaved forest and coniferous forest. In the past 3800 years, due to climate changes and / or human activities, the vegetation cover in this area has been greatly reduced. The above vegetation changes indicate a climate change process from cool and humid, to warm and humid and finally to mild and dry.     

Vegetation and environment changes inferred from pollen records since 3000 cal. yr BP in Kanas wetland,Xinjiang

Aims Climate change can significantly affect the vegetation worldwide. Thus, paleovegetation and paleoclimate reconstruction should consider the quantitative relationship between modern vegetation and climate. The specific objectives of this study were (i) to assess the influence of environmental variables on pollen assemblages in the Kanas region, (ii) to reconstruct the evolution of vegetation over the past 3000 years using pollen records and (iii) to quantify historical climate change (including mean annual temperature and total annual precipitation) using a weighted averaging partial least squares regression method (WAPLS) applied to fossil pollen data from the Kanas wetland in Xinjiang, China.     

中国第四纪晚期孢粉记录整理

孢粉数据库是重建过去植被格局以及研究古气候变化和大气圈-生物圈-人类活动相互关系的基础,而孢粉取样信息的记录和整理是建立孢粉数据库的重要前提。该文在收集我国1960–2008年发表的孢粉研究文献的基础上,整理分析了第四纪晚期,尤其是2万年以来(全新世为主)全国孢粉采样点的信息,包括采样地点名称、详细采样位置、省份、采样点经纬度和海拔高度、样品类型、取样深度、孢粉样品数量、14C测年数量及年代记录、覆盖的时间段和参考文献。总结发现,我国目前共有2324个表土/湖泊表层花粉采样点和987个第四纪晚期的地层沉积剖面和钻孔,其中高质量的地层孢粉采样点714个。虽然我国以及部分国际上从事第四纪研究的科学家尽了最大努力开展中国疆域的孢粉学研究,但由于人力、物力以及地形条件的限制,在我国仍然存在部分孢粉采样的"地理空隙",比如北方和西北荒漠地区、青藏高原无人区、中南部山区和东部人类活动频繁区域。然而,该数据信息库的不断完善,将为中国第四纪孢粉数据库的建立奠定良好基础。