Vegetational and Climatic Changes in the Past 30,000-10,000 Years in Beijing

This paper is based on the informations of the sporopollen assemblages of 52 samples obtained from the Fenzhuang field outcrop and its drilling core near Zhoukoudian in the vicinity of Beijing. About 30,000 years ago of the Dali glacial period, spruce-fir forests became predominant in the low land and the plain in Beijing. At that time the annual mean temperature was about 7 ℃ lower than that of the present. Based on the characteristics of Fenzbuang sporo-pollen assemblages four zones may be subdivided in ascending order as follows: 1. In the first zone (FⅠ), the herbaceous plants, such as Artemisia, Chenopodiaceae, Gramineae, etc., were predominant. The climate was rather dry and cold. 2. In the second zone (FⅡ), the vegetation during the past 22000–13000 years was dominate of a subalpine conifer forest, consisting of Picea, Abics, Larix, etc., Water plants Myriophyllum, Typha, Sparganium and some members of Cyperaeeae and Green algae, Mougeotia, Zygnema apparently increased. Annual mean temperature was lower than that of the present. The climate was wet with an annual precipitation about 800–1000 mm and cool. 3. In the third zone (FⅢ), the vegetation was represented by a warm temperate forest, predominant of Pinus, Tilia, Selaginella sinensis and Typha. The climate of Beijing was rather wet, with an annual mean precipitation more than that of the present, and warm. The Lakes and bogs were better developed. According to the temperature increasing at this zone, we think the Pleistocene-Holocene boundary should be maked at about 12000 B.P. 4. In the Zone Ⅳ (FⅣ), Tilia was still flourishing and the water plants were better developed at his initial stage but afterwards they were obviously reduced, since 10000 years ago.     

Palynoflora of the Qarhan Saline Lake and Its Significance in Geography and Botany The S poro-Poilen Assemblages from CK2022 Drilling Core at the Bieletan

The pollen analytical investigations of a 101 m deep CK2022 drilling core from Bieletan of the Qarhan saline lake have been carried out. The Qarhan saline lake is situated at the Qaidam Basin. The climate is cold and dry. Annual mean temperature is about 0.1 ℃, and annual precipitation is 28–40 mm. The vegetation is of desert type, mainly composed of Chenopodiaceae, Compositae, Tamaricaceac, Cruciferae, Zygophyllaceae, Leguminosae and Gramineae. Gymnospermae are very poorly represented e. g. Ephedra and Sabina. Ferns are even scanty. Based on the characteristics of CK2022 drilling core sporopollen assemblages 32,000 4,000 years ago five zones may be subdivided in ascending order as follows: 1. In the first zone, the vegetation during the past 31, 000–25, 600 years was represented by a temperate shrub and semi-shrub desert plants, such as Chenopodiaceae, Artemisia and Nitraria were predominant. The hydrophytes, such as Typha and Pediastrum boryanum, apparently increased. The climate was wet and rather warm. By this time, lakes and bogs were better developed in this area. 2. In the second zone (Ⅱ), green algae was very flourishing, which indicates a shallow, stagnant and more or less mesotrophic fresh water habitat. The climate was wet and cold, The lakes and bogs were better developed. 3 . In the third zone (Ⅲ), the vegetation consisted of Ephedra, Chenopodiaceae, Artemisia and Nitraria. At the same time subalpine conifer and Betula may have grown by rivers. The climate was warmer and drier than before. 4. In the fourth zone (Ⅳ), Shrubby and semi-shrubby deserts were better developed, but trees, ferns and algae were obviously reduced 18, 000–11, 000 years ago. The climate was very dry and cold. 5. In the fifth zone (Ⅴ), Ephedra, Chenopodiaceae, Artemisia and Nitratia were still flourishing. Hydrophytes, some trees and mesophytes plants and Polypodiaceae appeared again. Due to the increased temperature at this zone, the Pleistocene Holocene boundary should be demarcated at about 11000 years. BP Since 30000 years age there were alternation of dilution and salinization once and again.     

The Paleovegetation and Paleoclimate during Time of Homudu People

The Homudu site was discovered closed to the northeastern part of the village Homudu in the Lochiang Commune of Yu-yao zhejiang sheng. The excavations were conducted in 1973–1974 and 1977–1978. Four layers of cultural deposits are super-posed one upon the other. The first and topmost layer corresponds to the middle layer at Sun-tse in Ch’ing-p’n Country, while the second layer represents the Ma-jla-bin Culture of Chiahsing Country. The third and fourth layers belong to a hitherto unknown culture, which has been provisionally named as the Homudu Culture. A palynologicai and paleobotanical study is made for showing the paleovcgetation and palcoclimate of that time. 1. The first sporo-pollen assemblage, obtaind from the fourth and lower part of third layers is marked by predominence of Gramineae pollen (11%–71%). The majority of Gramineae pollen is of large size. Exine is thin and more psilate. Annulus of the single pore is about 2.5–3.7 μm in wide. This kind of pollen very much resembles that of the recent rice (Oryza sativa). Besides that, the herbaceous pollen of Artemisia, Caulophyllum, Actinostemma, Polygonum, Rubia and some elements of Cyperaceae,Chenopodiaceae, Umbelliferae are noted. Pollen of trees and shrubs belong to Quercus, Castanopsis, Liquidambar, Mallotus, etc. Fern spores are of Lygodium. Ophioderma, Lemmaphyllum, Microsorium and Pyrrosia. A lot of plant remains (leaves and seeds) have been observed in the fourth layer: Chloran- thus fortunei, Magnolia coco? Phoebe sheareri, Lindera glauca, Camptotheca acumninata Prunus davidiana, Choerospondias axillaris, Trapa bispinosa, Quercus myrsinaefolia, Cas- tanopsis tibetana, etc. Sporo-pollen assemblage and plant remains reflect a subtropical everygreen and deciduous broad-leaved mixed forests flourished on mountain slopes and some rice fields scattered in the plains around the site. The climate of that time was warm and humid and rather warmer than that of the present. Radiocarbon tests of an acorn and a wood fragment unearthed from the fourth layer reveal that they date from about seven thousand years ago, corresponding to the Atlan- tic period of Europe. 2. The second sporopollen assemblage, obtained from the middle and the upper parts of third layer is predominent by pollen of trees, such as Quercus spp., Liquidambar formosana and others. In herbs, the pollen of Gramineae, Cypcraceae and water plants deereased, but those of Artemisia and Chenopodiaceae increased. The climate than was warm but somewhat drier than that of previous period. 3. The sporo-pollen assemblages from the second and the first layers were mainly composed of temperate elements, such as Quercus, Ulmus, Salix, Where the subtropical elements Liquidambar and Altingia decreased or completely disappeared.. These indicate that the climate become cooler than that of the previous periods. Radiocarbon tests of a wood fragment obtained from the second layer reveal that its date was from 5600 years ago, then the age of the second layer would correspond to the Subboreal period of Europe. A lot of rice pollen grains, along with a large amount of the remains of rice busks were obtained from the fourth layer in the site, which indicats that the rice plants were cultivated in China at least seven thousand years ago.     

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.     

Palynoflora at Late Miocene?aEarly Pliocene from Leijiahe of Lingtai,Gansu Province,China

Vegetation and climate changes of Late Miocene-Early Pliocene have been deduced based on pollen research from Wenwanggou and Xiaoshigou sections near Leijiahe village (ca 35°04′15″N,107°43′30″E). The two sections are quite famous of rich micromammalian fossils. Before ca. 6.5 Ma, open forest-grassland was distributed in the studied area indicating a temperate and humid condition at that time. In the period between ca.6.5 and 5.8 Ma BP (Late Miocene) predominance of Chenopodiaceae and Artemisia implies that desert or desert-grassland was developed in the area and the climate should be cold and dry. During the time interval from ca.5.8 to 3.4 Ma BP mixed conifer and broad leaved deciduous forest with a few subtropical tree taxa had replaced the arid desert vegetation indicating a warm and humid climate. The climate aridity event of Late Miocene can be correlated with the global climatic event.     

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。     

Airborne pollen calendar of the central region of Bursa (Turkey)

This report describes qualitatively and quantitatively the level of pollen in the atmosphere in the central region of Bursa. Turkey. In 1991, the season of maximum pollen concentration was from April to June, with a prevalence of arboreal pollen during the initial months, and of pollen from herbaceous plants in the latter months. During the year of research, 24 taxa of arboreal and 12 taxa of herbaceous pollen grains were collected and identified. In the region investigatedPinus, Cupressaceae/Taxaceae,Abies nordmanniana, Platanus orientalis, Olea europaea, Gramineae, Urticaceae, Chenopodiaceae/Amaranthaceae,Artemisia and Compositae were responsible for the greatest amounts of pollen. Some important allergenic pollens such asOlea europaea, Gramineae and Urticaceae were also found in high concentration. In this study, a pollen calendar for the region is presented.     

哈尔滨地区第四纪孢粉分析及其在地质学和植物学上的意义

本文依据哈尔滨地区不同地貌单元内三个钻孔和三个自然剖面孢粉分析资料,结合古地磁测试,热释光和放射性碳素年令测定,进行钻孔和剖面间对比,初步建立起哈尔滨地区第四纪孢粉组合特征,进而讨论了哈尔滨地区第四纪以来植物群发展和气候变化。     

Species richness and phylogenetic diversity of seed plants across vegetation zones of Mount Kenya,East Africa

Mount Kenya is of ecological importance in tropical east Africa due to the dramatic gradient in vegetation types that can be observed from low to high elevation zones. However, species richness and phylogenetic diversity of this mountain have not been well studied. Here, we surveyed distribution patterns for a total of 1,335 seed plants of this mountain and calculated species richness and phylogenetic diversity across seven vegetation zones. We also measured phylogenetic structure using the net relatedness index (NRI) and the nearest species index (NTI). Our results show that lower montane wet forest has the highest level of species richness, density, and phylogenetic diversity of woody plants, while lower montane dry forest has the highest level of species richness, density, and phylogenetic diversity in herbaceous plants. In total plants, NRI and NTI of four forest zones were smaller than three alpine zones. In woody plants, lower montane wet forest and upper montane forest have overdispersed phylogenetic structures. In herbaceous plants, NRI of Afro‐alpine zone and nival zone are smaller than those of bamboo zone, upper montane forest, and heath zone. We suggest that compared to open dry forest, humid forest has fewer herbaceous plants because of the closed canopy of woody plants. Woody plants may have climate‐dominated niches, whereas herbaceous plants may have edaphic and microhabitat‐dominated niches. We also proposed lower and upper montane forests with high species richness or overdispersed phylogenetic structures as the priority areas in conservation of Mount Kenya and other high mountains in the Eastern Afro‐montane biodiversity hotspot regions.     

Characteristics of the Later Hoocene Epoch Sporo-pollen Assemblage and Their Significance in Dabusu Lake,Qianan County,Jilin Province

According to the sporo-pollen analysis of the ten localities in Dabusu lake, it could be divided into two sporo-pollen assemblage zones from bottom to top: the lower series (1–2 bed) of Equisetum, lsoites sporo-pollen zone and upper series (3–6 bed) of Ranunculaceae, Chenopodiaceae, Aritemisia sporo-pollen zone. This paper deals also with the course that in the middle later period of the later Holocene Epoch the obvious change of paleogeographic environment is no less than twice in the area surounding Dabusu lake. As for the vegetation, the wet grassy marshland of temperate zone in which the pteridophyta Predominated turned towards meadow -steppe in which herbs predominated. While the wet climate turned towards arid climate and the fresh water lake turned towards salt lake.     

根据孢粉分析论青藏高原西部和北部全新世环境变化

通过对青藏高原西部班公湖钻孔和北部中昆仑山３个湖相剖面的孢粉研究,揭示青藏高原西部和北部地区全新世１万年期间植被的演替和气候变化,西部在全新世早期９９００－７８００ｙｒ．Ｂ．Ｐ．植被由荒漠转为草原,气候好转;中期７８００－３５００ｙｒ．Ｂ．Ｐ．,草原发展,气候较适宜,以７２００－６３００ｙｒ．Ｂ．Ｐ．为高温湿期,５５００ｙｒ．Ｂ．Ｐ．和３５００ｙｒ．Ｂ．Ｐ．出现干旱,晚期从３５００ｙｒ．Ｂ．Ｐ．至今植被为荒漠,气候干旱,其中７００ｙｒ．Ｂ．Ｐ．气候恶化。北部地区全新世时期为荒漠植被,当气候温湿时,蒿和禾本科,莎草科成份增加,藜科减少,气候干旱时则相反,北部全新世的气候分期和干湿波动与西部相近,两地在晚期气候朝干旱化发展。     

A Preliminary investigation on the Vegetational and Climatic Changes Since 11, 000 Years in Qinghai Lake An Analysis Based on Palynology in Core QH85-14C

Qinghai Lake is the largest inland saline lake in China. it is situated in the northeastern part of the Qinghai Xizang Plateau. This paper is based on the information of the sporo-pollen assemblages of 47 samples from the drill core and surface samples. The general treads of vegetational and climatic changes since 11,000 years B. P. may be subdivided in ascending order as follows: In the first stage which corresponds to zone Ⅰ of the sporo-pollen assemlage, the vegetation during the past of 11,000–10,000 years was represented by a temperate shrub, semi-shrub and steppe, consisting of Chenopodiaceae. Artemisia, Nitraria, Ephedra and Gramineae were predominant. At the same time, some subalpine conifers, Pinus, Picea and Betula, would grow by the side of rivers and lakes, the climate was warmer and wetter than that of the Late Pleistocene. Due to the rising temperature in this zone, the Pleistocene-Holocene boundary might be estimated at about 11,000 years B. P.. The vegetation of the first stage belonges to temperate steppe with a few trees: In the second stage (ZoneⅡ of pollen), the vegetation was characterized by a temperate forest steppe during this period of 10,000 to 8,000 years B. P. Forest area apparently increased and some broadleaf deciduous and need leaf evergretn trees, such as Quercus, Betula, Pinus and Picea, grew by lakes and on mountains. At this time, the climate was warmer and wetter than that of the first stage. In the third stage (Zone Ⅲ) between B,000 and 3,500 years B. P, The vegetation was composed of a temperate mixed broad-leaf deciduous and needle-leaf evtrgreen forest. The needle-leaf evergreen forest consisting of Picea, Pinus, Abies, Betula grew in temperate zone mountains. The climate was relatively warm and wet. The fouth stage (zone IV), the vegetation was dominated by shrub semishrub, dwarf semishrubs, steppe and semi-arbors. Some trees consisting of Betula, Picea, and Pinus decreased in number in the lake regions. Some subalpine cold temperature evergreen trees, such as Abies and picea disappeared from the lake region. This indicated that the climate was warmer and drier during the past 3500–1500 years B. P. than the third zone. In the fifth stage (pollen zone V), the vegetation comprised steppe and desert from 1500 years ago to the present time. Some arborealtrus such as Betula and Pinus were less increased about 500 years B. P. at this time the temperate and wet slightly, rose up. From the above analysis, it is clear that the Qinghai lake region has been confronted with the vegetational and climatic changes since ll,000 years B. P. Therefore, the palynoflora of the Qinghai lake has its significance in Geography and vegetational history.     

湖北秭归盆地中侏罗世陈家湾组孢粉组合的发现及其意义

本文首次报道了湖北秭归盆地陈家湾组孢粉组合,该组合可归入Cyathidites minor-Classopollis Callialasporites为代表的组合,时代属中侏罗世。陈家湾组孢粉组合的特征反映了秭归盆地中侏罗世泄滩组、陈家湾组和沙溪庙组三个组的孢粉组合的面貌基本一致,仅早期组合与中、晚期组合略有差别。建议以Gyathidites minor-classopollis-callialasportes组合代表湖北西部——重庆地区中侏罗世孢粉组合,早期为Lunzisporites pallidus亚组合,中晚期为Converrrcosisporites venitus亚组合。根据孢粉植物群在本区侏罗纪垂直分布情况,提出早侏罗世时期属亚热带一热带炎热潮湿气候环境,植物生长茂盛;早侏罗世之后,潮湿的气候仍占主导地位,但出现了干旱的先兆;中侏罗世早期进入了半干旱阶段,随后即为炎热干旱的气候所笼罩;至晚侏罗世达到非常干旱的程度,植物种类十份单调,唯有掌鳞杉科植物占据着统治地位。     

云南元谋盆地上新世甘棠组植物和孢粉组合及其古气候意义

云南元谋盆地湾堡甘棠组植物群的叶化石和孢粉化石合计107种类型,分属86属,47科。植物叶化石包括18科,24属,35种。除一种裸子植物外,其它均为被子植物。被子植物中,榆科、桦木科、豆科无论属种或者化石数量都是最多;杨柳科、槭科、蔷薇科次之;壳斗科、樟科、杨梅科、鼠李科、忍冬科、胡颓子科、杜鹃科、香蒲料、禾本科均有代表。甘棠组的孢粉植物群也相当丰富,合计97个类型,分属72属,44科。以松科、榆科、禾本科及蕨类植物的水龙骨科最为丰富,胡桃科、壳斗科、金缕梅科及蕨类植物的凤尾蕨属也很常见。被子植物花粉占孢粉总数的50%--60%,以禾本科和榆属花粉含量最高,多在10%以上。裸子植物绝大部分为松科花粉,占孢粉总数的20%-30%。孢子以水龙骨科和凤尾蕨属为主,二者各占孢粉总数的5%-10%。发现于元谋盆地湾堡甘棠组的植物叶化石以及孢子花粉组合在成分上都是混合的类群。组合中既有相当多的湿润亚热带常绿阔叶林成分,也有耐干旱的胡颓子、杨梅、旱蕨等灌木、小乔木或草本分子,同时还有含量很高的、在半干旱环境下也能生存的禾本科、榆科花粉。据此推测甘棠组的植物群和孢粉组合反映了上新世时元谋地区的植被已经分化,盆地的周围山地生长有松科、壳斗科、樟科、胡桃科、金缕梅科为主的常绿和落叶阔叶树木或林块,可能有少许杜鹃科小乔木混杂其中,属于地带性植被。而在盆地内则是以禾本科、蔷薇科等为主,杂以大戟科、豆科、忍冬科、杨梅科等灌木或草本植物以及榆科、桦木科等树木组成的稀树灌丛草原型植被。盆地内的植被所反映的气候和周边地区相比,显得明显干旱。因此推测元谋盆地在2-3百万年前的中晚上新世已经发育成为金沙江流域的干热河谷盆地之一。     

The late Pleistocene climates of the Lake Zeribar region (Kurdistan,western Iran) deduced from the ecology and pollen production of nonarboreal vegetation

The concept of an arid pleniglacial in the Middle East depends primarily on the interpretation of pollen diagrams including those of Lake Zeribar in the Zagros Mountains of western Iran. It has been assumed that Lake Zeribar was surrounded by a Chenopodiaceae-Artemisia steppe and that the climate was therefore dry. Both assumptions are questioned. The environment of Pleistocene Lake Zeribar may have been similar to the tragacanthic or alpine zone of the modern Zagros Mountains. The dominance by pollen of Chenopodiaceae and Artemisia is explained by low pollen production of high-altitude vegetation, preferential incorporation of pollen of late-blooming plants into the sediments, and high production and long-distance transport of lowland pollen. In any case, high percentages of Chenopodiaceae and Artemisia pollen do not necessarily indicate low annual precipitation but a highly seasonal climate with cold winters and hot, dry summers. Such a climatic regime was in effect continuous except for a period beginning about 10600 B. P. during which summer rainfall or reduced summer drought occurred. This change in seasonality resulted in the dominance of Poaceae pollen and the initial increase in arboreal pollen. A moisture curve based on the ratio between Chenopodiaceae and Artemisia pollen indicates a pleniglacial climate with wet winters and a late-glacial and early-Holocene climate with periods of intense aridity. The climatic history presented here is compatible with non-palynological evidence of regional late Pleistocene climates and with seasonality changes suggested by climatic modelling based on orbital parameters.Abbreviations C/A Chenopodiaceae-Artemisia ratio     

太湖东部平原平望孔全新世环境演变地层记录

通过对太湖东部平原平望钻孔的年代、有孔虫和孢粉分析,探讨了该区域全新世植被变化与环境特征。结果显示全新世(11.5 kaBP)以来,太湖东部平原未受到广泛海侵的影响,主要是以淡水湖泊-沼泽沉积为主。该区域在4 kaBP以后,才有大面积的水稻种植。11.0—9.1 kaBP,以常绿-落叶阔叶林为主,花粉浓度较小,木本植物和水生湿生植物花粉含量增加,整体环境温凉偏干,但湿度逐渐增大,指示东亚季风逐渐加强。9.1—5.8 kaBP,花粉浓度最大,木本植物花粉含量略有减小,草本植物含量明显增加,主要是水生、湿生花粉的含量增加明显,平均达到32%,藻类含量为整个钻孔最大,其中在8—7 kaBP前后常绿类花粉含量较大,水生湿生花粉、淡水藻类的含量达到整个剖面最大,推测此时区域湿度最大,东亚夏季风最为强盛。5.8—1.3 kaBP常绿阔叶林百分比含量增加,落叶阔叶花粉含量减少,陆生草本植物的含量增加,水生湿生草本的含量减小,主要以常绿-落叶阔叶林为主,环境较前一带略干,东亚夏季风减弱。     

西欧地中海地区中新世以来的植被演化和现代地中海植被的形成

从距今2500万年的中新世初到更新世,欧洲地中海沿岸地区的植被是从东亚型的热带——亚热带常绿阔叶林逐渐过渡为旱生性的蒿——藜草原。古热带和亚洲、北美成份从晚中新世起逐渐消失,少数一直延续到中更新世。孢粉分析表明,地中海成分从中上新世起有明显增加,地中海常绿硬叶林的发展与北极冰盖的形成密切相关。     

A survey of modern pollen and vegetation along a south–north transect in Mongolia

Aim This modern pollen‐rain study documents the spatial and quantitative relationships between modern pollen and vegetation in Mongolia, and explores the potential for using this relationship in palaeoclimatic reconstructions. Location East‐central Mongolia. Methods We collected 104 pollen surface samples along a south–north transect across five vegetation zones in Mongolia. Discriminant analysis was used to classify the modern pollen spectra into five pollen assemblages corresponding to the five vegetation zones. Hierarchical cluster analysis was used to divide the main pollen taxa into two major groups and seven subgroups representing the dry and moist vegetation types and the main vegetation communities within them. Results Each vegetation zone along the transect can be characterized by a distinctive modern pollen assemblage as follows: (1) desert zone: Chenopodiaceae–Zygophyllaceae–Nitraria–Poaceae pollen assemblage; (2) desert‐steppe zone: Poaceae–Chenopodiaceae pollen assemblage; (3) steppe zone: Artemisia–Aster‐type–Poaceae–Pinus Haploxylon‐type pollen assemblage; (4) forest‐steppe zone: Pinus Haploxylon‐type–Picea–Artemisia–Betula, montane forb/shrub and pteridophyte pollen assemblage; and (5) mountain taiga zone: Pinus Haploxylon‐type–Picea–Poaceae–Cyperaceae, montane forb/shrub and Pteridophyte pollen assemblage. Main conclusions Based on the ratio between the major pollen taxon groups and subgroups, we propose two pollen–climate indices that represent the precipitation and temperature conditions in the study region. When plotted along our south–north transect, the moisture indices (M) and temperature indices (T) mimic the regional gradients of precipitation and temperature across Mongolia very closely. These pollen–climate indices can be used for palaeoclimatic reconstruction based on fossil pollen data.     

青藏高原东南部18ka以来气候与水文变化

青藏高原东南部众多封闭小湖的湖相沉积记录着重要的地理信息,是恢复当地晚更民以来古环境演变的理想材料。西藏海登湖和仁同分辨率的花粉组合,ＡＭＳ＾１４Ｃ测年及磁化率和有机质含量测定,揭示了研究区与鳊季风密切相关的古植被,古气候和古水文变化历史。高分辨率的花粉记录反映,在１６ｋａＢｍ,Ｐ,以前花粉组合以黎科（Ｃｈｅｎｏｐｏｄｉａｃｅａｅ）和蒿属（Ａｒｔｅｍｉｓｉａ）为主,花粉浓度很低,应为荒漠草原植被。     

Late Holocene palaeoenvironment change in central Tianshan of Xinjiang,northwest China

The northern slopes of central Tianshan Mountains in Xinjiang, northwestern China can provide an ideal database to research palaeoclimate as disturbance by human impact is relatively low and the vegetation zones reflect climatic gradients. In order to establish the correlation between modern climatic factors and surface pollen assemblages and to reconstruct palaeoclimate on the northern slope of central Tianshan Mountains, three Holocene sections in Daxigou, Huashuwozi and Sichanghu located at different elevations and vegetation zones were chosen for study. A total of 80 surface pollen samples in 86 vegetation quadrats were collected for pollen‐vegetation relationship analysis. The Warmth Index (WI) and Moisture Index (MI) were calculated based on averaged modern climate data during 1951 – 2000 at eight weather stations in the study area. Pollen percentages of Picea, Artemisia, Chenopodiaceae, Ephedra, and Tamarix, as well as A/C (Artemisia/Chenopodiaceae) and AP/NAP (arboreal/nonarboreal pollen) ratio were selected as pollen variables and WI and MI were chosen as climatic variables. The relationship between pollen percentages (Picea, Artemisia, Chenopodiaceae and Tamarix), A/C, AP/NAP ratio, WI and MI values were estimated (95% confidence interval) using stepwise multiple linear regression analysis. WI and MI values for the three sections were calculated using these regression equations, and palaeoclimate for the study area could be reconstructed. The results showed periods of both cool‐humid and warm‐dry conditions on the northern slopes of Tianshan Mountain during the late Holocene.