内蒙古自治区几个考古地点的孢粉分析在古植被和古气候上的意义

本文依据内蒙古自治区四个考古地点的孢粉分析资料,指出呼伦贝尔盟东部地区,在11400±230年前,不仅湖沼棋布,而且生长着由松、榆、椴、胡桃等组成的繁茂的温带针叶—阔叶混交林。公元前1700年,昭乌达盟敖汗旗一带,分布着暖温带针叶—阔叶混交林,从花粉分析说明那时的人类已摆脱了单纯狩猎,开始种植作物、饲养动物。自晚更新世以来,内蒙古植被由混交林向草原迅速的发展。     

黑石顶针阔叶混交林演替过程中群落结构动态

分析了黑石顶针阔叶混交林在１０年演变过程中的群落结构变化。结果表明,群落垂直分层日益明显;群落水平结构指标,盖度、密度、胸高断面积均有较大幅度增加;群落物种组成结构总体上变幅不大,但针叶树马尾松、杉木的优势地位明显衰弱,阔叶树木荷、腺叶山矾、鸭脚木等种的优势地位显著增强,整个群落由针叶阔叶混交林朝着阔叶针叶混交林演变;群落乔木层物种多样性、均匀度在增加,生态优势度在降低,群落向着复杂化、多层化方向     

长江三角洲东缘晚新近纪沉积的孢粉与古环境研究

作者对长江三角洲东缘地区的南汇鹤鸣孔(Hm)、东海1井、高桥G2孔3口钻井晚新近纪地层的孢粉作了研究和对比,划分出了6个孢粉组合带和3个亚带,恢复了本地区植被演替、气候波动的6个阶段:第1阶段为稀疏的针叶、落叶阔叶混交林,反映气候凉冷稍湿;第2阶段为针叶阔叶混交林草地,反映气候温凉略湿;第3阶段为含常绿阔叶树的针叶阔叶混交林,反映气候温和略干;第4阶段为以常绿栎类、栲属、杨梅等为主的常绿阔叶林,反映气候热暖潮湿;第5阶段是以栎、松、禾本科为主的针叶、阔叶混交林,反映气候温暖略干;第6阶段是以落叶栎类、常绿栎类、松为主的落叶阔叶、常绿阔叶、针叶混交林草地,反映气候温暖湿润。这种气候波动与世界性气候变化相一致,为本地区的地层年代划分和对比提供了新的证据,为晚新近纪古植被、古气候、古环境的重建提供了重要的孢粉学资料。     

鼎湖山马尾松针阔叶混交林土壤有效氮动态的初步研究

用离子交换树脂袋法测定了鼎湖山生物圈保护区马尾松针阔叶混交林土壤有效氮变化情况。鼎湖山马尾松针阔叶混交林土壤各季节平均总有效氮(铵态氮+硝态氮)在18.87～93.20μg/d*g干树脂之间,且具有明显的季节性变化特点。然而,这些季节性变化根据土层和有效氮组分的不同而异。总有效氮主要由铵态氮组成(>90%)。总有效氮和铵态氮在土层0～10cm和10～20cm之间各个季节均无显著的差异,但硝态氮在春、夏两季差异较大,尤其在夏季两土层之间的差异达显著水平(P<0.05)。在本研究样地中,硝化速率受铵态氮供应的影响不甚明显。与同一地区的马尾松纯林和阔叶混交林比较,硝态氮为针叶纯林<针阔叶混交林<阔叶混交林;铵态氮则为针阔叶混交林〉针叶纯林＞阔叶混交林。     

陕西省化龙山森林植被垂直分布的初步研究

 本文对陕西省化龙山植被的垂直分布特点进行了初步研究。文中采用了数量分类结合对群落生态特点及区系组成的分析,划分出森林植被垂直带如下：常绿、落叶阔叶混交林带,海拔1600m以下;落叶阔叶林带,海拔1600—2200m;亚高山针叶林带,海拔2200—2917m。     

太行山区不同植被群落土壤微生物学特征变化

为评价太行山区不同植被群落土壤微生物学特征,比较分析了针阔混交林、针叶混交林、针叶纯林、落叶阔叶纯林、灌丛和裸露地6种不同植被群落中的土壤微生物区系、微生物生物量和呼吸强度等指标的变化.结果表明,6种不同植被群落土壤中的微生物学特征存在较大差异. 灌丛地在微生物数量和微生物生物量两项指标中均为最高,其余植被群落在这两项指标中的顺序从大到小依次为落叶阔叶纯林＞针阔混交林＞针叶纯林＞针叶混交林＞裸地,土壤呼吸强度也有相似的变化趋势.在进行退化山地的植被恢复时,应充分重视生态系统的自然恢复能力.     

秭归县防护林健康评价指标体系的建立及应用

以秭归县防护林为研究对象,通过传统生态学调查和相关室内分析,在林分水平上建立了包括林分结构、林分功能、生态环境和健康风险4个一级指标、20个二级指标的防护林健康评价指标体系。在综合相关林分健康评价的基础上,制定防护林健康评价指标优劣等级表,采用Delphi-AHP法设置指标权重,利用生态系统健康综合指数模型计算防护林健康指数,分析秭归县防护林健康状况。结果表明:秭归县防护林健康综合指数的范围在0.5000—0.9000之间,健康指数均值为0.6921,秭归县防护林整体处于亚健康状态;9种防护林类型健康状况排序为:阔叶混交林针阔混交林针叶混交林阔叶纯林马尾松纯林柏木纯林其它针叶纯林经济林灌木林,即是混交林纯林经济林灌木林;秭归县防护林健康指数具有空间变异性,在水平方向上,秭归县辖下乡、镇防护林健康指数从南向北有逐渐递减的趋势,在垂直方向上,防护林健康指数随海拔增高逐渐增大,海拔1000 m以上逐渐降低,健康指数表现出随海拔升高由小变大、又由大变小的变化特点。     

北京市3种配置模式绿化带降噪效果的空间变化规律

为明确不同配置模式绿化带对噪声衰减效果的空间变化规律,以北京市的刺槐(Robinia pseudoacacia Linn.)纯林(代表阔叶纯林)、刺槐-小花溲疏(Deutzia parviflora Bunge)混交林(代表阔叶混交林)和侧柏〔Platycladus orientalis(Linn.)Franco〕-圆柏〔Sabina chinensis(Linn.)Ant.〕混交林(代表针叶混交林)3类绿化带为研究对象,设置不同高度、距噪声源不同水平距离和不同噪声频率3组变量,对3类绿化带的降噪值进行比较分析.结果表明:3类绿化带的降噪效果由高至低依次为针叶混交林、阔叶混交林、阔叶纯林.在不同高度和距噪声源不同水平距离处,3类绿化带对不同频率噪声有各自的降噪优势;其中,在高度0.5和1.5 m处,阔叶混交林对250~1000 Hz噪声的衰减效果总体上优于阔叶纯林,而阔叶纯林对4000 Hz的噪声衰减效果却优于阔叶混交林,并且,针叶混交林对250、500、1000和8000 Hz噪声的衰减效果总体上优于阔叶纯林;整体上看,在距噪声源水平距离超过10 m处,3类绿化带对125~1000 Hz噪声的衰减效果最优.相关性分析结果表明:3类绿化带的降噪率与噪声频率呈负相关,与距噪声源水平距离和单位面积三维绿量总体上呈正相关.其中,在高度0.5、1.5和2.5 m处,3类绿化带的降噪率与噪声频率和距噪声源水平距离总体上显著相关;而在高度0.5和1.5 m处,3类绿化带的降噪率与单位面积三维绿量总体上显著相关.从3类绿化带的降噪规律看,在距噪声源水平距离相同的位置,高度越低,绿化带的降噪值越大,其中高度2.5 m以下绿化带的降噪值均较大;在相同高度上,距噪声源水平距离10和15 m处3类绿化带的降噪值总体上较大,但在距噪声源水平距离15和20 m处针叶混交林的降噪值明显大于其他2类绿化带.根据上述研究结果,建议绿化带宽度应在10 m以上,在配置绿化带时,应选择分枝点低、枝叶密度大的树种,且在不影响树木生长的条件下尽量密植并适度配置灌木.     

琼东南盆地渐新统——上新统孢粉、藻类记录

本次工作对来自南海北部大陆架地区琼东南盆地LS33-1-1井和LS2-1-1井渐新统—上新统的孢粉、藻类进行了系统研究。通过孢粉分析,确定孢粉植物群,恢复古植被,推测古气候,建立了与气候变化趋势相关的孢粉组合序列。结果显示,研究区内渐新统崖城组、陵水组时期的植被类型是热带、亚热带常绿阔叶林及针叶、常绿、落叶阔叶混交林,气候条件较温凉湿润;中新统三亚组时期植被发展为热带、亚热带常绿阔叶林及常绿、落叶阔叶混交林,气候条件暖而湿润;中新统梅山组时期是气候逐渐变化的过渡期;中新统黄流组的植被类型为亚热带针叶阔叶、常绿和落叶阔叶混交林,气候条件温凉略干燥;上新统莺歌海组山地植被中针叶林或针阔叶混交林多有分布,常绿阔叶落叶阔叶林混交林继续扩大,草本植物空前发展,气候趋于凉干。孢粉组合所反映的渐新世—上新世气候变化特征与全球气候变化趋势具有较好的可比性。通过孢粉、藻类资料对沉积环境进行了初步研究,研究区渐新世以近岸浅海的沉积环境为主,为陆架边缘到内陆架区,中新统梅山组及其以上地层应形成于距岸较远海水较深的浅海环境。     

都江堰野生杜鹃花的垂直分布

都江堰市位于四川盆地西北部平原向高山峡谷区的过渡地带,区内自然生态条件变化剧烈,在仅约５０公里的水平范围内,海拔高度就从平坝地区的５９２米直升至境内最高峰光光山４５８２米,垂直高差达３９９０米;在面积约３００平方公里的范围内,具有平原、丘陵、中低山直至高山的各种地貌。随着海拔梯度的变化,区内保存着７个明显的植被垂直带,自下而上分别为：⑴中亚热带山地常绿阔叶林带;⑵中亚热带山地常绿、落叶阔叶混交林带;⑶山地常绿针叶、落叶阔叶混交林带;⑷亚高山暗针叶林带;⑸亚高山、高山灌丛带;⑹亚高山、高山草甸带;…     

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.     

青海湖地区植被及其分布规律

青海湖地区位于青藏高原东北部。境内复杂的地貌类型及青海湖的存在对植被有重要影响。本区植物种类贫乏,现有种子植物52科、174属、445种。主要植被类型有寒温性针叶林、高原河谷灌丛、高寒灌丛、沙生灌丛、温性草原、高寒草原、高寒草甸、沼泽草甸、高寒流石坡植被等。植被分布表现出明显的规律性变化。草原分布于湖盆及河谷地带,由东而西植被类型有更加适应寒旱趋势。温性草原以青海湖为中心;呈环带状分布,而高寒草原的分布则与生境寒冷干旱相一致。山地垂直带谱表现为草原带、高寒灌丛与高寒草甸带以及高寒流石坡植被带。本区植被水平地带性分异受到青海湖的影响,其植被组合及特征表现出与青藏高原植被的明显相似性。作为祁连山南麓中部地区的一个大型山间盆地,其东西方向界于青海省东部地区和柴达木盆地之间,植被东西方向的水平地带性并未表现出明显的过渡特征。根据植被特点及分布规律分析,本区植被有其自身的特殊性,并与青藏高原隆升之后气候寒冷干旱相一致。因此,青海湖地区就整体而言应属祁连山地区植被一个相对独立的组成部分。     

Mid-Holocene environmental and human dynamics in northeastern China reconstructed from pollen and archaeological data

A pollen record from the Taishizhuang site (40°21.5′N, 115°49.5′E) located in the transitional forest-steppe zone near the present-day limit of the summer monsoon is used to reconstruct vegetation and climate. Quantitative biome reconstruction suggests that between ca. 5700 and 4400 cal. years B.P. temperate deciduous forest dominated the vegetation cover around the Taishizhuang site. After that time the landscape became more open and the scores of the steppe biome were always higher than those of the temperate deciduous forest except for two oscillations dated to ca. 4000 cal. years B.P. and ca. 3500 cal. years B.P. However, ca. 3400-2100 cal. years B.P. the common vegetation became steppe and the landscape was more open in comparison with the previous time interval. The results of the pollen-based precipitation reconstruction suggest that annual precipitation was ca. 550-750 mm (ca. 100-300 mm higher than present) during the mid-Holocene ‘forest phase’, and ca. 450-650 mm during the following ‘forest-steppe phase’. From ca. 3400 cal. years B.P. during the ‘steppe phase’ annual precipitation was similar to modern values (ca. 300-500 mm). Archaeological records from 100 sites prove the habitation of northeastern China during the prehistoric and early historic periods from ca. 8200 cal. years B.P., but do not provide evidence of the use of wood resources intensive enough to influence the regional vegetation development and to leave traces in the pollen assemblages. Both archaeological and palaeoenvironmental data support the conclusion that changes in pollen composition in northeastern China between 5700 and 2100 cal. years B.P. reflect natural variations in precipitation and not major deforestation caused by humans.     

华北泥河湾盆地植被、气候与早期人类生存环境研究进展

中国北方泥河湾盆地可以与非洲奥杜威峡谷相媲美,它们具有十分相似的地质演化过程,这里河湖相沉积发育,并且蕴藏着丰富的古生物化石和大量古人类遗迹,是研究东亚早期人类生存环境变化的重要区域。基于前人积累的晚上新世以来植被、气候及早期人类生存环境的大量研究资料,经分析发现在大约2.6Ma(百万年),泥河湾盆地的植被由阔叶林转变为以针叶林为主;大约1.92 Ma以后,植被以温带森林-草原(主要是松属、蒿属及藜科)/温带草原(主要是蒿属和禾本科等)为主。通过对比发现,晚上新世以来中国北方从西部到中部,由森林转变为以森林-草原为主的植被类型出现的时段呈现明显的阶梯型。此外,泥河湾盆地气候出现了13个冷暖旋回, 15个干湿旋回,显著的冷干事件发生在2.8 Ma、2.6 Ma、1.92 Ma及143.8 ka (千年),湿润事件发生在43、32和6.6 ka。早期人类生活在森林-草原或以草原为主的植被环境中,气候冷暖干湿波动较大,水源丰富,大量哺乳动物共存。建议在建立泥河湾人类遗址更为精细地层的年代框架下,开展古气候温度与降水参数的定量化研究,将有助于精准重建古人类生存环境及揭示其变化规律。     

Environmental Reconstruction of Tuyoq in the Fifth Century and Its Bearing on Buddhism in Turpan,Xinjiang, China

The Thousand Buddha Grottoes of Tuyoq, Turpan, Xinjiang, China were once a famous Buddhist temple along the ancient Silk Road which was first constructed in the Fifth Century (A.D.). Although archaeological researches about the Grottoes have been undertaken for over a century, the ancient environment has remained enigmatic. Based on seven clay samples from the Grottoes’ adobes, pollen and leaf epidermis were analyzed to decipher the vegetation and climate of Fifth Century Turpan, and the environmental landscape was reconstructed in three dimensions. The results suggest that temperate steppe vegetation dominated the Tuyoq region under a warmer and wetter environment with more moderate seasonality than today, as the ancient mean annual temperature was 15.3°C, the mean annual precipitation was approximately 1000 mm and the temperature difference between coldest and warmest months was 24°C using Co-existence Approach. Taken in the context of wheat and grape cultivation as shown by pollen of Vitis and leaf epidermis of Triticum, we infer that the Tuyoq region was an oasis with booming Buddhism in the Fifth Century, which was probably encouraged by a 1°C warmer temperature with an abundant water supply compared to the coeval world that experienced the 1.4 k BP cooling event.     

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.     

A reciprocal transplant experiment within a climatic gradient in a semiarid shrub-steppe ecosystem: effects on bunchgrass growth and reproduction, soil carbon, and soil nitrogen

We investigated the effect of climate change on Poa secunda Presl. and soils in a shrub‐steppe ecosystem in south‐eastern Washington. Intact soil cores containing P. secunda were reciprocally transplanted between two elevations. Plants and soils were examined, respectively, 4.5 and 5 years later. The lower elevation (310 m) site is warmer (28.5 °C air average monthly maximum) and drier (224 mm yr^?1) than the upper elevation (844 m) site (23.5 °C air average monthly maximum, 272 mm yr^?1). Observations were also made on undisturbed plants at both sites. There was no effect of climate change on plant density, shoot biomass, or carbon isotope discrimination in either transplanted plant population. The cooler, wetter environment significantly reduced percent cover and leaf length, while the warmer, drier environment had no effect. Warming and drying reduced percent shoot nitrogen, while the cooler, wetter environment had no effect. Culm density was zero for the lower elevation plants transplanted to the upper site and was 10.3 culms m^?2 at the lower site. There was no effect of warming and drying on the culm density of the upper elevation plants. Culm density of in situ lower elevation plants was greater than that of the in situ upper elevation plants. Warming and drying reduced total soil carbon 32% and total soil nitrogen 40%. The cooler, wetter environment had no effect on total soil C or N. Of the C and N that was lost over time, 64% of both came from the particulate organic matter fraction (POM, > 53 µ m). There was no effect of warming and drying on the upper population of P. secunda while exposing the lower population to the cooler, wetter environment reduced reproductive effort and percent cover. With the warmer and drier conditions that may develop with climate change, total C and N of semiarid soils may decrease with the active fraction of soil C also rapidly decreasing, which may alter ecosystem diversity and function.     

Evidence of a Cooler Continental Climate in East China during the Warm Early Cenozoic

The early Cenozoic was characterized by a very warm climate especially during the Early Eocene. To understand climatic changes in eastern Asia, we reconstructed the Early Eocene vegetation and climate based on palynological data of a borehole from Wutu coal mine, East China and evaluated the climatic differences between eastern Asia and Central Europe. The Wutu palynological assemblages indicated a warm temperate vegetation succession comprising mixed needle- and broad-leaved forests. Three periods of vegetation succession over time were recognized. The changes of palynomorph relative abundance indicated that period 1 was warm and humid, period 2 was relatively warmer and wetter, and period 3 was cooler and drier again. The climatic parameters estimated by the coexistence approach (CA) suggested that the Early Eocene climate in Wutu was warmer and wetter. Mean annual temperature (MAT) was approximately 16°C and mean annual precipitation (MAP) was 800–1400 mm. Comparison of the Early Eocene climatic parameters of Wutu with those of 39 other fossil floras of different age in East China, reveals that 1) the climate became gradually cooler during the last 65 million years, with MAT dropping by 9.3°C. This cooling trend coincided with the ocean temperature changes but with weaker amplitude; 2) the Early Eocene climate was cooler in East China than in Central Europe; 3) the cooling trend in East China (MAT dropped by 6.9°C) was gentler than in Central Europe (MAT dropped by 13°C) during the last 45 million years.     

Recent greening of grasslands in northern China driven by increasing precipitation

近年中国北方草地变绿受降水增加的驱动 中国北方的暖湿化是近期的热点话题,然而其对植被生长的影响仍不清楚。本研究基于长时间序列(1982–2018年)数据,研究了归一化植被指数(NDVI)的时间动态及其气候驱动因子之间的关系,以探索近年来气候的暖湿化是否会导致该区植被变绿。我们采用分段回归探测了NDVI的变化趋势是否存在转变点,用Pearson相关分析描述了植被指数与气候因子的关系。最后,采用逐步多元回归方法研究了气候因子对NDVI时间变化的贡献率。研究结果表明,NDVI时间变化趋势的转变点出现在2008年,GIMMS NDVI在1982–2008年略有增加,上升速率为0.00022 yr⁻¹,在2008–2015年上升速率达到0.002 yr⁻¹,MODIS NDVI在2008–2018年上升速率为0.0018 yr⁻¹。降水是NDVI变化的主要驱动因子,气温和饱和水汽压差(VPD)对NDVI的变化影响较小。总体看来,NDVI时间序列变化趋势存在转变点,并且近期气候的暖湿化主导了中国北方草地植被变绿,这为今后更好地预测该地区气候变化下的植被覆盖变化提供了依据。     

青海可可西里地区的植被

青海可可西里地区位于青藏高原腹地,总面积8万多平方公里,平均海拔高度4600—5000m,是青藏高原,也是我国植被科学研究最大的空白地区。 根据1990年夏为期3个月的实地考察,发现本区由东南到西北主要分布着高寒草甸,高寒草原和高山冰缘植被。垫状植被、高寒荒漠和高山河谷灌丛等也有分布。植物区系组成以青藏高原成分为主,其次为中亚高山分布的种。各种植被类型的分布往往与地形部位和基质状况存在着密切的联系。