全新世中国典型地区孢粉记录的生态环境与新石器文化关系

新石器文化与全新世生态环境变化的关系是学术界关注的热点问题。通过对筛选出的中国典型地区孢粉记录的生态环境和具有年代数据考古遗址的综合分析,初步认为:1)典型地区全新世生态环境变化与新石器文化之间具有较密切的关系,中全新世温暖湿润期的生态环境宜于这一时期的文化发展; 2)东亚季风是影响典型地区新石器文化发展的重要因素之一;不同地区的地形和水位在一定程度上也影响了区域文化的发展; 3)约4.3～4.2 ka BP的全球事件在典型地区表现明显,太阳辐射减少和东亚冬夏季风的变化可能是影响典型地区生态环境变化和新石器文化衰退乃至消失的主要因素; 4)高分辨率孢粉记录的生态环境、考古遗址的系统测年、生态环境与文化发展的耦合机制等是未来需要深入研究的方向。     

中亚河中地区青铜时代以来绿洲农业的演化与文明的交流

中亚河中地区是东西方文明交流的重要通道,当地干旱的气候对环境变化十分敏感,同时大量保存良好的考古遗迹使得该地区十分适合进行农业活动与文明交流的相关研究。本研究通过年代学与植物考古学方法,对阿姆河流域范围青铜时代晚期至萨珊波斯时期的考古遗址进行研究,尝试重建区内全新世人类农业活动的发展过程,并分析研究4000 BP以来人类的农业活动对环境变化的响应与适应。研究结果显示,河中地区农业的作物构成自4000 BP的青铜时代晚期就已表现出高度的复杂性。虽然在不同的时期不同类型作物的种植比例存在一定的差别,但当地的作物始终以大麦、小麦为主,辅以粟、黍、豆类等谷物及葡萄等果木,自青铜时代晚期形成后这种综合了东西方元素的绿洲农业便保持稳定;后期虽有水稻等作物加入但并没有对已有结构产生较大的影响。本研究为进一步了解中亚内陆干旱-半干旱地区绿洲农业的结构演化及其对环境变化的响应,以及探究不同起源地区作物在亚欧大陆的传播提供了基础资料和新的视角。     

哈克地区全新世生态环境演变与人类文化的发展轨迹

哈克遗址是呼伦贝尔地区一处重要的细石器遗址,对划分和确立东北地区细石器文化的类型及其渊源具有重要的价值。遗址位于海拉尔河东、北、南三面环绕而形成的半封闭式高平台小岛上,自下而上基本存在着四个时期的文化堆积,其中,包含细石器文化遗存的堆积物的厚度最大。岩性、岩相、碳酸钙含量检测和植物孢粉分析等方面的综合信息表明,全新世以来地层垂直沉积和气候变迁波动是同步发展的。人类依环境优劣而留居或迁徙,其文化发展从早到晚经历了新石器、辽至蒙元、明清时期的历史演变,变化始终伴随着气候的波动,表现出以适应为特征的生存与繁衍轨迹。     

宁晋泊晚更新世孢粉组合及其古环境演变

宁晋泊是河北平原南部三大古湖群之一,通过LN42．5m厚沉积剖面的孢粉分析,获得古植物群演替达近20次,反映古气候变化具明显冷暖气候旋回5次以上,其中有2次寒冷期,3次湿暖期。结合6．4m以上~(14)C年龄数据推断计算晚更新世与全新世界线在7．5m,这一界线与孢粉植物群、古气侯与古环境等分异界线非常吻合。因此作者推断宁晋泊的形成、发展与消亡时代相应在晚更新世早期的温暖期,全新世高温期再次复兴,后被河流沉积物所掩埋而消亡形成洼地。     

偃松次生木质部的结构及其对环境的适应

用光学显微镜,偏振光显微镜和扫描电镜野生与栽培偃松的次生木质部结构,研究表明,茎与要支条生长轮均呈现偏心生长、心;边材区明显,管胞具螺纹裂隙及径裂隙及径列条,胞间具明显的胞间隙。射线管胞分布于射线边缘或中间,或只由射线管胞组成低射线。横生树脂道位于纺锤形射线中,纵生树脂道的数目与生长轮宽度有负的相关性,交叉场纹孔式窗格状。野生的矮化偃松,表现出一定的应压木特征。     

气候变化背景下我国农业热量资源的变化趋势及适应对策

根据区域气候模式PRECIS输出的未来A2气候情景（2011-2050年）以及基准气候时段（1961-1990年）的逐日资料,对2011-2050年我国农业热量资源的变化趋势进行了预测.结果表明: 与1961-1990年相比,未来A2气候情景下,2011-2050年我国大部分地区的平均无霜期日数延长趋势明显,主要表现为终霜冻日的提前和初霜冻日的推迟;各地日均气温稳定通过0 ℃的持续日数也明显延长,大部分地区延长了1～14 d,其中2041-2050年,青藏地区大部、长江中下游地区大部、甘新地区西部和西南地区北部均可延长49 d;我国大部分地区≥0 ℃积温均呈增加趋势.为适应未来农业热量资源的变化,应进一步调整农业种植制度、优化农业生产布局和发展生物技术等,以实现我国农业的可持续发展.     

未来10年黄土高原气候变化对农业和生态环境的影响

利用区域气候模式PRECIS输出的未来A2和B2气候情景及基准气候时段逐日资料,选择生态环境极其脆弱的黄土高原为研究区,分析了未来10a黄土高原气候变化特征及其对主要农作物和生态环境的影响。结果表明,未来10a,黄土高原光热资源增加,降水量减少。增温将对冬小麦和春玉米产量影响较大,对马铃薯产量的影响程度可能较小,但降水量减少对主要农作物的产量都有较大影响。在主要作物品种不发生较大变化的前提下,作物生育期太阳辐射和积温增加可能导致生育期需水量增加10%-15%,冬小麦、春玉米和马铃薯的播期分别延迟或提前1-3d,收获期提前1-2d,生育期缩短3-5d,可能引起冬小麦和春玉米气候产量下降50%-100%。未来10a,降水量减少可能导致草地盖度的增幅下降和人工林地稀疏化,引起黄土高原片状水力侵蚀程度下降。但突发性暴雨洪水和土地利用现状改变可能增强切沟溯源冲蚀能力,增加了黄土高原水土流失和农田及道路被冲毁的风险。     

中国农业环境效率时空演变及其驱动因素

农业环境效率是衡量经济与资源环境协调发展的重要指标,研究农业环境效率对实现农业资源的高效率利用具有重要意义。基于2004-2019年中国30个省（市、区）面板数据,运用SBM （Slacks-based model）模型、空间马尔科夫链、GIS技术和空间计量模型,分析了农业环境效率的时空演变特征,研究了农业环境效率变动的驱动因素。结果表明：（1）2004-2019年,考虑非期望产出的农业环境效率要低于不考虑非期望产出情况,呈持续上升趋势;区域差异整体呈倒"V "型变化趋势,东西方向上递减,南北方向上呈" U"型趋势特征。（2）中国不同等级的农业环境效率空间差异明显,地理空间格局在空间演变过程具有重要作用,空间关联性特征显著,不同类型的演变存在显著的时空惯性。（3）中国农业环境效率存在空间溢出效应,农业经济水平、环境规制、农业生产能力是提升农业环境效率的关键因素,财政支农水平、工业化水平、农作物种植结构、农业机械强度则是制约效率提升的约束要素。     

中国红树植物营养器官的结构与生态适应的研究Ⅲ.茎

本文主要报道分布在我国热带、亚热带海岸的10科13属17种红树植物,在特殊的生态环境下,茎的形态结构特征与趋同适应。阐明生境对植物形态结构的密切影响。     

气候变化对呼伦湖湿地及其周边地区生态环境演变的影响

利用呼伦湖湿地的气象资料、水体面积、水位深度和生态环境等资料,回归统计分析表明:(1)呼伦湖湿地近45 a来的气候变化呈现出暖干化趋势,并且是造成水资源短缺和周边地区生态环境恶化等问题的重要原因.(2)呼伦湖水域面积和水位逐渐减小的变化趋势一致.水域面积和水位变化率分别为34.78km2/10a、 0.27m/10a.且1959～1963年、1983～1991年为缓慢的增加(上升)时期,1964～1982年、1992～2006年为逐年减少(下降)时期,21世纪初至今减少(下降)幅度最大.(3)降水量与湖面面积、水位呈正相关,年及四季降水量增加10mm,湖面面积约增加2～19km2.气温和蒸发量与湖面面积、水位相关为显著的负相关,年及四季气温升高1℃,湖面面积约减少28～80km2,水位约下降4cm左右.(4)受显著的暖干化影响,湖周边沙漠化面积已超过100km2;到1997年草场的退化面积占可利用草场总面积的30%以上;1974年以来植被的盖度降低15%～25%,连续干旱的2003～2005年与降水量较多的2002年相比,克氏针茅高度降低11cm,羊草、苔草、多根葱和小针茅降低2～4cm;草地初级生产力下降30%～50%;优良牧草比重下降,严重退化草场的产草量不足原来的20%.     

张掖西城驿遗址新石器时代晚期-青铜时代人类冶金活动的元素地球化学记录

本文通过张掖西城驿遗址文化层沉积物及现代表土沉积物元素地球化学分析,结合高分辨率碳化植物种子¹⁴C 测年和最新考古发掘资料,揭示了西城驿遗址4200-3500 BP cal期间人类活动特征,佐证了不同文化阶段人类冶金活动强度变化。Rb/Sr比值、磁化率和重金属元素(Cu、Zn、Pb、As、Ni)含量变化过程显示,西城驿地区4200-4000 BP cal马厂文化时期人类活动增强,冶金活动开始出现;4000-3700 BP cal西城驿文化时期出现了冶金高峰期;四坝文化时期(3700-3500 BP cal)冶金活动强度相对减弱。     

Similarities and dissimilarities,synchronisms and diachronisms in the Holocene vegetation history of the Balearic Islands and Sicily

In some continental and island sites in the western Mediterranean basin, the Holocene vegetation and climate dynamics seem to show the same patterns in time and space. Nevertheless, different synchronous scenarios have been proposed from other south European, North African and Near Eastern pollen records from around the Mediterranean basin. Striking similarities and synchronisms have been found between Sicily and the Balearic Islands. These islands, although under different bioclimatic influences, show similarities in the main trends of vegetation and climate dynamics during the Post-glacial. Lago di Pergusa is the only natural inland lake in Sicily and because of its geographical location, has a good potential sensitivity to the climatic changes of the Mediterranean basin. Likewise, coastal sediments from Minorca and Majorca, the Balearic Islands, have similar peculiarities. The present-day environmental situation, now that most of the natural vegetation in these islands has disappeared, has been brought about either by a climatic trend towards increasing aridity or an increase in human activities. It seems clear that prehistoric human people alone could not have caused all the environmental changes recorded in the last millennia in both places.     

Vegetation history of the SE section of the Zagros Mountains during the last five millennia; a pollen record from the Maharlou Lake, Fars Province, Iran

A pollen diagram was derived from a 150 cm core taken from the shallow hypersaline Lake Maharlou in the south-eastern part of the Zagros Mountains, SW Iran. The pollen record shows that Quercus brantii woodland and Pistacia–Amygdalus scrub dominated the area during the late Holocene. The record starts at around 5700 cal b.p. with a dry period during which both Pistacia–Amygdalus scrub and Quercus brantii woodland were at their minimum extent. This period was followed by the expansion of Pistacia–Amygdalus scrub in the area and the spread of Quercus brantii woodlands at higher altitudes. An important occupation phase, characterized by the appearance of several cultivated tree species such as Juglans, Olea, Vitis and Platanus, started at ca. 4300 cal b.p., coinciding with the onset of the Bronze Age civilization of Jiroft in Central Iran. Human activities become very clear after 3700 cal b.p. Around 2700 cal b.p., extensive stands of Pistacia–Amygdalus scrub became profoundly degraded, presumably under strong human pressure coinciding with the beginning of the Persian Empires. The maximum expansion of the Quercus brantii woodland occurred about 2100 to 1700 cal b.p. This woodland remained relatively stable until the end of the diagram at 400 cal b.p.     

Annually laminated lake sediments and environmental changes in Bashang Plateau, North China

Angulinuo Lake is the biggest lake on the Bashang Plateau, North China, and is 47.6 km² in area and 2-6 m in depth. A core from the inner part of Angulinuo Lake was sliced and the sediment was observed by Scanning Electronic Microscope (SEM). Annual laminations characterized by variable color and grain size were found and interpreted as recording the cyclic deposition of lacustrine clay and aeolian dust. The results of chemical analysis of coarse grains conducted by SEM-EDAX, and grain size analysis of modern aeolian dust in the ice on Angulinuo Lake, support an aeolian origin for the light coarse layers. Image analysis technique was used to calculate the size and number of coarse grains in each layer. The coarse grains were fractionated into four classes: > 42 μm, 14-42 μm, 14-4.2 μm and 1.4-4.2 μm. In general, the abundance of the four classes shows similar temporal variation patterns. Around Angulinuo Lake, the winter monsoon is strong and transports aeolian dust into the lake. When the winter monsoon is strong, the size and amount of coarse grains are expected to increase. We infer that the winter monsoon was weaker during 8430-5440 year BP, and was unstable in the later part of this period. From 5440 year BP, the winter monsoon became stronger, and then weaker from 3250 to 2490 year BP. During 2490-1170 year BP, the winter monsoon was slightly stronger, but since 1170 year BP, it has become weaker again. The changes of the winter monsoon intensity recorded in the annual laminations in Angulinuo Lake sediments correspond well to environmental changes in North China and to changes in sea level during the same period. Periods of weaker winter monsoon correspond to times of higher sea levels while the periods of stronger winter monsoon correspond to the Neoglaciation stage in China and the periods of lower sea levels.     

Reconstruction of climate change during the Holocene in western and central Europe based on pollen records of indicator species

On the basis of distribution maps showing the first pollen occurrences in the Holocene of the well-known climate indicators Hedera, Ilex and Viscum as well as data for Corylus, a series of maps have been prepared that show summer and winter isotherms at various time intervals during the Holocene. From these maps climate curves for Amsterdam, the Netherlands have been set out. These were compared with curves for the Eemian at the same site. In both of these warm periods there is evidence for increased seasonality in the early phases which were relatively continental. Changes in insolation could account for such differences. Summer optima occurred earlier than winter optima. Changes in land-sea distribution are important, especially with regard to the patterns in winter climate. During the latter half of the Eemian, the climate was distinctly more oceanic than in the Holocene. Early in the Holocene, an influx of warm ocean water resulted in higher winter temperatures in the Gulf of Biscay, the Irish Sea, and areas east of Skagerrak-Kattegat. Temperature decline after the climatic optimum was greatest in the north, i.e. at 60°N, where a depression in the order of 2°C in summer and 2–3°C in winter occurred. Temperature decline was less farther south, i.e. at ca. 50°N, where a distinct west-east gradient in temperature change can be observed.     

黄土高原中南部农果复合型生态农业生产力特征

以黄土高原中南部的西坡、飞马河和南沟3村为对象,研究了农果复合型生态农业的生产力特征.结果表明,(1)同一植物各器官的生产力果实最大,茎叶次之,根最小;(2)农果复合型生态农业中,农业子系统越发达,系统生物生产力越高,经济生产力越小,经济产值越低;果业子系统越发达,系统生物生产力越小,经济生产力越高,经济产值越高;(3)畜牧业子系统生产力均处于相对较低的水平,制约了系统总生产力的提高.     

环境因子对农业土壤有机碳分解的影响

为研究环境因子对有机C在农业土壤中分解的影响 ,在不同温度、水分及土壤质地下进行小麦和水稻秸秆及其根培养实验 ,结果表明 ,在同样的水热条件下 ,秸秆有机C的分解量大于根的分解量 .在温度较低情况下 ,升高温度促进了有机C的分解 ;而在温度较高的情况下 ,升高温度对有机C分解的促进作用降低 .在非淹水条件下 ,温度对有机C分解的影响随着时间的延长而逐步减小 .淹水条件下培养一周后 ,温度对有机C分解的影响不随时间而变化 .当含水量为 30 0 g·kg-1和 5 0 0 g·kg-1时 ,有机C分解较快 ,而在 2 0 0 g·kg-1和淹水条件下则分解较慢 ,空白对照培养结果的趋势是分解速率随水分含量的增加而加快 .培养实验的第一个月内 ,小麦秸秆有机C的分解量与土壤粘粒含量呈负相关     

甘南高原农户对极端天气的适应障碍及适应意向

基于入户调查数据,探讨了甘南高原农户对极端天气的适应障碍,并采用二元Logistic回归模型分析了适应障碍对农户适应意向的影响。结果发现:(1)甘南高原农户面临的规范性障碍最严重,信息技术障碍次之,再次为制度障碍和认知障碍。不同生计农户面临的适应障碍存在差异,其中,纯农户主要面临信息技术障碍,兼业户和非农户则主要面临规范性障碍。(2)纯农户对极端天气的适应意向主要受认知障碍、信息准确性障碍、适应策略选择时机障碍、政策激励障碍和牲畜拥有量的影响,兼业户主要受认知障碍、技术服务障碍、政策激励障碍影响,非农户主要受认知障碍、资源获取性障碍影响。除适应策略选择时机障碍外,其余适应障碍越小,不同生计农户的积极适应意向均越强。最后,提出了解决农户适应障碍的对策建议。