Yanshan Mountains Research Articles

Three new species of Candolleomyces (Agaricomycetes, Agaricales, Psathyrellaceae) from the Yanshan Mountains in China

Three new species, Candolleomycesincanus, C.subcandolleanus and C.yanshanensis, were found and described from Yanshan Mountains in China. The identification is based on morphological observation combined with phylogenetic analysis of ITS-LSU-Tef1α-TUB2. This study enriched the species diversity of Candolleomyces in Yanshan Mountains and provided important data support for the systematic study of Candolleomyces in the future.

环京津城市群生态系统服务的时空演变与驱动因素

PDF HTML阅读 XML下载 导出引用 引用提醒 环京津城市群生态系统服务的时空演变与驱动因素 DOI: 10.5846/stxb202111203270 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中央高校基本科研业务费专项资金资助（2021ZY33）；国家林草局重点项目（2019132703，2020132109） Spatial and temporal evolution and drivers of ecosystem services in Beijing, Tianjin and the Beijing-Tianjin Ring urban agglomeration Author: Affiliation: Fund Project: The National Natural Science Foundation of China（NO.51908034） 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市群已成为全球经济竞争的新空间单元，在促进城镇化建设，实现资源优质配置和发挥辐射带动作用等方面发挥着重要的功能。但剧烈的社会经济活动必然会对城市群生态系统服务造成破坏，因此开展城市群生态系统服务的时空演变研究，进而探索不同驱动因子对其的作用机制具有重要意义。目前，在已有的研究中缺少对城市群尺度和长时间跨度下的生态系统服务水平演变与驱动因素探究。为此，选取京津及环京津地区为研究区域，通过总结区域生态问题，构建起研究区域生态系统服务评价体系，并对2000-2018年生态系统服务进行计算，分析时空演变特征。然后，通过最小二乘法模型（Ordinary Least Squares，OLS）筛选出潜在的驱动因子，并导入地理加权回归模型（Geographically Weighted Regression，GWR）进行地理加权回归计算。最后，通过对结果分析，探讨自然和社会因子对生态系统服务的作用机制。研究结果表明：1）2000-2018年，研究区域生态系统服务呈现出先上升后下降，在2015年达到最高值的发展特征。2）在空间上，研究区域生态系统服务内总体上呈现燕山山脉及太行山山脉北部区域为生态系统服务的高值区域，坝上区域为低值区的空间分异特征。同时，生态系统服务演变在空间上呈现以燕山和太行山为界，燕山和太行山区域呈现先减弱后提升的趋势，西北区域整体呈现减弱趋势，东南区域从2015年起逐渐降低的空间演化特征。3）在驱动因素方面，自然环境和社会经济因素对生态系统服务的驱动作用从强到弱排列依次是：降雨量 > 土壤含沙 > 人口密度 > 温度 > 基础设施密度。4）其中，人口密度、土壤含沙量、基础设施呈较为明显的负相关驱动特征，降雨量呈较为明显的正相关驱动特征，温度则呈南部负相关，北部正相关，由东南向西北影响增强的趋势。本研究通过评估环京津城市群生态系统服务，分析区域生态系统服务的分析演变特征，并探索区域自然、社会因子对生态系统服务的驱动作用，为环京津城市群未来的生态环境保护和规划策略制定提供了科学指导和决策依据。 Abstract:Urban agglomerations have become a new spatial unit for global economic competition and had important functions in promoting urbanization, achieving high-quality allocation of resources and driving economic development. Intense socio-economic activities, however, are bound to cause damage to the ecosystem services of urban agglomerations. It is important to conduct studies on the spatio-temporal evolution of the ecosystem services of urban agglomerations and explore its driving factors. In this study, Beijing, Tianjin and the Beijing-Tianjin Ring were selected as the study area. The experiments constructed an ecosystem service evaluation system for the study area by summarizing regional issues, calculated ecosystem services from 2000-2018, and also analyzed their spatial and temporal evolution characteristics. Then, the potential drivers were screened out by the ordinary least squares model of the experimental data and imported into the geographically weighted regression model for regression. Finally, the driving role of natural and social factors on ecosystem services is explored, through an analysis of geographically weighted regression results. Firstly, the ecosystem services of the Beijing-Tianjin-Hebei urban agglomeration showed an upward and then downward trend from 2000 to 2018, reaching the highest value in 2015. Secondly, Spatially, the ecosystem services in the study area generally show the spatial differentiation characteristics of high value areas in the northern regions of Yanshan Mountains and Taihang Mountains, and low value areas in the dam area. At the same time, the evolution of ecosystem services spatially shows the boundary between Yanshan and Taihang Mountains, with the Yanshan and Taihang Mountains regions showing a trend of first weakening and then improving, while the northwest region shows an overall weakening trend and the southeast region gradually decreases from 2015 onward. Thirdly, Natural environment and socio-economic factors drive ecosystem services in descending order of strength:rainfall > soil sand content > population density > temperature > infrastructure density. Fourth, the population density, soil sediment concentration and infrastructure showed significantly negative correlation driving characteristics, while the rainfall showed significantly positive correlation driving characteristics, while the temperature showed negative correlation in the south and positive correlation in the north, with an increasing trend from southeast to northwest. Overall, by assessing the ecosystem services of the Beijing-Tianjin urban agglomeration, analyzing the analytical evolution characteristics of regional ecosystem services, and exploring the driving roles of regional natural and social factors on ecosystem services, this study provides scientific guidance and decision basis for the future ecological environmental protection and planning strategy formulation of the Beijing-Tianjin urban agglomeration. 参考文献 相似文献 引证文献

Characteristics of Terrestrial Heat Flow and Lithospheric Thermal Structure in Typical Intermountain Basin at the Eastern Foot of Yanshan Mountain, North China

The Yanshan area is rich in geothermal resources. However, limited research has been done on the geothermal resources of intermountain basins in the area, which restrict the exploration and development of geothermal resources. In this study, the Yanheying Basin, a typical intermountain basin located in the eastern foothills of Yanshan Mountain, is selected to perform a comprehensive analysis regarding heat flow and lithospheric thermal structure, to have a better understanding of the geothermal background and resource utilization potential of the area. The methods of deep borehole temperature logging, and rock sampling and testing were applied. With geological and geophysical data collected in the surrounding basins, the thermophysical parameters of rock formations, terrestrial heat flow and temperature distribution on a crustal-scale around the basin were analyzed. Results show that the ratio of crust heat flow to that of the mantle in the Yanheying Basin is 0.68, which falls in the range of that of the North China Plain (0.6–0.8), showing an obvious result of lithospheric thinning. The results also show that both crust and mantle heat flows in the Yanheying Basin are far lower than those of the North China Plain. it indicates that the crust of the Yanheying Basin and the entire Yanshan area has experienced a low degree of damage. That provides a piece of good thermodynamic evidence for the spatial variation of North China Craton destruction. The depth of the Curie surface in the study area is estimated to be about 24 km, which is consistent with the results of aeromagnetic data analysis. It confirms the results of lithospheric thermal structure and deep temperature distribution in the Yanheying Basin. The Yanheying Basin has certain potential for geothermal resources utilization in the depth of 2–6 km, where probably exist several carbonate thermal reservoirs with medium-temperature geothermal water. The above results can provide new insights into the geothermal research and exploration of intermountain basins in the Yanshan area.

Diurnal Variation and Distribution of Short-Duration Heavy Rainfall in Beijing–Tianjin–Hebei Region in Summer Based on High-Density Automatic Weather Station Data

The distribution and diurnal variation of short-duration heavy rainfall (SDHR) and the influence of a complex underlying surface were studied by using fine-scale hourly precipitation data in the Beijing–Tianjin–Hebei (BTH) region during the summers of 2014–2020. Areas prone to SDHR are located mainly in the southern foothills of the Yanshan Mountains, the foothills area, and the trumpet-shaped topographic entrance area north of Beijing, areas inland of the west coast of Bohai Bay, and the northern Beijing urban area. Owing to the influence of topography and the geographical location, the distribution and diurnal variation SDHR is significantly different in the western and northern mountainous areas, the foothills, and the plains. Compared to the underlying urban surface, the topography and the land–sea interface have considerable effects on the distribution of SDHR. A key finding is that the foothills of northern of Beijing, eastern slope and piedmont area of the Taihang Mountains, and the land–sea interface of Bohai Bay play important roles in the formation and propagation of SDHR.

Characteristics and chemical reactivity of biogenic volatile organic compounds from dominant forest species in the Jing-Jin-Ji area, China

BackgroundBiogenic volatile organic compounds (BVOCs) play an essential role in tropospheric atmospheric chemical reactions. There are few studies conducted on BVOCs emission of dominant forest species in the Jing-Jin-Ji area of China. Based on the field survey, forest resources data and the measured standard emission factors, the Guenther model developed in 1993 (G93) was applied in this paper to estimate the emission of BVOCs from several dominant forest species (Platycladus orientalis, Quercus variabilis, Betula platyphylla, Populus tomentosa, Pinus tabuliformis, Robinia pseudoacacia, Ulmus pumila, Salix babylonica and Larix gmelinii) in the Jing-Jin-Ji area in 2017. Then the spatiotemporal emission characteristics and atmospheric chemical reactivity of these species were extensively evaluated.ResultsThe results showed that the total annual BVOCs emission was estimated to be 70.8 Gg C·year− 1, consisting 40.5 % (28.7 Gg C·year− 1) of isoprene, 36.0 % (25.5 Gg C·year− 1) of monoterpenes and 23.4 % (16.6 Gg C·year− 1) of other VOCs. The emissions from Platycladus orientalis, Quercus variabilis, Populus tomentosa and Pinus tabulaeformis contributed 56.1 %, 41.2 %, 36.0 % and 31.1 %, respectively. The total BVOCs emission from the Jing-Jin-Ji area accounted for 61.9 % and 1.8 % in summer and winter, respectively. Up to 28.8 % of emission was detected from Chengde followed by Beijing with 24.9 %, that mainly distributed in the Taihang Mountains and the Yanshan Mountains. Additionally, the Robinia pseudoacacia, Populus tomentosa, Quercus variabilis, and Pinus tabulaeformis contributed mainly to BVOCs reaction activity.ConclusionsThe BVOCs emission peaked in summer (June, July, and August) and bottomed out in winter (December, January, and February). Chengde contributed the most, followed by Beijing. Platycladus orientalis, Quercus variabilis, Populus tomentosa, Pinus tabulaeformis and Robinia pseudoacacia represent the primary contributors to BVOCs emission and atmospheric reactivity, hence the planting of these species should be reduced.

Variation in fractional vegetation cover and its attribution analysis of different regions of Beijing-Tianjin Sand Source Region, China

Based on the MODIS NDVI data from 2000 to 2018, we estimated the fractional vegetation cover (FVC) using the dimidiate pixel model and analyzed the spatiotemporal characteristics of FVC in the Beijing-Tianjin sand source region (BTSSR). The geographical detector model was used to estimate the impacts of natural and human factors on FVC spatial distribution at the regional scale. The results showed that the FVC of the BBTSR showed an increasing trend from 2000 to 2018, with an annual growth rate of 0.013·(10 a)-1 and a vegetation increase rate of 8.2%. The area with high FVC was concentrated in the Yanshan Mountain water source protection area, followed by the pastoral transitional zone desertified land control area and the Otindag sandy land area. The area with poor FVC was concentrated in the northern arid grassland area. The explanatory power of driving factors to FVC varied across different regions. Among the natural factors, annual precipitation was the main driving factor for the spatial distribution of FVC in the northern arid grassland area, the Otindag sandy land area and the Yanshan Mountain water source protection area. Slope was the main driving factor for the spatial distribution of FVC in the pastoral transitional zone desertified land control area. Among different human activities, the number of large livestock at the year-end was the main driving factor controlling the spatial distribution of FVC in the northern arid grassland area and the pastoral transitional zone desertified land control area, while population density was the main driving factor controlling the spatial distribution of FVC in the Otindag sandy land area and the Yanshan Mountain water source protection area. There were regional differences in the influen-ce of other factors on FVC spatial distribution. The results of the interaction detector showed that the two-factor interactions were mainly the double-synergy and nonlinear synergy. The interaction of human activities with annual precipitation and slope could more fully explain the spatial variations of FVC. The range of suitable vegetation growth identified by the risk detector was the area with annual precipitation of 316.4-486.0 mm, average relative humidity of 48.4%-57.6%, and average annual temperature of 2.5-7.9 ℃, while other driving factors were different in different zones.

Spatiotemporal Characteristics of Drought in the North China Plain over the Past 58 Years

Understanding the spatiotemporal characteristics of regional drought is of great significance in decision-making processes such as water resources and agricultural systems management. The North China Plain is an important grain production base in China and the most drought-prone region in the country. In this study, the monthly standardized precipitation evapotranspiration index (SPEI) was used to monitor the spatiotemporal variation of agricultural drought in the North China Plain from 1960 to 2017. Seven spatial patterns of drought variability were identified in the North China Plain, such as Huang-Huai Plain, Lower Yangtze River Plain, Haihe Plain, Shandong Hills, Qinling Mountains Margin area, Huangshan Mountain surroundings, and Yanshan Mountain margin area. The spatial models showed different trends in different time stages, indicating that the drought conditions in the North China Plain were complex and changeable in the past 58 years. As an important agricultural area, the North China Plain needs more attention since this region shows a remarkable trend of drought and, as such, will definitely increase the water demand for agricultural irrigation. The strong correlation between these spatial distribution patterns indicates that the climate and weather conditions leading to drought are consistent and that drought conditions are independent for regions that are not correlated. If this trend continues, the characteristics of drought variability in the North China Plain will become more complex, and a more detailed water management strategy will be needed to address the effects of drought on agro-ecosystems. Recognizing the drought variability in the North China Plain can provide a basis for agricultural disaster reduction planning and water resources allocation.

Ecological risk assessment of heavy metal contamination of mining area soil based on land type changes: An information network environ analysis

In this study, a grid-based network environ analysis (FEM-NEA) framework was developed to identify the ecological risks of the internal components within a landscape scale mining ecosystem with multiple land types. In this framework, an information-based network analysis is applied for addressing ecological risk assessments (ERA) based on control allocation (CA) and energy flow matrix, which can quantificationally reflect the relationship between soil ecosystems and ecological communities. In order to improve the computational accuracy and efficiency, the FEM and information-based network analysis are combined to further quantify the flow risk among different components within each grid as well as the whole ecosystem. Compared with the existing NEA-ERA model, various risk factors and receptors are compatible with the proposed FEM-NEA framework and both direct and indirect effects can be taken into consideration altogether. By taking an abandoned mining area of the Yanshan mountain as an example, risk propagation between all component of the ecosystem concerning both direct risk and integral risk dynamic were quantified. The results showed that contaminated soil normally poses risks to surrounding ecological environment, thereby affecting local vegetation and microorganisms. Afterward, the risks are passed throughout the ecosystem, forming threats to herbivores and predators via the food chain. Here, the probability of risk is ranked as follows: village> farmland> bare land> woodland. Moreover, the influence of input energy and data attributes on the prediction results are also discussed. When the input energy rises by 50%, the control allocation (CA) from herbivores to soil microorganisms correspondingly increases by 1.00% but the value from herbivores to carnivores decreases by 0.71%. This highlights the robustness of the proposed ecological risk assessment framework (FEM-NEA). In general, the FEM-NEA results not only presents the macro-scale risk distribution caused by the interaction of each component, but also reflects the potential migration direction of the risk center. Findings can provide a new perspective and method for assessing ecological risks and also help support remediation techniques for contaminated areas with different land types.

Ecological and health risk assessment of heavy metals in soil and Chinese herbal medicines.

As medicinal plants can accumulate harmful metals from the native soil, people's consumption of these materials may cause the human body to accumulate toxic metal elements. This has given rise to people’s concerns about the quality and safety of Chinese medicinal materials. This research aims to determine the levels of Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in four medicinal plant species (Aster tataricus L.f., Salvia miltiorrhiza Bge, Radix Aucklandiae, Scutellaria baicalensis Georgi) and their native soil. All samples were collected from Qian’an city, beside Yanshan Mountain Range in Tangshan city, east Hebei Province, north China. The contents of heavy metals we detected in the soil conformed to the current limits. However, the Cd and Hg in the soil had a very high potential ecological risk because of their contents higher than the base level of local soil. The contents of Cu, Cd, Hg and Pb in some medicinal herbs exceeded the standards. The content of Cu in Radix Aucklandiae exceeded the standard by 3 times, and others exceeded the standard by less than one time. The comprehensive health risk assessment of heavy metals with chronic non-carcinogenic effects for human body showed that none of the four medicinal herbs can create a health risk. Thus, there is no strong positive correlation between heavy metal pollution in medicinal herbs and that in the native soil. Further research should be investigated to the connection between the heavy metal levels in the soil and plants, and the comprehensive effects of soil, air and irrigation water on heavy metal pollution of Chinese herbal medicines. We also recommend that Chinese herbal medicines should be cultivated and gathered only from controlled or uncontaminated areas.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10653-021-00978-z.

Nonstructural carbohydrates, carbon and nitrogen concentrations in fine roots of Quercus variabilis secondary forests after two different periods of regeneration

Aim of study: Quercus variabilis is a sclerophyllous oak with strong resprouting capabilities and whose regeneration is facilitated by the development of stump shoots following disturbance. During secondary forest regeneration, fine roots are important organs relative to changes in stand characteristics. Here, we aimed to provide novel insights into the chemical composition variations in roots with seasonality and root order hierarchy in a Q. variabilis forest at different periods of regeneration.Area of study: The forest is located next to the Baxianshan National Reserve in the southern part of the Yanshan Mountains, Tianjin, China.Materials and methods: Six plots were established in stands with either eight or 40 years of regeneration for the repeated sampling of fine roots during the growing season of 2019. All roots were classified by branch order. The first three root orders were collected to analyse the concentrations of nonstructural carbohydrate, carbon, and nitrogen.Main results: Short-term regeneration stands showed a reduction in soil moisture and an increase in soil temperature because of the lower canopy cover, compared to long-term stands. Soluble sugar and starch were lower in roots of short-term stands than in those of long-term stands, and the decreasing ratio of both parameters was observed in short-term stands. Less carbon and greater nitrogen concentrations of fine roots were found in short-term stands than in long-term stands, which resulted in weaker C/N ratio values. Nonstructural carbohydrate was stored more in higher order roots than terminal roots and presented greater sensitivity to forest regeneration. Redundancy discriminate analysis demonstrated that the nonstructural carbohydrate concentrations in roots were affected positively by canopy cover and negatively by soil temperature.Research highlights: The seasonal dynamics and branch allocation of chemical reserves in fine roots varied in the different periods of forest regeneration because of the discrepancy between the canopy cover and soil traits. Less nonstructural carbohydrate and a lower C/N ratio at the onset of forest regeneration may elevate the risk of root death.Keywords: soluble sugar; starch; forest regeneration; root order; C/N ratio; redundancy discriminate analysis.

Thrust duplexing and transpression in the Yanshan Mountains: Implications for early Mesozoic orogenesis and decratonization of the North China Craton

AbstractThe configuration and kinematics of fold‐thrust belts are essential for clarifying the plate boundary conditions through which ancient orogenic belts evolved. Temporal and spatial variations in extension versus contraction within convergent plate margins are related to changes in plate kinematics and subduction geometry. The Yanshan Mountains, located along the northeastern margin of the North China Craton and bounded by the Central Asian Orogenic Belt to the north and the Pacific subduction zone to the east, underwent multiple phases of intra‐continental deformation during the Mesozoic. The issue of whether early Mesozoic deformation was extensional or contractional has remained controversial. New regional structural mapping and detailed sedimentological investigations, coupled with age constraints provided by zircon U‐Pb geochronology, provide sufficient temporal and spatial resolution to show that shortening and thrust‐top basin systems dominated during the early Mesozoic. Our results show that the Dengzhangzi Basin within the Lingyuan fold‐thrust belt developed during the construction of a major Late Triassic Chapeng antiformal‐stack duplex system, with episodic, east‐vergent forward‐breaking thrusts and subsequent ‘beheading’ by out‐of‐sequence, top‐to‐east thrusting in the latest Triassic or earliest Jurassic. The neighbouring Guojiadian Basin in the east was generated during top‐to‐SSE sinistral transpression along the Niuyingzi thrust system in the Middle to earliest Late Jurassic. These results support a new model of early craton decratonization involving (a) thrusting along the northern margin of the North China Craton and (b) transpressional deformation in the east driven by the Central Asian Ocean collision and flat‐slab subduction of the Palaeo‐Pacific Plate beneath the East Asian continental margin. Our findings suggest that large‐scale shortening and crustal/lithospheric thickening, triggered by flat‐slab subduction in the North China Craton, were fundamental components of craton decratonization. Subsequent slab roll‐back during the Cretaceous led to lithospheric thinning and crustal extension in the North China Craton.

Studying the coupling coordination degree between socio-economic and eco-environment of Jing-Jin-Ji urban agglomeration during 2001-2015

With the fast urbanization process of China, many problems also have arisen. Under such background, pursuing the coordinated development of the socio-economic subsystem and eco-environment subsystem has become a hot spot. However, existing researches seldom investigated the regional coupling coordination degree at the gridded level. In this study, combined with the coupling coordination degree model, remote sensing datasets, and other socio-economic datasets at the raster format, we explored the coupling coordination degree of JJJ from 2001 to 2015 at the gridded level. The result of our study showed that (1) The eco-environment of JJJ had improved during 2001∼2015, among it, the eco-environment with high RSEI value mainly located in the mountainous area of JJJ, including the Yanshan mountain, and Taihangshan mountain. In contrast, the eco-environment with relatively low RSEI value was mostly located in the central Hebei plain and urban zone. (2) The spatial coupling coordination degree of JJJ showed a decreased trend, with the decrease of high, relatively high, and medium grades area, and the increase of low, and relatively low grades area. Generally, these high coupling coordination degree regions mainly located in the city’s central zone, while these mountainous regions and central Hebei plain mainly displayed a low coupling coordination degree due to the socio-economic lag. These findings may provide more useful information for the relevant policy-makers.

燕山山脉黄檗种群结构与动态特征

燕山山脉黄檗种群结构与动态特征

北京市域乡村人居林树冠覆盖及其区域差异分析

乡村人居林建设是落实新农村建设、实施乡村振兴战略和振兴农村生态文明的重要举措。以北京市为对象，基于北京市域2017年0.5m分辨率航空影像与2017年1：10万土地利用（LUCC）图等基础资源，在全市范围内随机选择260个行政村，从研究区域内乡村人居林树冠覆盖率、功能类型、斑块等级和景观格局特征四个层面展开区域差异特征分析。研究结果显示，北京市整体乡村人居林树冠覆盖率为18.32%，其中平原区和山区分别为18.40%和17.83%。在平原区范围内，乡村人居林树冠覆盖率呈近郊区（21.70%） > 远郊区（13.87%） > 延庆盆地区域（16.34%）；在山区内部，乡村人居林树冠覆盖率呈现低山区（24.45%） > 浅山区（16.55%） > 深山区（12.41%），太行山区（20.98%） > 燕山区（14.11%）。在乡村人居林功能类型分布中，片林为各分区最主要类型，在平原区和山区中分别占比55.75%和57.15%。在斑块等级结构方面，乡村人居林斑块总体呈现小而分散的特点，其中小斑块数目在区域中占比达93.03%，而各等级斑块在规模大小方面呈现"平分秋色"的特点。就景观格局指数特点而言，平原区内近郊区，山区内的深山区和燕山区乡村人居林斑块复杂程度、受人为干扰强度和多样性更高。综上特征，究其动因，农村居民点聚落规模、集聚形式和建设类型以及森林资源本底是影响乡村人居林建设条件的重要原因。;Construction of village human habitat forest is an important initiative to implement the new rural construction, the rural revitalization strategy and the rural ecological civilization. On the basis of resources such as remote sensing image with 0.5 resolution and 1:10<sup > 5</sup > LUCC map in 2017, 260 sample villages were selected randomly in Beijing. Then, the differences in canopy coverage, functional types, patch structure and landscape pattern of village human habitat forest in different districts were analyzed. The results showed that, the canopy coverage of village human habitat forest was 18.32% in the whole city, 17.40% in the plain area and 17.83% in the mountain area, respectively. In the plain area, the canopy coverage of village human habitat forest showed suburban area (21.70%) > outer suburban area (13.87%) > Yanqing basin area (16.34%). In the mountain area, the canopy coverage of village human habitat forest showed low mountain area (24.45%) > shallow mountain area (16.55%) > deep mountain area (12.41%), and the canopy coverage of village human habitat forest showed Taihang mountain area (20.98%) > Yan mountain area (14.11%). In the distribution of village human habitat forest types, the most important type in each district is patch forest, accounting for 55.75% in the plain area and 57.15% in the mountain area. In terms of the distribution of patch structure, the overall characteristic was small and scattered, the number of small patches accounted for 93.03% in Beijing, while there was no significant difference in the area of each grade of patches. In terms of the characteristic of landscape pattern index, patch complexity, intensity and diversity of human disturbance were more intense in the suburban area, the deep mountain area and the Yanshan mountain area. The main factors influencing the construction conditions of village human habitat forest are the scale, agglomeration form and construction type of the rural residential area and the background abundance of forest resources.

Demographic history and genetic differentiation of an endemic and endangered Ulmus lamellosa (Ulmus)

BackgroundUlmus lamellosa (one of the ancient species of Ulmus) is an endemic and endangered plant that has undergone climatic oscillations and geographical changes. The elucidation of its demographic history and genetic differentiation is critical for understanding the evolutionary process and ecological adaption to forests in Northern China.ResultsPolymorphic haplotypes were detected in most populations of U. lamellosa via DNA sequencing. All haplotypes were divided into three phylogeographic clades fundamentally corresponding to their geographical distribution, namely THM (Taihang Mountains), YM (Yinshan Mountains), and YSM (Yanshan Mountains) groups. The YSM group, which is regarded as ancestral, possessed higher genetic diversity and significant genetic variability in contrast to the YSM and YM groups. Meanwhile, the divergence time of intraspecies haplotypes occurred during the Miocene-Pliocene, which was associated with major Tertiary geological and/or climatic events. Different degrees of gene exchanges were identified between the three groups. During glaciation, the YSM and THM regions might have served as refugia for U. lamellosa. Based on ITS data, range expansion was not expected through evolutionary processes, except for the THM group. A series of mountain uplifts (e.g., Yanshan Mountains and Taihang Mountains) following the Miocene-Pliocene, and subsequently quaternary climatic oscillations in Northern China, further promoted divergence between U. lamellosa populations.ConclusionsGeographical topology and climate change in Northern China played a critical role in establishing the current phylogeographic structural patterns of U. lamellosa. These results provide important data and clues that facilitate the demographic study of tree species in Northern China.

Response of photosynthesis and carbon/nitrogen metabolism to drought stress in Chinese chestnut 'Yanshanzaofeng' seedlings

Drought is a main factor affecting the growth and yield of Chinese chestnut trees in Yan-shan Mountains. To investigate the responses of chestnut seedlings to drought stress, the growth and physiological indices, including photosynthetic characteristics, biomass, proline, malondialdehyde, carbon and nitrogen contents were measured in roots, stems, and leaves after the Chinese chestnut 'Yanshanzaofeng' seedlings in the pots were treated by simulating drought for 22 days. The results showed that, compared with the normal irrigation, water contents in the roots, stems and leaves were decreased by 18.3%, 29.0% and 62.8%, respectively, accompanied by the considerable increases in the contents of proline (355.0%-1586.7%) and malondialdehyde except in the stems (41.1%-81.3%). The non-photochemical quenching coefficiency and net photosynthetic rate in the leaves were significantly decreased by 49.4% and 77.4%, respectively. The contents of non-structural carbohydrates were increased by 21.4% in stems and 69.5% in leaves, but that in roots did not change. The contents of nitrate were increased by 28.9% in stems and 26.8% in leaves, but that in roots did not change. Ammonium nitrogen was increased by 16.2%, 12.9% and 217.6% in roots, stems, and leaves, but being statistically significant in the leaves. These results indicated that drought stress led to serious damage to 'Yanshanzaofeng' chestnut seedlings, which inhibited photosynthetic performance, but they could improve their adaptation to drought stress by enhancing carbon and nitrogen metabolism. Our results provide a reference for the breeding and cultivation of drought resistance of the local Chinese chestnut resources.

Chloroplast phylogeography ofIris dichotoma(Iridaceae), a widespread herbaceous species in East Asia

Both a complex topography and climate change have huge impacts on the distribution and genetic structure of extant species. Due to the lack of relevant molecular research, little is definitively known about the phylogeography of herbaceous plants in East Asia. Here we investigate the genetic diversity, population structure and historical population dynamics ofIris dichotomaPallas, a widespread perennial herbaceous species in northeastern and northern China. Twenty‐nine populations, totalling 297 individuals, were sampled throughout the Chinese distributional range ofI. dichotoma. The combined sequences of six chloroplast DNA fragments (petA‐psbE,rps18‐clpp,psbJ‐petA,trnD‐trnT,rps16andndhA) were used to identify 13 haplotypes, of which six were private ones restricted in a single population. Genetic differentiation amongI. dichotomapopulations, enabled us to infer potential refugia during the glacial period in the Yinshan Mountains–Yanshan Mountains, where high levels of haplotype and nucleotide diversity were detected. The results of a neutral test and mismatch distribution analysis both indicated thatI. dichotomaunderwent a recent population expansion. In East Asia, postglacial environmental and climatic changes appear to have promoted genetic diversification not only in better‐studied woody species, but also in herbaceous ones likeI. dichotoma. Future studies of more herbaceous plant species are needed to obtain better insight into how modern temperate biodiversity has developed in East Asia.

기원전 13~11세기 중원계 청동기의 북상과 연산산맥 남북지역의 청동문화

기원전 13~11세기 중원계 청동기의 북상과 연산산맥 남북지역의 청동문화

Using full-length metabarcoding and DNA barcoding to infer community assembly for speciose taxonomic groups: a case study

How insect communities are assembled in nature remains largely unknown. In particular, whether habitat filtering or competition serves as the main mechanism in forming insect communities is rarely subject to an in-depth investigation. One bottleneck lies in the difficulty of species identification when dealing with a large number of diverse insects. However, high-throughput sequencing technology coupled with classic DNA barcoding offers a great opportunity to infer community assembly for this speciose group. In this study, using 13,909 full-length barcodes obtained by Sanger sequencing or the full-length metabarcoding method (SOAPBarcode), we showed that competition was the main assembly mechanism for the moth communities in the younger Taihang Mountain, while habitat filtering for those in the old Yanshan Mountain. The two sequencing methods showed highly consistent results with regards to both diversity composition and community assembly mechanism. Significant phylogenetic signals and structure suggested that the focal moth communities were the result of the non-neutral assembly process, which was further confirmed by results of neutral assembly test that accounted for immigration and speciation rates. Our study showed that the full-length metabarcoding method can facilitate community assembly inferences, even for speciose taxonomic groups.

Geological control of the eastern Great Wall: Mountain-basin relationships in the eastern North China Craton

The E–W trending Yanshan belt, an intraplate fold-thrust belt located in the northern North China Craton, has experienced several episodes of Mesozoic deformation, which resulted in the widely distributed magmatism and mountain-basin tectonics that completely re-shaped the topography of the eastern North China Craton. The eastern part of the famous Chinese Great Wall was built on the high range of the southeastern Yanshan mountain belt juxta-posed to the plain, which directly relates to the Bohai Bay basin. Our study focuses on which tectonic processes created such mountain-basin couple in Mid-Late Mesozoic times. The U-Pb LA-ICP-MS dating of zircons yield ages of 114 to 201 Ma for various granites and 115 to 116 Ma for volcanic rocks from Yixian and Jiufotang Fms. The detrital zircons from the Lower Cretaceous sandstones yield four age groups of 2587 to 2460 Ma, 2222 to 1828 Ma, 297 to 190 Ma and 187 to 100 Ma, which are all sourced from the Qinglong and surrounding areas and indicating that the Qinglong area started to uplift after the Middle Jurassic. The Qinglong area underwent multiple deformation by NE–SW compression in the Middle-Late Jurassic times, WNW–ESE compression in the Late Jurassic to Early Cretaceous, ENE–WSW extension in the Early Cretaceous and NNW–SSE compression in the Late Cretaceous during the final stage of the Yanshanian orogeny. Meanwhile, widely distributed granite intrusions and emplacement of the Upper Jurassic-Lower Cretaceous volcanic rocks indicate a large amount of magma input into the area. The Qinglong area with the Great Wall along its southern margin close to adjacent plain to the south was uplifted to form the Qinglong highland and surrounding related basins by combination of the following three processes: the multiple tectonic Late Jurassic and Late Cretaceous shortening processes related to Yanshanian orogeny, Early Cretaceous regional extension triggered by slab-retreat of the Paleo-Pacific ocean and inflation of large amount magma at depth during Jurassic and Early Cretaceous.