Arbor Layer Research Articles

Ecological Restoration Increases the Diversity of Understory Vegetation in Secondary Forests: An Evidence from 90 Years of Forest Closures

Ecological restoration and biodiversity are currently hot issues of global environmental concern. However, knowledge about the specific impacts of restoration duration on understory vegetation diversity remains limited. Therefore, this study comprehensive employed a spatial approach to compare the differences in understory plant diversity and species composition among secondary forests with varying ecological restoration ages (0, 10, 30, 60, and 90-year-old stands) in Huangfu Mountain National Forest Park. This methodology allowed us to clarify the key factors affecting the composition of the understory plant community and investigate the regulatory mechanisms influencing changes in understory plant diversity. The results showed that shrub Shannon’s index value, shrub evenness, herb Shannon’s index value, herb richness, and herb evenness were significantly affected by the years of restoration, with 10 years and 90 years being the highest and 60 years being the lowest. Substrate diversity was the main factor influencing plant diversity in the shrub layer. Overstory richness, soil C/N, soil C, soil N, soil bacterial Observed OTUs, soil bacterial Chao1, soil bacterial Pielou_e, and substrate diversity were the drivers of plant diversity in the herb layer. Overstory evenness had a direct effect (0.256) and an indirect effect (0.284) on herb evenness through light availability and fungal Simpson’s index value. Light availability directly negatively affected herb evenness (−0.360). In addition, 52.6% of the factors affecting the herb evenness index were from the arboreal layer evenness, light availability, and fungal Simpson’s index value. To sum up, moderate disturbance of the understory environment of natural secondary forests can be carried out after 10 years of restoration, which is more conducive to the increase of understory plant diversity. This comprehensive study provides a theoretical basis for formulating ecological restoration measures for secondary forests, particularly in understanding the optimal timing and nature of disturbance in the restoration process, reassuring the audience about the validity and reliability of the findings.

Seasonal variations in psychophysiological stress recovery from street greenery: A virtual reality study on vegetation structures and configurations

The benefits of street greenery for well-being in urban development are widely recognized. However, few studies have explored seasonal variations in the psychophysiological stress recovery effects of different street greenery. To address this gap, we conducted field research in the Guanzhong region of China and created virtual streetscapes representing different seasons using Mars 2020 software. This study categorized vegetation into various layers based on their biological attributes: deciduous and evergreen trees for the arbor layer, evergreen and colourful foliage hedges for the shrub layer, observable and unobservable flowering herbs for the herb layer. They were then classified into Tree, Tree-Shrub, Tree-Herb, and Tree-Shrub-Herb structures, all of which had different seasons and vegetation configurations. 1,136 participants were recorded for psychophysiological changes in different street greenery virtual reality scenarios. The results were as follows: 1. Streets with greenery exhibited greater stress recovery effects than those without greenery. Seasonally, the physiological stress recovery effects were greater in autumn and winter, and there was an interaction between season, structure, configuration factors. 2. Overall, the Tree-Shrub structure was most effective for stress recovery, the Tree-Shrub-Herb structure was least effective. However, the Tree-Shrub-Herb structure proved to be the best in winter. 3. Rich color and stable green coverage were most effective for improving psychological and physiological stress recovery, respectively. However, the optimal vegetation types and configurations for stress recovery vary with specific viewing periods within each season. These findings offer a theoretical foundation and practical reference for designing health-oriented street greenery and seasonal landscapes in future.

Altitudinal Variation in Species Diversity, Distribution, and Regeneration Status of a Secondary Picea Forest in Guandi Mountain, Northern China

Altitude plays a crucial role in shaping the diversity and distribution of species in forest landscapes in mountainous regions. However, existing studies often lack comprehensive analysis of the intricate relationships among environmental factors, disturbances, and species diversity. This study aims to address this gap by thoroughly analyzing major species’ diversity, distribution, and regeneration status, along with their influencing factors, across different altitudinal gradients (1850 to 2350 m). Field surveys were conducted to examine the major species in different vegetation layers of the secondary Picea forest in Guandi Mountain. The key findings from the study include the following: (1) the study area recorded a total of nine species of adult trees, belonging to eight genera in five families, fourteen species of shrubs from eight genera in five families, and fifty-two herb species representing forty-eight genera in twenty-six families. Dominant species varied across layers, with Picea asperata Mast. and Larix principis-rupprechtii Mayr. dominating the arborous layer, Lonicera ferdinandii Franch. and Cotoneaster acutifolius Turcz. in the shrub layer, and Poa pratensis L. and Duchesnea indica (Andrews.) Focke in the herb layer. (2) Altitude significantly influenced species diversity, with the most pronounced effects observed in the shrub and herb layers. (3) Tree species regeneration varied with altitude, with Picea asperata exhibiting the highest regeneration performance, particularly in the high-altitude zone (2250–2350 m). Regeneration parameters were significantly correlated with species diversity indices in both tree and shrub layers. (4) Redundancy analysis revealed that, apart from altitude, cutting (p = 0.015) influenced the species diversity of the tree layer, while annual precipitation (p = 0.006) and temperature (p = 0.01) determined the diversity of the shrub layer. Grazing (p = 0.042) was identified as a determining factor for species diversity in the herb layer. Overall, these findings provide valuable insights into the sustainable management of forest ecosystems in the study area and offer practical guidance for forest management in similar mountainous landscapes worldwide.

Niche characteristics and dynamics of dominant species in arbor layer of 4hm2Pinus tabuliformis-Quercus wutaishansea mixed forest in Lingkong Mountain

The ability of community species to adapt to the environment and use resources and the importance of species in the ecological system in time and space are generally represented by ecological niche. In order to study the niche characteristics and dynamic changes of the dominant species in the arbor layer of the 4hm2Pinus tabuliformis-Quercus wutaishansea mixed forest sample plot in Lingkong Mountain,and to gain a better understanding of the competition and coexistence among species in the sample plot, this study was conducted based on a typical community investigation. Four indices of important value, niche width, niche overlap, and niche similarity were chosen to calculate and analyze the niche characteristics and examine dynamic changes over a period of 10 years from 2011 to 2021. The results showed that: (1) In 2021, the important values for Quercus wutaishansea and Pinus tabuliformis were 19.906 and 13.906, respectively.The niche widths were 0.962 and 0.555, which showed difference compared to those in 2011. Both were much larger than other species, indicating that they occupied an absolutely dominant position in the community. (2) The mean values of niche overlap and similarity of dominant species in the arbor layer of the Lingkong Mountain sample plot have both increased over the past 10 years. Additionally, the species pairs with the highest overlap and similarity values have changed, suggesting an intensification of competition among these species.

Interspecies Association and Community Stability of Plants in the Core Distribution Area of Thuja sutchuenensis

The protection of endangered species is a hot topic for scholars worldwide, and interspecific association and community stability analysis are important methods with which to explore the structure and function of the endangered species community. Thuja sutchuenensis Franch. is an endangered species; however, studies on the T. sutchuenensis community remain insufficient. Here, based on the data of the plot survey of the T. sutchuenensis community in the Ta-pa Mountains and Xuebao Mountains, we analyzed the interspecific associations, niche width, and niche overlap of major species in the arborous and shrub layers, as well as community stability. The results showed that the overall interspecies association between the species of the arbor layer was non-significantly negatively associated, while the shrub layer was non-significantly positively associated. The Chi-square test results showed that the species pairs without interspecific association in the arbor layer and the shrub layer were much higher than those with significant interspecific association; in other words, the interspecific association of species in the T. sutchuenensis community was loose. The results of interspecific association coefficient analysis showed that the number of negatively associated species pairs was significantly higher than that of positive association species pairs, but Pearson’s correlation coefficient and Morisita’s niche overlap index analysis showed that the degree of competition between species in the community was small. In the arbor layer, the niche width of T. sutchuenensis was the widest, while in the shrub layer, the niche width of T. sutchuenensis was relatively high, indicating that T. sutchuenensis had a strong ability to adapt to the environment and use available resources. In addition, the intersection point of community stability (32.11, 67.89) in the vegetative community of T. sutchuenensis suggested that the community displayed a better stability. The survival strategy of T. sutchuenensis is based on its strong adaptability to the harsh environment to escape the competition among species, and this knowledge can provide a reference for the protection and restoration of endangered species.

林火干扰对广东木荷林生态系统碳库的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 林火干扰对广东木荷林生态系统碳库的影响 DOI: 10.5846/stxb202004240980 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划重点专项(2018YFE0207800);广东省自然科学基金项目(2021A1515010946);广东省林业科技创新项目(2020KJCX003);广西自然科学基金项目(2014GXNSFBA118108) Effects of forest fire disturbance on carbon pools of Schima superba forest ecosystem in Guangdong Province Author: Affiliation: Fund Project: 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:森林碳库在调节CO2浓度及减缓温室效应中发挥重要作用。选择广东木荷林为研究对象,通过相邻样地法,进行植被生物量、凋落物生物量和土壤样品的采样与分析,研究不同林火干扰强度对生态系统各碳库(植被、凋落物和土壤有机碳)及生态系统碳库产生的变化规律和空间分布格局及其影响因素。结果表明:(1)植被碳密度随着林火干扰强度增强而减少,但不同组分的植被碳密度表现不同,乔木碳密度在不同林火干扰强度下变化与植被碳密度变化一致,而草本碳密度则呈现相反的变化趋势。相同林火干扰强度下,植被各组分碳密度均以乔木层降低幅度最大。林火干扰均显著降低了凋落物碳密度(P<0.05),并随林火干扰强度的增加其降低幅度增大,但不同林火干扰强度对凋落物碳密度的影响有所差异。林火干扰降低了土壤有机碳密度,且降低幅度随土层深度增加而逐渐变小。(2)林火干扰有效改变了生态系统碳库的空间分布格局。对照样地木荷林土壤有机碳库占比为61.59%,重度林火干扰后,土壤有机碳库占比为70.96%呈上升趋势,占生态系统碳库的优势地位,而植被和凋落物碳库占比呈下降趋势,处于生态系统碳库的次要地位。(3)双因素方差分析表明,林火干扰强度和土层深度及其交互作用均对土壤有机碳密度有显著影响。林火干扰强度解释了土壤有机碳密度变异的8.78%,土层深度解释了土壤有机碳密度变异的70.29%,林火干扰强度和土层深度之间的交互作用解释了土壤有机碳密度变异的8.16%。研究发现:林火干扰降低了生态系统碳库,且随林火干扰强度增加,生态系统碳库减少幅度增大。轻度林火干扰对森林生态系统碳库的影响差异不显著,而中度和重度林火干扰对森林生态系统碳库的影响差异显著。研究结果对深化亚热带森林固碳效应的影响机制提供理论支撑。 Abstract:Forest carbon pools play an important role in regulating CO2 concentration and mitigating the greenhouse effect. In this study, the Schima superba forest in Guangdong was selected as the research object. Through the adjacent plot method, the sampling and analysis of vegetation biomass, litter biomass and soil samples were conducted to study the impact of different forest fire disturbance intensities on the various carbon pools (vegetation, vegetation, litter and soil organic carbon) and the change law and spatial distribution pattern of ecosystem carbon pool and its influencing factors. The results showed that the vegetation carbon density decreased with the increase of forest fire disturbance intensity, but the vegetation carbon densities of different components were different. The change of tree carbon density under different forest fire disturbance intensities was consistent with the change of vegetation carbon density. The carbon density showed the opposite trend. Under the same fire disturbance intensity, the arbor layer had the largest decrease in the carbon density of each component of vegetation. The forest fire disturbance significantly reduced the litter carbon density (P<0.05), and the decrease range increased with the increase of the forest fire disturbance intensity, but the effects of different forest fire disturbance intensities on the litter carbon density were different. The forest fire disturbance reduced soil organic carbon density, and the reduction range gradually became smaller with the increase of soil depth. Forest fire disturbance has effectively changed the spatial distribution pattern of the ecosystem carbon pool. The proportion of soil organic carbon reservoir in the control plot was 61.59%. After severe forest fire disturbance, the proportion of soil organic carbon pool was 70.96%, showing an upward trend, accounting for the dominant position of ecosystem carbon pool, while the proportion of vegetation and litter carbon pool showed a downward trend, which was in the secondary position of ecosystem carbon pool. ANOVA showed that the intensity of forest fire disturbance and the depth of soil layer and its interaction had a significant impact on soil organic carbon density. The intensity of forest fire interference explained 8.78% of the soil organic carbon density variation, the soil layer depth explained 70.29% of the soil organic carbon density variation, and the interaction between the forest fire interference intensity and the soil layer depth explained 8.16% of the soil organic carbon density variation. The study found that forest fire disturbance reduced the ecosystem carbon pool, and as the intensity of forest fire disturbance increased, the reduction in ecosystem carbon pool increased. The impact of low forest fire disturbance on forest ecosystem carbon pool was not significant, while the impact of moderate and high forest fire disturbance on forest ecosystem carbon pool was significant. The research results provide theoretical support for the impact mechanism of deepening the carbon sequestration effect of subtropical forests. 参考文献 相似文献 引证文献

Vegetation community dynamics during naturalized developmental restoration ofPinus tabulaeformisplantation in North warm temperate zone

AbstractThe study is to explore the dynamics of community structure, diversity, interspecific relationships and stability during naturalized developmental vegetation restoration which realized by natural interaction between plantation and native trees without human’s involvement. The naturalized developmental restored forests in Baxianshan National Reserve were divided into three typical stages (i.e. Pinus tabulaeformis forest stage, mixed forest stage and near-natural forest stage) according to the ratio of P. tabulaeformis coverage to arbor layer, and the zonal natural secondary forests for control. According to the data of each wood gauge, we focused on the dynamics of community in terms of structure, diversity and stability. We found that, (i) The composition of dominant populations kept stable since the mixed forests stage and the α-diversity increased with restoration; (ii) The diameter class structure of tree layer exhibited a tendency of bell-shaped type toward inverted J-type, indicating an active regenerating and developmental status; (iii) Niche width of dominant populations such as Juglans mandshurica, Quercus mongolica, Quercus variabilis and Tilia amurensis increased during restoration, while that of Quercus dentata population decreased after playing a pioneer role; (iv) The proportion of negative association and high niche overlapped population pairs (&amp;gt;0.5) both decreased with restoration. In summary, naturalized developmental restoration has promoted the actively developing and regenerating of populations and improved the healthy restoration of plantation community. The status and interrelationships of populations were still being adjusted. The results provide a reference for revealing the dynamic characteristics of vegetation community development in naturalized developmental restoration of plantations.

Flora of the former Kolokolnikov estate (Tyumen)

The article presents for the first time data on the species diversity of vascular plants growing on the territory of the former estate of the Kolokolnikovs, which has a history of formation for a century and a half and is today a place of rest for the citizens of Tyumen. In 2021, most of the study area was classified as a natural monument of regional significance «Lesopark (Parkland) Zatyumensky». For the spring-summer period 2021, 182 species of vascular plants belonging to 136 genera, 56 families were identified. Among the leading families: Asteraceae (22 species), Rosaceae (21), Poaceae (19), Fabaceae (14), Brassicaceae (9), Salicaceae (8), Caryophyllaceae (7), Apiaceae (6), Ranunculaceae (5), which accounted for 61 %. The arboreal layer is dominated by Betula pendula and Tilia cordata, and the grass-shrub layer is dominated by Aegopodium podagraria, Centaurea scabiosa, Geranium sibiricum, Glechoma hederacea, and Poa pratensis. On the territory there are species listed in the Red Book of the Tyumen region: Tilia cordata and Cerasus fruticosa (Prunus fruticosa). In a comparative analysis with herbarium funds, 33 plant species were not identified in the modern flora of the study area. According to the biomorphological analysis according to the system of life forms of K. Raunkier, most plants belong to hemicryptophytes (40.7 %), I. G. Serebryakova - long-rhizomatous polycarpics (21.5 %), O. V. Smirnova et al. - mono-centric type (52.2 %).

Numerical Simulation of the Thermal Environment during Summer in Coastal Open Space and Research on Evaluating the Cooling Effect: A Case Study of May Fourth Square, Qingdao

Urban green space is considered an important part of urban ecological construction be-cause of the efficiency of green space in reducing ambient temperature. It was previously reported that the quantity and layout of arbors and paving are very important factors for cooling. To research the combination mode of the quantity and layout of arbors and paving able to effectively lower the temperature during the summer in a coastal open space environment where little architecture exists, we built a numerical model of heat transfer using ENVI–met numerical modeling simulation, for which the May Fourth Square in Qingdao was selected. The results showed that the ratio coverage of the arbor layer and pavement fragmentation were positively correlated with the cooling effect. We found that setting the passageway conformed to the sea breeze by arbors and close planting at the air outlet effectively reduced the site temperature. After optimizing the site’s greening layout, the cooling effect over the process of time decreased in the height direction. At the same time, the cooling effect increased before 15:00 and then reduced gradually in the time dimension. Compared to the original site, the total cooling efficiency reached 1.41 × 108 J, equaling electric energy of about 39.2 kW·h. This research solves the issue of the synergy between planting and pavement for cooling coastal open spaces in summer and provides a basis to formulate a promotion strategy for landscape design areas with similar geographical and climatic conditions.

Impacts of Moso bamboo (Phyllostachys pubescens) invasion on species diversity and aboveground biomass of secondary coniferous and broad-leaved mixed forest.

In recent decades, Moso bamboo has been largely increasing in the subtropical area of China, raising ecological concerns about its invasion into other native forest ecosystems. One concern is whether the invasion of Moso bamboo significantly simplifies forest community composition and structure and declines biomass. This study adopted the space-for-time method to investigate a secondary coniferous and broad-leaved mixed forest (SF) being invaded by an adjacent Moso bamboo forest (MB) in the Wuxie forest reserve, Zhejiang Province. Three plots were established in each SF, MB, and transitional forest. The results showed that the species composition and species dominance of the arborous layer changed significantly (P < 0.05), which was indicated by the significantly decreased species richness (Margalef index, Shannon–Wiener index, and Simpson index) and evenness (Pielou evenness index). In contrast, the species richness of the shrub and herbaceous layers had two divergent indications (increasing or unchanged), and the evenness remained unchanged. The total and arborous-layer aboveground biomass of the forest community has had no noticeable change (P < 0.05). However, the biomass of the shrub and herbaceous layers showed an increasing trend (shrub significant but herbaceous not), but they only occupied a small proportion (∼1%) of the total biomass. Finally, the aboveground biomass and the diversity index had no significant correlation in each layer and overall stands. We hope that the findings could provide a theoretical basis for the invasion mechanism and ecological consequences of the Moso bamboo invasion.

Effects of mixing proportions on carbon storage and allocation in mixed plantation of Larix olgensis and Fraxinus mandshurica

In this study, four types of mixed Larix olgensis and Fraxinus mandshurica plantations were selected according to the rows-mixing proportions (type Ⅰ: 5:3, type Ⅱ: 6:4, type Ⅲ: 5:5, type Ⅳ: 1:1). The see-mingly unrelated biomass models of L. olgensis and F. mandshurica were developed for obtaining biomass values, and the difference and composition of carbon storage in each forest layer and ecosystem were analyzed. The results showed that carbon storage of arbor layer in different stand types was 39.86-50.12 t·hm-2, the carbon storage of arbor layer inⅠ, Ⅱ and Ⅳ was significantly higher than that in type Ⅲ. The carbon storage of understory was 0.10-0.30 t·hm-2, with that in type Ⅱ being significantly higher than other types. Carbon storage of litter layer was 4.43-6.96 t·hm-2, with type Ⅱ and Ⅲ being significantly higher than those of the other types. In the soil layer, carbon storage was 34.97-54.66 t·hm-2. The carbon storage of soil layer in type Ⅱ was significantly greater than those in the other types. At the whole ecosystem level, carbon storage of type Ⅰ-Ⅳ was 90.43, 108.27, 85.83 and 89.92 t·hm-2, respectively. Type Ⅱ had significantly greater carbon storage than the other types. The arbor layer and soil layer were the major carbon pools in the ecosystem, which accounted for 43.3%-55.7% and 38.7%-50.5% of the total, respectively. Our results suggested that mixing by six rows of L. olgensis and four rows of F. mandshurica was better for future planting.

大兴安岭多布库尔国家级自然保护区植物多样性和群落结构特征

天然林植物多样性保护对于其生态服务功能至关重要，大兴安岭是我国重要国有林区，现有国家级自然保护区保护区林分特征及其耦合关系揭示是天然林保护与生态服务综合提升的基础。于2017年8-9月对多布库尔国家级自然保护区的乔、灌、草和更新层个体大小特征、群落特征和植物多样性特征进行详细调查，冗余分析与方差分解分析解析植物多样性和群落结构特征的耦合关系。结果表明：1）多布库尔保护区主要树种为落叶松，相对多度为42%，其次是白桦和黑桦；灌木中榛所占比例最高，达到60%；草本共记录116种，其中莎草科的羊须草所占比例最大，超过10%；更新层主要树种为蒙古栎，相对多度达54%，其次为白桦。2）多布库尔保护区乔木胸径和树高仅相当于1970年代的55%，乔木和草本丰富度较大兴安岭核心地区（呼中保护区）高出50%-60%。3）冗余分析和方差分解分析结果表明林分个体大小特征的独立效应和乔木层特征对多样性变化贡献最大，乔木层树高与植物多样性变化具有最紧密关系。大兴安岭地区森林已经全部纳入国家天然林保护工程，上述国家自然保护区相关数据是当地本底数据（当地森林以幼龄林为主，尚需要更长时间保护），将为进一步保护区政策制定与天然林保护工程实施提供支持。;Biodiversity conservation including plant species in natural forests is very important for their ecosystem service function. Daxing'anling is an important state-owned forest region in China. The characteristics and coupling relationship of the existing national nature reserves are the basis for the comprehensive improvement of natural forest protection and ecological services. In this paper, from August to September of 2017, the individual size characteristics, community characteristics and plant diversity characteristics of arbor, shrub, herb and regeneration layer were investigated in Duobukuer National Nature Reserve. The redundant analysis and variance partitioning analysis were conducted to analyze the coupling association and possible factors responsible for diversity variations. The results showed that:(1) Larix gmelinii is the main tree species in Duobukuer, had a relative abundance of 42%, followed by Betula platyphylla and Betula dahurica. The proportion of hazelnut (Corylus heterophylla) is the highest among shrubs, reaching 60%. A total of 116 species of herb layers were found, of which Carex callitrichos accounted for the largest proportion, exceeding 10%. The main tree species in the regeneration layer was Quercus mongolica (54%), followed by Betula platyphylla. (2) The diameter and height of trees were only 55% of those in 1970s, and the richness of trees and herbs was about 50%-60% higher than that in Huzhong Nature Reserve of the central Daxing'anling. (3) Redundancy analysis and variation partitioning showed that the individual size (rather than community features), and arbor layer characteristics (rather than shrub and herb layer) contributed the most to the plant diversity variation observed in this study. Of all the tested parameters, tree height gave the most significant explaining power for the plant diversity variations. The forests in Daxing'anling Mountain have been fully included in the Natural Forest Protection Program (NFPP, completely inhibited timber harvest since 1999). The above-mentioned data from the National Nature Reserve, as a local background data, clearly showed that the forests in this region were still in their young stage and long-term protection are necessary. These data will provide supports for further national reserve policy making and implementation of the NFPP in northeast China.

2013-2018年武夷山亚热带常绿阔叶林乔木层动态

PDF HTML阅读 XML下载 导出引用 引用提醒 2013-2018年武夷山亚热带常绿阔叶林乔木层动态 DOI: 10.5846/stxb202007051746 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中央级公益性科研院所基本科研业务专项（GYZX200203）；生态环境部生物多样性保护重大工程（ZDGC2019-007-04）；中央级科学事业单位修缮购置专项（2060503） Dynamics of arbor layer in the Subtropical Evergreen Broad-leaved Forest in the Wuyi Mountains, Fujian Province, southeastern China in 2013-2018 Author: Affiliation: Fund Project: 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:从植物群落组成和结构的角度研究森林群落的演替规律，是探究森林群落的退化与恢复过程及相关机制的重要途径，对于指导天然林保护和恢复具有重要理论价值和实践意义。2018年，对面积为9.6 hm2的武夷山亚热带常绿阔叶林样地进行了第2轮调查，并从重要值、物种多度、物种丰富度、Shannon-Wiener多样性指数、Simpson指数、Margalef丰富度指数、Pielou均匀度指数、死亡率、补员率、种群大小变化率、相对适合度、胸径变异系数等角度分析了乔木层群落动态。结果表明：2018年的乔木个体为48科88属174种，较2013年增加了1种。Margalef丰富度指数上升，Shannon-Wiener多样性指数、Simpson指数、Pielou均匀度指数均略有下降。DBH≥1 cm的乔木个体从68336个减少到63897个，共死亡7430个个体，补员2991个个体。群落的年死亡率为2.30%，年补员率为0.96%，种群大小变化率为-1.34%，相对适合度为0.42。群落的平均胸径从5.02（±0.02） cm上升为5.49（±0.03） cm。28个重要值之和由71.92%下降为71.81%，年死亡率为2.46%，年补员率为0.79%，种群大小变化率和相对适合度分别为-1.67%和0.46。物种数增加和群落总个体数下降对Margalef丰富度指数的上升产生直接影响。常见种减少，稀有种增加，预示着一般性扰动会给常见种的种群带来更大的影响。建落种或优势种的缺乏且许多物种优势程度接近，可能使处于同一林冠层的树种对光照等资源的激烈竞争产生导致的高死亡率和低补员率。赤杨叶（Alniphyllum fortunei）、木荷（Schima superba）等阳生树种的种群更新困难可能意味着群落发生了有利于中生和阴生树种的变化。 Abstract:Studying the forest community succession by understanding the characteristics of plant community composition and structure is an important way to explore the degradation and restoration processes, as well as the related mechanisms of forest communities. The study also has important theoretical and practical significance for guiding the conservation and restoration of natural forests. In 2018, relevant data was gathered by the second investigation in the Subtropical Evergreen Broad-leaved Forest plot with an area of 9.6 hm2 in the Wuyi Mountains, Fujian Province, southeastern China. Community dynamics of arbor layer was analyzed based on the perspectives of importance value, species abundance, species richness, Shannon-Wiener Index, Simpson Index, Margalef Index, Pielou Index, mortality rate, recruitment rate, rate of population size change, fitness, and coefficient of diameter at breast height (DBH) variation. The results showed that the community of trees was 48 families, 88 genera, 174 species in 2018, which increased by 1 species compared with 2013. Margalef Index rose, while Shannon-Wiener Index, Simpson Index and Pielou Index declined in the past 5 years. The tree individuals with DBH ≥ 1 cm was reduced from 68336 to 63897, with 7430 dead, and 2991 recruited individuals. Annual mortality rate, annual recruitment rate, rate of population size change, and fitness of the community were 2.30%, 0.96%, -1.34%, and 0.42, respectively. The average DBH of all trees in this community increased from 5.02 (±0.02) cm to 5.49 (±0.03) cm. The total of importance value for the 28 common tree species with higher importance value (>1%) decreased from 71.92% in 2013 to 71.81% in 2018. Annual mortality rate, annual recruitment rate, rate of population size change, and fitness for these common species were 2.46%, 0.79%, -1.67% and 0.46, respectively. The increase of species number and decrease of total tree individuals of community caused a direct impact on the increase of Margalef Richness Index. The decrease of common species and the increase of rare species indicated that the general disturbance would have a greater impact on the population of common species. The lack of constructive species or dominant species and the close dominance of many species may lead to high mortality rate and low recruitment rate of tree species in the same canopy layer for some resources such as light. The difficulty of population regeneration of sun plants such as Alniphyllum fortune, Schima superba may mean that the community has changed in favor of medium and shade plants. 参考文献 相似文献 引证文献

Forest characteristics and population structure of a threatened palm tree Caryota obtusa in the karst forest ecosystem of Yunnan, China

Abstract Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China, India, Myanmar, Thailand, Laos and Vietnam. It is an economically important and threatened species and appears as a canopy dominant in some karst areas in Yunnan. We aim to clarify the forest structure, species diversity, population status and regeneration dynamics of C. obtusa in the karst forest ecosystem of Yunnan, China. We established 56 vegetation plots dominated by C. obtusa in 10 counties of southern Yunnan. Based on the plot data, we analyzed the community stratification, floristic composition and C. obtusa’s population structure. We used questionnaires to interview local people and recorded the human activity history in C. obtusa-dominated forests. Caryota obtusa palm forests were distributed on limestone mountain slopes and gullies. There were seven forest community types. The stratification of each community included arborous layer, shrub layer and understory. The communities had rich species composition. For all the plots as a whole of each community type, Shannon–Wiener diversity index of either woody or herbaceous species ranged from 2.1 to 3.8. The diameter at breast height (DBH)-class frequency distribution of C. obtusa was a multimodal type. The regeneration was sporadic and dependent on intermediate natural disturbances. In the current population structure, a number of C. obtusa trees with small DBHs consisted mainly of the forest communities with no or a slight degree of human disturbances. Intensive human activities terribly hindered recruitment of C. obtuse, followed by the medium intensity of human activities.

Effects of Stand Structure and Topography on Forest Vegetation Carbon Density in Jiangxi Province

Stand structure and topography are important factors affecting forest vegetation carbon density (FVCD). Revealing the interaction mechanisms between stand structure and topography on FVCD is of great significance for enhancing forest vegetation carbon storage and achieving regional carbon neutrality. Based on stratified sampling, systematic distribution and forest continuous inventory sample plots in Jiangxi province, the variation characteristics of FVCD and its correlations with stand structure and topographic factors were studied. The results are as follows: (1) The average FVCD in Jiangxi province was 44.23 Mg/ha, which was dominated by the carbon density of the arbor layer, accounting for about 81.39% of the total forest—far lower than the average level of global FVCD, which proved that the forest in Jiangxi province was dominated by middle-age and young forests with low carbon density, and also showed that the potential for forest vegetation carbon storage in Jiangxi province was huge. (2) Except for vegetation carbon densities of shrub and herb layers, the vegetation carbon densities of other forest layers in Jiangxi province were significantly different among different forest types. Volume per unit area was the most important factor affecting the vegetation carbon densities of arbor and total forest, and vegetation carbon density–volume models of the main forests were built for vegetation carbon density calculation in Jiangxi province. (3) The vegetation carbon densities of arbor layer, snag and log layer, and total forest increased significantly with increases in elevation and slope. Except for the shrub layer and herb layer, the vegetation carbon densities of the other layers and the total forest had extremely significant or significant differences between slope position gradients—indicating that the effect of topography on FVCD in Jiangxi province was significant, mainly through influencing of forest distribution and human disturbance intensity.

Functional relationship between woody plants and insect communities in response to Bursaphelenchus xylophilus infestation in the Three Gorges Reservoir region.

To study the effect of the invasion of Bursaphelenchus xylophilus on the functional relationship between woody plants and insect communities, the populations of tree species and insect communities were investigative in the Masson pine forests with different infestation durations of B. xylophilus. In this study, the number of Pinus massoniana began to decrease sharply, whereas the total number of other tree species in the arboreal layer increased gradually with the infestation duration of B. xylophilus. The principal component analysis ordination biplot shows that there was a significant change in the spatial distribution of woody plant species in different Masson pine forest stands. Additionally, a total of 7,188 insect specimens were obtained. The insect population showed an upward trend in stand types with the increase of pine wilt disease infection periods, which demonstrated that the insect community had been significantly affected by the invasion of B. xylophilus. However, the insect diversity indexes were not significantly different among Masson pine forest stands. The structure of insect functional groups changed from herbivorous (He) > omnivorous (Om) > predatory (Pr) > parasitic (Pa) > detritivorous (De) in the control stand to He > Pa > Om, De > Pr after B. xylophilus infestation in the forests. The results showed that the populations of He, Pa, and De increased after the invasion of B. xylophilus, but the populations of Pr decreased. Moreover, the redundancy analysis ordination biplots reflected the complicated functional relationship between woody plant communities and insects after the invasion of B. xylophilus. The present study provides insights into the changes in the community structure of woody plants and insects, as well as the functional relationship between woody plant communities and insect communities after invasion of B. xylophilus.

Investigation on Carbon Sequestration Capacity of Typical Subtropical Evergreen Broad-leaved Forest in Jiulianshan Nature Reserve

Nine investigation sample plots (each 20m×20m) were set up to investigate the biomass and soil bulk density of three typical subtropical evergreen broad-leaved forests (Castanopsis eyrei, Schima superba, Cyclobalanopsis glauca) in Jiulianshan National Nature Reserve in Jiangxi Province in 2015 and 2020. The vegetation carbon density and carbon storage, soil carbon density and carbon storage, the carbon density and carbon storage of the investigation sample plots were calculated according to the organic carbon content of vegetation and soil. In addition, the changes in carbon sequestration capacity of three typical subtropical evergreen broad-leaved forests in Jiulianshan National Nature Reserve in Jiangxi Province in 2015 and 2020 were analyzed. The investigation results had shown that:Compared with 2015, the average organic carbon content of Castanopsis eyrei, Cyclobalanopsis glauca, and Schima superba of Jiulianshan National Nature Reserve in Jiangxi Province increased by 10.36%, 10.13% and 7.73% in 2020. The average organic carbon content of leaf, branch, stem and root increased also by 10.60%, 10.38%, 11.13% and 5.29% respectively. The soil organic carbon content of different soil layers in 2020 and 2015 were all decrease with the increase of soil depth. Compared to 2015, the organic carbon content increased while the soil bulk density decreased in 2020.The average carbon density of the forest vegetation layer in the investigation plots of Jiulianshan National Nature Reserve in Jiangxi Province had increased from 82.63t/hm2 in 2015 to 108.94t/hm2 in 2020. The carbon density of the arbor layer had increased from 76.11t/hm2 in 2015 to 106.09t/hm2 in 2020, while the carbon density of the shrub layer, herbaceous layer and litter layer in 2020 was lower than that in 2015. In 2015 and 2020, the carbon density of different vegetation layers in the three typical subtropical evergreen broad-leaved forest of Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca were all ranked as arbor layer, shrub layer, litter layer and herbaceous layer.The average soil carbon density (calculated by 10cm) at different depths in 2020 and 2015 in Jiulianshan National Nature Reserve of Jiangxi Province all decreased with the increase of the soil depth. The total average soil carbon density in 2020 was 168.03t/hm2, which was 35.4%% lower than that of 2015(288.05t/hm2).The average carbon storage in the sample plot (20m×20m) in Jiulianshan National Nature Reserve in Jiangxi Province decreased from 13771.04kg in 2015 to 10688.11kg in 2020 with a decrease of 22.38%. The average carbon storage of vegetation decreased from 3305.20kg in 2015 increased to 4357.60kg in 2020 with an increase of 31.8%, while the average soil carbon storage decreased from 10137.04kg in 2015 to 6475.51kg in 2020 whit a decrease of 36.1%.

Structure and species diversity of Cerasus community in Dawei Mountain of Hunan, China.

To provide a scientific basis for the conservation and exploitation of wild Cerasus species in Dawei Mountain, we investigated the community characteristics and species diversity of Cerasus species. The results showed that there were four Cerasus communities, C. campanulata, C. diel-siana, C. conradinae and C. xueluoensis, in Dawei Mountain. Phaenerophyte in the life form and pantropical elements in the local flora were both dominant. The shrub layer had higher species diversity than that of the arbor layer. Species diversity of those four communities was following the order of C. dielsiana, C. conradinae, C. campanulata and C. xueluoensis. The community structure was relatively stable when young and mature individuals of Cerasus predominated. The ground dia-meter class structure indicated that the C. xueluoensis population was a growing population with a typical pyramid structure. The C. conradinae community was mono-dominated by C. conradinae, with C. dielsiana and C. campanulata as the important companion species. Those three Cerasus species would be replaced by other coniferous and broadleaved species due to the shortage of natural regeneration.

Investigation on carbon sequestration capacity of typical subtropical evergreen broad-leaved forest in Wuyi Mountain National Nature Reserve

Three typical substropical evergreen broad-leaved forests (Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca) in Wuyi Mountain National Nature Reserve of Jiangxi Province were selected to investigate its carbon sequestration capacity. The biomass and soil bulk density of sample investigation were get by setting sample investigation, field quadrat sampling, indoor sample making, experimental analysis testing, data statistics and analysis. The organic carbon content of vegetation layer (arbor layer, shrub layer and herbaceous layer, litter layer) and soil layer (0-10cm, 10-20cm, 20-30cm, 30-50cm and 50-100cm) were also get. The carbon density and carbon storage of subtropical evergreen broad-leaved forests vegetation and soil were estimated which including Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca. The investigation results had shown that: The average organic carbon content of each vegetation layer in the investigation plot (400 m2) of Wuyi Mountain National Nature Reserve was arbor layer (54.07%)&gt; shrub layer (52.8%)&gt; herbaceous layer (47.5%), in which the average organic carbon content of the three subtropical evergreen broad-leaved forests in the arbor layer was close 52.97% to 54.87% and the total average content was 54.07%. The average carbon density of the forest vegetation layer was 178.3587t/hm2, the average carbon density of the vegetation layer was arbor layer (176.0273t/hm2)&gt; shrub layer (1.3043t/hm2)&gt; litter layer (0.8144t/hm2)&gt; herbaceous layer (0.2127t/hm2); the average carbon density of each forest species was Castanopsis eyrei (213.5141t/hm2)&gt; Schima superba (168.9069t/hm2)&gt; Cyclobalanopsis glauca (152.6551t/hm2). Investigation sample of subtropical evergreen broad-leaved forest (400 m) in Wuyi Mountain National Nature Reserve, Jiangxi Province2 The average soil bulk density of each soil layer cm 0-100 g/cm was 0.868-1.816 g/cm3 both soil organic carbon content and soil carbon density decreased with the increase of soil depth. The average organic carbon content of each soil layer was between 3.75% and 12.48%, and the average soil carbon density was between 62.85t/hm2 and 146.14t/hm2. The average total carbon density of the soil in the investigated sample plots was 754.77t/hm2, of which the average soil carbon density in investigation sample plots in Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca was 911.49t/hm2, 762.56t/hm2 and 543.22t/hm2 respectively. The average carbon storage of the investigation sample plot (400m2) in Jiangxi Wuyi Mountain National Nature Reserve were Castanopsis eyrei forest (45.0002t) &gt;Cyclobalanopsis glauca forest (36.6087t) &gt; Schima superba forest (28.4850t), the average soil carbon storage(30.1908t) was 4.23 times the average carbon storage(7.1314t).

桂林岩溶石山常绿落叶阔叶混交林乔木层优势物种生态位研究

采用样方法对不同资源位群落进行调查，通过冗余分析（RDA）结合Monte Carlo随机置换检验筛选出对桂林岩溶石山常绿落叶阔叶混交林乔木层优势物种分布影响显著的土壤资源轴（土壤有机质、土壤水溶钙、土壤速效氮、土壤全氮、土壤pH值和土壤厚度）。利用Levins生态位宽度指数和Pianka生态位重叠指数对桂林岩溶石山常绿落叶阔叶混交林乔木层14个优势物种在土壤有机质、土壤水溶钙、土壤速效氮、土壤全氮、土壤pH值和土壤厚度6个土壤资源轴上的生态位特征进行研究。结果表明：（1）在土壤有机质和土壤水溶钙资源轴上，生态位宽度最大值为常绿物种檵木（0.89、0.94）；在土壤pH值资源轴上，生态位宽度最大值为常绿物种粗糠柴（0.96）；在土壤速效氮、土壤全氮和土壤厚度资源轴上，生态位宽度最大值为落叶物种南酸枣（0.87、0.99、0.97）。（2）14个优势物种在6个土壤资源轴上，生态位重叠均值由大到小依次为土壤厚度 > 土壤全氮 > 土壤水溶钙 > 土壤速效氮 > 土壤pH值 > 土壤有机质，且均表现为常绿物种与常绿物种形成的种对生态位重叠均值（0.84） > 常绿物种与落叶物种（0.74） > 落叶物种与落叶物种（0.66）。（3）综合6个土壤资源轴，生态位重叠值≥0.5的种对高达480对，占总种对数的87.91%，暗示桂林岩溶石山常绿落叶阔叶混交林乔木层优势物种在资源匮乏且资源异质性高的特殊生境中存在激烈竞争，且乔木层种间关系相对不稳定。;The sample method was employed to investigate the communities with different resource positions. The soil resource axes (soil organic matter, soil water-soluble calcium, soil available nitrogen, soil total nitrogen, soil pH value, and soil depth) which have significant influence on the distribution of dominant species in arbor layer of evergreen deciduous broad-leaved mixed forest in karst hills of Guilin were selected by Redundancy analysis (RDA) with Monte Carlo random replacement test. Niche characteristics of 14 dominant species which in the arbor layer of evergreen deciduous broad-leaved mixed forest in karst hills of Guilin along soil organic matter, soil water-soluble calcium, soil available nitrogen, soil total nitrogen, soil pH value and soil depth were analyzed by Levins niche breadth index and Pianka niche overlap index. The results showed that:(1) on the soil organic matter and soil water-soluble calcium resource axis, the maximum niche width was evergreen species, which were Loropetalum chinense (0.89, 0.94); on the soil pH value resource axis, the maximum niche width was the evergreen species Mallotus philippensis (0.96); on the soil available nitrogen, soil total nitrogen and soil depth resource axis, the maximum niche width was deciduous species, which were Choerospondias axillaris (0.87, 0.99, 0.97). (2) The 14 dominant species composed 91 species pairs on 6 soil resource axes, and their niche overlap averages in descending order were as follows:soil depth > soil total nitrogen > soil water-soluble calcium > soil available nitrogen > soil pH value > soil organic matter. And the six soil resource axes were all showed as the mean niche overlap of species pair between evergreen dominant species and evergreen dominant species (0.84) > evergreen dominant species and deciduous dominant species (0.74) > deciduous dominant species and deciduous dominant species (0.66). This showed that the 14 dominant species have the most intense competition on the soil depth resource axis, followed by soil total nitrogen resource axis, and soil organic matter resource was axis relatively small. Furthermore, the competition between evergreen species was the most intense, followed by competition between evergreen and deciduous species, and between deciduous species competition was relatively small. (3) Based on the six soil resource axes, there were 480 species pairs with niche overlap value ≥ 0.5, accounting for 87.91% of the number of total species pairs. It implies that the dominant species in the arbor layer of the evergreen and deciduous broad-leaved mixed forest in the karst hills in Guilin have fierce competition in the special habitats with scarce resources and high resource heterogeneity, and the interspecific relationship of arbor layer is relatively unstable.