Ectomycorrhizal fungal diversity and saprotrophic fungal diversity are linked to different tree community attributes in a field‐based tree experiment

Exploring the link between above‐ and belowground biodiversity has been a major theme of recent ecological research, due in large part to the increasingly well‐recognized role that soil microorganisms play in driving plant community processes. In this study, we utilized a field‐based tree experiment in Minnesota, USA, to assess the effect of changes in plant species richness and phylogenetic diversity on the richness and composition of both ectomycorrhizal and saprotrophic fungal communities. We found that ectomycorrhizal fungal species richness was significantly positively influenced by increasing plant phylogenetic diversity, while saprotrophic fungal species richness was significantly affected by plant leaf nitrogen content, specific root length and standing biomass. The increasing ectomycorrhizal fungal richness associated with increasing plant phylogenetic diversity was driven by the combined presence of ectomycorrhizal fungal specialists in plots with both gymnosperm and angiosperm hosts. Although the species composition of both the ectomycorrhizal and saprotrophic fungal communities changed significantly in response to changes in plant species composition, the effect was much greater for ectomycorrhizal fungi. In addition, ectomycorrhizal but not saprotrophic fungal species composition was significantly influenced by both plant phylum (angiosperm, gymnosperm, both) and origin (Europe, America, both). The phylum effect was caused by differences in ectomycorrhizal fungal community composition, while the origin effect was attributable to differences in community heterogeneity. Taken together, this study emphasizes that plant‐associated effects on soil fungal communities are largely guild‐specific and provides a mechanistic basis for the positive link between plant phylogenetic diversity and ectomycorrhizal fungal richness.     

北京城市公园常见乔木土壤真菌群落特征及影响因素

快速城市化引起的城市环境污染问题日趋严重,由城市中心到城郊往往呈规律性递变趋势。北京城市公园作为城市绿地主体,不仅是城市居民重要的休闲游憩场所,也能在一定程度上反应环境污染,如土壤重金属污染的作用规律。以北京市这一典型大城市为研究区域,根据不同城市公园的建成时间、所处位置和距离市中心的远近选择六个公园作为研究样点,选取公园常见6种乔木下土壤,通过对土壤重金属含量、土壤理化性质以及土壤真菌群落测定和测序,旨在探讨城市公园植被下土壤真菌群落特征（多样性和群落结构组成）以及影响因素。研究结果表明：北京城市公园乔木下的土壤真菌群落多样性、群落组成以及优势类群受到土壤pH值、土壤养分和水分以及重金属铅的调控。其中公园土壤重金属铅含量增加会降低土壤真菌多样性、显著影响优势类群子囊真菌（占真菌群落73%）以及土壤真菌功能类群病原真菌群落组成。研究揭示了北京城市公园土壤真菌群落特征及调控因素,特别是重金属铅对土壤真菌群落的影响,这对提高城市公园科学管理和环境健康具有积极的应用价值。     

西藏昆诺阿藜种子可培养内生真菌多样性

探究西藏不同地区昆诺阿藜种子内生真菌的物种组成、多样性等群落结构特征,丰富昆诺阿藜种子相关微生物的可利用资源,对于微生物资源利用和昆诺阿藜病害的生物防控具有重要意义。本研究收集西藏不同海拔3个地区(日喀则、拉萨和林芝)的昆诺阿藜种子,利用传统分离方式进行了真菌的培养。从46份昆诺阿藜种子中共分离出947株真菌,经ITS序列分析结合形态观察鉴定为1门9目12科26属77种。所有的真菌都归类为子囊菌门Ascomycota,菌株数量相对丰度最高的3个属为链格孢属Alternaria (40.2%)、镰刀菌属Fusarium (17.4%)和茎点霉属Phoma (13.9%)。按照多样性指数,日喀则地区的昆诺阿藜内生可培养真菌的多样性明显高于拉萨和林芝两个地区。     

南岭东西段植物群落物种组成及其树种多样性垂直格局的比较

根据沿海拔梯度设置的样地的调查资料,对南岭东段的莽山和西段的猫儿山植物群落乔木层物种多样性的垂直分布格局进行了比较研究。莽山和猫儿山的植被类型差异不大,但相同植被类型的物种组成有比较明显的差异。随海拔的上升,两山体乔木的最大树高均呈现显著下降趋势。猫儿山乔木的最大胸径、胸高断面积之和以及立木密度在海拔梯度上呈单峰曲线变化趋势。莽山乔木的最大胸径、胸高断面积之和与海拔呈明显的负相关性,而立木密度的变化规律不明显。这种单峰曲线格局或负相关关系与中尺度上的海拔高度以及小尺度上的土壤特性、小地形以及人为干扰强度等因素有关。在海拔1000m以下的常绿阔叶林群落和1700m以上的山顶矮林群落,莽山乔木的物种丰富度均明显高于猫儿山。两山体的乔木种数与海拔之间都显示出负相关性,但莽山由于高海拔群落受人为干扰的影响,这种相关性不显著。乔木层α多样性沿海拔梯度没有表现出明显的变化规律,并且在两山体之间也看不出明显的差别。本文最后还对两山脉低海拔区段的常绿阔叶林群落的物种组成和多样性进行了对比分析,结果表明人为干扰导致猫儿山常绿阔叶林的物种丰富度(S)和α多样性(H’)明显低于莽山的原生性常绿阔叶林群落,而且落叶阔叶树种和毛竹(Phyllostachys pubescens)开始入侵到群落中。     

The spatial scaling of saprotrophic fungal beta diversity in decomposing leaves

Assembly of fungal communities remains poorly understood in part because of the daunting range of spatial scales that may be involved in this process. Here, we use individual leaves as a natural sampling unit, comprising spatially distinct habitat and/or resource patches with unique histories and suites of resources. Spatial patterns in fungal beta diversity were tested for consistency with the metacommunity paradigms of species sorting and neutral dynamics. Thirty senesced leaves were collected from the forest floor (O horizon) in replicate upland forest, riparian forest and vernal pool habitats. We quantified spatial distance between leaves, and fungal community composition was assayed by terminal restriction fragment length polymorphism. Significant distance‐decay relationships were detected at all but one upland site. This is the first study where changes in fungal community composition were quantified across discrete adjacent habitat patches, providing evidence that fungal distance decay is operational at a scale of centimetres. Although leaves of differing lignin contents were sampled from each site, leaf type was not consistently important in explaining variation in fungal community composition. However, depth of a leaf within the forest floor significantly influenced community composition at five of six sites. Environmental heterogeneity associated with depth could include moisture gradients, relative influence of soil or spore colonization, and impact of forest floor biotic community (i.e. collembola and earthworms). Because the influence of spatial distance and depth on fungal community composition could not be disentangled, both species‐sorting and neutral processes may be embedded within the distance‐decay relationships that we found.     

三峡库区马尾松林土壤真菌群落特征及影响因素

土壤真菌是地下生物多样性的重要组成部分,在土壤碳和养分循环中发挥重要功能。本研究基于高通量测序技术对三峡库区22个马尾松林表层土壤(0～10 cm)真菌群落进行研究。结果表明: 子囊菌门与担子菌门为优势真菌类群,常见类群包括散囊菌目、红菇目和银耳目。真菌功能群以腐生真菌与外生菌根真菌为主,欧石南类菌根真菌也较常见。冗余分析表明,无论是对整个土壤真菌群落还是不同真菌功能群,环境变量对群落结构的影响均强于空间变量,说明在较小的空间尺度上生境过滤对土壤真菌群落结构的影响超过扩散限制。地上生物量、电导率、有效磷、容重、碳氮比、硝态氮、粉粒占比是影响真菌群落结构的主要环境因子,但影响不同真菌功能群的最关键环境因子存在差异。     

Dematiaceous hyphomycetes inhabiting decaying blackish needles ofAbies firma and their distribution in the Kanto district, Japan

Dematiaceous mitosporic fungi darkening decaying fir needles on the ground were studied. Fungal communities on decaying, blackish fir needles were investigated in nine sites of the Kanto district, Japan, using a washing method. A total 108 taxa was recorded from 540 sampled needles. Among abundantly occurring dematiaceous fungi,Anungitea continua, A. uniseptata andEndophragmiella uniseptata were recognized as the major colonizers, forming a hyphal network on the surface of decaying fallen needles and darkening them. The effects of climate on the distributions of seven dematiaceous fungi included the major colonizers were analyzed. The abundance (proportion of needles colonized by a fungal species) ofChaetopsina fulva showed a significantly positive correlation with annual mean air temperature at each sampling site. No other significant correlations between the selected climatic factors and the distributions of dematiaceous fungi were recognized. Contribution No. 176 from Sugadaira Montane Research Center, University of Tsukuba.     

Beta‐diversity in temperate and tropical forests reflects dissimilar mechanisms of community assembly

Site‐to‐site variation in species composition (β‐diversity) generally increases from low‐ to high‐diversity regions. Although biogeographical differences in community assembly mechanisms may explain this pattern, random sampling effects can create this pattern through differences in regional species pools. Here, we compared assembly mechanisms between spatially extensive networks of temperate and tropical forest plots with highly divergent species pools (46 vs. 607 species). After controlling for sampling effects, β‐diversity of woody plants was similar and higher than expected by chance in both forests, reflecting strong intraspecific aggregation. However, different mechanisms appeared to explain aggregation in the two forests. In the temperate forest, aggregation reflected stronger environmental correlations, suggesting an important role for species‐sorting (e.g. environmental filtering) processes, whereas in the tropics, aggregation reflected stronger spatial correlations, more likely reflecting dispersal limitation. We suggest that biogeographical differences in the relative importance of different community assembly mechanisms contribute to these striking gradients in global biodiversity.     

Chronosequential change in a butterfly community after clear-cutting of deciduous forests in a cool temperate region of central Japan

Transect counts of butterflies were conducted in the northern part of Ibaraki, central Japan, from 1997 to 2001 at 11 census sites, composed of successive stages of deciduous forest development: grassland (one site, early abandoned stage); cutover land (one site, 1–5 years after clear‐cutting); secondary forests (very young (two sites, 6–9 years), middle (two sites, 16–22 years) and old (two sites, 47–51 years)) and old‐growth natural forests (three sites, ≥124 years old). A total of 86 species and 8858 individual butterflies were recorded by 29 sets (406 times) of transect counts. The species richness (number of species), abundance (number of individuals) and diversity indices (Shannon–Wiener H′ and Simpson's 1–λ) of butterflies were high in the early stages (grassland, cutover land and very young secondary forests) of secondary succession. Typical natural forest species increased with the progress of succession, and the old secondary forests and old‐growth natural forests had similar species composition. In contrast, most of the typical natural grassland species were recorded only in the grassland site. In the cutover land site, the number of individuals of grassland species considerably decreased from the first to the second year; furthermore, only one typical natural grassland species was recorded. Thus, the suitable stage for grassland butterfly species lasts for only 1–2 years after clear‐cutting. Old secondary forests (approximately>50 years old) would be able to give refuge to the forest butterfly species, including typical natural forest species. Based on the results, a practical, forestry‐based plan to conserve butterfly diversity was proposed.     

五台山亚高山土壤真菌海拔分布格局与构建机制

生物多样性的海拔分布格局与维持机制是生物多样性与生态系统功能研究的热点领域。尽管微生物驱动着地球上许多重要的生物地球化学循环,但与大型生物体相比,对微生物多样性海拔梯度分布格局知之甚少。运用Illumina Miseq高通量测序技术,全面分析了五台山亚高山生态系统（海拔2000-3058 m范围内）土壤真菌群落组成和多样性变化特征。结果表明,子囊菌门（Ascomycota）、担子菌门（Basidiomycota）、接合菌门（Zygomycota）、壶菌门（Chytridimycota）为主要的优势菌门。非度量多维尺度分析（NMDS）和相似性分析（ANOSIM）表明真菌群落组成和结构在海拔梯度上存在显著的差异（P<0.05）。典范对应分析（CCA）显示pH、植物丰富度、总碳含量与土壤真菌群落结构存在显著相关性（P<0.05）。局域海拔尺度上,土壤真菌多样性与植物多样性（α和β多样性）呈显著正相关关系（P<0.05）。方差分解分析（VPA）和偏Mantel分析表明土壤真菌群落构建过程中,环境因子和空间变量都起作用,并且环境因子占绝对的优势。土壤真菌群落之间的Bray-Curtis距离与海拔距离呈显著正相关关系（P<0.05）,说明环境选择是亚高山土壤真菌海拔分布格局的决定因素。总之,五台山亚高山沿海拔梯度土壤真菌群落结构和多样性产生明显的变化,群落构建主要由确定性过程和随机过程驱动,但确定性过程占主导地位。土壤pH、植物丰富度、总碳含量是影响土壤真菌群落结构的重要因素。     

Comparison of lepidopteran larval communities among tree species in a temperate deciduous forest, Japan

Abstract.  1. The enormous diversity of phytophagous insects in forest canopies is hypothesised to be supported by the number of herbivorous species per host tree species or host specificity. It is therefore necessary to examine the effect of host plant species on compositional changes in the herbivore communities.
2. The lepidopteran larval communities were examined in the canopies of 10 tree species in a temperate deciduous forest of Japan. The phylogeny and leaf flush phenology of host plant species were taken into account as factors affecting the herbivore community assembly.
3. Examination of seasonal changes in the larval community structures on each tree species showed that larval species richness, abundance, and evenness decreased significantly from spring to summer. Larval species richness and abundance were characterised by family-level phylogenetic differences among tree species, whereas evenness was determined at a higher taxonomic level.
4. Compositional changes in the larval communities among tree species showed a remarkable pattern, with a phylogenetic effect at a high taxonomic level in spring, similar to evenness, but a phenological effect in summer. This suggests that host specificity could support the lepidopteran larval diversity in spring.
5. These results suggest that the differences in host utilisation of the herbivore, which reflects the phylogenetic effect of the host plants, can be important as a factor affecting the diversity of lepidopteran larval communities in temperate forests.     

Host phylogeny is the primary determinant of ectomycorrhizal fungal community composition in the permafrost ecosystem of eastern Siberia at a regional scale

Ectomycorrhizal (EM) fungal communities have been studied worldwide; however, those in the very cold and dry continental climate zone of northern Eurasia remain understudied. We investigated EM fungal community structure on plant roots and its determinants in eastern Siberia. We identified 291 EM fungal taxa belonging to 37 fungal genera from nine sites spanning 2100 km. In a variation partitioning analysis, host plant phylogeny was the primary factor that explained variation in fungal community composition, followed by spatial distance, soil, and climate. Host specificity and preference were attributed to differences in EM fungal community composition among host plants. The EM fungal community on Larix cajanderi, the dominant canopy tree in the region, was characterized by a high proportion of Suillus and Rhizopogon species. This implies that these specialist fungal symbionts have a close ecological relationship with pioneer Larix trees to adapt to the harsh continental climate of Siberia.     

三种温带森林大型土壤动物群落结构的时空动态

对帽儿山3种典型森林群落大型土壤动物进行了连续6个月的野外调查研究。通过系统分析,共获得大型土壤动物3604只,隶属于3门6纲17目50科。其中正蚓科(Lumbricidae)、线蚓科(Enchytraeidae)和石蜈蚣目(Lithobiomorpha)为优势类群,常见类群11类。结果表明:(1)水平分布上,密度和生物量红松人工林最高,其次为硬阔叶林,蒙古栎林最少;类群数硬阔叶林最多,蒙古栎林最少;香农指数和丰富度指数均为蒙古栎林最高,红松人工林最低;优势度指数与两者相反;均匀度指数蒙古栎林最高,硬阔叶林最低;(2)垂直分布上,个体密度、类群数及生物量均差异显著(P < 0.001)。3个样地大型土壤动物个体密度表聚性明显;类群数红松人工林自凋落物层向下减少,硬阔叶林和蒙古栎林0-10 cm最多;生物量在0-10 cm土层最大;香农指数随深度增加而减小,优势度指数则相反;(3)在时间变化上,5月和10月个体密度和类群数较多,9月生物量最大;香农指数和优势度指数差异显著(P < 0.01),其他指数各月间无明显差异;(4)与土壤环境因子关系上,总有机碳含量与类群数、个体密度及生物量显著正相关,容重与香农指数显著负相关;典型对应分析结果表明,不同类群大型土壤动物与环境相关性不同。     

昆明西山森林公园天然虫生真菌及其内生真菌的分离鉴定及多样性分析

【背景】不同地区虫草物种多样性的调查是虫草相关研究的热点之一,虫草真菌区系研究是真菌资源研究的重要内容。【目的】了解云南省昆明市西山森林公园天然虫生真菌及其内生真菌的多样性,增加对虫草真菌区系的认识。【方法】对该地区通过资源调查并采用组织分离法对采集的虫草样本进行虫生真菌及其内生真菌的分离,利用形态特征观察及ITS联合nr SSU、nr LSU、translation elongation factor-1α (tef-1α)、rpb1、rpb2多基因测序进行虫生真菌物种鉴定及多样性分析。【结果】共采集45份云南省昆明市西山森林公园天然虫草样本,鉴定结果表明隶属于2科5属12种,包括虫草科(Cordycipitaceae)的鳞翅虫草属(Samsoniella)(2种,含疑似新种1个)、虫草属(Cordyceps)(4种)和白僵菌属(Beauveria)(4种),以及线虫草科(Ophiocordycipitaceae)的紫枝孢属(Purpureocillium)(1种)和弯颈霉属(Tolypocladium)(1种,为疑似新种),优势属为虫草属(Cordyceps),优势种为环链虫草(C...     

Drivers of macrofungal species composition in temperate forests,West Hungary: functional groups compared

The most influential environmental drivers of macrofungal species composition were studied in managed, even-aged, mixed forests of Őrség National Park, Hungary. Functional groups of macrofungi were analyzed separately by non-metric multidimensional scaling and redundancy analysis exploring their relations to tree species composition, stand structure, soil/litter conditions, microclimate, landscape, and management history. There was some evidence that macrofungi are related to drivers that are relatively easy to measure. Wood-inhabiting fungal species composition is driven primarily by the species composition of living trees, while substratum properties and microclimate play minor roles. The terricolous saprotrophic community was determined principally by a litter pH gradient involving tree species composition and soil/litter properties. Microclimate had no concordant effect. No obvious underlying gradients were detected on ectomycorrhizal fungal species composition; however, tree size and litter pH had significant effects. For each group, no clear responses to landscape or management history were detected.     

Structure,dynamics and disturbance regime of temperate broad-leaved forests in Japan

Abstract. Structure, diversity and dynamics of five Japanese temperate old-growth forests were compared, differing from each other in, i.a., climate, dominant tree type, topography, disturbance regime. The forests were Aya, Ogawa, Kanumazawa Riparian, Kanumazawa upland and Senju. A permanent plot (1–6 ha) was established in each forest and trees were censused several times at intervals of two years. Mean annual recruitment rates and mortality rates in these forests were both in the range of 0.5 to 4.6 %/yr at the community level. Analyses of the structure and dynamics of populations showed that the underlying process was different among the forests. Some forests experienced compositional shifts in their canopies, others had a constant canopy composition but appeared to lack effective regeneration in recent years. The recruitment rate appeared to be strongly affected by competitive undergrowth vegetation such as dwarf bamboo which has been controlled by natural disturbance or human impact. It is likely that the forests with mostly low recruitment rates had a low species diversity. The current variation in structure, diversity and dynamics of the studied forests might have been determined not only by physical conditions (e.g. climate) but also by chance factors (e.g. disturbance, outbreak of deer population).     

Tree shape, forest structure and diversity of drosophilid community: Comparison between boreal and temperate birch forests

Some models, based on the latitudinal variation in sun angle distribution, predict that trees at high latitudes have narrowly conical crowns and constitute simple-layered forests, whereas trees at low latitudes have shallowly dome-shaped and form more structurally complex multilayered forests. There is a hypothesis that structurally complex habitats can harbor potentially more species than simple ones. In this study, we examined latitudinal correlations between tree shape, forest structure and diversity in drosophilid communities, comparing boreal and cool-temperate forests. We selected secondary birch forests with a common canopy tree species, white birch (Betula platyphylla Sukatchev), as study sites. The crown shape of white birch tended to be spherical in the cool-temperate forest, but narrowly conical in the boreal forest. The foliage structure differed between the two forests. The cool-temperate forest was characterized by a clearly two-layered structure, whereas foliage in the boreal forest was less clearly stratified, being distributed somewhat continuously from the ground to the canopy at lower densities. The structural complexity expressed by foliage height diversity was greater in the cool-temperate forest than in the boreal forest. Various measures of drosophilid diversity were higher in the cool-temperate forest than in the boreal forest, probably resulting from the impoverishment of the canopy subcommunity in the boreal forest. Thus, a physical environmental factor (i.e. the angle of solar inclination) could be a potentially important factor in structuring latitudinal patterns of sylvan animal communities through changes in plant structure at the individual and community levels.     

Plant species richness and productivity determine the diversity of soil fungal guilds in temperate coniferous forest and bog habitats

Fungi have important roles as decomposers, mycorrhizal root symbionts and pathogens in forest ecosystems, but there is limited information about their diversity and composition at the landscape scale. This work aimed to disentangle the factors underlying fungal richness and composition along the landscape‐scale moisture, organic matter and productivity gradients. Using high‐throughput sequencing, we identified soil fungi from 54 low‐productivity Pinus sylvestris‐dominated plots across three study areas in Estonia and determined the main predictors of fungal richness based on edaphic, floristic and spatial variables. Fungal richness displayed unimodal relationship with organic matter and deduced soil moisture. Plant richness and productivity constituted the key predictors for taxonomic richness of functional guilds. Composition of fungi and the main ectomycorrhizal fungal lineages and hyphal exploration types was segregated by moisture availability and soil nitrogen. We conclude that plant productivity and diversity determine the richness and proportion of most functional groups of soil fungi in low‐productive pine forests on a landscape scale. Adjacent stands of pine forest may differ greatly in the dominance of functional guilds that have marked effects on soil carbon and nitrogen cycling in these forest ecosystems.     

卵孢小奥德蘑覆土真菌群落特征及其影响因素

卵孢小奥德蘑Oudemansiella raphanipes是一类依赖覆土栽培的食用菌。本文采用Illumina MiSeq高通量测序技术结合生态学及统计学分析方法研究卵孢小奥德蘑覆土真菌群落特征和影响因素。结果表明,与原始覆土内真菌群落相比,种植卵孢小奥德蘑后的覆土内真菌群落多样性显著下降;在组成方面,虽然优势菌门仍为子囊菌门Ascomycota,但其中的Cladosporium、Acremonium、Gibberella和Emericellopsis等属的相对丰度有所降低,而隶属于被孢霉门Mortierellomycota的Stilbella、Neocosmospora、Pseudogymnoascus和Preussia等属的相对丰度呈增加趋势。卵孢小奥德蘑覆土真菌以腐生营养型为主,与原始覆土相比,种植卵孢小奥德蘑后的粪生营养型真菌和木腐菌呈增加的趋势;进一步研究发现pH、速效钾、速效磷和总氮等覆土土壤理化性质显著影响真菌群落的多样性和结构,pH和速效钾含量与真菌群落的丰富度和多样性呈显著负相关关系。研究结果为深入解析卵孢小奥德蘑覆土微生态机制奠定基础。