Influence of bark pH on the occurrence and distribution of tree canopy myxomycete species

This study compares the occurrence and distribution of myxomycete species in the canopy of living trees and neighboring grapevines. Corticolous myxomycetes of three temperate forests in southeastern USA were studied on six tree species (30 trees) and grapevines (30 vines) to determine distribution and occurrence of myxomycete species relating to geographic location, host species, and bark pH. The double-rope climbing technique was used to access the canopy and sample bark up to 16.5 m. Bark samples were examined in 580 moist chamber cultures and 44 myxomycete species were identified representing 21 genera, averaging 3.0 +/- 2.1 species per sample site. Jaccard's coefficient determined community similarity between five individuals of six tree species, Acer saccharum, Fraxinus americana, Liquidambar styraciflua, Liriodendron tulipifera, Platanus occidentalis and Tsuga canadensis, and neighboring grapevines, Vitis aestivalis and V. vulpina. Vertical variation in species richness was significantly different only for Platanus occidentalis and might be attributable to flaking of bark with increasing height in the canopy. Tsuga canadensis and neighboring grapevines had greatest community similarity. Cribraria violacea was observed on all tree and grapevine species except T. canadensis and neighboring grapevines. Occurrence and species assemblages of myxomycetes were associated with bark pH, not geographic location. Bark of V. aestivalis (pH 4.5) was more acidic than neighboring T. canadensis (pH 4.1), compared to grapevines of the same species neighboring other tree species. Results indicated that most species are not regionally restricted, and although some myxomycetes are associated with a certain pH range, others develop on any substratum. Future research protocols for corticolous myxomycetes should emphasize sampling adequate amounts of substrata in a local region from different host species that have a wide range of bark pH, ensuring a representative sample of species for an entire region.     

Geographical distribution of myxomycetes living on Cryptomeria japonica bark in Japan

There is little available data on the biogeography of myxomycetes at the regional scale within any given climate zone. To investigate the geographical distribution of these protozoans, we focused on corticolous myxomycetes associated with the bark of Cryptomeria japonica trees, which we sampled extensively throughout Japan. Myxomycete sporophores developed in 73% of 2244 moist-chamber cultures of 188 bark samples from 24 regions, including 31 species. The most abundant species were Paradiacheopsis rigida and Cribraria confusa, which accounted for over 20% of all myxomycetes sampled. Non-metric multidimensional scaling was used to analyze the distribution of myxomycetes in relation to geographical variables and bark pH. The distribution of myxomycetes was influenced by altitude, temperature and bark pH. Temperature gradients and relative abundance of species were negatively correlated in P. rigida and Comatricha laxa and positively correlated in C. confusa, Macbrideora cornea, and Diderma chondrioderma. Bark pH was also positively correlated with the relative abundance of C. confusa, D. chondrioderma, and Physarum nutans and negatively correlated with that of P. rigida, P. cribrata, Enerthnema papillatum, and E. melanospermum. Geographical distribution of corticolous myxomycete communities was determined based on temperature and bark pH, which acted as local barriers in our study area.     

影响广东黑石顶树附生苔藓分布的环境因子

通过对广东省黑石顶自然保护区内5个2500 m2样地内树附生苔藓的调查及有关环境因子的测定,研究了树附生苔藓的分布格局及其与环境因子的关系.树附生苔藓在不同高度的分布存在一定梯度,20 cm高处树附生苔藓的种类数与盖度均大于60 cm及更高处,且其群落优势种的数量组成与后者存在较大差异.不同树种附生苔藓盖度和种数差异较大.基于附生苔藓植物的盖度进行DCA排序及聚类分析将树种分成四组,马尾松(Pinus massoniana)因具有两种特有的网藓(巴西网藓Syrrhopodon prolifer和鞘刺网藓S.armatus)单独一组,福建青冈(Quercus chungii)亦与其余各种的差异均较大,形成一组,其余阔叶树种根据其所处的森林类型分成两组,针阔叶混交林内的阔叶树种和次生阔叶林内的阔叶树种各形成一组.对环境因子及树皮含水量和pH的分析显示,垂直梯度上空气湿度的差异可能是造成附生苔藓在不同高度分布差异的主要影响因子之一,不同树种附生苔藓的差异在一定程度上受树皮pH的影响,而与树皮含水量无关.同一树种上树附生苔藓的分布又在一定程度上受森林类型的影响.     

Spatiotemporal distribution and dynamic changes of myxomycetes in subtropical forests of China

The spatiotemporal distribution and dynamic changes of species composition of myxomycetes in humid subtropical forests of Houhe National Nature Reserve in southern China were studied by collecting samples of bark and ground litter within four seasons for isolation of myxomycetes in moist chamber cultures and by collecting fruiting bodies in the field from June to October. A total of 725 specimens of myxomycete fruiting bodies representing 77 species of 25 genera were registered, among them 302 records/51 species from field collections and 423 records obtained from 600 moist chamber cultures of ground litter and bark of living trees, which resulted in 35 and 39 species, respectively. Cornuvia serpula and Perichaena microspora were recorded for the first time in China. Both myxomycete species richness and diversity were significantly different in ground litter among sites and field collections among months. NMDS combined with Permanova indicated that the site had a greater impact on the myxomycete community of bark and litter than the season, while the month of field collections had a greater impact than the sampling sites. CCA and VPA analysis showed that the bark-inhabiting myxomycete species were mainly affected by spatial variables, while the litter-inhabiting and field collected species were more affected by climatic factors.     

Seasonal occurrence and distribution of myxomycetes on different types of leaf litter in a warm temperate forest of western Japan

The seasonal occurrence and distribution of myxomycetes on different types of newly defoliated leaf litter were examined in a secondary forest in a warm temperate region of western Japan. The two types of leaf litter (deciduous trees, Prunus verecunda and Quercus variabilis, and evergreen trees, Q. glauca and Cinnamomum camphora) were incubated in trays on the forest floor. A total of 45 myxomycete species were recorded from 3021 collected samples that occurred at the July peak during the warmest and humidest season from April to November. The occurrence of species was significantly related to the changes in mean temperature and minimum temperature on both leaf types under humid conditions. Myxomycete assemblages were divided into three seasonal phases. Most of the species occurred in June–September, while a few species demonstrated characteristic distributions; i.e., Didymium melanospermum appeared in April– May and Diderma umbilicatum appeared in October– November. The respective leaf types supported the reproduction of myxomycetes with high species richness and diversity, with 34 species and H’ = 2.59 on deciduous trees and similarly 30 species and H’ = 2.49 on evergreen trees. Several species, however, exhibited a preference for either the deciduous tree or evergreen tree leaves. Thus, a mixed forest that defoliates during different two seasons yields a greater species diversity of myxomycete assemblage.     

Patterns of occurrence of corticolous myxomycetes on white oak trees of two different size classes

Data were obtained on the assemblages of corticolous myxomycetes (plasmodial slime moulds or myxogastrids) associated with the bark surface of living white oak (Quercus alba) trees from two different size classes. Bark samples obtained from larger trees were characterized by higher values for both species richness and diversity when compared to those collected from smaller trees. This might have been expected since the former possess a larger surface area and presumably have persisted over a longer period of time. However, the myxomycete assemblage associated with smaller trees was appreciably different and did not simply represent a depauperate version of the assemblage associated with larger trees. This suggests that the differences observed between size classes cannot be simply attributed to size alone.     

后河保护区柳杉林中黏菌群落组成

柳杉是中国特有树种,对于广泛分布于森林生态系统的黏菌而言,单纯的柳杉林是一种特殊的生境。为探索柳杉林中黏菌的物种多样性,本研究在武陵山区东北部的湖北省后河国家级自然保护区柳杉林样地中采集柳杉树皮和凋落物,在120个培养湿室中,发生黏菌的湿室68个,占56.67%。从两种基物上获得黏菌6目7科12属24种,优势种为混淆筛菌Cribraria confusa,相对丰度达到19.01%。柳杉林凋落物上发生的黏菌种类和数量高于柳杉树皮,凋落物和柳杉树皮上发生的黏菌共有种为4种,种群间的Sørensen相似性系数为Cs=0.333。在不同季节间,黏菌物种的群落组成与多样性也表现出差异,春季Shannon-Wiener多样性指数Hʹ=0.2987±0.1564,夏季Hʹ=0.1105±0.0949,秋季Hʹ=0.1968±0.0589,冬季Hʹ=0.2726±0.0875。黏菌物种数量发生最多的是春季和冬季,均有15种,仅在春季发生的黏菌物种为粗壮发菌Comatricha suksdorfii、鲜黄绒泡菌Physarum luteolum、暗红团网菌Arcyria denudata和极小无丝菌Licea minima,仅在冬季发生的黏菌物种为钙丝绒泡菌Physarum decipiens、小筛菌Cribraria microcarpa和暗褐无丝菌Licea belmontiana。典型对应分析（canonical correspondence analyses,CCA）表明,影响柳杉林中黏菌物种群落组成与多样性的主要环境因素是基物类型。     

Myxomycete distribution varies among leaf litters of different vegetation in a local secondary forest of warm-temperate western Japan

Although many myxomycetes inhabit leaf litter on the forest floor and have feeding stages in litter layers, there has been little understanding regarding how the different types of leaf litter in a forest influence myxomycetes to distribute. In this study, I focused on the microhabitat distribution of foliicolous myxomycetes within a local secondary forest that consisted of various vegetation types in warm-temperate western Japan. Newly defoliated leaf litters were collected from the ground surfaces of seven different sites and then incubated in trays at a forested site throughout the entire fruiting seasons (in situ incubation method). Forty-eight species of myxomycetes (with varieties treated as species) were found in a total of 4042 samples. Leaf litters derived from different vegetation sites yielded diverse myxomycete assemblages, i.e. the Quercus glauca site yielded the richest myxomycete community (26 species), followed by Quercus variabilis site (24), Prunus verecunda site (22), Cinnamomum camphora site (21), Castanopsis cuspidata site (18), Pinus densiflora site (7) and bamboo site (7). Several myxomycete species were found to be preferentially distributed in deciduous broadleaf or evergreen leaf litter. The fraction of vegetative cover of deciduous and evergreen trees influenced the species richness and diversity of myxomycetes. Leaf litter heterogeneity derived from forest vegetation and defoliation season influenced the myxomycete distribution and species diversity. Research using in situ incubation method demonstrated that heterogeneous myxomycete microhabitats are distributed at a small spatial scale in a local forest.     

Four years in the Caucasus – observations on the ecology of nivicolous myxomycetes

Abundance and habitat requirements of nivicolous myxomycetes were surveyed over 4 yr at the northwestern Greater Caucasus ridge (Russia). An elevational transect spanning 3.66 km from 1 700 to 3 000 m a.s.l. was established at the summit Malaya Khatipara situated within the Teberda State Biosphere reserve. Between 2010 and 2013 1177 fructifications of nivicolous myxomycetes were recorded, with 700 of these determined to 44 species, varieties, and forms. Virtually all fructifications developed near or at the margin of a snow field. Abundance of myxomycete fructifications varied extremely between years, ranging from near zero to hundreds of colonies. At sites with known myxomycete occurrences 16 data loggers were installed in the years 2011 and 2012, measuring relative humidity and temperature at the soil surface. Together with weather data recorded on the nearby Klukhor pass and experiments with myxamoebae cultured on agar, these data explain the observed extreme fluctuations in myxomycete abundance. A sudden frost (one night below −10 °C) occurring before the first lasting snow in Nov. 2011 was most likely the reason for the nearly complete absence of myxomycete fruiting in spring 2012. Culture experiments showed that amoebae survived a slow decrease in temperature, as occurs under a sheltering snow cover, but are killed by sudden freezing. Extreme temperature changes recorded at the margin of snow fields explain why nivicolous myxomycetes must fruit before snow melt is complete, and the different transmittance of snow packs for light of different wave lengths may be crucial for triggering the formation of fruiting bodies. The high abundance of fructifications in nivicolous myxomycetes suggests them to be important predators of microbial communities under snow.     

黏菌物种多样性及其与影响因子关系的研究进展

黏菌是一类具有独特特征且广泛分布在陆地生态系统中的菌物,具有调节微生境微生物群落、影响营养和生物量分配等作用。黏菌的物种多样性及影响因素一直是黏菌生态学的研究热点。本文综述了不同微生境中黏菌的发生情况以及影响黏菌物种多样性的非生物因子和生物因子3个方面的研究进展,进一步揭示黏菌在生态系统中的生态功能。     

Association between myxomycetes and the decay stage of coarse woody debris in an evergreen broadleaf forest in warm temperate Japan

Myxomycetes inhabit coarse woody debris in varying stages of decay; however, their ecology in the dead wood of evergreen broadleaf trees is not well known. In this study, we examined the relationships between myxomycete species and the decay stage of wood from fallen trees in an evergreen broadleaf forest in Japan. Myxomycete species richness and abundance were calculated for eight stages of decay in fallen logs, according to the appearance and wood hardness of log portions. A total of 70 myxomycete species (including varieties) were found on the logs. Moderately decayed wood was the preferred habitat of myxomycetes (57 species; 81% of the total) and most species inhabited moist decayed wood. Analysis by nonmetric multidimensional scaling enabled the differentiation of myxomycete assemblages, with five groupings recognized across the progression of decay. Forty-two species preferred a particular decay stage, represented by the decay index. Physarum viride and Stemonitis splendens particularly preferred the less-decayed wood and Stemonitopsis typhina var. similis especially inhabited the well-decayed wood. Species from the order Physarales dominated the less-decayed wood, whereas Trichiales and Liceales species dominated the softer well-decayed wood. Myxomycetes diversity was high in and varied among logs with various stages of decay in a typical Japanese evergreen forest.     

Tree and stand-scale factors affecting richness and composition of epiphytic bryophytes and lichens in deciduous woodland key habitats

Conservation and sustainable forestry are essential in a multi-functional landscape. In this respect, ecological studies on epiphytes are needed to determine abiotic and biotic factors associated with high diversity. The aim of the present study was to evaluate relative sensitivity of conservation targets (epiphytic bryophytes and lichens) in relation to contrasting environmental variables (tree species, tree diameter at breast height, bark crevice depth, pH, tree inclination, pH, forest stand age, area and type) in boreo-nemoral forests. The study was conducted in Latvian 34 woodland key habitat (WKH) boreo-nemoral forest stands. Generalized linear mixed models and canonical correspondence analysis showed that tree species and tree bark pH were the most important variables explaining epiphytic bryophyte and lichen composition and richness (total, Red-listed, WKH indicator species). Forest stand level factors, such as stand size and habitat type, had only minor influence on epiphytic species composition and richness. The results of the present study indicate a need to maintain the diversity of tree species and large trees, particularly Acer platanoides, Carpinus betulus, Fraxinus excelsior, Populus tremula, Tilia cordata, Ulmus glabra and Ulmus laevis in conservation of epiphytic bryophyte and lichen communities in the future.     

Geographical distribution of myxomycetes on coniferous deadwood in relation to air temperature in Japan

This study obtained information on the biogeographical distribution of lignicolous myxomycetes in temperate regions in Japan. It examined how climatic variables are related to patterns of occurrence in myxomycete communities. Sixty-four taxa were recorded on coniferous wood in 15 forest sites in summer. Common species that were abundant and widely distributed in Japan included Stemonitis axifera, Lycogala epidendrum, and Cribraria cancellata. In addition, Lindbladia cribrarioides was characteristic on dead Pinus densiflora wood in southwestern Japan. The species diversity index (H′) of the myxomycete communities was positively correlated with the annual mean temperature. The distribution of myxomycete communities was analyzed using nonmultidimensional scaling (NMDS). The ecological nature of the gradients expressed by the first two NMDS axes was that the first axis was found to correspond strongly to changes in the average minimum temperature and the latitude, and the second axis was related to a complex of factors, including altitude. The relative abundance of certain species in a myxomycete community on Japanese red pine changed in relation to the annual mean temperature, e.g., Lycogala epidendrum correlated negatively while Stemonitopsis hyperopta did so positively. We conclude that air temperatures can be used to predict the geographical distribution of lignicolous myxomycetes in this temperate region of Japan.     

Host specificity of ambrosia and bark beetles (Col., Curculionidae: Scolytinae and Platypodinae) in a New Guinea rainforest

Abstract.  1. Bark and ambrosia beetles are crucial for woody biomass decomposition in tropical forests worldwide. Despite that, quantitative data on their host specificity are scarce.
2. Bark and ambrosia beetles (Scolytinae and Platypodinae) were reared from 13 species of tropical trees representing 11 families from all major lineages of dicotyledonous plants. Standardised samples of beetle-infested twigs, branches, trunks, and roots were taken from three individuals of each tree species growing in a lowland tropical rainforest in Papua New Guinea.
3. A total of 81 742 beetles from 74 species were reared, 67 of them identified. Local species richness of bark and ambrosia beetles was estimated at 80–92 species.
4. Ambrosia beetles were broad generalists as 95% of species did not show any preference for a particular host species or clade. Similarity of ambrosia beetle communities from different tree species was not correlated with phylogenetic distances between tree species. Similarity of ambrosia beetle communities from individual conspecific trees was not higher than that from heterospecific trees and different parts of the trees hosted similar ambrosia beetle communities, as only a few species preferred particular tree parts.
5. In contrast, phloeophagous bark beetles showed strict specificity to host plant genus or family. However, this guild was poor in species (12 species) and restricted to only three plant families (Moraceae, Myristicaceae, Sapindaceae).
6. Local diversity of both bark and ambrosia beetles is not driven by the local diversity of trees in tropical forests, since ambrosia beetles display no host specificity and bark beetles are species poor and restricted to a few plant families.     

Succession in myxomycete communities on dead <Emphasis Type="Italic">Pinus densiflora</Emphasis> wood in a secondary forest in southwestern Japan

Changes in myxomycete communities and species were investigated over an 8-year period in relation to the decay state of dead Pinus densiflora Siebold & Zucc. wood on which myxomycete fruiting bodies occurred. The study was carried out during three different seasons in a pine forest in southwestern Japan. A total of 44 species and seven varieties of myxomycetes were recorded. The species richness and diversity of the annual myxomycete communities did not clearly change in relation to the series of years, but the percent similarity of the myxomycete community from the beginning of the survey through the following years tended to decrease every season. The ordination of the annual communities, analyzed using non-metric multidimensional scaling (NMDS), indicated that seasonal factors on the first axis and the decay state of the wood on the second axis were significantly related. Species colonization patterns were arranged using succession indices and the distribution of certain species at particular times of the year: Arcyria ferruginea, A. obvelata, Lamproderma arcyrionema, and Physarum viride early in the year and Stemonitopsis hyperopta, Cribraria intricata, Lindbladia cribrarioides, Lamproderma columbinum, Tubifera ferruginosa, and Trichia verrucosa later on. Changes in the relative abundance of colony sizes of several species showed annual trends. Species using slightly decayed wood at the beginning were replaced by those using more brittle wood as the years progressed. Myxomycete succession on dead wood changed through time as the wood decayed, based on species preferences for particular decay stages.     

Community of dark-spored myxomycetes in ground litter and soil of taiga forest (Nizhne-Svirskiy Reserve,Russia) revealed by DNA metabarcoding

The diversity of dark-spored myxomycetes in forest ground litter and soil from four study plots across a fire chronosequence in Nizhne-Svirskiy Nature Reserve (northwest of Russia) was assessed by a DNA metabarcoding approach. The history of fire disturbances and the season of sampling influenced the composition of myxomycete assemblages. Several species showed substrate preferences different from what is known from fruiting body records. A high abundance of nivicolous species in the majority of the samples suggests that this ecological group constitutes a common element of soil microbial communities in lowland taiga forests. Four species are reported for the Leningrad region for the first time. Our results support the hypothesis that amoebae populations of myxomycetes may have much wider ecological niches than indicated by records of fructifications, and further environmental studies may provide valuable new insights on myxomycete ecology and distribution.     

Macroecology of high-elevation myxomycete assemblages in the northern Neotropics

A number of recent studies have been directed towards developing a more complete understanding of myxomycete ecology throughout the world. However, the lack of comparative data obtained using standard methodologies makes the results of these studies somewhat speculative. The objective of this investigation was to examine the evidence of macroecological patterns in myxomycete assemblages in high-elevation areas of the northern Neotropics. For this, a series of study areas in Mexico, Guatemala, and Costa Rica, as well as two external study areas (one in the United States and the other in Thailand), were selected to compare the diversity-environment relationships exhibited by myxomycetes. Altogether, the 2592 moist chamber cultures prepared yielded a total of 1377 myxomycete records, representing 89 different species. A trend of decreasing species richness with decreasing latitude was observed for the species assemblages associated with the study areas in the Neotropics. As latitude increased, species assemblages in the Neotropical study areas became increasingly similar to the temperate study area. The difference in species richness between study areas in Mexico and Thailand, along with the results obtained for a series of macroclimatic patterns evaluated in the study areas of the Neotropical region, suggests that forest structure plays an important role in the structure of myxomycete assemblages. In contrast, soil chemical characteristics and the pH of the substrates present seem to be indirectly related to the diversity estimators used for analysis, suggesting that they are probably more important at a smaller ecological scale.     

海南岛热带天然针叶林附生维管植物多样性和分布

作为热带林中一个重要的特征性组分, 附生维管植物对于维持热带森林的物种多样性及其生态系统功能均具有重要作用。该文首次系统地报道了热带天然针叶林中的附生维管植物多样性和分布特征。以海南岛霸王岭国家级自然保护区保存完好的热带天然针叶林(我国唯一较大面积分布的南亚松(Pinus latteri)天然林)中的附生维管植物为研究对象, 通过样带调查(共设置12个10 m × 50 m的样带, 记录每个样带内胸径(DBH) ≥ 5 cm树木上附生维管植物的物种名称、株数及附生高度), 分析附生维管植物的物种多样性和空间分布特征。结果表明: 1)热带针叶林0.6 hm ²面积内共有附生维管植物769株, 分属于7科17属27种, 附生兰科植物和萝摩科植物为优势类群; 2)附生维管植物在水平方向上呈现出聚集分布; 3)附生维管植物在垂直方向上, 在中等高度层次(10-20 m)分布最多, 在下层(0-5 m)也有较多的分布; 4)少数附生维管植物对南亚松表现出一定的选择性, 如华南马尾杉(Phlegmariurus fordii)、玫瑰毛兰(Eria rosea)、眼树莲(Dischidia chinensis)和铁草鞋(Hoya pottsii)等; 5)附生维管植物的物种丰富度及多度与宿主胸径均存在显著的正相关关系。     

Influence of tree age, tree size and crown structure on lichen communities in mature Alpine spruce forests

Testing the relations between tree parameters and the richness and composition of lichen communities in near-natural stands could be a first step to gather information for forest managers interested in conservation and in biodiversity assessment and monitoring. This work aims at evaluating the influence of tree age and age-related parameters on tree-level richness and community composition of lichens on spruce in an Alpine forest. The lichen survey was carried out in four sites used for long-term monitoring. In each site, tree age, diameter at breast height, tree height, the first branch height, and crown projection area were measured for each tree. Trees were stratified into three age classes: (1) <100 years old, immature trees usually not suitable for felling, (2) 100–200 years old, mature trees suitable for felling, and (3) >200 years old, over-mature trees normally rare or absent in managed stands. In each site, seven trees in each age class were selected randomly. Tree age and related parameters proved to influence both tree-level species richness and composition of lichen communities. Species richness increased with tree age and related parameters indicative of tree size. This relation could be interpreted as the result of different joint effects of age per se and tree size with its area-effect. Species turnover is also suspected to improve species richness on over-mature trees. Similarly to species richness, tree-level species composition can be partially explained by tree-related parameters. Species composition changed from young to old trees, several lichens being associated with over-mature trees. This pool of species, including nationally rare lichens, represents a community which is probably poorly developed in managed forests. In accordance to the general aims of near-to-nature forestry, the presence of over-mature trees should be enhanced in the future forest landscape of the Alps especially in protected areas and Natura 2,000 sites, where conservation purposes are explicitly included in the management guidelines.