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.     

Indirect effects of hiking trails on the community structure and diversity of trunk-epiphytic bryophytes in an old-growth fir forest

Abstract

Forest hiking trails may influence local microclimate and biodiversity, but the effects on community structure and diversity of epiphytic bryophytes on trees are currently unknown. Epiphytic bryophytes on 82 Abies faxoniana Rehder & Wilson tree trunks (41 along the hiking trail edge and 41 controls in the forest interior) were investigated at four heights from the ground (10, 50, 120, and 180 cm). At each site, air temperature and humidity were monitored for 1 year. The light radiation levels and air temperature were higher, and the canopy leaf area index and air humidity lower at the trail edge, indicating deterioration in microclimate, resulting from the trail establishment. The epiphytic bryophyte species richness, community cover, and mean cover of dendroid and pendent growth forms on trunks were significantly lower at the trail edge than the control site, suggesting that trail construction caused these reductions. One marked effect of the presence of the trail was the increase in some sun-loving species and decrease in shade-tolerant species. Moreover, the trail also slightly influenced species richness and epiphytic bryophyte cover at both community and species population levels along the height gradient. Comprehensive analyses showed that microclimate deterioration was mainly driven by the trail establishment, and that the change in micro-climate along the trail, rather than any host traits, played an important role in the declining epiphytic bryophyte community structure and diversity at the trail edge, confirming the initial hypothesis that the presence of a raised boardwalk (hiking trail) indirectly influences epiphytic bryophyte community and diversity by altering the microclimate.     

The effects of stand structure on ground-floor bryophyte assemblages in temperate mixed forests

The effect of tree species composition, stand structure characteristics and substrate availability on ground-floor bryophyte assemblages was studied in mixed deciduous forests of Western Hungary. Species composition, species richness and cover of bryophytes occurring on the soil and logs were analysed as dependent variables. The whole assemblage and functional groups defined on the basis of substrate preference were investigated separately. Substrate availability (open soil, logs) was the most prominent factor in determining species composition, cover and diversity positively, while the litter of deciduous trees had a negative effect on the occurrence of forest floor bryophytes. Besides, bryophyte species richness increased with tree species and stand structural diversity, and for specialist epiphytic and epixylic species log volume was essential. Sapling density and light heterogeneity were influential on bryophyte cover, especially for the dominant terricolous species. Many variables of the forest floor bryophyte community can be estimated efficiently by examining stand structure in the studied region. Selective cutting increasing tree species diversity, stand structural heterogeneity and dead wood volume can maintain higher bryophyte diversity in this region than the shelter-wood system producing even-aged, monodominant, structurally homogenous stands.     

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.     

Bole epiphytic bryophytes on <Emphasis Type="Italic">Lithocarpus xylocarpus</Emphasis> (Kurz) Markgr. in the Ailao Mountains,SW China

Epiphytic bryophytes growing on Lithocarpus xylocarpus (Kurz) Markgr. trunks of different diameter classes in primary (132 plots) and secondary (84 plots) Lithocarpus forests in the Ailao Mountains, SW China, were surveyed and analyzed to determine species composition and richness, and to identify environmental variables that may affect it. Among the 65 species (belonging to 32 genera, 19 families) found, 28 occurred in both forests, with Syrrhopodon gardneri (Hook.) Schwaegr. predominanting. Species richness and total coverage in primary forest were significantly higher than in secondary forest. We suggest that a period of perhaps much more than 110 years is necessary for the recovery of epiphytic bryoflora in montane forest of SW China. Fan, turf, and smooth mat are the most important life forms, with high occurrences in both forests. The life form composition of epiphytic bryophytes is determined mainly by microhabitat and host age. Tree age, the presence of primary forest, bark pH, and plot exposure are the environmental variables that have significantly influenced the composition of epiphytic bryophytes. Tree age explained most variations in epiphytic bryoflora. Bark pH is another important parameter that significantly influenced the epiphytic bryophyte community, but seemed indirectly correlated with tree age. Primary forest is a favorable habitat for epiphytes, due mainly to its diversified canopy structure and the presence of large diameter hosts. Moisture-laden southwest trade winds and forest structure could differentiate microclimate and impel a distinct composition of epiphytes in windward and leeward exposures.     

Tree and stand level variables influencing diversity of lichens on temperate broad-leaved trees in boreo-nemoral floodplain forests

Tree and stand level variables affecting the species richness, cover and composition of epiphytic lichens on temperate broad-leaved trees (Fraxinus excelsior, Quercus robur, Tilia cordata, Ulmus glabra, and U. laevis) were analysed in floodplain forest stands in Estonia. The effect of tree species, substrate characteristics, and stand and regional variables were tested by partial canonical correspondence analysis (pCCA) and by general linear mixed models (GLMM). The most pronounced factors affecting the species richness, cover and composition of epiphytic lichens are acidity of tree bark, bryophyte cover and circumference of tree stems. Stand level characteristics have less effects on the species richness of epiphytic lichens, however, lichen cover and composition was influenced by stand age and light availability. The boreo-nemoral floodplain forests represent valuable habitats for epiphytic lichens. As substrate-related factors influence the species diversity of lichens on temperate broad-leaved trees differently, it is important to consider the effect of each tree species in biodiversity and conservation studies of lichens. Nomenclature Randlane et al. (2007) for lichens; Leht (2007) for vascular plants.     

Vertical distribution of epiphytic bryophytes in an Indonesian rainforest

We studied species richness, composition and vertical distribution of epiphytic bryophytes in submontane rainforest of Central Sulawesi. Bryophytes were sampled on eight canopy trees and on eight trees in the forest understorey. Microclimate was measured at trunk bases and at crown bases. The total recorded number of 146 epiphytic bryophyte species is among the highest ever reported for tropical forests and underlines the importance of the Malesian region as a global biodiversity hotspot. Species composition differed significantly between understorey trees and canopy tree trunks on the one hand, and the forest canopy on the other. Fourty-five percent of the bryophyte species were restricted to canopy tree crowns, 12% to the understorey. Dendroid and fan-like species mainly occurred in the forest understorey whereas tufts were most species rich in the tree crowns. The findings reflect the different microclimatic regimes and substrates found in the understorey and in the forest canopy. The results indicate that assessments of the bryophyte diversity of tropical forests are inadequate when understorey trees and tree crowns are excluded.     

辽东山地古石河冰缘地貌森林生态系统苔藓物种多样性研究

基于9个20 m×30 m森林群落样地的调查数据,采用物种丰富度、α和β多样性指数,对辽东山地古石河冰缘地貌不同林型石生、树生苔藓植物物种多样性进行定量研究,采用皮尔逊相关分析方法对其影响因素进行分析。结果显示,古石河冰缘地貌苔藓植物共有26科46属59种;不同林型石生、树生苔藓植物物种丰富度和α多样性指数均为:暗针叶林针阔混交林落叶阔叶林;石生苔藓植物β多样性指数最高为落叶阔叶林-针阔混交林间(0.44),最低为落叶阔叶林-暗针叶林间(0.33);树生苔藓植物β多样性指数最高为针阔混交林-暗针叶林间(0.40),最低为落叶阔叶林-暗针叶林间(0.25);分析表明,林冠层郁闭度、海拔高度是影响辽东山地古石河冰缘地貌森林生态系统苔藓物种多样性的重要因子。     

Epiphytes of Sitka spruce (<Emphasis Type="Italic">Picea sitchensis</Emphasis>) plantations in Ireland and the effects of open spaces

The epiphytes of the trunks and branches of mature Sitka spruce (Picea sitchensis) trees were studied in twelve plantations containing open spaces (glades, rides and roads) in the east and southwest of Ireland. A pair of trees was studied at each site: one tree at the south-facing edge of an open space and one in the forest interior. Spruce trees were found to support a moderately diverse range of bryophytes and lichens, including two relatively rare bryophyte species. Clear patterns in vertical distribution were identified, with bryophyte richness and cover decreasing and lichen richness and cover increasing from the tree base to the upper trunk. The open spaces themselves did not appear to affect overall epiphyte diversity, with no significant differences in any of the diversity measures between edge and interior trees. The main effect of open spaces was on the epiphyte cover of the edge trees. This was related to increased light levels combined with the presence of live branches from close to ground level on the south sides of the edge trees, which produced optimum conditions for bryophytes at the tree base and lichens in the upper plots. However, this dense side-canopy negatively affected epiphyte diversity on the north sides of the edge trees. Further research is required to assess the effects of open spaces within forestry plantations on epiphyte diversity.     

Epiphytes of Sitka spruce (<Emphasis Type="Italic">Picea sitchensis</Emphasis>) plantations in Ireland and the effects of open spaces

The epiphytes of the trunks and branches of mature Sitka spruce (Picea sitchensis) trees were studied in twelve plantations containing open spaces (glades, rides and roads) in the east and southwest of Ireland. A pair of trees was studied at each site: one tree at the south-facing edge of an open space and one in the forest interior. Spruce trees were found to support a moderately diverse range of bryophytes and lichens, including two relatively rare bryophyte species. Clear patterns in vertical distribution were identified, with bryophyte richness and cover decreasing and lichen richness and cover increasing from the tree base to the upper trunk. The open spaces themselves did not appear to affect overall epiphyte diversity, with no significant differences in any of the diversity measures between edge and interior trees. The main effect of open spaces was on the epiphyte cover of the edge trees. This was related to increased light levels combined with the presence of live branches from close to ground level on the south sides of the edge trees, which produced optimum conditions for bryophytes at the tree base and lichens in the upper plots. However, this dense side-canopy negatively affected epiphyte diversity on the north sides of the edge trees. Further research is required to assess the effects of open spaces within forestry plantations on epiphyte diversity.     

Hidden crown jewels: the role of tree crowns for bryophyte and lichen species richness in sycamore maple wooded pastures

Tree crowns typically cover the vast majority of the surface area of trees, but they are rarely considered in diversity surveys of epiphytic bryophytes and lichens, especially in temperate Europe. Usually only stems are sampled. We assessed the number of bryophyte and lichen species on stems and in crowns of 80 solitary sycamore maple trees (Acer pseudoplatanus) at six sites in wooded pastures in the northern Alps. The total number of species detected per tree ranged from 13 to 60 for bryophytes, from 25 to 67 for lichens, and from 42 to 104 for bryophytes and lichens considered together. At the tree level, 29 % of bryophyte and 61 % of lichen species were recorded only in the crown. Considering all sampled trees together, only 4 % of bryophyte, compared to 34 % of lichen species, were never recorded on the stem. Five out of 10 red-listed bryophyte species and 29 out of 39 red-listed lichen species were more frequent in crowns. The species richness detected per tree was unexpectedly high, whereas the proportion of exclusive crown species was similar to studies from forest trees. For bryophytes, in contrast to lichens, sampling several stems can give a good estimation of the species present at a site. However, frequency estimates may be highly biased for lichens and bryophytes if crowns are not considered. Our study demonstrates that tree crowns need to be considered in research on these taxa, especially in biodiversity surveys and in conservation tasks involving lichens and to a lesser degree also bryophytes.     

武汉市城区苔藓植物多样性和分布及与环境因子的关系

对武汉市7个中心城区和部分远郊城区共26个样点73个样地的苔藓群落进行调查,采集苔藓植物样本共431份。经鉴定调查区内共有苔藓植物20科35属91种,其中狭叶小羽藓（Haplocladium angustifolium（Hampe et C.Muell.）Broth.）和钝叶绢藓（Entodon obtusatus Broth.）等为优势种,分布于其中的24个样点。多样性指数分析结果显示,位于青龙山国家森林公园的α多样性Patrick和Shannon-Wiener指数最高,说明该样点苔藓植物群落的复杂程度高,群落所含信息量大。Patrick指数与环境因子的Pearson相关性分析结果显示,土壤含水率和与主要干道距离是显著影响地面生苔藓植物多样性的环境因子,而显著影响树附生苔藓植物多样性的环境因子仅与距主要干道距离相关。用典范对应分析法（CCA）研究26个样点中苔藓植物的盖度与主要环境因子的关系,结果发现人为干扰程度、草本盖度、与城市主要干道的距离等对地面生和树附生苔藓植物的分布都有显著影响。其中地面生苔藓植物的分布受人为干扰和草本盖度影响最为显著;而树附生苔藓植物的分布受附生树干胸径及与主要干道距离影响最为显著。研究结果表明武汉市区苔藓植物的多样性和分布受人为干扰较大,树附生苔藓对汽车尾气等因素更为敏感。     

Up in the Tree – The Overlooked Richness of Bryophytes and Lichens in Tree Crowns

Assessing diversity is among the major tasks in ecology and conservation science. In ecological and conservation studies, epiphytic cryptogams are usually sampled up to accessible heights in forests. Thus, their diversity, especially of canopy specialists, likely is underestimated. If the proportion of those species differs among forest types, plot-based diversity assessments are biased and may result in misleading conservation recommendations. We sampled bryophytes and lichens in 30 forest plots of 20 m × 20 m in three German regions, considering all substrates, and including epiphytic litter fall. First, the sampling of epiphytic species was restricted to the lower 2 m of trees and shrubs. Then, on one representative tree per plot, we additionally recorded epiphytic species in the crown, using tree climbing techniques. Per tree, on average 54% of lichen and 20% of bryophyte species were overlooked if the crown was not been included. After sampling all substrates per plot, including the bark of all shrubs and trees, still 38% of the lichen and 4% of the bryophyte species were overlooked if the tree crown of the sampled tree was not included. The number of overlooked lichen species varied strongly among regions. Furthermore, the number of overlooked bryophyte and lichen species per plot was higher in European beech than in coniferous stands and increased with increasing diameter at breast height of the sampled tree. Thus, our results indicate a bias of comparative studies which might have led to misleading conservation recommendations of plot-based diversity assessments.     

Epiphytic bryophyte diversity and range distributions along an elevational gradient in Marojejy,Madagascar

Describing spatial variation in species richness and understanding its links to ecological mechanisms are complementary approaches for explaining geographical patterns of richness. The study of elevational gradients holds enormous potential for understanding the factors underlying global diversity. This paper investigates the pattern of species richness and range-size distribution of epiphytic bryophytes along an elevational gradient in Marojejy National Park, northeast Madagascar. The main objectives are to describe bryophyte species composition and endemism in Marojejy National Park, to describe the species richness and distribution patterns of epiphytic bryophytes along an elevational gradient from 250 m to 2050 m and to evaluate the explanatory value of environmental variables for the observed patterns. Bryophyte samples were collected following a nested design with four hierarchical levels: elevational belts, plots, quadrats, and microplots. In total, 254 epiphytic bryophyte species were recorded, comprising 157 liverworts and 97 mosses. Twenty-three of these are endemic to Madagascar. Species richness exhibits a hump-shaped pattern along the elevational gradient, peaking at 1,250 m. Eighty-seven percent of the total recorded species have a range distribution lower than 1,000 m, at which point 36% are restricted to these single elevations. Our results suggest that mean temperature, relative humidity, and vapor pressure deficit play important roles in shaping the richness pattern observed in this study. While the liverwort richness pattern did not correlate to vapor pressure deficit and responded only weakly to relative humidity, the richness pattern shown by mosses correlates well with mean temperature, relative humidity, and vapor pressure deficit.     

Factors influencing epiphytic bryophyte and lichen species richness at different spatial scales in managed temperate forests

The effect of management related factors on species richness of epiphytic bryophytes and lichens was studied in managed deciduous-coniferous mixed forests in Western-Hungary. At the stand level, the potential explanatory variables were tree species composition, stand structure, microclimate and light conditions, landscape and historical variables; while at tree level host tree species, tree size and light were studied. Species richness of the two epiphyte groups was positively correlated. Both for lichen and bryophyte plot level richness, the composition and diversity of tree species and the abundance of shrub layer were the most influential positive factors. Besides, for bryophytes the presence of large trees, while for lichens amount and heterogeneity of light were important. Tree level richness was mainly determined by host tree species for both groups. For bryophytes oaks, while for lichens oaks and hornbeam turned out the most favourable hosts. Tree size generally increased tree level species richness, except on pine for bryophytes and on hornbeam for lichens. The key variables for epiphytic diversity of the region were directly influenced by recent forest management; historical and landscape variables were not influential. Forest management oriented to the conservation of epiphytes should focus on: (i) the maintenance of tree species diversity in mixed stands; (ii) increment the proportion of deciduous trees (mainly oaks); (iii) conserving large trees within the stands; (iv) providing the presence of shrub and regeneration layer; (v) creating heterogeneous light conditions. For these purposes tree selection and selective cutting management seem more appropriate than shelterwood system.     

西双版纳热带雨林和热带山地常绿阔叶林附生苔藓的组成与多样性格局

为探讨西双版纳热带雨林和热带山地常绿阔叶林附生苔藓的组成、多样性格局及其维持机制,该文对两种植被的树干附生苔藓植物进行了调查与分析.所选择的样地位于西双版纳勐腊县,每种植被类型选择10个20 m×20 m的样方,每个样方选择约10棵样树.结果表明:(1)本调查共记录到附生苔藓20科39属60种,其中热带雨林附生苔藓有1...     

Epiphytic ferns and bryophytes of Tasmanian tree‐ferns: A comparison of diversity and composition between two host species

Abstract Ferns, bryophytes and lichens are the most diverse groups of plants in wet forests in south‐eastern Australia. However, management of this diversity is limited by a lack of ecological knowledge of these groups and the difficulty in identifying species for non‐experts. These problems may be alleviated by the identification and characterization of suitable proxies for this diversity. Epiphytic substrates are potential proxies. To evaluate the significance of some epiphytic substrates, fern and bryophyte assemblages on a common tree‐fern species, Dicksonia antarctica (soft tree‐fern), were compared with those on a rare species, Cyathea cunninghamii (slender tree‐fern), in eastern Tasmania, Australia. A total of 97 fern and bryophyte species were recorded on D. antarctica from 120 trunks at 10 sites, and 64 species on C. cunninghamii from 39 trunks at four of these sites. The trunks of C. cunninghamii generally supported fewer species than D. antarctica, but two mosses (particularly Hymenodon pilifer) and one liverwort showed significant associations with this host. Several other bryophytes and epiphytic ferns showed an affinity for the trunks of D. antarctica. Species assemblages differed significantly between both sites and hosts, and the differences between hosts varied significantly among sites. The exceptionally high epiphytic diversity associated with D. antarctica suggests that it plays an important ecological role in Tasmanian forests. Evidently C. cunninghamii also supports a diverse suite of epiphytes, including at least one specialist species.     

Tree age‐dependent changes among epiphytic bryophyte communities in Mediterranean environments. A case study from Sicily (Italy)

Abstract

The epiphytic bryophytes inhabiting trees of different size/age in a Quercus ilex wood from Madonie Mountains (northern Sicily, Italy) were studied with the purpose of describing the changes that take place in the bryophyte stratum during the tree lifespan. Results indicate an increase of bryophyte cover combined with a progressive decrease of epiphytic lichens and the existence of an active process of species and community substitution. The way these processes take place corresponds to a succession sequence, which is characterised by a high number of pioneer species on the youngest trees and a sharp decline of species number on middle‐aged and old trees due to the great spread of Leptodon smithii and a few other pleurocarpous mosses. The comparison of these traits to those from central Spain evidences differences in patterns of tree colonisation by epiphyte bryophytes between the two areas and suggests that climatic conditions play a chief role in the epiphytic bryophyte establishment and succession in Mediterranean areas.     

广东黑石顶森林苔藓群落特征初探

通过对5个面积为2500m2的样地中树附生和地面苔藓植物的定量调查,初步研究了广东黑石顶森林中苔藓植物多样性特征。本次调查共发现苔藓植物50种,包括30种苔类和20种藓类。样地中树附生苔藓植物40种,地面苔藓植物24种,前者远高于后者。各样地中地面苔藓植物的种类为8-13种,盖度0.59%-1.12%,坡度及小生境的多样性对地面苔藓植物物种多样性及盖度均有很大影响;树附生苔藓植物12-20种,盖度0.63%-1.63%。结果显示30a的次生林中苔藓植物的物种丰富度及盖度均可恢复到与成熟阔叶林接近的水平。相似性分析表明,成熟阔叶林内苔藓植物种类组成与针阔叶混交林及30a的次生阔叶林差异不明显,但前者的苔藓植物群落结构与后者的差异较大。     

Effects of environmental factors and heavy metals on the vertical distribution of bryophytes in a sinkhole environment

• A sinkhole ecosystem, as a refuge for plant diversity, has been subjected to intensive exploitation, leading to ecosystem destruction of sinkholes in China. Understanding the responses of bryophyte distribution to destruction of the sinkhole environment are crucial to implementing protection measures for bryophyte diversity.
• Haolong sinkhole in Guangxi Zhuang Autonomous Region of China, the third largest sinkhole in the world, was selected as the study area. The Wilson Shmida index was used to analyse bryophyte species diversity; a Generalized Linear Model (GLM) was used to reveal species vertical distribution of bryophytes, the Single and Multiple Species Distribution Models (SSDM, MSDM) were used for analysis of the relationship between bryophyte species distribution, environmental factors and heavy metals.
• A total of 183 species from 74 genera in 36 families of bryophytes were collected from Haolong sinkhole, of which 26 species are endemic to China. Bryophyte species diversity was ranked in the order: agricultural section < forest section < grassland. In the vertical direction, bryophyte distribution was divided into point, disjunctive and continuous distributions using the GLM. The SSMA and MSDM indicated that bryophyte species of each of these three distributions can be divided into a temperature–slope zone, light–depth–pH–humidity zone, Pb (B)–Hg (B) zone and mixed heavy metals zone according to the effect of environmental factors and heavy metals such as As.
• Environmental factors or heavy metals, such as As, in Haolong sinkhole effectively cooperate in bryophyte distribution. An effective way to protect bryophyte diversity, in particular species endemic to China in the sinkhole environment, is through education and involvement of the local villagers to minimize further damage to the sinkhole environment.