Species richness and substrate specificity of lignicolous fungi in the canopy of a temperate,mixed deciduous forest

In the more than twenty years in which long-term canopy research has been conducted, mycology has been largely disregarded. Our studies using a construction crane to gain access to the canopy of a forest in Leipzig, Germany are the first long term investigations assessing the diversity and ecology of wood-decaying fungi in a canopy. Thirty-seven individuals of nine different tree species with a large amount of dead wood were selected. Sampling focussed on the four most prominent tree species Acer pseudoplatanus, Fraxinus excelsior, Quercus robur and Tilia cordata. In the years 2002 and 2003 dead wood was collected in different canopy strata. Dead branches were removed and stored for two weeks in open boxes with high humidity to allow growth of fructifications in the laboratory. 118 different taxa were identified (108 species, 77 genera). Corticioid fungi (e.g., of Corticiaceae, Stereaceae, Hymenochaetaceae) dominated the fungal composition with 37 species, pyrenomycetes were present with 18 species. Agaric fungi (Agaricales and Cortinariales) were scarce. Species with minute basidiomes dominated the fungal composition of this systematic group. Agarics with larger sporomes were found only once and were restricted to strongly decayed branches in shaded canopy areas. Concerning species richness and fungal composition the four tree species mentioned above differed remarkably. As expected, many fungi that grew on bark or slightly decayed wood showed a distinct host and substratum specifity. It is noteworthy that fungi which are purportedly to be non-specific were found on single tree species only.     

Species richness and ecological characterization of myxomycetes and myxomycete-like organisms in the canopy of a temperate deciduous forest

The ecological community of myxomycetes and myxomycete-like organisms (MMLO) in the canopy of living deciduous trees was studied in a riparian deciduous forest at Leipzig, Germany. A systematic survey carried out with a total of 146 moist chamber cultures resulted in 386 records of 37 taxa, with 32 myxomycetes, two myxobacteria, two protostelids and the fruit body forming ciliate Sorogena stoianovitchae, the latter recorded for the first time for Europe. With 94% of all cultures positive for MMLO, these organisms are present consistently in the investigated sections of white-rotten twigs attached to living trees at 10-30 m above the ground. Our sampling recovered a majority of the likely species, with 37 out of the 42-45 predicted according to a species-accumulation curve and two other estimators of species richness. Nonmetric multidimensional scaling revealed pH, water-holding capacity and stage of decay to explain most of the variation in species distribution. Arcyria cinerea and Perichaena depressa as the most common species occurred in 32% and 29% of all samples, respectively. Viewing the sampled twigs as habitat islands and a single spore as sufficient to establish a population, a simulation program assuming a random spore rain estimated an average of 0.4 and 0.35 spore hits per twig as necessary to explain the observed frequencies. This is matched by the potential productivity of the substrate. All fruit bodies from the cultured twigs would be able to create a spore rain of 86 (A. cinerea) or 40 (P. depressa) spore hits per twig when dispersed evenly over the plot. The terminal fall velocity of spores was measured, revealing that it took about 5 h for a spore to land (30 m) in still air and indicating high dispersal ability for canopy-inhabiting MMLO.     

Diversity and distribution patterns of some mesophyll-feeding leaf hoppers of temperate woodland canopy

• 1 Temperate woodland canopy as a habitat for insects is discussed.
• 2 A general account is given of the Typhlocybinae as the mesophyll-feeding guild of canopy feeders.
• 3 Three sampling sites in South Wales are described, from which adult leaf-hoppers were sampled regularly from twelve species of trees during 1974.
• 4 Rearing records, based on the sampling of last instar nymphs and subsequent rearing of adults, are given.
• 5 Over 20 000 adult insects of thirty-five identified species were taken during 1974.
• 6 Results are analysed to compare species associations with different tree species. Most leaf-hoppers show very distinct specific plant-dependent distributions within the canopy. Many are dominantly associated with only one host plant. Others show more complicated patterns of associations. Only one species was found on all trees sampled.
• 7 The patterns of leafhopper distributions in woodland canopy are compared with previously described grassland habitats. The relative permanence and size of trees may be important factors.
• 8 Examples of groups of ecologically similar species coexisting together are discussed.

     

Disparate distribution patterns between canopy and subcanopy life-forms in two temperate North American forests

Quantitative vegetational data of canopy and woody subcanopy species (two life-forms adapted to occupy different strata at maturity) were compared with data collected in two temperate forest ecosystems to determine whether they exhibit a similar pattern of distribution. Tidal freshwater swamps (21 stands) and southern Appalachian forests (19 stands) were examined from data obtained using identical sampling methods. Separate structural analyses of the canopy, sapling, and subcanopy species were compared using the indirect ordination algorithm Detrended Correspondence Analysis. Environmental measurements collected in each stand were assessed for their relationship to the distribution of stands depicted by the ordination diagrams.Canopy trees and saplings showed a similar pattern of distribution, suggesting that the resource requirements of saplings and canopy-statured adults are similar. In contrast, the subcanopy species (species genetically adapted to an understory existence, i.e., shrubs and small understory trees) of neither ecosystem showed any discernable distributional relationship to the canopy or sapling layers (in tidal swamps, there was no clear way to even segregate subcanopy stands into communities). Environmental gradients associated with the subcanopy ordinations differed from those of the canopy and sapling strata in both forest systems, suggesting that subcanopy species partition different resources than do canopy species.If a lack of similarity in distribution patterns between canopy and subcanopy species is universal in temperate forests, then the common practice of combining sapling and subcanopy species in structural analyses may hinder our understanding of subcanopy structural patterns in forests.     

Species richness and canopy productivity of Australian plant communities

The species richness (number of vascular plants per hectare) of Australian plant communities (containing a mosaic of gap, regeneration, maturation and senescent phases) is correlated with the annual biomass productivity of the overstorey canopy.The annual production of leaves and stem in the canopy of the plant community is shown to be limited by the requirements of photosynthesis (particularly light and the availability of water) and the length of the growing season.The species richness of Australian plant communities is the product of the blance between the dominance of the overstorey and the response of the understorey to the shading of the overstorey. For all climatic regions and zones the species richness of the overstorey of the plant community is shown to be exponentially related to the annual shoot growth of the overstorey canopy, until the latitudinal or altitudinal tree line is reached. With latitudinal increase outside the tropics, overstorey canopies of forest communities absorb increasingly more of the incident solar radiation. markedly reducing the species richness of the understorey strata. In contrast, in these latitudes the overstorey of plant communities with widely spaced trees or tall shrubs will absorb far less solar radiation, thus enabling the species richness of the understorey to be maintained.     

Species richness measures fail in resolving diversity patterns of speciose forest moth assemblages

We used data from a light-trapping study at 28 sites on floodplain forest moths in eastern Austria to assess the performance of a variety of species richness and species diversity measures. At each site the data (32,181 individuals from 448 species) contain a large fraction of species represented only as singletons. Sampling effort was evenly spread across sites, but sampling success varied greatly. Influx of moths from the landscape matrix surrounding floodplain forest patches lead to substantial proportions of stray individuals from the regional species pool. Under these conditions, observed species numbers as well as eight extrapolation estimators of species totals failed to reflect differences between three study regions or between flooded and non-flooded forest habitats. Rarefied species numbers and Fisher’s α of the log-series distribution captured differences in moth diversity between regions, but failed to mirror flooding impact. Only Shannon’s diversity captured all expected diversity differences, at high significance levels. Application of Chao and Shen’s bias correction increased figures of Shannon’s diversity, but did not affect the outcome of statistical comparisons. We conclude that for species-rich incompletely sampled communities of highly mobile insects the evaluation of the complete species-abundance information using Shannon’s diversity is the most promising mode to compare local species diversity with a high degree of ecological resolution. Species richness measures apart from those obtained through rarefaction cannot be recommended, as they are sensitive to sources of bias that pertain to many empirical sets of field data.     

Species richness and distribution of understorey bryophytes in different forest types in Colombian Amazonia

Abstract

The first bryophyte survey results from Colombian Amazonia are presented. Bryophyte species, differentiated into mosses and liverworts, and further into four life-form classes, were sampled in 0.1-ha plots. These plots were distributed over four landscape units in the middle Caquetá area: floodplains, swamps, terra firme forests and white-sand areas. The total numbers of bryophyte species in the units were 50, 45, 45 and 32, respectively. The plots in floodplains and swamps were richer in moss species than the terra firme and white-sand plots, suggesting that coexistence of many moss species is favoured by high humidity. Moss species with fan life-forms preferred floodplains. On the other hand, liverwort species richness was highest in white-sand plots, which suggests that light incidence controls liverwort species-richness, perhaps more than humidity. All plots from the floodplain of the Caquetá River differed remarkably in species composition (of both mosses and liverworts) from the other landscape units. This may be due to the unique properties of this varzea system where, during yearly flooding events, soil, dead logs and stems are covered with a fresh layer of nutrient-rich fine silt, enhancing the surface for colonization and improving the conditions for productive bryophyte growth compared with elsewhere in the middle Caquetá area.     

Spatial distribution patterns of trees at different life stages in a warm temperate forest

We have investigated tree distributions in relation to topography between different tree life history stages, from the seed-dispersal stage to the adult stage in a warm temperate evergreen broadleaved forest on Yakushima Island, Japan, to clarify the critical stages in determining adult tree distributions. We conducted a census of all living trees > or =30 cm tall and collected seed falls over three years using 25 seed traps in a 50 m x 50 m quadrat. Four life stages were defined: stage 1, dispersed seed; stage 2, individuals taller than 30 cm and diameter at breast height (DBH) < 1 cm; stage 3, trunks 1 cm < or = DBH < 10 cm; stage 4, trunks with DBH > or = 10 cm. We classified 17 common tree species into three groups; group A was distributed mainly on the upper slope, group B on the lower slope, and group C on both. Most of group A and B trees at stages 2-4 showed an aggregated distribution along the topographical gradient. The densities at stage 1 showed weaker aggregations according to slope. Topography-specific tree distribution was probably determined at the regeneration stage, and later survival was less effective as a mechanism of vegetation differentiation.     

Factors influencing sapling composition in canopy gaps of a temperate deciduous forest

To detect the factors that affect sapling species composition in gaps, we investigated 55 gaps in an old-growth temperate deciduous forest in Ogawa Forest Reserve, central Japan. Gap size, gap age, gap maker species, topographic location, adult tree composition around gaps, and saplings of tree species growing in the gaps were censused. For gaps 5 m², mean gap size was 70 m² and the maximum was 330 m². Estimated ages of gaps had a tendency to be concentrated in particular periods relating to strong wind records in the past. The sapling composition in gaps was highly and significantly correlated to that under closed canopy, indicating the importance of advance regeneration in this forest. However, some species showed significant occurrence biases in gaps or under closed canopy, suggesting differences in shade tolerance. The result of MANOVA showed that gap size and topography were important factors in determining the sapling composition in gaps. Species of gap makers affected the sapling composition indirectly by influencing gap size. The existence of parent trees around gaps had effects on sapling densities of several species. Gap age did not have clear influences on sapling composition. Variations in gap size and topography were considered as important factors that contribute to maintenance of species diversity in this forest.     

Species richness and niche space for temperate and tropical folivores

We measured structural and chemical traits of the leaves of native, broad-leaved trees in two temperate localities [southern Ontario, Canada (34 species), and Missouri (36 species)] and one tropical locality [central Panama (samples of 21 and 23 species)] to test the hypothesis that the greater diversity of tree species and herbivore species in the tropics is associated with greater resource niche space for herbivores. Variables were leaf toughness, water content, dry mass per unit area, several structural and nutritional carbohydrates, common mineral elements, including nitrogen and phosphorus, and several defensive compounds, including tannins and alkaloids. The four samples were almost fully separable by discriminant analysis on the basis of these leaf traits. Variance in log-transformed trait values among species was lowest in the most northern sample, but did not differ significantly between Missouri and Panama. Niche space, estimated as the square root of the total variance in the log-transformed variables within each locality, varied approximately as Panama = 1, Missouri = 0.8, Ontario = 0.5. Although niche space decreases towards higher latitudes, the change does not match the ca. sixfold decrease in tree species richness or the ca. fourfold decrease in Lepidopteran species richness over the latitude range of our samples. Accordingly, tropical folivore diversity is associated with greater resource niche overlap, greater niche specialization, and/or more completely filled niches, or with variation in niche dimensions not measured in this study.     

Isolation of endophytic fungi from tropical forest in Indonesia

Endophytic fungi (EPF) are an important contributor to fungal diversity. It is surmised that EPF colonizing plant roots have high diversity. This study aimed to alleviate the scarcity of information regarding EPF in tropical forests, by isolationg and identifying EPF from a tropical forests in Indonesia. Soils were collected from five forests: (1) Tectona grandis monoculture; (2) Swietenia macrophylla monoculture; (3) Gmelina sp., Artocarpus champeden, Dipterocarp mixed; (4) Dipterocarp primary; (5) Macaranga sp. secondary. Four trees (Calliandra calothyrsus, Paraserianthes falcataria, Sesbania grandiflora, and Cassia siamea) and three crops (Sorghum bicolor, Allium fistulosum, and Trifolium repens) were grown in the forest soils to trap EPF. EPF were isolated from roots and isolation rates were calculated. Based on the isolation rates, P. falcataria and S. bicolor were chosen and grown again in forest soils. EPF were isolated and identified by their rDNA ITS1 region. Twelve and 21 EPF were isolated from 250 roots of P. falcataria and 300 roots of S. bicolor, respectively. Identified EPF were from genera Acrocalymma, Fusarium, Tolypocladium, Penicillium, Talaromyces, Exophiala, Dictyosporium, Pseudochaetosphaeronema, Mariannaea, Trichoderma, and Mycoleptodiscus. Acrocalymma, Tolypocladium, Penicillium, Exophiala, Pseudochaetosphaeronema, Mariannaea, and Mycoleptodiscus spp. were isolated from only one forest. Fusarium, Talaromyces, and Trichoderma spp. were isolated from more than one forest. The numbers of EPF isolated from Gmelina sp., Artocarpus champeden, Dipterocarp mixed forest, and Macaranga sp. secondary forest were higher than those from other forests, suggesting that different plant species in forests affect the root EPF community.     

The effect of canopy disturbance on species richness in a central Himalayan oak forest

Non-epiphytic species richness was studied in different disturbance classes within a Quercus semecarpifolia forest. Nine disturbance classes were defined according to the degree of biomass removal (lopping) and their spatial mixture. Six of these were observed in the study area. The species were divided into three functional groups: climbers, phanerophytes, and field-layer plants. The primary aim was to test if there is an elevated species richness under an intermediate disturbed canopy for (i) all vascular plants, (ii) lianas, (iii) phanerophytes and (iv) field-layer species. The richness of the different plant groups and all species were fitted against the disturbance gradient by means of Generalized Linear Models (GLM). Other environmental variables such as altitude, potential solar radiation, light intensity, canopy cover and soil parameters were also evaluated as predictors. Disturbance classes, canopy cover and light intensity were combined into a new variable, disturbance-complex, using Principal Component Analyses.Phanerophytes did not respond to any variable. Climbers were mostly related to pH and canopy cover, and were the only group related to altitude, nitrogen and loss-on-ignition. Herbaceous plants and total species richness showed a unimodal response to disturbance classes and the complex disturbance gradient, which supports the intermediate disturbance hypothesis. Relative radiation and slope also supported a unimodal response in herbaceous plants, but disturbance had a significant additional contribution to this pattern. The most significant predictor for these two groups was pH. The responses to organic carbon and phosphorus were not significant for any of the subsets.The results indicate that a small-scale lopping regime will enhance species richness of vascular plants; only a few species in the intermediate disturbed forest are weedy ruderals. In such a situation, the conservation policy may accept small-scale human impact as part of the forest landscape.     

Frequency and distribution patterns of zoosporic fungi from moss-covered and exposed forest soils

Uniflagellate zoosporic fungi (=Chytridiomycota and the zoosporic protista Hyphochytriomycota) are common inhabitants of soil. However, at what scale differences in their spatial distribution can be detected is poorly known. The first objective of this study was to assess the association of organismal distribution and frequency with two microhabitats: moss-covered and exposed forest soils, at four macroscopically similar but spatially separate sites in the Blue Ridge and Allegheny Mountains of Virginia. The second objective was to provide statistically either acceptance or denial of inferences derived from sampling regimes involving a more limited number of samples. To evaluate the scale where distributional differences may occur within a site, protocols involved four collection regimes and random point and linear transect sampling. Chytrid frequency on thalli of two moss genera was greatest in the soil surrounding and under the moss rhizoids. Random point sampling methods suggested differences in zoosporic fungal frequency between moss-covered soil and the exposed soil adjacent to mosses, as well as between two moss taxa. Linear transect sampling methods also suggested differences in zoosporic fungal frequencies between moss-covered soil and soil proximal to mosses. However, statistical analysis of random point samples using a goodness-of-fit test demonstrated that there was no significant difference in frequency of zoosporic fungi from moss-covered soil and exposed soil proximal to mosses. More importantly, there was a significant difference in the frequency of ubiquitous and common zoosporic fungal species between different moss/soil complexes. This study demonstrates that differences in chytrid distribution can be detected at a microscale while at a larger scale, similarity in frequency and distribution was found.     

Species richness and regional distribution of myrmecophilous beetles

Four major hypotheses have been put forward to explain local species richness of commensal or parasitic species. The resource distribution hypothesis predicts that regionally widespread host species are able to support higher local species richness of commensals or parasites. On the other hand, the resource size hypothesis predicts that larger hosts can support more species than smaller hosts, and comparably, the resource abundance hypothesis predicts that hosts that offer more resources are able to support more species. Finally, the resource concentration hypothesis predicts that hosts that occur in high-density patches support higher species richness. In this study, we tested the first three of the above hypotheses with myrmecophilous beetles and their host ants. In addition to species richness of myrmecophilous beetles, we also applied the above hypotheses to explain the distribution of the beetles. Our data are exclusively based on an extensive literature survey. Myrmecophilous beetles live in naturally fragmented environments composed of host ant colonies and they are exclusively dependent on ants. We found that the distribution of the host ants and the colony size of the host ants had a positive effect on both the species richness and the distribution of myrmecophilous beetles. In the same way, we found that myrmecophilous beetle species that are generalists, i.e. have more than one host ant species, and thus have more abundant resources, were more widely distributed than specialist species. Thus, we found support for the hypothesis that resource distribution, resource size and resource abundance have an effect on species richness and on the distribution of species.     

Root-exudate flux variations among four co-existing canopy species in a temperate forest,Japan

Plants allocate carbon to root exudates to mine nitrogen (N) from soil organic matter (SOM). Little is known about how the root-exudation rate varies among co-existing woody species. We conducted an in situ experiment in a warm temperate forest on two dominant species, Quercus serrata and Ilex pedunculosa, and two of their congeneric species, Quercus glauca and Ilex macropoda, respectively. We hypothesized that the root-exudation rate varies among these species because of their distinct functional traits and N demands. Root-exudation rates were measured using a non-soil culture method during the growing season from June 2013 to May 2014. We also measured foliar N concentrations and the activities of N-degrading enzymes in the rhizosphere soils. The annual demand for N was calculated from the growth rate and allometric equations for biomass. The root-exudation rates of Q. serrata and I. macropoda were consistently greater than those of their congeneric evergreen species on root-length, root-weight, and individual-tree bases. The variations of the annual N demand of these species mirrored this pattern. Within a species, root-exudation rates correlated positively to leaf N contents, suggesting a physiological linkage between photosynthetic capacities and belowground carbon allocation. Root-exudation rates also correlated positively to the activities of polyphenol oxidase, an enzyme that decomposes N from recalcitrant SOM. Our results suggest that the variations of the root-exudation among co-existing species relate to their functional traits and demand for N.     

Drought acclimation of two deciduous tree species of different layers in a temperate forest canopy

Water-use strategies of Populus tremula and Tilia cordata, and the role of abscisic acid in these strategies, were analysed. P. tremula dominated in the overstorey and T. cordata in the lower layer of the tree canopy of the temperate deciduous forest canopy. Shoot water potential (), bulk-leaf abscisic acid concentration ([ABA]_leaf), abscisic acid concentration in xylem sap ([ABA]_xyl), and rate of stomatal closure following the supply of exogenous ABA (v) decreased acropetally through the whole tree canopy, and foliar water content per area (w), concentration of the leaf osmoticum (c), maximum leaf-specific hydraulic conductance of shoot (L), stomatal conductance (g_s), and the threshold dose per leaf area of the exogenous ABA (d_a) required to reduce stomatal conductance increased acropetally through the tree canopy (from the base of the foliage of T. cordata to the top of the foliage of P. tremula) in non-stressed trees. The threshold dose per leaf dry mass of the exogenous ABA (d_w) required to reduce stomatal conductance, was similar through the tree canopy. After a drought period (3 weeks), the , w, L, g_s, d_a and d_w had decreased, and c and v had increased in both species. Yet, the effect of the drought period was more pronounced on L, g_s, d_a, d_w and v in T. cordata, and on , w and c in P. tremula. It was concluded that the water use of the species of the lower canopy layer—T. cordata, is more conservative than that of the species of the overstorey, P. tremula. [ABA]_leaf had not been significantly changed in these trees, and [ABA]_xyl had increased during the drought period only in P. tremula. The relations between [ABA]_leaf, [ABA]_xyl and the stomatal conductance, the osmotic adjustment and the shoot hydraulic conductance are also discussed.     

Heterogeneous dispersal of tree litterfall corresponding with patchy canopy structure in a temperate mixed forest

Spatial dispersal patterns of fine litter were analyzed in relation to forest structure within a temperate mixed stand, in northeastern Japan. The canopy layer was a mosaic of two types of patches, those of shade-tolerant Abies firma (estimated age being 81–146 yrs.) and early successional deciduous broad-leaved trees (about 45 yrs. of age). Litter input to the forest floor was observed for a period of three years using 38 traps set at a height of 1.2 m. The average annual total of fine litter was 6.233 (dw.) metric tons hectare^-1, 85.7% of the total litterfall. Fine litter was mostly leaves from the overstory (about 64%). Litter distribution maps were drawn, using the Davis's grid method, of the total fine litter and its two main elements, namely A. firma (a 36.1% share) and deciduous broad-leaved species (36.7%). The mosaic distribution of heterogeneous patches of litter was seem to corresponded with distribution of the canopy structure.