Lichens and bryophytes as indicators of old‐growth features in Mediterranean forests

Abstract

This study is focused on the selection of variables affecting lichen and bryophyte diversity in Mediterranean deciduous forests. Plots representing two forest types (Fagus sylvatica and Quercus cerris forests) and two forest continuity categories (old‐growth (OG) and non‐OG forests) were selected in the Cilento and Vallo di Diano National Park (Italy). The presence and the abundance of bryophytes and epiphytic lichens were recorded. Structural variables of the forests and vascular plant species richness have been used as predictors. A strong positive correspondence between the two groups of organisms was found. Higher species richness and the distribution of rare species are related to OG stands, while a qualitative (species composition) rather than a quantitative (species richness) difference between the two forest types was observed. Some species elsewhere considered as indicators of forest continuity, such as Lobaria pulmonaria, Antitrichia curtipendula, and Homalothecium sericeum, are associated with OG forests, independently from forest type, suggesting that they can be regarded as suitable indicators also in Mediterranean forests. Finally, our results suggest that old trees, high levels of basal area, a broad range of diameter classes, and high understory diversity are the main structural features affecting cryptogamic communities, while no correlation was found with the occurrence of deadwood.     

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.     

Impact of Flooding on the Species Richness, Density and Composition of Amazonian Litter-Nesting Ants

Litter-nesting ants are diverse and abundant in tropical forests, but the factors structuring their communities are poorly known. Here we present results of the first study to examine the impact of natural variation in flooding on a highly diverse (21 genera, 77 species) litter-nesting ant community in a primary Amazonian forest. Fifty-six 3 × 3 m plots experiencing strong variation in flooding and twenty-eight 3 × 3 m terra firme plots were exhaustively searched for litter-nesting ants to determine patterns of density, species richness and species composition. In each plot, flooding, litter depth, twig availability, canopy cover, plant density, percent soil nitrogen, carbon, and phosphorus were measured. Degree of flooding, measured as flood frequency and flood interval, had the strongest impact on ant density in flooded forest. Flooding caused a linear decrease in ant abundance, potentially due to a reduction of suitable nesting sites. However, its influence on species richness varied: low-disturbance habitat had species richness equal to terra firme forest after adjusting for differences in density. The composition of ant genera and species varied among flood categories; some groups known to contain specialist predators were particularly intolerant to flooding. Hypoponera STD10 appeared to be well-adapted to highly flooded habitat. Although flooding did not appear to increase species richness or abundance at the habitat scale, low-flooding habitat contained a mixture of species found in the significantly distinct ant communities of terra firme and highly flooded habitat.
     

The size and diversity of the soil seed banks and the light requirements of the species in sunny and shady natural communities of the Białowieża Primeval Forest

The research was conducted in two natural forest communities: Potentillo albae-Quercetum (oak forest) which allows much light to reach the forest floor and Tilio-Carpinetum typicum (hornbeam forest) which shades the herb layer heavily. The seed banks were estimated from numbers of seedlings emerging from soil samples over one growing season.(1) Our results confirm the hypothesis that persistent seed banks are mainly formed by species with high light requirements. Of the species found predominantly in the seed bank and absent from the herb layer or occurring there very rarely in both communities 83% of species and 70% of seedlings were strongly light-demanding (Ellenberg's light index 6–9). However, the results do not support the hypothesis that seed banks in natural deciduous forest communities are small, poor in species and do not reflect the species composition of herb layer.(2) The seed banks of both communities were rich in species and relatively large. Species richness in the oak forest turned out to be higher than in the hornbeam forest (51 vs 45 species/2.4 m₂), but size was smaller (2659 vs 5789 seedlings/2.4 m₂). In the oak forest the most abundant species in the seed bank was Galium boreale, but it constituted only 19% of the total number of seedlings, whereas in the hornbearn forest the dominant species, Urtica dioica, constituted 57% of the total.(3) In each community the species composition of the seed bank and the herb layer was very similar (>70%).(4) The seed bank was more diverse in the oak forest than in the hornbeam forest (H 2.34 vs 1.68).(5) The seed banks of both communities differed in the contribution of species with varied light requirements; in the sunny oak forest species with high light requirements dominated, whereas in the shady hornbeam forest both strongly and moderately light-demanding species had similar contributions.Nomenclature: Follows Ehrendorfer (1973) and Matuszkiewicz (1981).     

Diversity and similarity of butterfly communities in five different habitat types at Tam Dao National Park, Vietnam

Diversity and similarity of butterfly communities were assessed in five different habitat types (from natural closed forest to agricultural lands) in the mountains of Tam Dao National Park, Vietnam for 3 years from 2002 to 2004. The line transect count was used to record species richness and abundance of butterfly communities in the different habitat types. For each habitat, the number of species and individuals, and indices of species richness, evenness and diversity of butterfly communities were calculated. The results indicated that species richness and abundance of butterfly communities were low in the natural closed forest, higher in the disturbed forest, highest in the forest edge, lower in the shrub habitat and lowest in the agricultural lands. The indices of species richness, evenness and diversity of butterfly communities were low in agricultural lands and natural closed forest but highest in the forest edge and shrub habitats. The families Satyridae and Amathusiidae have the greatest species richness and abundance in the natural closed forest, with a reduction in their species richness and abundance from the natural closed forest to the agricultural lands. Species composition of butterfly communities was different among five different habitat types (40%), was similar in habitats outside the forest (68%) and was similar in habitats inside the forest (63%). Diversity and abundance of butterfly communities are not different between the natural closed forest and the agriculture lands, but species composition changed greatly between these habitat types. A positive correlation between the size of species geographical distribution range and increasing habitat disturbance was found. The most characteristic natural closed forest species have the smallest geographical distribution range.     

Species richness,composition, and spatial distribution of vascular epiphytes in Amazonian black-water floodplain forests

This study examines the occurrence of vascular epiphytic species in Central Amazonian black-water floodplain forests (igapó) and considers whether their horizontal and vertical distribution is influenced by the flood pulse, as is the case with tree species (phorophytes). Research was conducted in sixteen forest plots the Jaú National Park. In these, epiphytes on all phorophytes with DBH ≥ 10 cm were identified. We measured flood height using the watermark left by the last high-water period, then estimated the height relative to the ground of every epiphytic individual. We recorded 653 individuals in 37 species, distributed on 109 phorophytes. Igapó floodplain forests have much lower richness and abundance of vascular epiphyte species than do other Amazonian forests. This may reflect the limitation of available sites for colonization (only 24.9% of studied trees were occupied by epiphytes). Holoepiphytes predominated, and the combined presence of a flood-pulse, linked to the nutrient-poor soil poor seems to limit the occurrence of nomadic vines. Horizontal distribution of epiphytes followed the distribution of phorophytes, which in turn followed the flood-level gradient. Also flooding interacted strongly with vertical zonation to determine species richness. As already well-reported for trees, and unlike reports of epiphytes in other floodplains, flooding strongly influenced richness and distribution of vascular epiphytes in the studied igapó forests.     

Plant species diversity and composition of wetlands within an upland forest

Though often overlooked, small wetlands in an upland matrix can support diverse plant communities that increase both local and regional species richness. Here we characterize the full range of wetland vegetation within an upland forest landscape and compare the diversity and composition of different wetland plant communities. In an old-growth forest reserve in southern Quebec, Canada, we sampled wet habitats including lakeshores, permanent and seasonal ponds, swamps, glades, and streamsides. We used clustering, indicator species analysis, and nonmetric multidimensional scaling ordination to identify and compare vegetation types. The wetlands contained 280 species of vascular plants, 45% of the reserve's flora, in only 1.1% of its area. Local diversity averaged 24 ± 0.7 species per 7 m(2), much higher than in the surrounding upland forests. Plant communities sorted into five types, whose strongest indicator species were Osmunda regalis, Glyceria striata, O. cinnamomea, Deparia acrostichoides, and Matteuccia struthiopteris, respectively. Both local species richness and compositional variation among sites differed among the vegetation types. By combining species representative of the region's major wetlands with species from the upland forest matrix, the plant assemblages of these wetlands make disproportionately important contributions to landscape-level diversity.     

Tree species composition and diversity gradients in white-water forests across the Amazon Basin

Aim Attention has increasingly been focused on the floristic variation within forests of the Amazon Basin. Variations in species composition and diversity are poorly understood, especially in Amazonian floodplain forests. We investigated tree species composition, richness and α diversity in the Amazonian white‐water (várzea) forest, looking particularly at: (1) the flood‐level gradient, (2) the successional stage (stand age), and (3) the geographical location of the forests. Location Eastern Amazonia, central Amazonia, equatorial western Amazonia and the southern part of western Amazonia. Methods The data originate from 16 permanent várzea forest plots in the central and western Brazilian Amazon and in the northern Bolivian Amazon. In addition, revised species lists of 28 várzea forest inventories from across the Amazon Basin were used. Most important families and species were determined using importance values. Floristic similarity between plots was calculated to detect similarity variations between forest types and over geographical distances. To check for spatial diversity gradients, α diversity (Fisher) of the plots was correlated with stand age, longitudinal and latitudinal plot location, and flood‐level gradient. Results More than 900 flood‐tolerant tree species were recorded, which indicates that Amazonian várzea forests are the most species‐rich floodplain forests worldwide. The most important plant families recorded also dominate most Neotropical upland forests, and c. 31% of the tree species listed also occur in the uplands. Species distribution and diversity varied: (1) on the flood‐level gradient, with a distinct separation between low‐várzea forests and high‐várzea forests, (2) in relation to natural forest succession, with species‐poor forests in early stages of succession and species‐rich forests in later stages, and (3) as a function of geographical distance between sites, indicating an increasing α diversity from eastern to western Amazonia, and simultaneously from the southern part of western Amazonia to equatorial western Amazonia. Main conclusions The east‐to‐west gradient of increasing species diversity in várzea forests reflects the diversity patterns also described for Amazonian terra firme. Despite the fine‐scale geomorphological heterogeneity of the floodplains, and despite high disturbance of the different forest types by sedimentation and erosion, várzea forests are dominated by a high proportion of generalistic, widely distributed tree species. In contrast to high‐várzea forests, where floristic dissimilarity increases significantly with increasing distance between the sites, low‐várzea forests can exhibit high floristic similarity over large geographical distances. The high várzea may be an important transitional zone for lateral immigration of terra firme species to the floodplains, thus contributing to comparatively high species richness. However, long‐distance dispersal of many low‐várzea trees contributes to comparatively low species richness in highly flooded low várzea.     

西双版纳片段化石灰岩森林附生兰科植物多样性研究

西双版纳石灰岩地区拥有丰富的兰科植物资源,但近年来随着橡胶树的大面积种植,使得该地区很多石灰岩森林呈片段化。为了解片段化石灰岩森林中附生兰科植物多样性状况以及片段化对附生兰科植物的影响,该研究选取了生境片段化的青岩寨和曼纳览,以及连续生境的绿石林和巴卡新寨等4个样地的29个样方进行多样性调查和对比研究。结果表明:4个石灰岩森林样共记录到附生兰科植物34属76种1 528株(丛)。通过对坡向、坡度、海拔、地形、郁闭度和森林类型等6个环境因子与附生兰科植物丰富度进行CCA分析,发现石灰岩地区附生兰科植物的分布主要受海拔和森林类型2个因素的影响,在海拔较高的青岩寨和巴卡新寨附生兰科植物物种丰富度高于低海拔的绿石林和曼纳览,而片段化对附生兰科植物的物种多样性和多度均无显著影响,这可能与片段化的历史较短有关。虽然目前来看生境片段化对石灰岩地区的附生兰科植物多样性无显著影响,但生境脆弱的石灰岩森林植被的保护对于兰科植物多样性保护则更具重要性。     

三峡水库岛屿成岛前的植被特征与物种丰富度

三峡水库蓄水导致原有生境的岛屿化, 本文调查了三峡水库6个即将形成的岛屿蓄水前的植被特征, 并对这些岛屿上各类群落类型的物种丰富度进行了分析。共调查到群落类型28个, 其中草丛12个, 灌丛7个, 森林9个。研究结果表明, 绝大多数岛屿自然植被覆盖率低, 植被退化严重。主要表现为森林比重很小, 群落多样性低, 撂荒地上处于次生演替初始阶段的杂类草草丛占了相当大的比例。6个岛屿的植物种数分别为126、157、175、189、242、254; 其中森林群落的平均物种丰富度指数为42.19, 灌、草丛分别为15.96和17.89。杂类草草丛具有较高的丰富度指数, 而演替到较为稳定的退化草丛物种丰富度指数呈下降趋势。各类灌丛之间物种丰富度指数相差不大。在针阔混交林向阔叶林演替过程中, 物种丰富度指数表现为较大的波动性。由于自然植被被严重破坏, 岛屿上外来入侵种形成了较大的灾害。三峡库区即将形成的这些岛屿具有重要的研究价值, 建议选择一些岛屿建立保护区。     

Guidelines for RNA-seq projects: applications and opportunities in non-model decapod crustacean species

Understanding and predicting vegetation patterns in floodplains are essential for conservation and/or restoration of river floodplains subject to hydrological alterations. We propose a conceptual hydroecological model to explain the disturbance mechanisms driving species diversity across large river floodplains. These ecosystems harbor a unique set of flood-tolerant species different from the surrounding upland vegetation. In elevation gradients across pristine floodplains, the greater the flooding, the fewer the number of plant species. As terrain elevation increases, flood depth and duration decrease and it is more likely that species composition is influenced by external natural or human-driven disturbances. The spatial interaction between the natural flood regime and upland factors creates patterns of disturbance gradients that influence how floodplain vegetation establishes. In regions where upland conditions are subject to strong external disturbances, species diversity peaks at intermediate stages along the disturbance gradient. We demonstrate this concept with observations from the Central Amazon and Pantanal in Brazil, the Mekong’s Tonle Sap in Cambodia, and the Okavango Delta in Botswana. We discuss how this model could be further elaborated and validated to inform management of large river basins under the impact of upstream-induced flood pulse alterations.     

Do flood pulses structure amphibian communities in floodplain environments?

Beta diversity can provide insights into the processes that regulate communities subjected to frequent disturbances, such as flood pulses, which control biodiversity in floodplains. However, little is known about which processes structure beta diversity of amphibians in floodplains. Here, we tested the influence of flood pulses on the richness, composition, and beta diversity of amphibians in Amazonian floodplain environments. We also evaluated indicator species for each environment. We established linear transects in three environments: low várzea, high várzea, and macrophyte rafts. Species richness decreased and beta diversity increased according to the susceptibility of habitats to flood pulses. Indicator species differed among environments according to forest succession promoted by the flood pulse. The decrease in species richness between high and low várzea is due to non‐random extinctions. The higher rates of species turnover between várzeas and macrophyte rafts are driven by the colonization of species adapted to open areas. Our results highlight that the maintenance of complex environments is needed to protect biodiversity in floodplains.     

Epiphytic macrolichen communities along regional gradients in northern Norway

Abstract. Question: What are the relative influences of human impact, macroclimate, geographic location and habitat related environmental differences on species composition of boreal epiphytic macrolichen communities? Location: Troms county in northern Norway. Methods: Detrended Correspondence Analysis revealed the main gradient structure in lists of epiphytic macrolichen species from deciduous forests. By Canonical Correspondence Analysis with variance partitioning, the relative amount of variance in macrolichen species composition attributable to human impact, macroclimate, spatial context and environmental differences was quantified. Results: There was no significant effect of human impact on species composition of epiphytic macrolichens of deciduous forests. Macroclimate was the most important factor determining epiphytic macrolichen communities, which were also strongly influenced by ecological differences such as forest stand properties. Conclusions: Epiphytic macrolichen communities are determined by a macroclimatic gradient from the coastline to the interior of central north Norway. In marked contrast, the species composition of epiphytic macrolichen communities seems to be unaffected by human impact in the study area, where air pollution was marginal.     

Disturbance effects on diversity of epiphytes and moths in a montane forest in Ecuador

We sampled the diversity of epiphytes (lichens, bryophytes, vascular plants) and moths (Geometridae, Arctiidae) in mature and recovering forest and in open vegetation in the montane belt in Ecuador. No uniform pattern of change in species richness was detected among the different taxonomic groups with increasing disturbance. Species richness of epiphytic bryophytes and vascular plants declined significantly from mature forest towards open vegetation. In contrast, species richness of epiphytic lichens did not change with increasing forest alteration, while that of geometrid moths was significantly higher in recovering forest compared with mature forest and open habitats. Arctiidae were significantly more species-rich in recovering forest and open vegetation than mature forest. Hence, for some organisms, modified habitats may play an important role for biodiversity conservation in the Andes, whereas others suffer from habitat disturbance. However, trends of changes in species composition following deforestation were surprisingly concordant across most studied epiphyte and moth taxa.     

Diversity of the Western Carpathian flysch grasslands: Do extremely species-rich plant communities coincide with a high diversity of snails?

Upland fringes of the White Carpathians (Czech Republic) are known to support grasslands with the world’s highest local plant species richness. We investigated whether this unusually high plant richness has a parallel in snail communities, whether patterns of species composition of snail and plant communities in grasslands co-vary and how they are affected by local environment and landscape history. We compared plant and snail communities of dry to mesic grasslands in three neigh bouring regions: (1) hilly lowland of the Central Moravian Carpathians, (2) upland fringes and (3) upland of the White Carpathians. Both snail and plant communities exhibited a strong gradient in species composition associated with altitude, annual temperature and precipitation, soil calcium and pH. However, there was no correlation between local species richness of plants and snails in individual plots. The upland fringes of the White Carpathians were richest in snail species, probably due to intermediate environmental conditions, supporting the occurrence of species with contrasting environmental requirements. The highest local numbers of plant species were also recorded there, although differences among regions were not significant. The regional species richness of plants was also highest in the upland fringes, whereas that of snails was highest in the hilly lowland. Similarities in the diversity patterns of plants and snails among regions suggest the importance of regional factors for local richness, although local abiotic factors, which are partly correlated with the three regions, also influence local species composition and richness.     

Plant community development following reclamation of oil sands mines using four cover soil types in northern Alberta

Understanding the effects of reclamation treatments on plant community development is an important step in setting realistic indicators and targets for reclamation of upland oil sands sites to forest ecosystems. We examine trends in cover, richness, evenness, and community composition for four cover soil types (clay over overburden, clay over tailings sand, peat‐mineral mix over overburden, and peat‐mineral mix over tailings sand) and natural boreal forests over a 20 year period in the mineable oil sands region of northern Alberta, Canada. Tree, shrub, and nonvascular plant species cover showed similar increases over time for all reclamation treatments, with corresponding declines in forb and graminoid cover with time. These trends resemble those in the natural boreal forests of the region and the trajectory of community development for the reclamation treatments appears to follow typical early successional trends for boreal forests. Species richness and diversity of natural forest differed significantly from reclamation treatments. Nonmetric multidimensional scaling ordination and multi‐response permutation procedure revealed that species composition was not affected by reclamation treatment but clearly differed from natural forest. Analysis of species co‐occurrence indicated random plant community assembly following reclamation, in contrast to a higher proportion of nonrandom plant community assembly in natural forests. Thus, reclaimed plant communities appear to be unstructured through year 20 and assembly is still in progress on these reclaimed sites.     

Putting floodplain hyperdiversity in a regional context: an assessment of terrestrial–floodplain connectivity in a montane environment

Abstract Aim and location Alluvial flood plains support higher levels of vascular plant species richness than other terrestrial ecosystems. Whereas the spatial and temporal heterogeneity of these ecosystems has been considered the local determinant of high plant richness, regional influences, such as regional species pools have received little attention. In this study we surveyed plant species richness across the entire Nyack catchment (c. 21,000 ha), in Glacier National Park, USA, to determine the relation of upland ecosystem community structure to biodiversity patterns on montane floodplains that are relatively extensive and flood‐scoured ecosystems. Method We surveyed floodplain and other terrestrial ecosystems within the Nyack catchment using 50 × 2 m plots to record species present and visual estimates of percentage cover. Species pools from flood plains and three other terrestrial ecosystems (low elevation forests, sub‐Alpine forests and alpine) were analysed with nested subset analysis, detrended correspondence analysis (DCA), and an index of beta diversity to identify dissimilarity in species composition and richness, and the separate contributions of generalists (species occurring in more than one ecosystem) and specialists to richness in each ecosystem. Analysis of variance and post hoc Tukey–Kramer tests were used to identify where in the Nyack catchment each species was most abundant. Species life form and dispersal strategies were analysed to better understand influences on beta diversity. Results Our data show that in this pristine system, floodplain ecosystems host 202 (63%) of the 320 vascular plants identified within Nyack catchment. Of these species, the nested subset analysis showed that 146 (72%) are found in at least one adjacent upland ecosystem. While the DCA ordination scatter plots show statistically significant separations of ecosystems on the first two axes, values of beta diversity showed that substantial similarity exists between floodplain and all upland species pools. Further, of the 146 floodplain species shared with upland ecosystems, 61% were more frequent in upland ecosystems, whereas 55% were more abundant in uplands than flood plains (Tukey–Kramer P ≤ 0.05). Significant numbers of specialists were found on flood plains (24% of floodplain species), but also within upland ecosystems, where 23% and 40% of low elevation forest and alpine species were found to be specialists, respectively. Whereas 83% of herb generalists were wind dispersed, <70% of specialists were animal dispersed, indicating that similarity in species pools may be driven by wind dispersal. Main conclusions These results suggest a re‐evaluation of the contribution of floodplain ecosystems to regional plant species richness. While flood plains host specialists, other ecosystems had equal or higher levels of regional ‘endemism’. Furthermore, these data suggest that conservation of high levels of biodiversity on floodplain ecosystems may require consideration of upland ecosystems throughout the catchment as the majority of species were relatively rare on flood plains, indicating they may be sink habitats for some species.     

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.     

Logging impacts on avian species richness and composition differ across latitudes and foraging and breeding habitat preferences

Understanding the causes underlying changes in species diversity is a fundamental pursuit of ecology. Animal species richness and composition often change with decreased forest structural complexity associated with logging. Yet differences in latitude and forest type may strongly influence how species diversity responds to logging. We performed a meta‐analysis of logging effects on local species richness and composition of birds across the world and assessed responses by different guilds (nesting strata, foraging strata, diet, and body size). This approach allowed identification of species attributes that might underlie responses to this anthropogenic disturbance. We only examined studies that allowed forests to regrow naturally following logging, and accounted for logging intensity, spatial extent, successional regrowth after logging, and the change in species composition expected due to random assembly from regional species pools. Selective logging in the tropics and clearcut logging in temperate latitudes caused loss of species from nearly all forest strata (ground to canopy), leading to substantial declines in species richness (up to 27% of species). Few species were lost or gained following any intensity of logging in lower‐latitude temperate forests, but the relative abundances of these species changed substantially. Selective logging at higher‐temperate latitudes generally replaced late‐successional specialists with early‐successional specialists, leading to no net changes in species richness but large changes in species composition. Removing less basal area during logging mitigated the loss of avian species from all forests and, in some cases, increased diversity in temperate forests. This meta‐analysis provides insights into the important role of habitat specialization in determining differential responses of animal communities to logging across tropical and temperate latitudes.     

Influence of Habitat and Climate Variables on Arbuscular Mycorrhizal Fungus Community Distribution,as Revealed by a Case Study of Facultative Plant Epiphytism under Semiarid Conditions

In semiarid Mediterranean ecosystems, epiphytic plant species are practically absent, and only some species of palm trees can support epiphytes growing in their lower crown area, such as Phoenix dactylifera L. (date palm). In this study, we focused on Sonchus tenerrimus L. plants growing as facultative epiphytes in P. dactylifera and its terrestrial forms growing in adjacent soils. Our aim was to determine the possible presence of arbuscular mycorrhizal fungi (AMF) in these peculiar habitats and to relate AMF communities with climatic variations. We investigated the AMF community composition of epiphytic and terrestrial S. tenerrimus plants along a temperature and precipitation gradient across 12 localities. Epiphytic roots were colonized by AMF, as determined by microscopic observation; all of the epiphytic and terrestrial samples analyzed showed AMF sequences from taxa belonging to the phylum Glomeromycota, which were grouped in 30 AMF operational taxonomic units. The AMF community composition was clearly different between epiphytic and terrestrial root samples, and this could be attributable to dispersal constraints and/or the contrasting environmental and ecophysiological conditions prevailing in each habitat. Across sites, the richness and diversity of terrestrial AMF communities was positively correlated with rainfall amount during the most recent growing season. In contrast, there was no significant correlation between climate variables and AMF richness and diversity for epiphytic AMF communities, which suggests that the composition of AMF communities in epiphytic habitats appears to be largely determined by the availability and dispersion of fungal propagules from adjacent terrestrial habitats.