Phylogenetic Structure of Tree Species across Different Life Stages from Seedlings to Canopy Trees in a Subtropical Evergreen Broad-Leaved Forest

Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from seedlings to canopy trees, as well as forest gap influence on the phylogenetic structure of forest regeneration in a forest of the subtropical region in China. We investigate changes in phylogenetic relatedness (measured as NRI) of tree species from seedlings, saplings, treelets to canopy trees; we compare the phylogenetic turnover (measured as β_NRI) between canopy trees and seedlings in forest understory with that between canopy trees and seedlings in forest gaps. We found that phylogenetic relatedness generally increases from seedlings through saplings and treelets up to canopy trees, and that phylogenetic relatedness does not differ between seedlings in forest understory and those in forest gaps, but phylogenetic turnover between canopy trees and seedlings in forest understory is lower than that between canopy trees and seedlings in forest gaps. We conclude that tree species tend to be more closely related from seedling to canopy layers, and that forest gaps alter the seedling phylogenetic turnover of the studied forest. It is likely that the increasing trend of phylogenetic clustering as tree stem size increases observed in this subtropical forest is primarily driven by abiotic filtering processes, which select a set of closely related evergreen broad-leaved tree species whose regeneration has adapted to the closed canopy environments of the subtropical forest developed under the regional monsoon climate.     

浙江省主要亚热带森林群落类型物种和谱系水平的α和β多样性比较

了解不同森林群落类型的物种和谱系水平的α和β多样性, 有助于指导森林经营和生物多样性保护。本研究比较了浙江省内不同地点主要森林类型(包括常绿阔叶林、常绿落叶阔叶混交林、落叶阔叶林和针阔叶混交林)的物种α多样性和谱系α多样性, 以及物种β多样性和谱系β多样性。研究表明, 该地区主要森林类型的物种和谱系α多样性均存在较大差异, 但控制了空间和地形因子的作用后, 差异几乎全部消失; 森林类型内部及相互间的物种和谱系β多样性均存在显著差异, 同种森林类型内部的物种和谱系β多样性分别小于不同森林类型之间的物种和谱系β多样性, 且在控制了空间和地形因子的作用后, 以上差异仍然显著。本研究表明影响亚热带主要森林群落类型物种和谱系水平的α和β多样性的因素存在差异: α多样性可能主要受到空间和地形因子等的影响, 而β多样性则可能受到森林类型的重要影响。     

Impact of Logging and Forest Conversion to Oil Palm Plantations on Soil Bacterial Communities in Borneo

Tropical forests are being rapidly altered by logging and cleared for agriculture. Understanding the effects of these land use changes on soil bacteria, which constitute a large proportion of total biodiversity and perform important ecosystem functions, is a major conservation frontier. Here we studied the effects of logging history and forest conversion to oil palm plantations in Sabah, Borneo, on the soil bacterial community. We used paired-end Illumina sequencing of the 16S rRNA gene, V3 region, to compare the bacterial communities in primary, once-logged, and twice-logged forest and land converted to oil palm plantations. Bacteria were grouped into operational taxonomic units (OTUs) at the 97% similarity level, and OTU richness and local-scale α-diversity showed no difference between the various forest types and oil palm plantations. Focusing on the turnover of bacteria across space, true β-diversity was higher in oil palm plantation soil than in forest soil, whereas community dissimilarity-based metrics of β-diversity were only marginally different between habitats, suggesting that at large scales, oil palm plantation soil could have higher overall γ-diversity than forest soil, driven by a slightly more heterogeneous community across space. Clearance of primary and logged forest for oil palm plantations did, however, significantly impact the composition of soil bacterial communities, reflecting in part the loss of some forest bacteria, whereas primary and logged forests did not differ in composition. Overall, our results suggest that the soil bacteria of tropical forest are to some extent resilient or resistant to logging but that the impacts of forest conversion to oil palm plantations are more severe.     

青藏高原北部戈壁植物群落物种、功能与系统发育β多样性分布格局及其影响因素

戈壁荒漠广泛分布于全球干旱和极旱区域, 是我国陆地生态系统的重要组成部分。由于自然环境恶劣和交通条件限制, 目前有关戈壁植物群落物种、功能和系统发育等多维度β多样性形成机制的系统研究还很缺乏, 严重制约着对戈壁植物多样性维持机制的认知。本文以青藏高原北部61个典型戈壁生境植物群落为研究对象, 通过构建系统发育树和测量8个关键功能性状, 获取戈壁生境的物种、功能和系统发育β多样性, 比较3个维度β多样性格局与零模型的差异, 同时量化环境距离和地理距离对其的相对影响, 以探讨戈壁植物多样性的形成机制。结果显示: (1)戈壁植物的物种、功能和系统发育β多样性均表现出显著的距离衰减效应; (2)戈壁植物的物种、功能和系统发育β多样性均表现为非随机的格局; (3)由于功能性状趋同进化, 植物功能和系统发育β多样性变化趋势并不一致; (4)环境差异对植物3个维度β多样性均有着比空间距离更为重要的影响, 且土壤含水量、地表砾石盖度等局域生境因素的影响比气候更为强烈。以上结果表明, 戈壁植物的β多样性可能主要由局域生境过滤作用控制, 且不同维度的β多样性分布格局并不一致。     

Primates as Predictors of Mammal Community Diversity in the Forest Ecosystems of Madagascar

The geographic distribution of species is the typical metric for identifying priority areas for conservation. Since most biodiversity remains poorly studied, a subset of charismatic species, such as primates, often stand as surrogates for total biodiversity. A central question is therefore, how effectively do primates predict the pooled species richness of other mammalian taxa? We used lemurs as indicator species to predict total non-primate mammal community richness in the forest ecosystems of Madagascar. We combine environmental and species occurrence data to ascertain the extent to which primate diversity can predict (1) non-primate mammal α-diversity (species richness), (2) non-primate complementarity, and (3) non-primate β-diversity (species turnover). Our results indicate that primates are effective predictors of non-primate mammal community diversity in the forest ecosystems of Madagascar after controlling for habitat. When individual orders of mammals are considered, lemurs effectively predict the species richness of carnivorans and rodents (but not afrosoricids), complementarity of rodents (but not carnivorans or afrosoricids), and all individual components of β-diversity. We conclude that lemurs effectively predict total non-primate community richness. However, surrogate species alone cannot achieve complete representation of biodiversity.     

Biodiversity Promotes Tree Growth during Succession in Subtropical Forest

Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental manipulations of tree diversity will take decades to yield final results. To date, biodiversity effects in natural forests therefore have only been reported from sample surveys or meta-analyses with plots not initially selected for diversity. We studied biomass and growth of subtropical forests stands in southeastern China. Taking advantage of variation in species recruitment during secondary succession, we adopted a comparative study design selecting forest plots to span a gradient in species richness. We repeatedly censored the stem diameter of two tree size cohorts, comprising 93 species belonging to 57 genera and 33 families. Tree size and growth were analyzed in dependence of species richness, the functional diversity of growth-related traits, and phylogenetic diversity, using both general linear and structural equation modeling. Successional age covaried with diversity, but differently so in the two size cohorts. Plot-level stem basal area and growth were positively related with species richness, while growth was negatively related to successional age. The productivity increase in species-rich, functionally and phylogenetically diverse plots was driven by both larger mean sizes and larger numbers of trees. The biodiversity effects we report exceed those from experimental studies, sample surveys and meta-analyses, suggesting that subtropical tree diversity is an important driver of forest productivity and re-growth after disturbance that supports the provision of ecological services by these ecosystems.     

Enhancing the structural diversity between forest patches—A concept and real-world experiment to study biodiversity,multifunctionality and forest resilience across spatial scales

Intensification of land use by humans has led to a homogenization of landscapes and decreasing resilience of ecosystems globally due to a loss of biodiversity, including the majority of forests. Biodiversity–ecosystem functioning (BEF) research has provided compelling evidence for a positive effect of biodiversity on ecosystem functions and services at the local (α-diversity) scale, but we largely lack empirical evidence on how the loss of between-patch β-diversity affects biodiversity and multifunctionality at the landscape scale (γ-diversity). Here, we present a novel concept and experimental framework for elucidating BEF patterns at α-, β-, and γ-scales in real landscapes at a forest management-relevant scale. We examine this framework using 22 temperate broadleaf production forests, dominated by Fagus sylvatica. In 11 of these forests, we manipulated the structure between forest patches by increasing variation in canopy cover and deadwood. We hypothesized that an increase in landscape heterogeneity would enhance the β-diversity of different trophic levels, as well as the β-functionality of various ecosystem functions. We will develop a new statistical framework for BEF studies extending across scales and incorporating biodiversity measures from taxonomic to functional to phylogenetic diversity using Hill numbers. We will further expand the Hill number concept to multifunctionality allowing the decomposition of γ-multifunctionality into α- and β-components. Combining this analytic framework with our experimental data will allow us to test how an increase in between patch heterogeneity affects biodiversity and multifunctionality across spatial scales and trophic levels to help inform and improve forest resilience under climate change. Such an integrative concept for biodiversity and functionality, including spatial scales and multiple aspects of diversity and multifunctionality as well as physical and environmental structure in forests, will go far beyond the current widely applied approach in forestry to increase resilience of future forests through the manipulation of tree species composition.     

Tree recovery and seed dispersal by birds: Comparing forest, agroforestry and abandoned agroforestry in coastal Ecuador

We used a highly replicated study to examine vegetation characteristics between patches of intervened forest, abandoned agroforestry systems with coffee and actively managed agroforestry systems with coffee in a tropical landscape. In all habitats, plant structural characteristics, individual abundance, species richness and composition were recorded for the three plant size classes: adult trees, saplings and seedlings. Furthermore, bird species richness and composition, and seeds dispersed by birds were recorded. Tree abundance was higher in forest habitats while saplings and seedlings were more abundant in abandoned coffee sites. Although species richness of adult trees was similar in the three habitats, species richness of saplings and seedlings was much higher in forest and abandoned coffee than in managed coffee sites. However, in spite of their relatively low species richness, managed coffee sites are an important refuge for tree species common to the almost disappeared mature forest in the area. Floristic similarity for adult trees was relatively low between land use types, but clearly higher for seedlings, indicating homogenizing processes at the landscape level. More than half of the saplings and seedling were not represented by adults in the canopy layer, suggesting the importance of seed dispersal by birds between habitats. Our results show that each of the studied ecosystems plays a unique and complementary role as seed source and as habitat for tree recovery and tree diversity.     

Structure,composition and diversity of plant communities in FSC-certified,selectively logged forests of different ages compared to primary rain forest

The impact of logging on plant communities was studied in forest that has been logged selectively 1, 5 and 10 years previously (following a certified procedure): diversity was compared with that of primary rain forest in the Berau region of East Kalimantan, Indonesia. Four sets of 20 transects located within an area of 6 ha were sampled for all trees, saplings and seedlings, and records were made of topographic position, structure, composition and species diversity. There was a high level of floristic similarity between primary forests at the study sites compared to primary forest elsewhere in Kalimantan. The impact of logging is therefore likely to be the most important factor determining any differences between the plant communities of the selectively logged and primary forest sites. We found differences in species composition and abundance of most plants between selectively logged and primary forest. Overall, stem densities of trees in the primary forest were higher than in the three selectively logged forest sites. Stem densities of saplings were equivalent in all four forests. Seedling stem densities were higher in the forest site logged 10 years previously than in primary forest. Our results showed that the forests logged selectively under certified regimes still have a high plant diversity, possibly indicating that biodiversity values may be conserved by following certification procedures.     

广东石门台亚热带典型常绿阔叶林和亚热带山顶矮林群落特征

为了研究亚热带典型常绿阔叶林和亚热带山顶矮林的物种组成和群落结构,在广东石门台国家自然保护区内分别建立了1 hm2亚热带典型常绿阔叶林样地和1 hm2亚热带山顶矮林样地,以样地内所有胸径（DBH）≥1 cm的乔木、灌木和藤本为研究对象,分析两种森林类型的物种组成、密度、径级和株高结构。结果显示：（1）两种森林的Srensen物种相似性指数为0.41,优势种不同,但优势科却较相似;其中,茶科和杜鹃花科在两种森林中所占比例较高;（2）亚热带典型常绿阔叶林的幼苗（1 cm≤DBH〈2.5 cm）和幼树（2.5 cm≤DBH〈12.5 cm）密度都显著小于亚热带山顶矮林,但两种森林的小树（12.5 cm≤DBH〈25 cm）和大树（DBH≥25 cm）密度均无显著差异;亚热带典型常绿阔叶林幼苗和大树的平均胸径都显著大于亚热带山顶矮林,而幼树的平均胸径则显著小于亚热带山顶矮林,小树的平均胸径无显著差异;亚热带典型常绿阔叶林中小树和大树的平均高度都显著大于亚热带山顶矮林,而幼苗的平均高度显著小于亚热带山顶矮林,幼树的平均高度无显著差异。综合分析表明,亚热带典型常绿阔叶林和亚热带山顶矮林的物种组成、密度、胸径和高度结构差异较大,亚热带典型常绿阔叶林群落稳定性强于亚热带山顶矮林。     

Change in Phylogenetic Community Structure during Succession of Traditionally Managed Tropical Rainforest in Southwest China

Tropical rainforests in Southeast Asia are facing increasing and ever more intense human disturbance that often negatively affects biodiversity. The aim of this study was to determine how tree species phylogenetic diversity is affected by traditional forest management types and to understand the change in community phylogenetic structure during succession. Four types of forests with different management histories were selected for this purpose: old growth forests, understorey planted old growth forests, old secondary forests (∼200-years after slash and burn), and young secondary forests (15–50-years after slash and burn). We found that tree phylogenetic community structure changed from clustering to over-dispersion from early to late successional forests and finally became random in old-growth forest. We also found that the phylogenetic structure of the tree overstorey and understorey responded differentially to change in environmental conditions during succession. In addition, we show that slash and burn agriculture (swidden cultivation) can increase landscape level plant community evolutionary information content.     

Forest edge-interior differentiation in the epiphytic lichen diversity of the forest steppe in the Khangai Mountains,Mongolia

Aims The effects of traditional land use by mobile livestock keepers on biodiversity in forest steppe ecotones are insufficiently studied. Epiphytes are an important part of forest plant diversity. Here we analyze differences in the diversity and composition of the epiphytic lichen vegetation between the edge and the interior of Siberian larch forests in the Khangai Mountains, western Mongolia, which are highly subdivided into patches. We asked whether the epiphytic lichen vegetation at the forest edge differs significantly from that in the interior, whether the edge is inhabited by more nitrophilous species than the interior and whether the density of nomad camps around the forest affects epiphytic lichen diversity.Methods Cover percentages of epiphytic lichen species were recorded from 20 trees per plot on 6 plots in the interior and 6 plots at the edge of Larix sibirica forests. The position of nomad summer camps was surveyed using Global Positioning System. Data were analyzed with pairwise significance tests, analysis of similarities, nonmetric multidimensional scaling and canonical correspondence analysis.Important findings The composition of the epiphytic lichen vegetation clearly differed between the two habitats, with more species being more frequent at the edge than in the interior. However, there was no difference in species richness (α-diversity). The epiphyte vegetation at the edge was more uniform and characterized by lower variation of tree-level α-diversity and lower β-diversity than in the interior. At the edge, only nitrophytic lichens were dominant, whereas in the interior, nitrophytes and acidophytes were among the dominant species. This pattern is probably attributable to the spatial heterogeneity of the intensity of forest grazing and was shown to be influenced by the density of nomad summer camps in the vicinity of the forests. Tree-level α-diversity increased with stem diameter, but high-diameter trees were rare. The results suggest that the present level of forest patchiness and the effect of forest grazing increases the diversity of epiphytic lichens on the landscape level, while logging of high-diameter trees reduces lichen diversity.     

A Multi‐Taxa Assessment of Biodiversity Change After Single and Recurrent Wildfires in a Brazilian Amazon Forest

In the last decades, due to human land management that uses fire as a tool, and due to abnormal droughts, many tropical forests have become more susceptible to recurrent wildfires with negative consequences for biodiversity. Yet, studies are usually focused on few taxa and rarely compare different fire frequencies. We examined if the effects of single and recurrent fires are consistent for leaf litter ants, dung beetles, birds (sampled with point‐counts PC and mist net‐MN), saplings, and trees. Recurrent fires had a great effect on forest structure, reducing live tree biomass and number of lianas, and increasing canopy openness and numbers of saplings alive. Recurrent fires had consistently stronger effects on species richness and composition across all sample groups than single fires, except ants. Birds and plants were more grouped in the congruence analysis. The average dissimilarities between control and recurrent‐burned forest were higher than between control and once‐burned forest for all sample groups, furthermore birds and vegetation communities in recurrent‐burned forest are almost entirely dissimilar from the unburned forest. While beta diversity of ants, birds (MN), and trees was not affected by the frequency of fire, it changed for dung beetles, birds (PC), and saplings. Effects of fire on faunal community structure were more due to indirect effects, through vegetation, than through the fire itself. These results reinforce the effect of single and recurrent fires on tropical forests, and highlight the mechanisms acting behind them. Policy‐makers need to explicitly address protection of tropical forests from wildfires in conservation planning.     

Matrix composition and landscape heterogeneity structure multiple dimensions of biodiversity in temperate forest birds

Quantifying how human-modified landscapes shape the distribution of biodiversity is critical for developing effective conservation strategies. To address this, we evaluated three hypotheses (habitat area, habitat configuration and matrix heterogeneity hypotheses) that predict responses of biodiversity to landscape structure in human-modified landscapes. We compared characteristics of landscape structure that influence taxonomic (TD), functional (FD), and phylogenetic (PD) dimensions of biodiversity of breeding birds in temperate forests. Relationships between biodiversity and landscape structure were assessed at multiple spatial scales for 20 forest interior sites in northeastern USA. We assessed if relationships with landscape structure were consistent among dimensions and assemblages of different groups (residents, migrants and all birds). Relationships between dimensions of biodiversity and landscape structure were more prevalent for FD and PD than for TD. Forest amount and configuration were rarely associated with any dimensions of biodiversity. In contrast, the identity of the matrix and heterogeneity of the landscape were frequently associated with biodiversity, but relationships differed among groups of birds. For example, FD of all birds was associated positively with landscape diversity but FD of residents was associated negatively with landscape diversity, suggesting that landscape diversity surrounding forests may increase overall FD of birds but that not all groups of species respond similarly. Indeed, biodiversity of migrants was only weakly related to landscape structure. Differences among relationships to landscape structure for bird groups and spatial scales suggests that management plans should consider local decisions within a regional framework to balance potentially conflicting needs of species groups in human-dominated landscapes.     

Niche and metabolic principles explain patterns of diversity and distribution: theory and a case study with soil bacterial communities

The causes of biodiversity patterns are controversial and elusive due to complex environmental variation, covarying changes in communities, and lack of baseline and null theories to differentiate straightforward causes from more complex mechanisms. To address these limitations, we developed general diversity theory integrating metabolic principles with niche-based community assembly. We evaluated this theory by investigating patterns in the diversity and distribution of soil bacteria taxa across four orders of magnitude variation in spatial scale on an Antarctic mountainside in low complexity, highly oligotrophic soils. Our theory predicts that lower temperatures should reduce taxon niche widths along environmental gradients due to decreasing growth rates, and the changing niche widths should lead to contrasting α- and β-diversity patterns. In accord with the predictions, α-diversity, niche widths and occupancies decreased while β-diversity increased with increasing elevation and decreasing temperature. The theory also successfully predicts a hump-shaped relationship between α-diversity and pH and a negative relationship between α-diversity and salinity. Thus, a few simple principles explained systematic microbial diversity variation along multiple gradients. Such general theory can be used to disentangle baseline effects from more complex effects of temperature and other variables on biodiversity patterns in a variety of ecosystems and organisms.     

Human impact diminishes seedling species richness in Kakamega Forest, Kenya

Anthropogenic forest fragmentation and other kinds of human disturbance, such as selective logging, can reduce the diversity of plant and animal species. To evaluate the impact of fragmentation and small-scale disturbance on forest regeneration, we assessed species richness and total abundance of adult trees in comparison with seedlings in the heavily fragmented and disturbed Kakamega Forest, western Kenya. In nine differently disturbed 1-ha study blocks distributed across the main forest and fragments, we mapped all trees >10 cm in diameter at breast height. Additionally, we established ninety 1-m² seedling plots within these 1-ha study blocks which were monitored over 2.5 years. We recorded altogether 74 species of adult trees (30–43 per block) and 64 seedling species (24–41 per block). Neither fragmentation nor small-scale disturbance had an impact on adult tree species richness or total tree abundance. Yet, fragmentation and especially small-scale disturbance significantly reduced seedling species richness, particularly of late-successional species. While human impact did not affect diversity of adults, the impoverished species richness of seedlings suggests a reduced potential for regeneration and a loss of tree diversity in the long-term.     

Assessing the effects of elephant foraging on the structure and diversity of an Afrotropical forest

African forest elephants (Loxodonta cyclotis) are ecosystem engineers that browse and damage large quantities of vegetation during their foraging and movement. Though elephant trail networks and clearings are conspicuous features of many African forests, the consequences of elephant foraging for forest structure and diversity are poorly documented. In this study in northeastern Gabon, we compare stem size, stem density, proportional damage, species diversity, and species relative abundance of seedlings and saplings in the vicinity of seven tree species that produce elephant-preferred fruits (“elephant trees”) relative to control trees that do not. Across 34 survey trees, with a combined census area of 2.04 ha, we recorded data on 26,128 woody stems in three sizes classes. Compared with control trees, the area around elephant trees had the following: (a) a significantly greater proportion of damaged seedlings and a marginally greater proportion of damaged saplings (with 82% and 24% greater odds of damage, respectively); (b) no significant difference in stem density or species diversity; and (c) a significantly greater relative abundance of seedlings of elephant tree species. Increasing distance away from focal elephant trees was associated with significantly reduced sapling stem damage, significantly increased sapling stem density, and significantly increased sapling species diversity. Considered in sum, our results suggest that elephants can affect the structure and diversity of Afrotropical forests through their foraging activities, with some variation based on location and plant size class. Developing a more complete understanding of elephants’ ecological effects will require continued research, ideally with manipulative experiments.     

Spatial and Temporal Patterns in Macrofaunal Diversity Components Relative to Sea Floor Landscape Structure

We examined temporal changes in macrofaunal α- and β-diversity over several spatial scales (within patches, among patches, across landscapes and across regions) in Long Island Sound on the northeast USA coast. Regional ε-diversity was estimated at 144 taxa, however γ-diversity fluctuated over time as did α- and β-diversity components. Based on additive partitioning, patch- and region-scale β-diversity components generally had the highest contributions to γ-diversity; lower percentages were found at within-patch and landscape scales. Multiplicative diversity partitioning indicated highest species turnover at within- and among patch scales. For all partition results, within-patch and patch-scale β-diversity increased sharply when hypoxia impacted benthic communities. Spatial variation in diversity components can be attributed to the collection of different patch types at varying spatial scales and their associated habitats across the benthic landscapes, as well as gradients in depth and other estuarine-scale characteristics. Temporal variation in diversity components across spatial scales may be related to seasonal changes in habitat heterogeneity, species population dynamics, and seasonal disturbances. Rare species were significant and temporally consistent components of macrofaunal diversity patterns over different spatial scales. Our findings agree with other marine and terrestrial studies that show diversity components vary significantly over different spatial scales and the importance of habitat/landscape heterogeneity in supporting diversity. However, our results indicate that the relative contributions of scale-specific β-diversity components can also change significantly over time. Thus, studies of diversity patterns across patches and landscapes based on data collected at one time, or assembled into a single data set from different times, may not capture the full suite of diversity patterns that occur over varying spatial scales and any time-specific determinants of those patterns. Many factors that shape and maintain sedimentary communities vary temporally, and appear to play an important role in determining and maintaining macrofaunal diversity over different spatial scales.     

Identifying the patterns of changes in α‐ and β‐diversity across Dacrydium pectinatum communities in Hainan Island,China

Exploring vegetation distribution spatial patterns facilitates understanding how biodiversity addresses the potential threat of future climate variability, especially for highly diverse and threatened tropical plant communities, but few empirical studies have been performed. Dacrydium pectinatum is a constructive and endangered species in the tropical mountain forests of Hainan Island, China. In this study, sixty‐eight 30 m × 30 m permanent plots of D. pectinatum were investigated, and species‐based and phylogenetic‐based methods were used to analyze the α‐ and β‐diversity pattern variation and its key drivers. Our study showed that species and phylogenetic α‐diversity patterns are different on a local scale. However, on a regional scale, the variations in the two α‐diversity patterns tend to converge, and they decrease with increasing elevation. The phylogenetic structure changes from overdispersion to convergence with increasing elevation. Soil (SOM, TP, AP), topography (EL, SL), and stand (CD) factors and α‐diversity showed close correlations. Species and phylogenetic β‐diversity have significant positive correlations with changing environmental distance and geographical distance; however, as a representative form of habitat heterogeneity, elevation distance has a greater impact on β‐diversity changes than geographical distance. In conclusion, the α‐ and β‐diversity patterns of the D. pectinatum community are mainly related to habitat filtering, especially in high‐elevation areas, and the colonization history of various regions also affects the formation of diversity patterns. Species‐based and phylogenetic‐based methods robustly demonstrated the key role of the habitat filtering hypothesis in community assembly. We believe that more plant diversity patterns need to be explored to understand the biodiversity formation mechanisms in tropical forests. We also recommend strengthening the construction and management of nature reserves to help address the biodiversity loss crisis in endangered tropical plant communities.     

Forest Age and Plant Species Composition Determine the Soil Fungal Community Composition in a Chinese Subtropical Forest

Fungal diversity and community composition are mainly related to soil and vegetation factors. However, the relative contribution of the different drivers remains largely unexplored, especially in subtropical forest ecosystems. We studied the fungal diversity and community composition of soils sampled from 12 comparative study plots representing three forest age classes (Young: 10–40 yrs; Medium: 40–80 yrs; Old: ≥80 yrs) in Gutianshan National Nature Reserve in South-eastern China. Soil fungal communities were assessed employing ITS rDNA pyrotag sequencing. Members of Basidiomycota and Ascomycota dominated the fungal community, with 22 putative ectomycorrhizal fungal families, where Russulaceae and Thelephoraceae were the most abundant taxa. Analysis of similarity showed that the fungal community composition significantly differed among the three forest age classes. Forest age class, elevation of the study plots, and soil organic carbon (SOC) were the most important factors shaping the fungal community composition. We found a significant correlation between plant and fungal communities at different taxonomic and functional group levels, including a strong relationship between ectomycorrhizal fungal and non-ectomycorrhizal plant communities. Our results suggest that in subtropical forests, plant species community composition is the main driver of the soil fungal diversity and community composition.