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International audience; A large part of the soil protist diversity is missed in metabarcoding studies based on 0.25 g of soil environmental DNA (eDNA) and universal primers due to ca. 80% co-amplification of non-target plants, animals and fungi. To overcome this problem, enrichment of the substrate used for eDNA extraction is an easily implemented option but its effect has not yet been tested. In this study, we evaluated the effect of a 150 μm mesh size filtration and sedimentation method to improve the recovery of protist eDNA, while reducing the co-extraction of plant, animal and fungal eDNA, using a set of contrasted forest and alpine soils from La Réunion, Japan, Spain and Switzerland. Total eukaryotic diversity was estimated by V4 18S rRNA metabarcoding and classical amplicon sequence variant calling. A 2- to 3- fold enrichment in shelled protists (Euglyphida, Arcellinida and Chrysophyceae) was observed at the sample level with the proposed method, with, at the same time, a 2-fold depletion of Fungi and a 3- fold depletion of Embryophyceae. Protist alpha diversity was slightly lower in filtered samples due to reduced coverage in Variosea and Sarcomonadea, but significant differences were observed in only one region. Beta diversity varied mostly between regions and habitats, which explained the same proportion of variance in bulk soil and filtered samples. The increased resolution in soil protist diversity estimates provided by the filtration-sedimentation method is a strong argument in favour of including it in the standard protocol for soil protist eDNA metabarcoding studies

AIM: Understanding the causes and consequences of biological invasions remains a challenge for several disciplines, including biogeography. One major issue in overcoming this challenge is disentangling the confounding mechanisms of species invasiveness and community invasibility. Here, we tackle this issue by applying a novel approach based on the phylogenetic affinities between exotic species and natives in the recipient community to elucidate naturalization and pre‐adaptation processes. LOCATION: Japan. TAXON: Seed plants. METHODS: Geographical co‐occurrence data for 1,094 exotics and 4,869 native species (including 1,676 endemics) were created at the 10‐km grid‐cell and vegetation‐plot levels. For individual exotic species, standardized effect size of phylogenetic species variability (PSVSES) of the recipient native assemblage (i.e. phylogenetic fields) was calculated and its clustering/over‐dispersion was tested, representing exotic invasiveness in relation to invasibility of native recipients. To identify drivers of species invasiveness, the correlation of PSVSES with species attributes, involving phylogenetic distance between each exotic and native species, was explored. RESULTS: Phylogenetic fields (PSVSES) showed significant over‐dispersion (~16% exotics) or clustering (~14% exotics). Interspecific variation of PSVSES among exotics was substantially explained by species ecological attributes. Geographical extent and climatic niche widths were negatively correlated with PSVSES. Preference for human influence was positively correlated with PSVSES at the 10‐km grid‐cell level, but negatively at the vegetation‐plot level. Exotics colonized from the Palearctic and Indo‐Malay regions, which belong to the same biogeographical region as East Asia, tended to have clustered phylogenetic fields. MAIN CONCLUSIONS: Environmental filtering and biotic sorting both played a key role in exotic plant colonization, supporting both of Darwin's contradictory hypotheses of naturalization versus pre‐adaptation. Clustered phylogenetic fields indicated that an exotic colonizes its recipient assemblage through abiotic filtering (i.e. pre‐adaptation); at the same time, phylogenetic over‐dispersion was indicative of naturalization for exotics that occupied a biotic niche space among native recipients (i.e. naturalization). Phylogenetic field patterns depended on species’ ecological attributes, including phylogenetic relatedness between exotics and recipient natives, especially reflecting invasibility at the local‐community level.

Aim: The species abundance distribution (SAD) is a fundamental pattern in macroecology. Understanding how SADs vary spatially, and identifying the variables that drive any change, is important from a theoretical perspective because it enables greater understanding of the factors that underpin the relative abundance of species. However, precise knowledge on how the form of SADs varies across large (continental) scales is limited. Here, we use the shape parameter of the gambin distribution to assess how meta-community-scale SAD shape varies spatially as a function of various climatic variables and dataset characteristics. Location: Eastern North America (ENA). Time period: Present day. Major taxa studied: Trees. Methods: Using an extensive continental-scale dataset of 863,930 individual trees in plots across ENA sampled using a standardized method, we use a spatial regression framework to examine the effect of temperature and precipitation on the form of the SAD. We also assess whether the prevalence of multimodality in the SAD varies spatially across ENA as a function of temperature and precipitation, in addition to other sample characteristics. Results: We found that temperature, precipitation and species richness can explain two-thirds of the variation in tree SAD form across ENA. Temperature had the largest effect on SAD shape, and it was found that increasing temperature resulted in more logseries-like SAD shapes (i.e. SADs with a relatively higher proportion of rarer species). We also found spatial variation in SAD multimodality as a function of temperature and species richness. Main conclusions: Our results indicate that temperature is a key environmental driver governing the form of ENA tree meta-community-scale SADs. This finding has implications for our understanding of local-scale variation in tree abundance and suggests that niche factors and environmental filtering are important in the structuring of ENA tree communities at larger scales. (Less)

Aim: This work explores whether the commonly observed positive range size–niche breadth relationship exists for Fagus, one of the most dominant and widespread broad-leaved deciduous tree genera in temperate forests of the Northern Hemisphere. Additionally, we ask whether the 10 extant Fagus species’ niche breadths and climatic tolerances are under phylogenetic control. Location: Northern Hemisphere temperate forests. Taxon: Fagus L. Methods: Combining the global vegetation database sPlot with Chinese vegetation data, we extracted 107,758 relevés containing Fagus species. We estimated biotic and climatic niche breadths per species using plot-based co-occurrence data and a resource-based approach, respectively. We examined the relationships of these estimates with range size and tested for their phylogenetic signal, prior to which a Random Forest (RF) analysis was applied to test which climatic properties are most conserved across the Fagus species. Results: Neither biotic niche breadth nor climatic niche breadth was correlated with range size, and the two niche breadths were incongruent as well. Notably, the widespread North American F. grandifolia had a distinctly smaller biotic niche breadth than the Chinese Fagus species (F. engleriana, F. hayatae, F. longipetiolata and F. lucida) with restricted distributions in isolated mountains. The RF analysis revealed that cold tolerance did not differ among the 10 species, and thus may represent an ancestral, fixed trait. In addition, neither biotic nor climatic niche breadths are under phylogenetic control. Main Conclusions: We interpret the lack of a general positive range size–niche breadth relationship within the genus Fagus as a result of the widespread distribution, high among-region variation in available niche space, landscape heterogeneity and Quaternary history. The results hold when estimating niche sizes either by fine-scale co-occurrence data or coarse-scale climate data, suggesting a mechanistic link between factors operating across spatial scales. Besides, there was no evidence for diverging ecological specialization within the genus Fagus.

QUESTION: To better understand the influence of deep-time diversification on extant plant communities, we assessed how community dissimilarity increases with spatial and climatic distances at multiple taxonomic ranks (species, genus, family, and order) in angiosperm trees. We tested the prediction that the dissimilarity–distance relationship should change across taxonomic ranks depending on the deep-time diversification in different biogeographical regions reflecting geohistories and geographical settings. LOCATION: Global. METHODS: Using a data set of plot-based surveys across the globe (861 plots), we compiled a community composition matrix comprising 21,455 species, 2,741 genera, 240 families, and 57 orders. We then calculated Sørensen's pairwise dissimilarity (βsor), and its turnover (βsim) and nestedness (βsne) components, among plots within seven biogeographical regions. Finally, we modeled the relationships between the biotic dissimilarities and the spatial/climatic distances at each taxonomic rank, and compared them among regions. RESULTS: βsor and βsim increased with increasing spatial and climatic distance in all biogeographical regions: βsim was dominant in all biogeographical regions in general, while βsne showed relatively high contributions to total dissimilarity in the temperate regions with historically unstable climatic conditions. The βsim-distance curve was more saturated at smaller spatial scales in the tropics than in the temperate regions. In general, the curves became flatter at higher taxonomic ranks (order or family), with the exception of Africa, North America, and Australia, pointing to region-specific geographical constraints. CONCLUSIONS: Compositional dissimilarity was generally shaped through the abrupt turnover of species along spatial/climatic gradients. The relatively high importance of the nestedness component in the temperate regions suggests that historical dispersal filters related to extinction/colonization may play important roles. Region-specific changes in the turnover and nestedness components across taxonomic ranks suggest differential imprints of historical diversification over deep evolutionary time in shaping extant diversity patterns in each biogeographical region. Financial support was provided by the Japan Society for the Promotion of Science (no. 20H03328), the Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers by the Japan Society for the Promotion of Science and the Environment Research and Technology Development fund (JPMEERF20184002) of the Ministry of the Environment, Japan. info:eu-repo/semantics/publishedVersion

Recently, a 2018 study by Ulrich et al. introduced the Weibull distribution as a flexible approach to model the distribution of species abundances in ecological communities. They pointed to possible limitations in the realized parameter spaces of this distribution as possibly indicating ecological constraints on species abundances. Here, we explore this question in detail using three large global data sets on quantitatively assessed plant, invertebrate, and vertebrate communities. By fitting the Weibull distribution to these communities, we confirm that only a minor amount of the possible ranges in the scale and the shape parameters of the Weibull distribution are realized. Shapes of distributions become more similar across taxa with increasing species richness and average abundances. This finding points to stochastic explanations for species abundance shapes, possibly linked to local colonization and extinction dynamics. We introduce the Weibull survival time parameter as a way to define the proportion of rare species in a community. This proportion increased with increasing species richness. Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science; National Science Center, Poland (UMO-2017/27/B/NZ8/00316) info:eu-repo/semantics/publishedVersion

We develop a novel class of measures to quantify sample completeness of a biological survey. The class of measures is parameterized by an order q ≥ 0 to control for sensitivity to species relative abundances. When q = 0, species abundances are disregarded and our measure reduces to the conventional measure of completeness, that is, the ratio of the observed species richness to the true richness (observed plus undetected). When q = 1, our measure reduces to the sample coverage (the proportion of the total number of individuals in the entire assemblage that belongs to detected species), a concept developed by Alan Turing in his cryptographic analysis. The sample completeness of a general order q ≥ 0 extends Turing's sample coverage and quantifies the proportion of the assemblage's individuals belonging to detected species, with each individual being proportionally weighted by the (q − 1)th power of its abundance. We propose the use of a continuous profile depicting our proposed measures with respect to q ≥ 0 to characterize the sample completeness of a survey. An analytic estimator of the diversity profile and its sampling uncertainty based on a bootstrap method are derived and tested by simulations. To compare diversity across multiple assemblages, we propose an integrated approach based on the framework of Hill numbers to assess (a) the sample completeness profile, (b) asymptotic diversity estimates to infer true diversities of entire assemblages, (c) non‐asymptotic standardization via rarefaction and extrapolation, and (d) an evenness profile. Our framework can be extended to incidence data. Empirical data sets from several research fields are used for illustration. Paid Open Access

There is an increasing potential to incorporate recent advances in our understanding of molecular-genetic pathways of flowering-time regulation to forecast shifts in flowering phenology in response to rising temperature. Recent studies developed models that integrate temperature and photoperiod signals into the network of floral regulatory genes, and predicted the shortening of flowering duration under warming based on the expression dynamics of major flowering-time genes in the perennial herb Arabidopsis halleri subsp. gemmifera. Nevertheless, empirical testing of the model prediction is still lacking. We performed temperature manipulation experiments and common garden experiments to test the model predictions using plants from two distant populations of A. halleri. We also quantified expression levels of two major flowering-time genes and compared the observed and predicted gene expression patterns. Our experiments in the laboratory and the field demonstrated that flowering duration of A. halleri was significantly shortened under warming conditions. Our results also revealed that the end of flowering was more sensitive to the climate warming than the onset of flowering in A. halleri. The observed gene expression dynamics in the warming condition were predicted well by the gene regulatory model. The transplant experiment of plants from Hokkaido, the northernmost island, to the subtropical field site in Okinawa, Japan, showed that plants flowered without significant activation of FLOWERING LOCUS T, a floral integrator crucial for the accelerated flowering in long days. The study suggested that the redundancy of flowering gene regulatory network could be beneficial to the persistence of flowering ability under extreme climatic conditions.

The classical “low latitude–high defense” hypothesis is seldom supported by empirical evidence. In this context, we tested latitudinal patterns in the leaf defense traits of deciduous broadleaved (DB) and evergreen broadleaved (EGB) tree species, which are expected to affect herbivore diversity. We examined the co-occurrence of leaf defense traits (tannin and phenol content, leaf mechanical strength, leaf dry matter content, leaf mass per area, and leaf thickness) in 741 broadleaved tree species and their correlations with species geographical range in East Asian island flora. We discovered contrasting latitudinal defense strategy gradients in DB and EGB tree species. DB species employed chemical defenses (increasing tannin and phenol content) at higher latitudes and physical defenses (softer and thinner leaves) at lower latitudes, whereas EGB tree species exhibited opposite latitudinal defense patterns. The “low latitude high defense” hypothesis included a paradoxical aspect in chemical and physical defense traits across broadleaved tree species. To reconcile paradoxical defense strategies along the latitudinal gradient, we conclude that interactive correlations among leaf traits are controlled by leaf longevity, which differs between DB and EGB tree species.

Competitive intransitivity, the existence of loops in competitive hierarchies, is one mechanism that can promote the local coexistence of competitors and maintain high local species diversity, although its prevalence and importance remain largely unknown. A full understanding of local community assembly needs knowledge of how transitive and intransitive competitive interactions are linked to species functional traits and the strength of biotic and abiotic filters. We apply a recently developed statistical tool to quantitative data on central European inland saltmarsh plant communities to infer causal relationships between soil characteristics, species occurrences and functional traits, and we estimated coefficients of competition. We found a predominance of intransitive competitive hierarchies. The proportion of such hierarchies was positively correlated with local species richness and compositional variability. Average soil characteristics were not correlated with competitive intransitivity, whereas high soil pH and the high variability in local pH and soil salinity decreased the overall impact of competition on community composition. In pairwise comparisons of species, dissimilarity in morphology, resource demand and reproductive phenology was significantly negatively correlated with differences in competitive performance, while higher environmental dissimilarity was particularly linked to intermediate degrees of competitive superiority. Our results suggest that habitat filtering for similar traits might intensify competitive interactions, but might also give rise to intransitive competitive loops that subsequently promote species coexistence and permit species’ functional equivalence. Intransitive competition appears to increase local diversity and small scale‐species turnover. The observed local differences in competitive structures suggest frequent competitive plasticity and context‐dependent competitive interactions. Finally, our results support the view that local abundance distributions can be used to infer the strength and outcome of competitive interactions. Synthesis. Our results confirm that intransitive competitive interactions might be a strong force structuring local plant communities. Intransitivity needs to be considered when studying plant community assembly and species co‐existence.

Fixation of linear alkylamine on the ordered mesoporous silica (MCM-41) is effective on not only in situ generation of gaseous and unstable trifluoroacetaldehyde from its hemiacetal but also successive syn-selective direct aldol reaction with cyclohexanone giving the corresponding syn-aldol product. As results, the aldol product produced from cyclohexanone was obtained in good to excellent yield without the formation of a complex mixture, compared to our previous results with a mixture of catalysts such as organic amine/amorphous silica or organic amine/acetic acid. The obtained syn-selectivity is opposite to the L-proline derivatives-catalyzed anti-selective direct aldol reaction. Not only various aldehydes but also 1,3-dicarbonyl compounds, such as 2,4-pentandione and ethyl 3-oxobutanoate, are also participated in the MCM-41-supported N-methylpropylamine direct aldol reaction of CF3CHO hemiacetal, respectively.

Aims: Quantifying β‐diversity (differences in the composition of communities) is central to many ecological studies. There are many β‐diversity metrics, falling mostly into two approaches: variance‐based (e.g., the Sørensen index), or diversity partitioning (e.g., additive β‐diversity). The former cannot be used when species–sites matrices are unavailable (which is often the case in island biogeography in particular) and only species richness data are provided. Recently, efforts have been made to partition additive β‐diversity, a metric calculated using only α‐diversity and γ‐diversity, into nestedness and turnover components (termed here “richness‐only β‐diversity partitioning”). We set out to test whether this form of β‐diversity partitioning generates interpretable results, comparable with metrics based on species incidence β‐diversity partitioning. Location: Global. Time period: Present day. Major taxa studied: Multiple taxa. Methods: We first provide a brief review of β‐diversity partitioning methods, with a particular focus on the development of richness‐only β‐diversity partitioning. Second, we use 254 empirical incidence matrices (provided with the paper) sourced from the literature to measure turnover and nestedness using incidence β‐diversity partitioning, comparing the resulting values with those calculated using richness‐only β‐diversity. Results: We provide an account of the emergence of β‐diversity partitioning, with particular reference to the analysis of richness‐only datasets, and to the definition and usage of the relevant metrics. Analytically, we report weak correlations between turnover and nestedness calculated using the two different approaches. We show that this is because identical values of α‐diversity and γ‐diversity can correspond to incidence matrices with a range of different structures. Main conclusions: Our results demonstrate that the use of richness‐only β‐diversity partitioning to measure turnover and nestedness is problematic and can produce patterns unrelated to conventional measures of turnover and nestedness. We therefore recommend that more accurate definitions are adopted for these terms in future studies.

Understanding the structure of and spatial variability in the species composition of ecological communities is at the heart of biogeography. In particular, there has been recent controversy about possible latitudinal trends in compositional heterogeneity across localities (β-diversity). A gradient in the size of the regional species pool alone can be expected to impose a parallel gradient on β-diversity, but whether β-diversity also varies independently of the size of the species pool remains unclear. A recently suggested methodological approach to correct latitudinal β-diversity gradients for the species pool effect is based on randomization null models that remove the effects of gradients in α- and γ-diversity on β-diversity. However, the randomization process imposes constraints on the variability of α-diversity, which in turn force γ- and β-diversity to become interdependent, such that any change in one is mirrored in the other. We argue that simple null model approaches are inadequate to discern whether correlations between α-, β- and γ-diversity reflect processes of ecological interest or merely differences in the size of the species pool among localities. We demonstrate that this kind of Narcissus effect may also apply to other metrics of spatial or phylogenetic species distribution. We highlight that Narcissus effects may lead to artificially high rejection rates for the focal pattern (Type II errors) and caution that these errors have not received sufficient attention in the ecological literature.

Understanding the mechanisms of secondary succession related to forest management practices is receiving increasing attention in community ecology and biodiversity conservation. Abiotic and biotic filtering are deterministic processes driving community reassembly. A functional trait or phylogeny-based approach predicts that environmental filtering induced by clearcut-logging results in functional/phylogenetic clustering in younger forests, while biotic filtering (competitive exclusion) promotes functional/phylogenetic overdispersion in old-growth forests. From this perspective, we examined the patterns of functional/phylogenetic structures using tree community data (147 species × 170 plots). These data were chronosequenced from clearcut secondary forests to old-growth subtropical forests in the Ryukyu Archipelago, with species’ trait data (leaf and stem) and species level phylogeny. To detect clustering or overdispersion in the functional and phylogenetic structures, we calculated the standardized effect size of mean nearest trait distance and mean nearest phylogenetic distance within the plots. Functional or phylogenetic clustering was relatively weak in secondary forests, and their directional change with increasing forest age was not generally detected. Mean nearest trait/phylogenetic distance for most plots fell within the range of random expectation. The results suggest that abiotic/biotic filtering related to functional traits or phylogenetic relatedness plays a diminished role in shaping species assembly during secondary succession in the subtropical forest. Our findings of functional and phylogenetic properties might shed light on the importance of dispersal (stochastic) processes in the regional species pool during community reassembly after anthropogenic disturbance. It will also contribute to the development of coordinated schemes that maintain potential species assembly processes in the subtropical forest.

Understanding biodiversity patterns on islands has long been a central aim in ecology and conservation biology. Island-specific biogeographical processes play substantial roles in the formation of endemic biota. Here, we examined how climate niche conservatism and geohistorical factors are interactively associated with in situ diversification of Tertiary relict flora in the east Asian continental islands. We generated two novel datasets for species distribution and phylogeny that included all of the known vascular plant species in Japan (5575). Then we tested phylogenetic signal of climatic tolerance, in terms of absolute minimum temperature and water balance, and explored environmental predictors of phylogenetic structure (evolutionary derivedness and clustering) of species assemblages. Although phylogenetic signal of climatic tolerance was significant across the phylogeny of most species, the strength of climatic niche conservatism differed among ferns, gymnosperms, angiosperm trees, and angiosperm herbs. For angiosperm trees, cold temperatures acted as environmental filters that generated phylogenetic derivedness/clustering of species assemblages. For fern and angiosperm herb species, however, phylogenetic properties were not associated with climatic harshness. These contrasting patterns among groups reflected climate niche evolution in vascular plants with different growth forms and traits; for example, diversification of angiosperm trees (but not fern and herb) occurred in response to historical climatic cooling. More importantly, geographical constraints contributed to evolutionary radiation that resulted from isolation by distance from the continent or by elevation. Quaternary climate change was also associated with clade-specific radiation in refugial habitats. The degree to which geographical, geological, and palaeoclimatic variables explain the phylogenetic structure underscores the importance of isolation- and habitat-stability-related geohistorical processes in driving in situ diversification despite climatic niche conservatism. We propose that the highly endemic flora of the east Asian islands resulted from the interplay of idiosyncratic regional factors, and ecological and evolutionary processes, such as climate niche assembly and adaptive/nonadaptive radiation.

Light foraging by trees is a fundamental process shaping forest communities. In heterogeneous light environments this behavior is expressed as plasticity of tree growth and the development of structural asymmetries. We studied the relative influence of neighborhood structure and directional solar radiation on horizontal asymmetry of tree crowns in late-successional high latitude (67–68°N) forests in northern Fennoscandia. We described crown asymmetries as crown vectors (i.e. horizontal vectors from stem center to crown center), which we obtained from canopy maps based on crown perimeter measurements in the field. To disentangle the influence of the two main determinants, inter-tree competition and directionality of above-canopy solar radiation at high latitudes, we applied circular statistical models, utilizing cylindrical distributions, to these data consisting of orientations and intensities of crown asymmetry. At the individual tree level, our model predicted crown asymmetry vectors from the current stand structure, and the predictions became better when the intensity of asymmetry (i.e. crown vector length) was higher. Competition was the main determinant of crown asymmetry for 2/3 of trees, and the model predictions improved when we incorporated the directionality of solar radiation. At the stand-level, these asymmetries had resulted in a small increment of the projected canopy area and an increased regularity of spatial structure. Our circular statistical modelling approach provided a quantitative evaluation of the relative importance of directionality of solar radiation and neighborhood stand structure, showing how both of these factors play a role in formation of crown asymmetries in high latitude forests. This approach further demonstrated the applicability of circular statistical modeling in ecological studies where the response variable has both orientation and intensity.

Questions Species–abundance distributions (SADs) have long been at the centre of ecological interest because they summarize various patterns of community assembly in condensed form. Here we link observed patterns of SAD shape and evenness to latitude and climatic conditions to infer global trends in abundance distributions. Location Global. Methods We compiled data on tree species abundances and climate covariates from 605 sites worldwide. We applied linear regression modelling and nonlinear least squares fitting of log-series and lognormal abundance distributions to species rank–order log-abundance plots to assess latitudinal and climatic gradients in abundance distributions and Pielou evenness. Results We observed significant latitudinal trends in SAD shape and evenness, even after accounting for richness and spatial effects. Evenness tended to increase towards lower latitudes and was positively correlated with actual evapotranspiration and negatively with climatic variability. We observed an excess of log-series SADs at lower latitudes and an increase in lognormal distributions towards northern latitudes. Accordingly, the proportion of species less abundant than expected from a log-series distribution decreased towards the tropics. Conclusions We speculate that the observed latitudinal trends are caused by respective gradients in the importance of dispersal for local tree community assembly. This interpretation implies the hypothesis that tropical communities tend to be more open and input-driven in comparison to temperate communities.

Aim A trait-based biogeographical approach can be used to shed light on species-sorting mechanisms that are driven by the interactions between species traits and abiotic conditions along large-scale gradients. We tested the hypothesis that geographical patterns of woody plant assemblages are driven largely by environmental filtering, in relation to climate harshness and seasonality, acting on key functional traits. Location Japanese archipelago. Methods Using a large-scale grid-based dataset of 773 woody species and five functional traits measured in the field, spanning the Japanese archipelago, we analysed the influence of climate harshness (absolute minimum temperature and precipitation of driest month) and climate seasonality (temperature and precipitation seasonality, and the length of period suitable for photosynthesis) on three aspects of community trait structure: community mean trait values, functional richness and functional divergence. To confirm whether the influence of climate-based species sorting on functional structure was stronger than the impact of dispersal limitation, we used null models that did or did not account for the difference in regional species pools as a result of vicariance. Results While climate harshness and historical dispersal limitation had a some influence on trait structure, temperature seasonality played a significant role. Greater seasonality was associated with functional similarity in wood density and leaf nitrogen concentration, but also contributed to increased diversity in leaf thickness, specific leaf area and maximum height. Main conclusions Our results demonstrate the importance of climate harshness and seasonality in shaping the geographical variation of functional trait structures in woody plant assemblages, while we found that species richness decreases with increasing climate harshness. Climate seasonality results in the convergence and divergence of co-occurring traits across different vegetation zones. This suggests that seasonal environmental variability acts not only as a filter of species traits but also as a driver creating a greater difference in functional strategies among woody plant species.

Aim To examine the roles of geohistorical and ecological factors in the development of butterfly assemblages on continental islands with multiple source pools. Location The Ryukyu Islands, Japan. This arc of continental islands is located between two source islands, Kyushu and Taiwan, and contains two major straits, the Tokara and Kerama gaps. Methods A total of 489 butterfly species were identified on 59 islands, including the two source islands. The influences on species richness and rarity of latitude, area, elevation, and distances from the nearest source and from the nearest larger island were analysed using generalized linear models. The relationships between differences in area, elevation, and distance and dissimilarity between island butterfly faunas were evaluated by multiple regressions on distance matrices. The relationships between area, elevation, and distance from the source and dissimilarity to the source fauna were examined using linear models. The dissimilarity was based on the Sorensen index and its nestedness and turnover components. Results Latitude, area and isolation determined species richness and rarity, whereas differences in elevation and distance regulated species turnover between islands. The gaps between islands were associated with nestedness between island faunas. Area consistently had a negative relationship with the total dissimilarity to source fauna. The overall dissimilarity to Kyushu decreased with the distance from Kyushu, whereas dissimilarity to Taiwan increased with distance from Taiwan. Main conclusions Both environmental filtering and dispersal limitation determine the geographical patterns of butterfly assemblages in the Ryukyus. The present study focuses on the unique pattern wherein migration from Kyushu is facilitated on islands farther from Kyushu, while migration from Taiwan is inhibited on islands farther from Taiwan. The two source islands have contrasting roles that affect butterfly distributions unidirectionally. This study highlights the importance of resolving dissimilarity into nestedness and turnover components to elucidate the formation of island biota.

Summary Understanding of the ecological impacts of logging practices on biodiversity and associated ecosystem processes is essential for developing sustainable forest management approaches. We documented the impacts of clearcutting on the functional structure of tree and herbaceous communities in hemiboreal, cool-temperate, warm-temperate and subtropical forests in the Japanese archipelago and identified forest vegetation that is vulnerable to deterioration of important ecosystem functions. We combined species data for leaf, stem, flower and fruit traits related to productivity, nutrient cycling and habitat quality for wildlife with phytosociological vegetation data from unmanaged and previously clearcut forests, then calculated functional structure indices [community mean (CM) of trait values, functional richness (FRic) and functional divergence (RaoQ)] of plant communities. For tree species, functional structure indices of specific leaf area (SLA), leaf carbon and nitrogen concentrations, maximum height, wood density and flower size differed between unmanaged and clearcut forests, while for herb species, only maximum height differed between the two forest types. Functional structure indices showed divergent patterns across forest vegetation zones. In hemiboreal, cool-temperate and warm-temperate forests, the CMs of SLA and leaf nitrogen concentration were greater and that of leaf carbon concentration was smaller in clearcut than in unmanaged forests. Although clearcut forests had greater species richness than unmanaged forests, FRic and/or RaoQ of maximum height were smaller in clearcut forests. In hemiboreal and cool-temperate forests, FRic and RaoQ of SLA were also smaller in clearcut forests. In contrast, subtropical forests showed no differences in species richness and functional structures between unmanaged and clearcut forests. Synthesis and applications. Functional redundancy of plant communities differs among traits and among forest vegetation zones. After intensive logging, hemiboreal, cool-temperate and warm-temperate forests were more vulnerable to the loss of ecosystem functions related to leaf and stem traits of tree species than were subtropical forests, which appeared relatively resilient. Locally adaptive management to maintain multiple ecosystem functions should be developed based on the degree of functional complementarity among plant species in forest communities.

We investigated the roles of climate, geography, and geology in plant diversity and endemicity on the east Asian continental islands, by testing predictions from contrasting hypotheses considering current climate, habitat stability, and isolation as major drivers of plant richness and endemicity. We created a fine-resolution map of vascular plant richness (5614 species) with 10 × 10 km grid cells. Using this large dataset and regression models, we explored correlations between species richness/number of endemics and temperature, precipitation, Quaternary temperature/precipitation changes, Quaternary alluvial development and volcanic disturbances (presence of alluvial plains and of pyroclastic flows), distance from the continent, and elevation. We applied these analyses to the vascular plant assemblage as a whole and separately to trees, herbs, and ferns. Temperature and precipitation were associated with the richness of vascular plants overall and of their endemics. Quaternary temperature change was negatively associated with the richness of vascular plants overall and of their endemics. The presence of pyroclastic flows and of lowland alluvial plains was negatively associated with those. Distance from the continent and elevation were positively associated with endemic species richness, especially those of trees and herbs. While current climate was an important predictor of species richness (especially of ferns), geographical isolation and habitat stability were the main predictors of the endemic species richness of trees and herbs. The relative importance of current climate and historical factors may be related to the dispersal ability of functional groups. Our results illustrate that the diverse geographical conditions reflecting the characteristics of the island led to the various historical effects on biodiversity patterns. The highly endemic flora on the east Asian islands resulted from species accumulation and in situ diversification, suggesting that the climate and historical hypotheses are not mutually exclusive, but can be reconciled as the interplay between recent ecological and evolutionary processes.

Phylogenetic signal of species traits is a potentially powerful tool in the conservation of biodiversity and wildlife management. To develop a predictor for evaluating deer foraging risk in forest ecosystems, we examined the phylogenetic patterns in susceptibility to bark-stripping by Cervus nippon across the Japanese archipelago. We tested the variance of phylogenetically independent contrasts among bark-stripped ratios of 180 tree species, and found a significant phylogenetic signal, i.e., phylogenetically closely related species had similar bark-stripped ratios. To assess evolutionary processes generating clade-specific patterns of bark-stripped ratios, we evaluated the strength of phylogenetic signal by using the K-statistics. The K-statistics were

Aim We addressed the roles of geohistorical and ecological factors on beta diversity patterns of woody plants in the Japanese archipelago. We scrutinized the contribution of recent diversification in shaping the woody plant diversity of insular areas in East Asia. Location The Japanese archipelago. Methods The distribution data of 1030 woody plant species were compiled for 65 localities in the archipelago. First, the relationships between geohistorical (straits, distance and area) and ecological (topographical heterogeneity, minimum temperature and annual precipitation) variables and taxonomic and phylogenetic beta diversity were tested using regression models. Second, geographical patterns of phylogenetic beta diversity were compared with those of taxonomic beta diversity using ordination and randomization tests. These analyses were applied to the woody plants overall and their functional groups defined by life-form (coniferous, deciduous broad-leaved and evergreen broad-leaved groups). Results Distance and minimum temperature showed significant positive relationships with both measures of beta diversity across the woody plants overall and the functional groups. The contributions of geographical barriers, topographical heterogeneity and annual precipitation varied among groups. Ordinations by phylogenetic beta diversity produced patterns that were consistent with those generated by taxonomic beta diversity, showing three clusters of localities in relation to geographical barriers, except in the coniferous group. The regression slopes of phylogenetic beta diversity versus distance were significantly smaller than those of taxonomic beta diversity versus distance across all groups. Main conclusions In the Japanese archipelago, the combination of geographical isolation and environmental filtering in response to geohistorical perturbations and environmental gradients has configured the beta diversity patterns of woody plants. The recent diversification of phylogenetically close relatives probably caused the spatial variations that exist in woody plant diversity. The archipelago functions as a refugium for relict taxa and as a hotspot for neoendemics, contributing to the broad-scale diversity bias favouring East Asia.

The fluorous prolinol methyl ether was prepared through the perfluorohexylethylation of (S)-1-tert-butyl 2-methyl pyrrolidine-1,2-dicarboxylate using commercially available perfluorohexylethyl iodide, methylation, and deprotection in three steps in 19 % overall yield. In the asymmetric Michael addition reaction of nitrostyrene with propanal, the diastereoselectivity (syn/anti=92:8) with the prepared fluorous prolinol methyl ether was much higher than that (syn/anti=87–80:13–20) with nonfluorinated prolinol methyl ethers that have two n-octyl groups or two phenyl groups in place of perfluorohexylethyl groups.

The trait-based approach has received much research attention as it provides a heuristic framework for evaluating the ecological impacts of anthropogenic activities on communities and ecosystems. In this study, functional diversity (or structure) measures, such as functional richness, functional evenness, functional divergence, and functional composition, were used to examine management impacts on subtropical forests on the Ryukyu Islands of Japan. Functional indices were compared in tandem with taxonomic diversity indices between three forest types with different management histories: intact old-growth forests, secondary forests after clear-cutting, and abandoned Pinus luchuensis plantations. Species diversity indices were not significantly different among the three forest types. In contrast, functional diversity indices were significantly different among intact forests and managed forests. Functional richness and functional evenness were significantly lower in secondary forests than in intact forests and P. luchuensis plantations. Functional divergence was significantly higher in secondary forests and P. luchuensis plantations than in intact forests. These differences suggest that management activities affected niche space and the patterns of niche differentiation among component species in the functional space of managed forests. Community weighted means for each functional trait were also different among the forest types. The managed forests had greater leaf thickness, leaf dry matter content and maximum height, and lower specific leaf area and leaf nitrogen concentration than intact forests. These differences in functional composition of traits suggested potential functional impacts. This study demonstrated the utilization of species functional traits and community functional structure as a tool of natural experiment for assessing impacts of forest management practices on woodland ecosystems. It was also suggested that logging activities that include large-scale clear-cutting or establishment of P. luchuensis plantations may be incompatible with the conservation of natural ecosystem properties in subtropical forests.

A direct, concise, and enantioselective synthesis of 2-substituted 4,4,4-trifluorobutane-1,3-diols based on the organocatalytic asymmetric direct aldol reaction of an ethyl hemiacetal of trifluoroacetaldehyde with various aldehydes was examined. A catalytic amount (30 mol %) of commercially available and inexpensive l-prolinamide is quite effective as an organocatalyst for the catalytic in situ generation of gaseous and unstable trifluoroacetaldehyde from its hemiacetal, and a successive asymmetric direct aldol reaction with various aldehydes in dichloromethane at 0 °C, followed by reduction with sodium borohydride, gives 2-substituted 4,4,4-trifluorobutane-1,3-diols in moderate to good yields (31–84 %) with low diastereoselectivities and good to excellent enantioselectivities (64–97 % ee).

Species abundance distributions of moth and beetle assemblages, in addition to beetle feeding guilds, were examined using data collected by light traps in a cool-temperate deciduous forest at Hokkaido, Japan. Four types of species abundance distributions with a continuous shift in shape (broken stick, log-normal, power function, and dispersal-limited multinomial) were fitted and compared, and then the deviation of observed data from that expected for the neutral model (dispersal-limited multinomial distribution) was tested using species evenness and richness. Significantly better fits were obtained for the neutral model than for the other models for all assemblages and all beetle guilds. This result implies that the better fits of the neutral model might be characteristic of transient assemblages having an excess of rare species. The evenness of species abundance distributions for assemblages and guilds, except for moths associated with the understorey and predatory beetles, significantly deviated from that expected by the neutral model. The departure of beetle guilds (detritivores, herbivores, and xylophages) from the neutral model suggests their microhabitat dependence. The neutral model may prove to be a viable null hypothesis for examining the species abundance distributions of insect assemblages. In this study, we found that although stochastic dynamics appeared to have an increasing influence on insect community assembly, there are also complex biological processes still likely to be present. The fits of the neutral model suggest that habitat connectivity and microhabitat diversity are potentially important for conserving moth and beetle diversity in a temperate forest.

Question: Abrupt increments in tree radial growth chronology are associated with gap formations derived from disturbances. If a forest has been primarily controlled by fine-scale disturbances such as single tree-fall, do these release events spatio-temporally synchronize at a fine scale such as 10 m and 5 years? Is it possible to quantify spatio-temporal patterns of synchronicity from tree rings and long-term inventories, and associate them with spatial forest patch dynamics? How and to what extent can we reconstruct the fine-scale synchronized growth and spatio-temporal forest patch dynamics from currently available information? Location: Cores were taken from Abies sachalinensis trees in a coniferous/deciduous mixed forest in the Shiretoko Peninsula, Hokkaido, northern Japan. Methods: We first eliminated short-term fluctuations and highlighted growth trends over the mid-term using a time-series smoothing technique. This helped identify release events, we then conducted fine-scale spatial analyses on released A. sachalinensis primarily with cluster analysis. Results: We specified the unit scale of synchronicity at 10 m, and classified released A. sachalinensis trees into spatially separated regions. Only once during the recent 50 years was extensive synchronicity over 40 m found. Most of the released A. sachalinensis were isolated, with non-released A. sachalinensis present in nearby, implying imperfect synchronization. The ambiguous 20–30 m A. sachalinensis patches present in the current forest were the result of connected and overlapping patches smaller than 10 m associated with different disturbances and different responses of understorey trees. Conclusion: Tree-ring series, long-term census and fine-scale spatio-temporal analyses revealed that this forest community has been controlled by two types of disturbance: frequent small disturbances such as single tree-fall and less frequent multiple tree-falls.

The article “A paradox of latitudinal leaf defense strategies in deciduous and evergreen broadleaved trees”, written by Saihanna Saihanna, Tomoe Tanaka, Yu Okamura, Buntarou Kusumoto, Takayuki Shiono, Toshihide Hirao, Yasuhiro Kubota, and Masashi Murakami, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 01 June 2018 without open access.

Matrix models have been widely used to investigate the population dynamics of plant species. To make use of this method, we first divide individuals into groups and estimate transition probabilities per pair of groups. When a continuous variable, such as plant size, is used for grouping, there is often a trade-off: if the class intervals are narrow each group will only include a small number of samples, but if the intervals are wider, this may obscure some changes. This paper introduces a new matrix model in which we no longer have to divide individuals into arbitrarily defined size classes. The methodology is based on the Bayesian non-parametric binary regression. We first divide the data into ‘very fine’ intervals. For estimating transition probabilities in a ‘large’ matrix, we do not use the observed transition rate per class directly, but we smooth neighboring observed rates and select the most appropriate degree of smoothing using an information criterion called the Akaike Bayesian Information Criterion (ABIC). Our approach is illustrated using long-term forest monitoring data from an old-growth, warm-temperate evergreen forest, in which we examined the population dynamics of four evergreen subcanopy tree species. Transition probabilities allowed us to represent d.b.h.-related growth and mortality patterns graphically, and matrix analysis provided stable size distributions, reproductive values and elasticity that vary smoothly for trees of different sizes. The quantitative approach makes it possible to determine characteristic patterns of population dynamics for qualitatively similar species.

Based on direct field measurement, this study quantitatively estimated the litter dynamics on the forest floor for a 1-year-period and then investigated its influence on the seedling dynamics of Castanopsis sieboldii, as well as interactions with adults in a subtropical forest in southern Japan. Litter dynamics is composed of three major components: falling litter, transport, and decomposition on the forest floor. Litterfall was measured by litter traps and did not exhibit clear spatial tendency. Lateral input was assessed by newly accumulated litter beneath the traps and showed no spatial variation, either. In contrast, lateral output of litter, which was quantified from disappearance of artificial litter, was correlated with local topography. Consequently, we found considerable spatial variations and seasonal changes in litter dynamics on the forest floor. In addition, we constructed survival models of C. sieboldii seedlings at the individual level. The lateral movement of accumulated litter had an influence on the survival of seedlings, which mostly occurred in periods of typhoons with heavy rain. Meanwhile, the distance from canopy trees, which is assumed to be a spacing mechanism due to seedling/adult interactions, played a lesser role in this subtropical forest. Our results suggest that the stability of accumulated litter on the forest floor was a predominant factor in the spatial dynamics of the early life stage of C. sieboldii.

Two commercially available simple ionic liquids, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 1-ethyl-2,3-dimethylimidazolium trifluoromethansulfonate, effectively promote the solvent-free dehydrative carbon–carbon (C–C) bond-forming reaction of a variety of diarylmethanols and triarylmethanols with π-rich heteroaromatics, such as pyrroles, indole, furan, and thiophene without ring-opening and polymerization to give the corresponding not only 2-substituted pyrroles, furan, and thiophene but also 3-substituted indoles in good to excellent yields with moderate to excellent regioselectivities. These dehydrative C–C bond formation reactions of alcohols offer several advantages, such as the use of stoichiometric amounts of π-rich heteroaromatics and ionic liquids, water is the only by-product, there is no need for either organic solvents or expensive metal or strong Bronsted acid catalysts in the reaction, and the diversity of diarylmethylation and triarylmethylation.

This paper developed statistical methods for quantitatively assessing spatial pattern ofcommunities with abundant species richness such as in tropical forests. Based on multivariate point processes, species richness and the Simpson’s diversity index can be extended to the functions illustrating basic characteristics of multispecies spatial pattern. The spatial extension of the species richness is a sum of the detectabilities of constituent species within a given distance. By means of calculating the functions for individuals belonging to specific size class, the size structure of multispecies spatial pattern can also be examined. Therefore, comprehensive analysis of species, size, and spatial pattern together with the roles of each species in a community can be conducted. This paper demonstrated its descriptive utility in exploratory analysis by applications to four subtropical forest tree communities of different ages in Okinawa Island, southern Japan, all of which have abundant species richness. The results quantitatively revealed the contrasts among the four stands ranging from a young secondary stand to an old-growth forest as well as changes of relative positions of species in communities depending on their ecologic properties.