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Dead trees are vital structural elements in forests playing key roles in the carbon and nutrient cycle. Stem traits and fungal community composition are both important drivers of stem decay, and thereby affect ecosystem functioning, but their relative importance for stem decomposition over time remains unclear. To address this issue, we used a common garden decomposition experiment in a Dutch larch forest hosting fresh logs from 13 common temperate tree species. In total 25 fresh wood and bark traits were measured as indicators of wood accessibility for decomposers, nutritional quality, and chemical or physical defense mechanisms. After one and four years of decay, we assessed the richness and composition of wood-inhabiting fungi using amplicon sequencing and determined the proportional wood density loss. Average proportional wood density loss for the first year was 18.5%, with further decomposition occurring at a rate of 4.3% yr-1 for the subsequent three years across tree species. Proportional wood density loss varied widely across tree species in the first year (8.7-24.8% yr-1) and subsequent years (0-11.3% yr-1). The variation was directly driven by initial wood traits during the first decay year, then later directly driven by bark traits and fungal community composition. Moreover, bark traits affected the composition of wood-inhabiting fungi and thereby indirectly affected decomposition rates. Specifically, traits promoting resource acquisition of the living tree, such as wide conduits that increase accessibility and high nutrient concentration, increased initial wood decomposition rates. Fungal community composition, but not fungal richness explained differences in wood decomposition after four years of exposure in the field, where fungal communities dominated by brown-rot and white-rot Basidiomycetes were linked to higher wood decomposition rate. Synthesis. Understanding what drives deadwood decomposition through time is important to understand the dynamics o, Dead trees are vital structural elements in forests playing key roles in the carbon and nutrient cycle. Stem traits and fungal community composition are both important drivers of stem decay, and thereby affect ecosystem functioning, but their relative importance for stem decomposition over time remains unclear. To address this issue, we used a common garden decomposition experiment in a Dutch larch forest hosting fresh logs from 13 common temperate tree species. In total 25 fresh wood and bark traits were measured as indicators of wood accessibility for decomposers, nutritional quality, and chemical or physical defense mechanisms. After one and four years of decay, we assessed the richness and composition of wood-inhabiting fungi using amplicon sequencing and determined the proportional wood density loss. Average proportional wood density loss for the first year was 18.5%, with further decomposition occurring at a rate of 4.3% yr-1 for the subsequent three years across tree species. Proportional wood density loss varied widely across tree species in the first year (8.7-24.8% yr-1) and subsequent years (0-11.3% yr-1). The variation was directly driven by initial wood traits during the first decay year, then later directly driven by bark traits and fungal community composition. Moreover, bark traits affected the composition of wood-inhabiting fungi and thereby indirectly affected decomposition rates. Specifically, traits promoting resource acquisition of the living tree, such as wide conduits that increase accessibility and high nutrient concentration, increased initial wood decomposition rates. Fungal community composition, but not fungal richness explained differences in wood decomposition after four years of exposure in the field, where fungal communities dominated by brown-rot and white-rot Basidiomycetes were linked to higher wood decomposition rate. Synthesis. Understanding what drives deadwood decomposition through time is important to understand the dynamics o

Dead trees are vital structural elements in forests playing key roles in the carbon and nutrient cycle. Stem traits and fungal community composition are both important drivers of stem decay, and thereby affect ecosystem functioning, but their relative importance for stem decomposition over time remains unclear. To address this issue, we used a common garden decomposition experiment in a Dutch larch forest hosting fresh logs from 13 common temperate tree species. In total, 25 fresh wood and bark traits were measured as indicators of wood accessibility for decomposers, nutritional quality and chemical or physical defence mechanisms. After 1 and 4 years of decay, we assessed the richness and composition of wood-inhabiting fungi using amplicon sequencing and determined the proportional wood density loss. Average proportional wood density loss for the first year was 18.5%, with further decomposition occurring at a rate of 4.3% year−1 for the subsequent 3 years across tree species. Proportional wood density loss varied widely across tree species in the first year (8.7–24.8% year−1) and subsequent years (0–11.3% year−1). The variation was directly driven by initial wood traits during the first decay year, then later directly driven by bark traits and fungal community composition. Moreover, bark traits affected the composition of wood-inhabiting fungi and thereby indirectly affected decomposition rates. Specifically, traits promoting resource acquisition of the living tree, such as wide conduits that increase accessibility and high nutrient concentration, increased initial wood decomposition rates. Fungal community composition, but not fungal richness explained differences in wood decomposition after 4 years of exposure in the field, where fungal communities dominated by brown-rot and white-rot Basidiomycetes were linked to higher wood decomposition rate. Synthesis: Understanding what drives deadwood decomposition through time is important to understand the dynamics of carb

Plant functional traits are increasingly used to understand ecological relationships and (changing) ecosystem functions. For understanding ecosystem-level biogeochemistry, we need to understand how (much) traits co-vary between different plant organs across species and its implications for litter decomposition. However, we do not know how the degree of synchronous variation in decomposition rates between organs across species could be influenced by different keystone invertebrates decomposing different senesced plant organs, especially in warm-climate forests. Here we asked whether interspecific patterns in wood and leaf decomposition rates and in the spectra of resource economics traits underpinning them, co-vary across woody species; and how (much) the keystone invertebrate decomposers of the litter of these organs enhance or lower such co-variation of decomposition rates through time. We addressed these questions through an 18-month ‘common-garden’ decomposition experiment using leaf, twig and branch litter of 41 woody species in two distant subtropical forest sites in east China. We quantified the effects of leaf, twig and branch functional traits and their respective key invertebrates (moth larvae, termites) on the decomposition rates of those organs. Interspecific variation in wood traits was partly decoupled from that in leaf traits across species, while strong coupling was found between twigs and branches. The co-variation between leaf and woody organ decomposition rates was altered dynamically through the shifting activities of the key decomposers, which created nonlinear relationships of invertebrate litter consumption as a function of species rankings along the resource economic trait spectra of leaves and branches. The deviations from coupling of decomposition rates between organs were likely caused by combinations of three mechanisms: (1) (de-)coupling between organs of other traits, not commonly considered in resource economics spectra (e.g. resins)

Earthworms are ecosystem engineers associated with important soil functions. Despite the large amount of literature on earthworm ecology, relatively few studies have examined earthworms in deadwood or quantified their importance in this habitat. We investigated earthworm communities in decaying deadwood and disentangled how their community dynamics are influenced by variation in tree species, wood decomposition stage, and forest environment. Decaying logs (of standardised size) of ten common, temperate tree species were laid out to decay on the soil surface for four years. The experiment was carried out in the “tree cemetery” experiment LOGLIFE, in two contrasting temperate forests in the central Netherlands. The decaying logs yielded surprisingly rich earthworm populations, with on average 19 individuals per meter of log and in total belonging to 12 different species. Our findings highlighted that earthworm communities in deadwood in terms of composition and abundance were influenced by tree species, wood decomposition stage and forest type with different soil properties, as well as their interactions. After one and two years of decay, earthworm abundance was higher in the logs of Picea abies and relatively fast decomposing Populus spp. than in other trees, while this pattern changed after four years with higher earthworm abundance observed in the other tree species. Overall, Populus spp. supported the highest earthworm abundance, followed by Picea abies and Quercus robur. The earthworm community composition in the logs in the two forest sites had broadly similar dynamic trends of first becoming very dissimilar between one and two years, then relatively more similar from two to four years of decay, although the community composition differed between sites. The interacting influences of tree species, wood decay stage and forest environment on earthworm communities strongly suggest that diversity in deadwood resources contributes to earthworm diversity in forests.

Litters of leaves and roots of different qualities occur naturally above- and below-ground, respectively, where they decompose in contrasting abiotic and biotic environments. Therefore, ecosystem carbon (C) and nitrogen (N) dynamics can be strongly affected by the combination of litter position and quality. However, it is poorly understood how C versus N turnover of litters depend on the interplay among plant functional type (PFT), organs, traits and litter position. In a semi-arid inland dune, soil surface and buried leaf litters and buried fine roots of 25 species across three PFTs (herbs, legume shrubs and nonlegume shrubs) were incubated for 3, 6, 9, 12, 18 and 24 months to investigate litter decomposition and C and N dynamics. Morphological and chemical (nutrient and NMR carbon) traits of initial litters of leaves and fine roots were determined. The litter decomposition rates (k values) of surface leaves and buried fine roots did not differ, but buried fine roots and buried leaf litter decomposed faster than surface leaf litter. Ratios of k values of surface leaves to buried leaves decreased with leaf C:N ratio. Herbs and legume shrubs decomposed faster than nonlegume shrubs for buried fine roots, but not for leaves. At given C loss, buried fine roots had higher N loss than leaf litters; legume shrubs with relatively higher N or lower C:N ratio had higher N loss than nonlegume shrubs. Stronger positive relationships between C and N losses were shown in leaves and legume shrubs than in fine roots and nonlegume shrubs respectively. Synthesis. The generality of faster N release of legume litters at given C release highlights the importance of legumes in N cycling in semi-arid ecosystems where N is the limiting factor. The dynamics and coordination of C versus N release as a function of litter quality are modulated by litter position and PFT. These findings have important implications for the development of process-based models on C and N cycles in the context o

Aim: The plant economics spectrum provides a fundamental framework for understanding functional trait variation along environmental gradients. However, it is unclear whether there is a general whole-plant economics spectrum across organs at the finer taxonomic scale (e.g. within genera), and if there is, which factors affect the trait coordination of the different organs. Here, we examined whether resource economics spectra of different organs (i.e. leaf, stem and root) can be integrated at the whole-plant level within a single genus, and how environment, intraspecific variation and taxonomic scale shape the whole-plant spectrum. Location: China. Time period: 2018. Major taxa studied: Artemisia. Methods: We sampled 1,022 individuals of 62 Artemisia species in central and eastern China to test trait coordination patterns from organ to whole-plant level. From the resource economics spectrum perspective, 15 traits were chosen to represent the trade-off between structural and nutrient investments, including organs’ C, N, P and dry matter content, specific leaf area, specific stem length and specific root length. Results: Pairwise trait correlations and the trade-off patterns along the resource economic axis were consistent at both organ and whole-plant levels. Environmental gradients did not strongly affect the correlations among leaf, stem and root economics spectra, that is, the intraspecific variation weakened but did not mask this coordination. Taxonomic scale did not affect the degree of trait coordination as the genus-wide whole-plant economics spectrum also emerged within each of the three subgenera. Main conclusions: Our results support the hypothesis that the coordination of economics spectra across organs forms a whole-plant economics spectrum representing a ‘fast–slow’ resource management strategy, which is robust to recent evolution (genotypic variation, even for species within a single genus) and present-day environmental variation. Further studies shoul

Previous studies showed that bark cover at early-decay stage had profound control on the invertebrate assemblages of bark and wood, with possible consequence for the decomposition process. However, previous experimental designs could not disentangle how bark versus wood traits affect the invertebrate assemblage process in bark and/or wood separately because wood traits of different tree species may vary independently from bark traits. Furthermore, we do not know whether such tree species-specific bark trait effects are still influential at mid-decay stage. To unravel whether and how bark and wood traits influence invertebrate communities in tree logs at mid-decay stage, we introduce reciprocal bark transplantation within pairs of different tree species as a new method. We applied this method to two pairs of phylogenetically contrasting species of gymnosperms (pair I: Araucaria araucana and Cryptomeria japonica, pair II: Picea abies and Thuja plicata) and another gymnosperm (Chamaecyparis lawsoniana) set as disturbance control to test for potential bark manipulation artefacts on invertebrate community composition. Our bark exchange experiment revealed that both bark and wood host abundant and divergent subsets of invertebrates on mid-decay logs of different tree species. We further documented that the invertebrate community composition was predominantly shaped by the traits of host tissue per se, while also being significantly but less strongly affected by the traits of the other tissue, that is, the adjacent bark or wood. Our results indicated that bark trait effects faded with time and how long bark trait effects persist greatly depends on bark thickness. Synthesis. Our study suggests that maintaining deadwood heterogeneity related to variation between tree species and bark versus wood, is important for nursing a large biodiversity of invertebrates. Combined with bark removal methodology, our bark exchange method can be further extended to more decay stages and mor

More than half of the net primary production in terrestrial ecosystems returns to the soil through leaf litter fall and decomposition. In terrestrial ecosystems, litter constitutes a mixture of mainly senescent foliage from multiple species. Yet, the effect of litter mixing on litter decomposition rate remains ambiguous. Quantification of the soil fauna contribution and inclusion of their interaction with litter could remove the prevailing ambiguity, as soil fauna might influence the direction and magnitude of litter mixture effects on decomposition. We carried out a global meta-analysis to elucidate how soil fauna influenced litter mixture decomposition rate based on 55 published studies with 873 fauna inclusion/exclusion observations in field litterbag experiments. We hypothesized that soil fauna inclusion in litter mixture experiments would cause a positive change in the magnitude of mixed litter decomposition. That is, the presence of soil fauna would lead to synergistic litter mixture effects while the absence of soil fauna would lead to antagonistic litter mixture effects. Furthermore, we hypothesized that soil fauna would have a greater positive impact on the litter mixture effect in environments with low precipitation. While litter mixture had a neutral effect on decomposition on average across studies, non-additive mixture effects were common, with a key role for soil fauna, which generally enhanced decomposition rate compared to the component single-species litters. In contrast, fauna exclusion resulted in diminished decomposition rate overall. The overall synergistic soil fauna effect on litter mixture decomposition increased under low precipitation. Under high precipitation, the litter mixture effect was positive in the absence of soil fauna but non-significant in the presence of fauna. Climate imposes a great effect on litter mixture, with synergistic effects increasing towards the equator. Synthesis. These results highlight the importance of soil fa

Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)—even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth’s surface.

Aim: The interactions between plants and soil microbes play crucial roles in modulating the function and stability of terrestrial ecosystems. However, the relationships between plant and soil microbial diversity for different taxa have remained been elusive. Location: Northern China. Major taxa: Plant and soil microbes of grassland ecosystems. Time period: 2018 and 2019. Methods: We conducted a transect survey across grasslands to measure plant diversity, plant traits, and soil microbial diversity. High throughput sequencing was used to assess soil microbial diversity for bacterial 16S ribosomal RNA (16S) and fungal internal transcribed spacer (ITS) regions on an Illumina MiSeq. The random forest algorithm was used to determine the important spatial and environmental variables in predicting plant and microbial diversity, and structural equation modelling was used to examine the direct and indirect effects of climatic and edaphic variables on plant and microbial diversity. Results: Plant diversity was positively correlated with the diversity of soil fungi, particularly for predicted arbuscular mycorrhizal fungi (AMF) and saprotrophic fungi, and they were positively related to soil nutrients and texture. However, the correlation between plant and bacterial diversity varied by phyla and functional guilds, resulting in decoupling between plant and soil bacterial diversity. Community weighted mean leaf C:N ratio indirectly decreased soil fungal diversity through a negative relationship with soil total nitrogen. Soil bacterial and fungal diversity increased with increasing functional richness of specific leaf area and stem density, respectively. Main conclusions: These findings have contributed to unravelling the direct and indirect linkages between plant and soil fungal diversity, highlighting particularly strong linkages between plant diversity and predicted AMF and saprotrophic fungi diversity. However, we failed to detect an overall linkage between plant and soil b

Foliar nitrogen (N) or phosphorus (P) status and their stoichiometric homeostasis are integral parts of the plant nutrient economy that determines the success of plant species in environments where N or P limits plant growth. Despite growing evidence for higher predictability of stoichiometric homeostasis of N (HN) than that of P (HP) on plant species abundance in temperate grasslands, no previous studies explicitly examined how foliar N and P status modulate the relationships between stoichiometric homeostasis and species distribution (regional species abundance) of woody plants, especially in P-limited (sub)tropical ecosystems. We hypothesized that species with a conservative foliar nutrient status but a higher HP (but not HN) would be regional abundant in P-limited forest. We measured foliar N (LNC) and P (LPC) contents of 54 woody species, community composition and soil N and P contents across 94 forest plots in Chinese subtropical forests. Then we evaluated the species' levels of N and P stoichiometric homeostasis and their regional abundance to test our hypotheses. HN and HP significantly increased with decreasing LNC and LPC. Foliar nutrient status positively correlated with the minimum values of both soil N and P contents, but only negatively associated with the maximum value of soil P content, indicating that conservative species can occupy a wider range of soil P- than N-based nutrient niche. Meanwhile, species abundance negatively correlated with LNC and LPC, and positively correlated with HN and HP. However, the structure equation model analysis showed that species abundance increased with decline of LNC but not yet with increased HN. In contrast, species abundance enhanced with increased HP and decreased LPC via HP, rather than directly with a decline of LPC. Synthesis. This study provides empirical evidence that species with conse

Although plant–plant interactions (i.e. competition and facilitation) have long been recognised as key drivers of plant community composition and dynamics, their global patterns and relationships with climate have remained unclear. Here, we assembled a global database of 10,502 pairs of empirical data from the literature to address the patterns of and climatic effects on the net outcome of plant interactions in natural communities. We found that plant interactions varied among plant performance indicators, interaction types and biomes, yet competition occurred more frequently than facilitation in plant communities worldwide. Unexpectedly, plant interactions showed weak latitudinal pattern and were weakly related to climate. Our study provides a global comprehensive overview of plant interactions, highlighting competition as a fundamental mechanism structuring plant communities worldwide. We suggest that further investigations should focus more on local factors (e.g. microclimate, soil and disturbance) than on macroclimate to identify key environmental determinants of interactions in plant communities.

Environmental changes, for example, in rainfall and land use, lead to changes in the environment experienced by subsequent generations of plant species. Environmental conditions of maternal plants can influence the fitness and phenotypes of subsequent generations via non-genetic mechanisms: transgenerational plasticity (TGP). However, relevant empirical evidence remains scarce and ambiguous. What are the adaptive consequences of TGP for plants in the face of environmental change? For how many generations does the TGP effect remain? We tried to answer these questions by measuring life-history traits and reproductive characteristics of progeny plants of the diaspore-heteromorphic annual halophyte Atriplex centralasiatica in a 3-year TGP experiment covering F0, F1 and F2 and partly F3. Plants from diaspore types A (low dispersal and high germination ability) and C (high dispersal and low germination ability) were grown in favourable versus stressful salinities over three generations in a fully factorial design. Transgenerational plasticity of plants grown in favourable versus stressful salinities decreased from F2 → F1 → F0. Compared to the favourable condition, the stressful condition decreased the length of the vegetative period, increased the length of reproductive time, reproductive allocation and progeny diaspore size. Salinity tolerance and phenotypic plasticity were higher in plants from diaspore A than in those from diaspore C. In the stressful condition, plants produced less plant biomass, larger diaspores, a higher proportion of diaspore C, but lower proportion of diaspore A. Production of the proportion of diaspore C increased with increase in number of previous generations that experienced stress. The stress experience of the great-great grandmother (F0) continued into the lower A:C ratio of the F3 diaspores. Synthesis. Our findings provide evidence for the ‘escape strategy’ of A. centralasiatica: TGP could spread the risk of environmental adversity by d

Biodiversity loss, exotic plant invasion and climatic change are three important global changes that can affect litter decomposition. These effects may be interactive and these global changes thus need to be considered simultaneously. Here, we assembled herbaceous plant communities with five species richness levels (1, 2, 4, 8 or 16) and subjected them to a drought treatment (no, moderate or intensive drought) that was factorially combined with an invasion treatment (presence or absence of the non-native Symphyotrichum subulatum). We collected litter of these plant communities and let it decompose for 9 months in the plant communities from which it originated. Drought decreased litter decomposition, while invasion by S. subulatum had little impact. Increasing species richness decreased litter decomposition except under intensive drought. A structural equation model showed that drought and species richness affected litter decomposition indirectly through changes in litter nitrogen concentration rather than by altering quantity and diversity of soil meso-fauna or soil physico-chemical properties. The slowed litter decomposition under high species diversity originated from a sampling effect, specifically from low litter nitrogen concentrations in the two dominant species. We conclude that effects on litter decomposition rates that are mediated by changing concentrations of the limiting nutrient in litter need to be considered when predicting effects of global changes such as plant diversity loss.

Here we provide the ‘Global Spectrum of Plant Form and Function Dataset’, containing species mean values for six vascular plant traits. Together, these traits –plant height, stem specific density, leaf area, leaf mass per area, leaf nitrogen content per dry mass, and diaspore (seed or spore) mass – define the primary axes of variation in plant form and function. The dataset is based on ca. 1 million trait records received via the TRY database (representing ca. 2,500 original publications) and additional unpublished data. It provides 92,159 species mean values for the six traits, covering 46,047 species. The data are complemented by higher-level taxonomic classification and six categorical traits (woodiness, growth form, succulence, adaptation to terrestrial or aquatic habitats, nutrition type and leaf type). Data quality management is based on a probabilistic approach combined with comprehensive validation against expert knowledge and external information. Intense data acquisition and thorough quality control produced the largest and, to our knowledge, most accurate compilation of empirically observed vascular plant species mean traits to date.

The functional traits of organisms within multispecies assemblages regulate biodiversity effects on ecosystem functioning. Yet how traits should assemble to boost multiple ecosystem functions simultaneously (multifunctionality) remains poorly explored. In a multibiome litter experiment covering most of the global variation in leaf trait spectra, we showed that three dimensions of functional diversity (dispersion, rarity, and evenness) explained up to 66% of variations in multifunctionality, although the dominant species and their traits remained an important predictor. While high dispersion impeded multifunctionality, increasing the evenness among functionally dissimilar species was a key dimension to promote higher multifunctionality and to reduce the abundance of plant pathogens. Because too-dissimilar species could have negative effects on ecosystems, our results highlight the need for not only diverse but also functionally even assemblages to promote multifunctionality. The effect of functionally rare species strongly shifted from positive to negative depending on their trait differences with the dominant species. Simultaneously managing the dispersion, evenness, and rarity in multispecies assemblages could be used to design assemblages aimed at maximizing multifunctionality independently of the biome, the identity of dominant species, or the range of trait values considered. Functional evenness and rarity offer promise to improve the management of terrestrial ecosystems and to limit plant disease risks.

Changes in the composition of plant functional traits may affect ecosystem processes through influencing trophic interactions. Bottom-up control by plant species through food availability to animals may vary with time. However, such dynamics and their consequences for deadwood turnover are poorly known for detrital food webs. We introduce a dynamic conceptual model of the feedback of tree functional traits, (deadwood-feeding) termite populations and deadwood decomposition. We hypothesized that tree functional diversity (in terms of a wood resource economic spectrum [WES]) supports the sustenance of termite populations via complementary food supplied through time, as deadwood varies in traits both initially across species and because of different decomposition rates. Simultaneously, driven by this temporal dynamics of food quality, the consumption of deadwood by termites should hypothetically sustain deadwood turnover in a functionally diverse forest over time. We tested our hypothesis through an 18-month termite-exclusion decomposition experiment by incubating coarse (i.e. 5 cm diameter) deadwood of 34 woody species in two subtropical forests in East China. One site still sustained a healthy population of pangolins as the keystone termite predator, whereas another had lost its pangolins due to hunting and illegal wildlife trade. The results supported our hypothesis: in the first 12 months, termites amplified the positive linear relationship between % wood mass loss and initial wood quality (WES). In contrast, between 12 and 18 months, termite-mediated consumption, and associated wood mass loss, showed a humpback relation with the initial WES. This shift in termite preference of deadwood species along the WES reflects complementary food availability to termites through time. Synthesis. Our findings imply that tree functional composition, with variation in deadwood quality through decomposition time, can help to sustain termite populations and thereby forest carbon

The functional traits of organisms within multispecies assemblages regulate biodiversity effects on ecosystem functioning. Yet how traits should assemble to boost multiple ecosystem functions simultaneously (multifunctionality) remains poorly explored. In a multibiome litter experiment covering most of the global variation in leaf trait spectra, we showed that three dimensions of functional diversity (dispersion, rarity, and evenness) explained up to 66% of variations in multifunctionality, although the dominant species and their traits remained an important predictor. While high dispersion impeded multifunctionality, increasing the evenness among functionally dissimilar species was a key dimension to promote higher multifunctionality and to reduce the abundance of plant pathogens. Because too-dissimilar species could have negative effects on ecosystems, our results highlight the need for not only diverse but also functionally even assemblages to promote multifunctionality. The effect of functionally rare species strongly shifted from positive to negative depending on their trait differences with the dominant species. Simultaneously managing the dispersion, evenness, and rarity in multispecies assemblages could be used to design assemblages aimed at maximizing multifunctionality independently of the biome, the identity of dominant species, or the range of trait values considered. Functional evenness and rarity offer promise to improve the management of terrestrial ecosystems and to limit plant disease risks.

Biomass allocation patterns reflect the adaptive strategies of plants growing in different environments, which is a central issue in comparative plant ecology and evolution. However, the factors underpinning specific allocation patterns across organs and the existence of general rules governing allocation remain contentious. Optimal partitioning theory (OPT) states that plants can respond to resource availability by allocating relatively more biomass to the organ that captures the most limiting resources to optimize growth. In contrast, allometric partitioning theory (APT) postulates that biomass allocation among organs is a power function of plant size independently of environmental variation. As phylogenetic and growth form constraints (e.g. formation of inert heartwood in tree clades) may also affect biomass allocation, comparison among and within closely related taxa of rather similar growth form may enable a more direct testing of which of these two theories prevails. To test whether OPT or APT was prevalent at wide geographical scale, we investigated biomass allocation patterns among leaves, stems and roots of 1,022 plants of 62 Artemisia species (Asteraceae) collected along broad climate (annual mean temperature range: −4.9 to 18.0°C, annual mean precipitation range: 193–1,668 mm) and soil gradients (soil carbon content range: 1.6–15.4 kg C m−2) in central and eastern China. There were strong allometric relationships among leaf mass (ML), stem mass (MS) and root mass (MR) at both interspecific and intraspecific levels. Moreover, the interspecific and intraspecific patterns were not different from general patterns for pooled plants, that is, ML/MR and ML/MS, but not MS/MR, generally decreased with plant size. However, the three organ mass ratios were not responsive to broad climatic or soil gradients after the effect of plant size was removed. Synth

Natural forests contain a large amount of deadwood, which is a key contributor to biodiversity, especially by providing dynamic habitats and resources for a huge variety of invertebrates. However, for managing forest biodiversity we need to better understand what drives the dynamics of invertebrate communities in deadwood. We hypothesized that the invertebrate communities in logs will converge from initial to middle decomposition stage among tree species and forest stands as the differentiating role of bark diminishes and xylem traits converge during decay. We investigated invertebrate communities in decomposing logs of ten tree species over 4 years in the “tree cemetery” LOGLIFE experiment in two contrasting forests in the Netherlands. The predominant faunal groups studied were Annelida (earthworms), Isopoda (woodlice), Chilopoda (centipedes), Diplopoda (millipedes), Diptera (flies, midges) and Coleoptera (beetles). We demonstrated that (1) tree species, decay stages and incubation forests all had effects on the invertebrate communities; (2) community compositions of fauna in logs first were very dissimilar and then became more similar among tree species through the decay years; and (3) this converging pattern of faunal community dynamics also manifested itself, both across and within given tree species, between two contrasting forests over decomposition time. Thus, invertebrate communities generally converged during deadwood decay, which adds fundamental insights into the role of interacting drivers of community succession. These findings also highlight that, both within and among forests, more functionally different tree species and logs in different decay stages, will support relatively high biodiversity of invertebrate communities; these patterns may inform forest management strategies aimed at maximizing biodiversity.

In the context of a recent massive increase in research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on generating cutting-edge, meaningful and integrated knowledge. Consideration of the below-ground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, will improve trait comparisons across studies and integration of information across databases by providing standardised methods and controlled vocabularies. It is meant to be used not only as starting point by students and scientists who desire working on below-ground ecosystems, but also by experts for consolidating and broadening their views on multiple aspects of root ecology. Beyond the classical compilation of measurement protocols, we have synthesised recommendations from the literature to provide key background knowledge useful for: (1) defining below-ground plant entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine-root vs coarse-root approach; (2) considering the specificity of root research to produce sound laboratory and field data; (3) describing typical, but overlooked steps for studying roots (e.g. root handling, cleaning and storage); and (4) gathering metadata necessary for the interpretation of results and their reuse. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers not to solely extract protocol recommendations for trait measurements from this work, but to take a moment to read and reflect on the extensive information contained in th

Motivation: Trait data are fundamental to the quantitative description of plant form and function. Although root traits capture key dimensions related to plant responses to changing environmental conditions and effects on ecosystem processes, they have rarely been included in large-scale comparative studies and global models. For instance, root traits remain absent from nearly all studies that define the global spectrum of plant form and function. Thus, to overcome conceptual and methodological roadblocks preventing a widespread integration of root trait data into large-scale analyses we created the Global Root Trait (GRooT) Database. GRooT provides ready-to-use data by combining the expertise of root ecologists with data mobilization and curation. Specifically, we (a) determined a set of core root traits relevant to the description of plant form and function based on an assessment by experts, (b) maximized species coverage through data standardization within and among traits, and (c) implemented data quality checks. Main types of variables contained: GRooT contains 114,222 trait records on 38 continuous root traits. Spatial location and grain: Global coverage with data from arid, continental, polar, temperate and tropical biomes. Data on root traits were derived from experimental studies and field studies. Time period and grain: Data were recorded between 1911 and 2019. Major taxa and level of measurement: GRooT includes root trait data for which taxonomic information is available. Trait records vary in their taxonomic resolution, with subspecies or varieties being the highest and genera the lowest taxonomic resolution available. It contains information for 184 subspecies or varieties, 6,214 species, 1,967 genera and 254 families. Owing to variation in data sources, trait records in the database include both individual observations and mean values. Software format: GRooT includes two csv files. A GitHub repository contains the csv files and a script in R to query t

Dead wood quantity and quality is important for forest biodiversity, by determining the wood-inhabiting fungal assemblages. We therefore evaluated how fungal communities were regulated by stem traits and compartments (i.e., bark, outer- and inner wood) of 14 common temperate tree species. Fresh logs were incubated in a common garden experiment in a forest site in the Netherlands. After 1 and 4 years of decay, the fungal composition of different compartments was assessed using Internal Transcribed Spacer amplicon sequencing. We found that fungal alpha diversity differed significantly across tree species and stem compartments, with bark showing significantly higher fungal diversity than wood. Gymnosperms and Angiosperms hold different fungal communities, and distinct fungi were found between inner wood and other compartments. Stem traits showed significant afterlife effects on fungal communities; traits associated with accessibility (e.g. conduit diameter), stem chemistry (e.g. C, N, lignin) and physical defence (e.g. density) were important factors shaping fungal community structure in decaying stems. Overall, stem traits vary substantially across stem compartment and tree species, thus regulating fungal communities and the long-term carbon dynamics of dead trees., Dead wood quantity and quality is important for forest biodiversity, by determining the wood-inhabiting fungal assemblages. We therefore evaluated how fungal communities were regulated by stem traits and compartments (i.e., bark, outer- and inner wood) of 14 common temperate tree species. Fresh logs were incubated in a common garden experiment in a forest site in the Netherlands. After 1 and 4 years of decay, the fungal composition of different compartments was assessed using Internal Transcribed Spacer amplicon sequencing. We found that fungal alpha diversity differed significantly across tree species and stem compartments, with bark showing significantly higher fungal diversity than wood. Gymnosperms and Angiosperms hold different fungal communities, and distinct fungi were found between inner wood and other compartments. Stem traits showed significant afterlife effects on fungal communities; traits associated with accessibility (e.g. conduit diameter), stem chemistry (e.g. C, N, lignin) and physical defence (e.g. density) were important factors shaping fungal community structure in decaying stems. Overall, stem traits vary substantially across stem compartment and tree species, thus regulating fungal communities and the long-term carbon dynamics of dead trees.