Search

Recent studies have demonstrated that ecological processes that shape community structure and dynamics change along environmental gradients. However, much less is known about how the emergence of the gradients themselves shape the evolution of species that underlie community assembly. In this study, we address how the creation of novel environments leads to community assembly via two nonmutually exclusive processes: immigration and ecological sorting of pre-adapted clades (ISPC), and recent adaptive diversification (RAD). We study these processes in the context of the elevational gradient created by the uplift of the Central Andes. We develop a novel approach and method based on the decomposition of species turnover into within- and among-clade components, where clades correspond to lineages that originated before mountain uplift. Effects of ISPC and RAD can be inferred from how components of turnover change with elevation. We test our approach using data from over 500 Andean forest plots. We found that species turnover between communities at different elevations is dominated by the replacement of clades that originated before the uplift of the Central Andes. Our results suggest that immigration and sorting of clades pre-adapted to montane habitats is the primary mechanism shaping tree communities across elevations.

International audience; The tree seed mycobiome has received little attention despite its potential role in forest regeneration and health. The aim of the present study was to analyze the processes shaping the composition of seed fungal communities in natural forests as seeds transition from the mother plant to the ground for establishment.We used metabarcoding approaches and confocal microscopy to analyze the fungal communities of seeds collected in the canopy and on the ground in four natural populations of sessile oak (Quercus petraea). Ecological processes shaping the seed mycobiome were inferred using joint species distribution models.Fungi were present in seed internal tissues, including the embryo. The seed mycobiome differed among oak populations and trees within the same population. Its composition was largely influenced by the mother, with weak significant environmental influences. The models also revealed several probable interactions among fungal pathogens and mycoparasites.Our results demonstrate that maternal effects, environmental filtering and biotic interactions all shape the seed mycobiome of sessile oak. They provide a starting point for future research aimed at understanding how maternal genes and environments interact to control the vertical transmission of fungal species that could then influence seed dispersal and germination, and seedling recruitment.

Diverse communities of fungi and bacteria in deadwood mediate wood decay. While rates of decomposition vary greatly among woody species and spatially distinct habitats, the relative importance of these factors in structuring microbial communities and whether these shift over time remains largely unknown. We characterized fungal and bacterial diversity within pieces of deadwood that experienced 6.3-98.8% mass loss while decaying in common garden 'rotplots' in a temperate oak-hickory forest in the Ozark Highlands, MO, USA. Communities were isolated from 21 woody species that had been decomposing for 1-5 years in spatially distinct habitats at the landscape scale (top and bottom of watersheds) and within stems (top and bottom of stems). Microbial community structure varied more strongly with wood traits than with spatial locations, mirroring the relative role of these factors on decay rates on the same pieces of wood even after 5 years. Co-occurring fungal and bacterial communities persistently influenced one another independently from their shared environmental conditions. However, the relative influence of wood construction versus spatial locations differed between fungi and bacteria, suggesting that life history characteristics of these clades structure diversity differently across space and time in decomposing wood.

High-throughput sequencing (e.g., amplicon and shotgun) has provided new insight into the diversity and distribution of fungi around the globe, but developing a framework to understand this diversity has proved challenging. Here we review key ecological strategy theories developed for macro-organisms and discuss ways that they can be applied to fungi. We suggest that while certain elements may be applied, an easy translation does not exist. Particular aspects of fungal ecology, such as body size and growth architecture, which are critical to many existing strategy schemes, as well as guild shifting, need special consideration in fungi. Moreover, data on shifts in traits across environments, important to the development of strategy schemes for macro-organisms, also does not yet exist for fungi. We end by suggesting a way forward to add data. Additional data can open the door to the development of fungi-specific strategy schemes and an associated understanding of the trait and ecological strategy dimensions employed by the world's fungi.

Invasive plants have the potential to affect decomposition both directly, by introducing novel substrates that may differ from native species in key structural or chemical properties, and indirectly through changes to soil properties and microbial communities. The relative importance of these two mechanisms is unclear, especially with regard to wood decomposition. To explore these questions, we used a novel method to rapidly assess the wood decay rates of 11 native and 11 invasive non-native angiosperm species. The study was repeated at three pairs of sites, each consisting of an invaded and a relatively uninvaded forest. The invaded sites had either been colonized by a non-native grass (Microstegium vimineum (Trin.) A. Camus), a non-native woody shrub (Ligustrum sinense Lour.) or by multiple invasive species. After one year in the field, mass loss varied more than two-fold among the 22 wood species (24.2–52.3%). Wood origin (i.e., native or non-native) was only important at the Microstegium sites, with non-native species decomposing marginally faster than native species. Wood decomposed faster at both the Ligustrum-invaded and multiply-invaded sites than in their respective uninvaded sites but there were no differences between sites invaded or not by Microstegium. We detected positive relationships overall between mass loss and pH, K, P and NO3−, but invasion had no consistent effects on these soil properties. The results from this study show that the differences in wood decay rates between native and non-native species and the effects of invasion are highly idiosyncratic, with effects depending greatly on species and ecological context.

We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge., Measurement(s)plant traitTechnology Type(s)digital curationSample Characteristic - OrganismViridiplantaeSample Characteristic - LocationAustralia Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.14545755

The era of big biodiversity data has led to rapid, exciting advances in the theoretical and applied biological, ecological and conservation sciences. While large genetic, geographic and trait databases are available, these are neither complete nor random samples of the globe. Gaps and biases in these databases reduce our inferential and predictive power, and this incompleteness is even more worrisome because we are ignorant of both its kind and magnitude. We performed a comprehensive examination of the taxonomic and spatial sampling in the most complete current databases for plant genes, locations and functional traits. To do this, we downloaded data from The Plant List (taxonomy), the Global Biodiversity Information Facility (locations), TRY (traits) and GenBank (genes). Only 17.7% of the world's described and accepted land plant species feature in all three databases, meaning that more than 82% of known plant biodiversity lacks representation in at least one database. Species coverage is highest for location data and lowest for genetic data. Bryophytes and orchids stand out taxonomically and the equatorial region stands out spatially as poorly represented in all databases. We have highlighted a number of clades and regions about which we know little functionally, spatially and genetically, on which we should set research targets. The scientific community should recognize and reward the significant value, both for biodiversity science and conservation, of filling in these gaps in our knowledge of the plant tree of life.

SummaryBiogeographic events occurring in the deep past can contribute to the structure of modern ecological communities. However, little is known about how the emergence of environmental gradients shape the evolution of species that underlie community assembly. In this study, we address how the creation of novel environments lead to community assembly via two non-mutually exclusive processes: 1) the immigration and ecological sorting of pre-adapted clades (ISPC), and 2) recent adaptive diversification (RAD). We study these processes in the context of the elevational gradient created by the uplift of the Central Andes.We develop a novel approach and method based on the decomposition of species turnover into within- and among-clade components, where clades correspond to lineages that originated before mountain uplift. Effects of ISPC and RAD can be inferred from how components of turnover change with elevation. We test our approach using data from over 500 Andean forest plots.We found that species turnover between communities at different elevations is dominated by the replacement of clades that originated before the uplift of the Central Andes.Our results suggest that immigration and sorting of clades pre-adapted to montane habitats is the primary mechanism shaping communities across elevations.

Assessment of endophytic and saprotrophic microbial communities from wood-extracted DNA presents challenges due to the presence of surface microbes that contaminate samples and plant compounds that act as inhibiting agents. Here, we describe a method for decontaminating, sampling, and processing wood at various stages of decay for high-throughput extraction and purification of DNA.

Assessment of endophytic and saprotrophic microbial communities from wood-extracted DNA presents challenges due to the presence of surface microbes that contaminate samples and plant compounds that act as inhibiting agents. Here, we describe a method for decontaminating, sampling, and processing wood at various stages of decay for high-throughput extraction and purification of DNA.

Trees provide critical contributions to human well-being. They sequester and store greenhouse gasses, filter air pollutants, provide wood, food, and other products, among other benefits. These benefits are threatened by climate change, fires, pests and pathogens. To quantify the current value of the flow of ecosystem services from U.S. trees, and the threats they face, we combine macroevolutionary and economic valuation approaches using spatially explicit data about tree species and lineages. We find that the value of five key ecosystem services with adequate data generated by US trees is $114 billion per annum (low: $85 B; high: $137 B; 2010 USD). The non-market value of trees from carbon storage and air pollution removal far exceed their commercial value from wood products and food crops. Two lineages—pines and oaks—account for 42% of the value of these services. The majority of species face threats from climate change, many face increasing fire risk, and known pests and pathogens threaten 40% of total woody biomass. The most valuable US tree species and lineages are among those most threatened by known pests and pathogens, with species most valuable for carbon storage most at risk from increasing fire threat. High turnover of tree species across the continent results in a diverse set of species distributed across the tree of life contributing to ecosystem services in the U.S. The high diversity of taxa across U.S. forests may be important in buffering ecosystem service losses if and when the most valuable lineages are compromised.

As the primary decomposers of organic material in terrestrial ecosystems, fungi are critical agents of the global carbon cycle. Yet our ability to link fungal community composition to ecosystem functioning is constrained by a limited understanding of the factors accounting for different wood decomposition rates among fungi. Here we examine which traits best explain fungal decomposition ability by combining detailed trait-based assays on 34 saprotrophic fungi from across North America in the laboratory with a 5-y field study comprising 1,582 fungi isolated from 74 decomposing logs. Fungal growth rate (hyphal extension rate) was the strongest single predictor of fungal-mediated wood decomposition rate under laboratory conditions, and accounted for up to 27% of the in situ variation in decomposition in the field. At the individual level, decomposition rate was negatively correlated with moisture niche width (an indicator of drought stress tolerance) and with the production of nutrient-mineralizing extracellular enzymes. Together, these results suggest that decomposition rates strongly align with a dominance-tolerance life-history trade-off that was previously identified in these isolates, forming a spectrum from slow-growing, stress-tolerant fungi that are poor decomposers to fast-growing, highly competitive fungi with fast decomposition rates. Our study illustrates how an understanding of fungal trait variation could improve our predictive ability of the early and midstages of wood decay, to which our findings are most applicable. By mapping our results onto the biogeographic distribution of the dominance-tolerance trade-off across North America, we approximate broad-scale patterns in intrinsic fungal-mediated wood decomposition rates.

Fil: Díaz, Sandra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología. Instituto Multidisciplinario de Biología Vegetal; Argentina. Fil: Díaz, Sandra. Consejo Nacional de Investigaciones Científicas y Técnica. Instituto Multidisciplinario de Biología Vegetal; Argentina. Fil: Zafra Calvo, Noelia. Future Earth; España. Fil: Purvis, Andy. Natural History Museum; Reino Unido. Fil: Verburg, Peter H. VU University Amsterdam. Institute for Environmental Studies: Países Bajos. Fil: Obura, David. Coastal Oceans Research and Development Indian Ocean; Kenia. Fil: Leadley, Paul. Université Paris-Sud. Ecologie Systématique Evolution; Francia. Fil: Chaplin Kramer, Rebecca. Stanford University. Natural Capital Project; Estados Unidos. Fil: De Meester, Luc. Leibniz Institut für Gewässerökologie und Binnenfischerei; Alemania. Fil: Dulloo, Ehsan. Bioversity International; Mauricio. Fil: Martín- López, Berta. Leuphana University of Lüneburg. Faculty of Sustainability; Alemania. Fil: Shaw, Rebecca. The World Wide Fund for Nature; Estados Unidos. Fil: Visconti, Piero. International Institute for Applied Systems Analysis. Ecosystem Services and Management Program; Austria. Fil: Broadgate, Wendy. Future Earth; Suecia. Fil: Bruford, Michael W. Cardiff University. School of Biosciences and Sustainable Places Institute; Reino Unido. Fil: Burgess, Neil D. UN Environment Programme World Conservation Monitoring Centre; Reino Unido. Fil: Cavender Bares, Jeannine. University of Minnesota. Department of Ecology, Evolution and Behavior; Estados Unidos. Fil: DeClerck, Fabrice. EAT Foundation; Noruega. Fil: Fernández Palacios, José María. Universidad de La Laguna. Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias; España. Fil: Garibaldi, Lucas A. Universidad Nacional de Río Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. Río Negro, Argentina. Fil: Garibaldi, Lucas A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. Río Negro, Argentina. Fil: Hill, Samantha L. L. UN Environment Programme World Conservation Monitoring Centre; Reino Unido. Fil: Isbell, Forest. University of Minnesota. Department of Ecology, Evolution and Behavior; Estados Unidos. Fil: Khoury, Colin K. International Center for Tropical Agriculture; Colombia. Fil: Krug, Cornelia B. University of Zurich. Department of Geography; Suiza. Fil: Liu, Jianguo. Michigan State University; Estados Unidos. Fil: Maron, Martine. The University of Queensland; Australia. Fil: McGowan, Philip J. K. Newcastle University. School of Natural and Environmental Sciences; Reino Unido. Fil: Pereira, Henrique M. German Centre for Integrative Biodiversity Research; Alemania. Fil: Reyes García, Victoria. Catalan Institution for Research and Advanced Studies; España. Fil: Rocha, Juan. Future Earth; Suecia. Fil: Rondinini, Carlo. Sapienza University of Rome. Department of Biology and Biotechnologies. Global Mammal Assessment Program; Italia. Fil: Shannon, Lynne. University of Cape Town. Department of Biological Sciences; Sudáfrica. Fil: Shin, Yunne-Jai. University of Cape Town. Department of Biological Sciences; Sudáfrica. Fil: Snelgrove, Paul V. R. Memorial University of Newfoundland. Departments of Ocean Sciences and Biology; Canada. Fil: Spehn, Eva M. Swiss Academy of Sciences. Swiss Biodiversity Forum; Suiza. Fil: Strassburg, Bernardo. Pontifical Catholic University. Department of Geography and the Environment. Rio Conservation and Sustainability Science Centre; Brasil. Fil: Subramanian, Suneetha M. United Nations University. Institute for the Advanced Study of Sustainability; Japón. Fil: Tewksbury, Joshua J. University of Colorado; Estados Unidos. Fil: Watson, James E. M. Wildlife Conservation Society; Estados Unidos. Fil: Zanne, Amy E. George Washington University. Department of Biological Sciences; Estados Unidos. Global biodiversity policy is at a crossroads. Recent global assessments of living nature (1, 2) and climate (3) show worsening trends and a rapidly narrowing window for action. The Convention on Biological Diversity (CBD) has recently announced that none of the 20 Aichi targets for biodiversity it set in 2010 has been reached and only six have been partially achieved (4). Against this backdrop, nations are now negotiating the next generation of the CBD's global goals [see supplementary materials (SM)], due for adoption in 2021, which will frame actions of governments and other actors for decades to come. In response to the goals proposed in the draft post-2020 Global Biodiversity Framework (GBF) made public by the CBD (5), we urge negotiators to consider three points that are critical if the agreed goals are to stabilize or reverse nature's decline. First, multiple goals are required because of nature's complexity, with different facets—genes, populations, species, deep evolutionary history, ecosystems, and their contributions to people—having markedly different geographic distributions and responses to human drivers. Second, interlinkages among these facets mean that goals must be defined and developed holistically rather than in isolation, with potential to advance multiple goals simultaneously and minimize trade-offs between them. Third, only the highest level of ambition in setting each goal, and implementing all goals in an integrated manner, will give a realistic chance of stopping—and beginning to reverse—biodiversity loss by 2050.

Deadwood in tropical ecosystems represents an important but poorly studied carbon (C) pool. Biologically mediated decay of this pool occurs by both saprotrophic microbes and macro‐invertebrates, such as termites. The activity of these decay agents is influenced by abiotic conditions, especially water availability in tropical systems. While saprotrophic microbial activity is directly controlled by moisture, termites employ various morphological and behavioural modifications that should allow for continued activity in dry conditions. We therefore hypothesized that the relative role of termites would be enhanced in the dry season and a dry compared to a wet site. We deployed a novel wood bait (Pinus radiata) at two sites (rainforest and savanna), with or without access holes cut into termite‐excluding mesh. Mass loss from wood baits was measured after a dry season and after a full dry/wet annual cycle. Mass loss was higher at the rainforest site, demonstrating the overall role of moisture in driving wood decay. Counter to expectations, we found no evidence that the relative role of termites was higher at the dry site, nor during the dry season. However, the prevalence of termites was higher in the savanna compared to the rainforest. While termites clearly impact wood decay, these findings indicate that the relative importance of termites in the fate of deadwood may not reflect their mere presence within and across ecosystems. If moisture availability shifts under climate change, our results suggest similar functional responses between termites and saprotrophic microbes in driving C loss from deadwood.

Pest outbreaks are driving tree dieback and major influxes of deadwood into forest ecosystems. Understanding how pulses of deadwood impact the climate system requires understanding which factors influence greenhouse gas production during wood decay. Recent analyses identify stem diameter as an important control, but report effects that vary in magnitude and direction. This complexity may reflect interacting effects of soil contact, geometry and variable tissue properties. To dissect these effects, we implemented a three-way factorial experiment in Fraxinus americana, (white ash), an iconic North American species threatened by an invasive beetle. Soil contact accelerated decay rates by an order of magnitude with an effect that varied with stem diameter, not bark presence. After experimentally controlling surface area-to-volume ratio, half-buried wide stems decayed more slowly than half-buried narrow stems but more quickly than the aggregate decay rate of buried and suspended stems. These results closely matched variation in moisture content within and among samples, suggesting that limited vertical conduction of soil moisture through deadwood mediates the effect of stem diameter on wood decay. Soil contact also influenced greenhouse gas concentrations reinforcing recent evidence that deadwood acts as a source for CO2 and CH4 while acting as a sink for N2O. Our results suggest that managing tree species affected by pest outbreaks, including F. americana, for biomass salvage and greenhouse gas mitigation requires understanding traits that mediate wood permeability and diffusivity to soil moisture and greenhouse gases.

Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro-organismal populations. Although technological advances are improving the detection and identification of fungi, there still exist key gaps in our ecological knowledge of this kingdom, especially related to function. Trait-based approaches have been instrumental in strengthening our understanding of plant functional ecology and, as such, provide excellent models for deepening our understanding of fungal functional ecology in ways that complement insights gained from traditional and -omics-based techniques. In this review, we synthesize current knowledge of fungal functional ecology, taxonomy and systematics and introduce a novel database of fungal functional traits (FunFun ). FunFun is built to interface with other databases to explore and predict how fungal functional diversity varies by taxonomy, guild, and other evolutionary or ecological grouping variables. To highlight how a quantitative trait-based approach can provide new insights, we describe multiple targeted examples and end by suggesting next steps in the rapidly growing field of fungal functional ecology.

SummaryRationaleThe era of big biodiversity data has led to rapid, exciting advances in theoretical and applied biological, ecological and conservation sciences. While large genetic, geographic and trait databases are available, these are neither complete nor random samples of the globe. Biases in species absence in these databases create problems, reducing our inferential and predictive power.MethodsWe performed a comprehensive examination of the taxonomic and spatial sampling in the most complete current databases for plant genes, locations, and traits.ResultsOnly 17.7% of the world’s described land plants feature in all three databases, meaning that more than 82% of plant biodiversity lacks representation in at least one database. Species coverage is highest for location data and lowest for genetic data. Bryophytes and orchids stand out taxonomically and the equatorial region stands out spatially as poorly represented in all databases.ConclusionWe have highlighted a number of clades and regions about which we know little functionally, spatially and genetically, on which we should set research targets. The scientific community should recognize and reward the significant value, both for biodiversity science and conservation, of filling in these gaps in our knowledge of the plant tree of life.

Environmental forces and biotic interactions, both positive and negative, structure ecological communities, but their relative roles remain obscure despite strong theory. For instance, ecologically similar species, based on the principle of limiting similarity, are expected to be most competitive and show negative interactions. Specious communities that assemble along broad environmental gradients afford the most power to test theory, but the communities often are difficult to quantify. Microbes, specifically fungal endophytes of wood, are especially suited for testing community assembly theory because they are relatively easy to sample across a comprehensive range of environmental space with clear axes of variation. Moreover, endophytes mediate key forest carbon cycle processes, and although saprophytic fungi from dead wood typically compete, endophytic fungi in living wood may enhance success through cooperative symbioses. To classify interactions within endophyte communities, we analyzed fungal DNA barcode variation across 22 woody plant species growing in woodlands near Richmond, New South Wales, Australia. We estimated the response of endophytes to the measured wood environment (i.e., 11 anatomical and chemical wood traits) and each other using latent-variable models and identified recurrent communities across wood environments using model-based classification. We used this information to evaluate whether (1) co-occurrence patterns are consistent with strong competitive exclusion, and (2) a priori classifications by trophic mode and phylum distinguish taxa that are more likely to have positive vs. negative associations under the principle of limiting similarity. Fungal endophytes were diverse (mean = 140 taxa/sample), with differences in community composition structured by wood traits. Variation in wood water content and carbon concentration were associated with especially large community shifts. Surprisingly, after accounting for wood traits, fungal species were still more than three times more likely to have positive than negative co-occurrence patterns. That is, patterns consistent with strong competitive exclusion were rare, and positive interactions among fungal endophytes were more common than expected. Confirming the frequency of positive vs. negative interactions among fungal taxa requires experimental tests, and our findings establish clear paths for further study. Evidence to date intriguingly suggests that, across a wide range of wood traits, cooperation may outweigh combat for these fungi.

Whether global change will drive changing forests from net carbon (C) sinks to sources relates to how quickly deadwood decomposes. Because complete wood mineralization takes years, most experiments focus on how traits, environments and decomposer communities interact as wood decay begins. Few experiments last long enough to test whether drivers change with decay rates through time, with unknown consequences for scaling short-term results up to long-term forest ecosystem projections. Using a 7 year experiment that captured complete mineralization among 21 temperate tree species, we demonstrate that trait effects fade with advancing decay. However, wood density and vessel diameter, which may influence permeability, control how decay rates change through time. Denser wood loses mass more slowly at first but more quickly with advancing decay, which resolves ambiguity about the after-life consequences of this key plant functional trait by demonstrating that its effect on decay depends on experiment duration and sampling frequency. Only long-term data and a time-varying model yielded accurate predictions of both mass loss in a concurrent experiment and naturally recruited deadwood structure in a 32-year-old forest plot. Given the importance of forests in the carbon cycle, and the pivotal role for wood decay, accurate ecosystem projections are critical and they require experiments that go beyond enumerating potential mechanisms by identifying the temporal scale for their effects.

Deadwood plays important roles in forest ecosystems by storing carbon, influencing hydrology, and provisioning countless organisms. Models for these processes often assume that deadwood does not move and ignore redistribution that occurs when trees fall. To evaluate the effects of treefall, we provide the first direct estimates for the magnitude, direction, and drivers of deadwood movement in a long-term oak–hickory forest dynamics plot in Missouri, USA. Among 1871 total pieces of deadwood, logs today pointed downslope more often than branches and occurred at lower elevation than snags. Of these, 477 logs retained tags from which we reconstructed movement using new formulae for reconciling survey coordinates and calculating log shape. Relocated logs occurred at lower elevation than their original rooting location, with the magnitude of the drop dependent on log size, degree of decay, and slope. Although changes in elevation were modest, the log centroids moved up to several meters horizontally. Consequently, as large trees fall, they predictably redistribute deadwood downhill, suggesting that models of deadwood dynamics in small inventory plots may gain accuracy by incorporating import and export along with recruitment and decay. We highlight implications of small-scale deadwood movement for forest inventories, carbon dynamics, and biodiversity.

Selective logging, the targeted harvesting of timber trees in a single cutting cycle, is globally rising in extent and intensity. Short-term impacts of selective logging on tropical forests have been widely investigated, but long-term effects on temporal dynamics of forest structure and composition are largely unknown. Understanding these long-term dynamics will help determine whether tropical forests are resilient to selective logging and inform choices between competing demands of anthropogenic use versus conservation of tropical forests. Forest dynamics can be studied within the framework of succession theory, which predicts that temporal turnover rates should decline with time since disturbance. Here, we investigated the temporal dynamics of a tropical forest in Kibale National Park, Uganda over 45 years following selective logging. We estimated turnover rates in stems, species composition, and functional traits (wood density and diameter at breast height), using observations from four censuses in 1989, 1999, 2006, and 2013, of stems ≥ 10 cm diameter within 17 unlogged and 9 logged 200 × 10 m vegetation plots. We used null models to account for interdependencies among turnover rates in stems, species composition, and functional traits. We tested predictions that turnover rates should be higher and decrease with increasing time since the selective logging event in logged forest, but should be less temporally variable in unlogged forest. Overall, we found higher turnover rates in logged forest for all three attributes, but turnover rates did not decline through time in logged forest and was not less temporally variable in unlogged forest. These results indicate that successional models that assume recovery to pre-disturbance conditions are inadequate for predicting the effects of selective logging on the dynamics of the tropical forest in Kibale. Selective logging resulted in persistently higher turnover rates, which may compromise the carbon storage capacity of Kibale’s forest. Selective logging effects may also interact with effects from other global trends, potentially causing major long-term shifts in the dynamics of tropical forests. Similar studies in tropical forests elsewhere will help determine the generality of these conclusions. Ultimately, the view that selective logging is a benign approach to the management of tropical forests should be reconsidered in the light of studies of the effects of this practice on long-term forest dynamics.

Roughly 3% of the Earth's land surface burns annually, representing a critical exchange of energy and matter between the land and atmosphere via combustion. Fires range from slow smouldering peat fires, to low-intensity surface fires, to intense crown fires, depending on vegetation structure, fuel moisture, prevailing climate, and weather conditions. While the links between biogeochemistry, climate and fire are widely studied within Earth system science, these relationships are also mediated by fuels—namely plants and their litter—that are the product of evolutionary and ecological processes. Fire is a powerful selective force and, over their evolutionary history, plants have evolved traits that both tolerate and promote fire numerous times and across diverse clades. Here we outline a conceptual framework of how plant traits determine the flammability of ecosystems and interact with climate and weather to influence fire regimes. We explore how these evolutionary and ecological processes scale to impact biogeochemical and Earth system processes. Finally, we outline several research challenges that, when resolved, will improve our understanding of the role of plant evolution in mediating the fire feedbacks driving Earth system processes. Understanding current patterns of fire and vegetation, as well as patterns of fire over geological time, requires research that incorporates evolutionary biology, ecology, biogeography, and the biogeosciences., This work was a result of a National Evolutionary Synthesis Center (NESCENT) catalysis meeting on 'The co-evolution of plants and fire and consequences for the Earth system' November 2013. TH and BL acknowledge the support from the Australian Research Council (DP120103389), and BR acknowledges support from NASA ABoVE (NNX15AU56A). Sally Archibald was funded by the Friedel Sellschop award.

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall.

Nonlinear relationships between species and their environments are believed common in ecology and evolution, including during angiosperms' rise to dominance. Early angiosperms are thought of as woody evergreens restricted to warm, wet habitats. They have since expanded into numerous cold and dry places. This expansion may have included transitions across important environmental thresholds. To understand linear and nonlinear relationships between angiosperm structure and biogeographic distributions, we integrated large datasets of growth habits, conduit sizes, leaf phenologies, evolutionary histories, and environmental limits. We consider current-day patterns and develop a new evolutionary model to investigate processes that created them. The macroecological pattern was clear: herbs had lower minimum temperature and precipitation limits. In woody species, conduit sizes were smaller in evergreens and related to species' minimum temperatures. Across evolutionary timescales, our new modeling approach found conduit sizes in deciduous species decreased linearly with minimum temperature limits. By contrast, evergreen species had a sigmoidal relationship with minimum temperature limits and an inflection overlapping freezing. These results suggest freezing represented an important threshold for evergreen but not deciduous woody angiosperms. Global success of angiosperms appears tied to a small set of alternative solutions when faced with a novel environmental threshold.

Summary Woody plants store large quantities of carbon (C) and nutrients. As plants senesce and decay, these stores transfer to the soil or other organisms or are released to the atmosphere. Exogenous factors such as topographic position and microclimatic and edaphic conditions tied to locations affect decay rates; however, we know less about how exogenous relative to endogenous factors such as morphological, anatomical and chemical construction tied to plant species affect these rates, especially across different tissue types. We monitored stem, fine branch and leaf decay over 1 year in ‘rot plots’ distributed across four watersheds in ridge top and valley bottom habitats in a temperate deciduous oak-hickory forest at Tyson Research Center, MO, USA, in the Ozark Highlands for 21 species of woody plants that vary in their constructions. We found poor coordination across tissues in construction and decay, which likely reflects how functional constraints on living tissues influence recalcitrance to decay. Additionally, for all three tissues, species membership and construction were better predictors of decay than was location. Of the construction traits, chemical composition including total fibre, lignin, cellulose, hemicellulose and concentrations of multiple microelements were the best predictors of decay, although the strength of these relationships differed among tissues. Synthesis. We have long known that rates of biogeochemical cycling are influenced by exogenous factors, such as climatic and edaphic factors. Here, we show across plant tissues that endogenous factors, including species identity and tissue construction, can have stronger controls on rates of decay within our study system than do exogenous factors. However, it is likely that the relative strengths of these different controls change through time and among tissues. We predict that anatomical and morphological controls may be more important at early stages and exogenous factors may be more important at later stages of decay.

PREMISE OF THE STUDY Wood density is the top predictor of growth and mortality rates (vital rates) but with modest explanatory power at best. Stronger links to vital rates are expected if wood density is decomposed into its anatomical properties at sapling and adult stages, since saplings and adults differ in wood traits and vital rates. We examined whether anatomical determinants of wood density and strength of the relationship between wood traits and vital rates shift between saplings and adults. METHODS Using wood segments from near pith (sapling) and near bark (adult) for 20 tree species (three adults each) from Barro Colorado Island, Panama, we quantified wood traits. Vital rates for saplings and adults were obtained from an earlier study. KEY RESULTS Anatomical predictors of wood density were similar for sapling and adult wood, with wood density variation largely explained by fiber lumen area and fiber wall fraction. In sapling wood only, growth rates decreased with fiber wall fraction and increased with fiber lumen area, while mortality rates increased with vessel area but decreased with fiber wall fraction and vessel density. CONCLUSIONS Wood traits of sapling trees provide functional insight into the growth-mortality tradeoff. Sapling wood with relatively large fiber lumen area and wide vessels, enabling faster hydraulic transport but less mechanical strength, is associated with fast growth and high mortality. Sapling wood with relatively more fiber wall and many narrow vessels, enabling greater mechanical strength but slower hydraulic transport, is associated with slow growth and low mortality.

Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well as plant impacts on ecosystem processes. Despite significant progress capturing trait variation within and among stems and leaves, identification of trait syndromes within fine-root systems and between fine roots and other plant organs is limited. Here we discuss three underappreciated areas where focused measurements of fine-root traits can make significant contributions to ecosystem science. These include assessment of spatiotemporal variation in fine-root traits, integration of mycorrhizal fungi into fine-root-trait frameworks, and the need for improved scaling of traits measured on individual roots to ecosystem-level processes. Progress in each of these areas is providing opportunities to revisit how below-ground processes are represented in terrestrial biosphere models. Targeted measurements of fine-root traits with clear linkages to ecosystem processes and plant responses to environmental change are strongly needed to reduce empirical and model uncertainties. Further identifying how and when suites of root and whole-plant traits are coordinated or decoupled will ultimately provide a powerful tool for modeling plant form and function at local and global scales.

Coarse woody debris (CWD) plays important roles in forests including carbon storage. Calculating the size of this carbon pool from survey data entails estimating the volume and density of dead wood. Density is highly correlated with other mechanical parameters in intact wood, explaining how penetrometers, which measure a mechanical parameter related to hardness, have proven useful for estimating dead wood density. However, the relationship between wood density and hardness varies with three key factors that vary in CWD: moisture content, tree species and degree of decay. We estimated how these factors influence penetrometer measurements across conditions ranging from lab standards to field conditions during a CWD survey. When measuring experimentally decayed wood under standard conditions, penetrometer distance was highly correlated with sample density and the effects of moisture content and interspecific variation were similar to those expected from analyses of intact wood. However, when we relaxed experimental controls and included samples that had decayed for different lengths of time, these relationships shifted such that penetrometer measurements no longer correlated with intact wood hardness and tended to increase relative to density and moisture content. The decoupling of mechanical properties in decaying wood is consistent with case hardening, which developed differently in different species and contributed to high variability in penetrometer measurements during the CWD survey. These results demonstrate temporal changes in decaying wood mechanical properties that have implications for surveying CWD and understanding carbon dynamics in temperate hardwood forests.

Summary 1. The question posed by the title of this study is a basic one, and it is surprising that the answer is not known. Recently, assembled trait data sets provide an opportunity to address this, but scaling these data sets to the global scale is challenging because of sampling bias. Although we currently know the growth form of tens of thousands of species, these data are not a random sample of global diversity; some clades are exhaustively characterized, while others we know little to nothing about. 2. Starting with a data base of woodiness for 39 313 species of vascular plants (12% of taxonomically resolved species, 59% of which were woody), we estimated the status of the remaining taxonomically resolved species by randomization. To compare the results of our method to conventional wisdom, we informally surveyed a broad community of biologists. No consensus answer to the question existed, with estimates ranging from 1% to 90% (mean: 31.7%). 3. After accounting for sampling bias, we estimated the proportion of woodiness among the world’s vascular plants to be between 45% and 48%. This was much lower than a simple mean of our data set and much higher than the conventional wisdom. 4. Synthesis. Alongside an understanding of global taxonomic diversity (i.e. number of species globally), building a functional understanding of global diversity is an important emerging research direction. This approach represents a novel way to account for sampling bias in functional trait data sets and to answer basic questions about functional diversity at a global scale.

 Premise of the study: Wood specifi c gravity (WSG) mediates an interspecifi c trade-off between growth and mortality and is a key measure for estimating carbon stocks. Most studies use species mean values to represent WSG, despite variation at different levels of biological organization. We examined sources of variation in WSG across four nested scales (segments within cores, cores within trees, trees within species, and species), compared the pattern of radial variation in WSG among species differing in growth strategies, and investigated the effect of WSG radial variation on aboveground biomass estimates.  Methods: We took two perpendicular cores from six individuals each of 20 tropical tree species representing a broad range of mean WSGs and growth–mortality strategies in a lowland tropical moist forest in Panama. Cores were divided into 1-cm segments, and WSG was determined for each segment.  Key results: The bulk of the total variance in WSG was dominated by interspecies variation (88%), whereas variation due to measurement error, segments within cores, and cores within trees (8%) was minimal. Radial variation in WSG, defi ned as change in WSG with increasing distance from the pith, was signifi cant in 17 of the 20 species and included signifi cant monotonic increases in 6 species and nonmonotonic patterns in 11 species. Radial variation in WSG resulted in a small but signifi cant bias in aboveground biomass estimates.  Conclusions: Radial variation in WSG is related to a species’ growth strategy and, though minimal compared with interspecifi c variation in WSG, can cause a downward bias when not incorporated into aboveground biomass estimates.

Aim Recent meta-analyses have revealed that plant traits and their phylogenetic history influence decay rates of dead wood and leaf litter, but it remains unknown if decay rates of wood and litter covary over a wide range of tree species and across ecosystems. We evaluated the relationships between species-specific wood and leaf litter decomposability, as well as between wood and leaf traits that control their respective decomposability. Location Global. Methods We compiled data on rates of wood and leaf litter decomposition for 324 and 635 tree species, respectively, and data on six functional traits for both organs. We used hierarchical Bayesian meta-analysis to estimate, for the first time, species-specific values for wood and leaf litter decomposability standardized to reference conditions (k*wood and k*leaf) across the globe. With these data, we evaluated the relationships: (1) between wood and leaf traits, (2) between each k* and the selected traits within and across organs, and (3) between wood and leaf k*. Results Across all species k*wood and k*leaf were positively correlated, phylogenetically clustered and correlated with plant functional traits within and across organs. k* of both organs was usually better described as a function of within- and cross-organ traits, than of within-organ traits alone. When analysed for angiosperms and gymnosperms separately, wood and leaf k* were no longer significantly correlated, but each k* was still significantly correlated to the functional traits. Main conclusions We demonstrate important relationships among wood and leaf litter decomposability as after-life effects of traits from the living plants. These functional traits influence the decomposability of senesced tissue which could potentially lead to alterations in the rates of biogeochemical cycling, depending on the phylogenetic structure of the species pool. These results provide crucial information for a better representation of decomposition rates in dynamic global vegetation models.

Summary The capacitative release of water from sapwood allows photosynthesis to continue for longer into dry periods, both diurnally and seasonally. However, costs of high capacitance include increased vulnerability to xylem cavitation. The degree of reliance on stored water is predicted to differ among environments as a result of this trade-off. Xylem water potential and sapwood capacitance were measured on 32 evergreen sclerophyll shrub and tree species in eastern Australia, sampled from four sites contrasting in soil nutrients and rainfall. Capacitance calculated over species' typical shoot water potential operating range was threefold higher for species from high compared to low-rainfall sites, and 1·5-fold higher for species from high compared to low-nutrient sites. To determine whether these site differences were related to extrinsic (e.g. water availability) or intrinsic (e.g. species anatomical construction) factors, we calculated capacitance at two common operating ranges; that is, the mean range in water potential observed for low-rainfall species (ΔΨlow rain) and the mean range for high-rainfall species (ΔΨhigh rain). While no difference was seen between low- and high-rainfall species in release of stored water across ΔΨhigh rain, across ΔΨlow rain, the high-rainfall species released 38% more stored water than low-rainfall species. Presumably these differences reflect underlying differences in anatomy, such as wood density, which was lower in high-rainfall species. These results accord with predictions that (i) species from wetter sites exhibit less negative stem water potentials and high sapwood capacitance, enabling them to maintain function under variable conditions characterized by many short, dry periods, while (ii) species from low-rainfall sites have wood anatomies conferring tolerance to very low water potentials, with low sapwood capacitance, enabling them to survive longer through unpredictable and extended periods of low rainfall. The finding that the degree to which species rely on stem-stored water varies with site rainfall suggests that changes in drought regimes (e.g. incidence, duration and severity) under future climates could differentially affect species according to the capacitance properties of their woody tissues.

The conservation implications of large-scale rainforest clearing and fragmentation on the persistence of functional and taxonomic diversity remain poorly understood. If traits represent adaptive strategies of plant species to particular circumstances, the expectation is that the effect of forest clearing and fragmentation will be affected by species functional traits, particularly those related to dispersal. We used species occurrence data for woody plants in 46 rainforest patches across 75,000 ha largely cleared of forest by the early 1900s to determine the combined effects of area reduction, fragmentation, and patch size on the taxonomic structure and functional diversity of subtropical rainforest. We compiled species trait values for leaf area, seed dry mass, wood density, and maximum height and calculated species niche breadths. Taxonomic structure, trait values (means, ranges), and the functional diversity of assemblages of climbing and free-standing plants in remnant patches were quantified. Larger rainforest patches had higher species richness. Species in smaller patches were taxonomically less related than species in larger patches. Free-standing plants had a high percentage of frugivore dispersed seeds; climbers had a high proportion of small wind-dispersed seeds. Connections between the patchy spatial distribution of free-standing species, larger seed sizes, and dispersal syndrome were weak. Assemblages of free-standing plants in patches showed more taxonomic and spatial structuring than climbing plants. Smaller isolated patches retained relatively high functional diversity and similar taxonomic structure to larger tracts of forest despite lower species richness. The response of woody plants to clearing and fragmentation of subtropical rainforest differed between climbers and slow-growing mature-phase forest trees but not between climbers and pioneer trees. Quantifying taxonomic structure and functional diversity provides an improved basis for conservation planning and management by elucidating the effects of forest-area reduction and fragmentation. Efectos de la Forma de Crecimiento y Atributos Funcionales en la Respuesta de Plantas Lenosas al Desmonte y Fragmentacion de Bosque Lluvioso Subtropical.

* The evolution of lignified xylem allowed for the efficient transport of water under tension, but also exposed the vascular network to the risk of gas emboli and the spread of gas between xylem conduits, thus impeding sap transport to the leaves. A well-known hypothesis proposes that the safety of xylem (its ability to resist embolism formation and spread) should trade off against xylem efficiency (its capacity to transport water). * We tested this safety–efficiency hypothesis in branch xylem across 335 angiosperm and 89 gymnosperm species. Safety was considered at three levels: the xylem water potentials where 12%, 50% and 88% of maximal conductivity are lost. * Although correlations between safety and efficiency were weak (r2 < 0.086), no species had high efficiency and high safety, supporting the idea for a safety–efficiency tradeoff. However, many species had low efficiency and low safety. Species with low efficiency and low safety were weakly associated (r2 < 0.02 in most cases) with higher wood density, lower leaf- to sapwood-area and shorter stature. * There appears to be no persuasive explanation for the considerable number of species with both low efficiency and low safety. These species represent a real challenge for understanding the evolution of xylem. Fil: Gleason, Sean M.. Macquarie University. Department of Biological Sciences ; Australia. USDA-ARS. Water Management Research; Estados Unidos Fil: Westoby, Mark. Macquarie University. Department of Biological Sciences; Australia Fil: Jansen, Steven. Ulm University. Institute of Systematic Botany and Ecology; Alemania Fil: Choat, Brendan. Western Sydney University. Hawkesbury Institute for the Environment; Australia Fil: Hacke, Uwe G.. University of Alberta. Department of Renewable Resources; Canadá Fil: Pratt, Robert B.. California State University. Department of Biology; Estados Unidos Fil: Bhaskar, Radika. Haverford College. Department of Biology; Estados Unidos Fil: Brodibb, Tim J.. University of Tasmania. School of Biological Sciences; Australia Fil: Bucci, Sandra Janet. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "san Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; Argentina Fil: Cao, Kun-Fang. Guangxi University. College of Forestry. Utilization of Subtropical Agro-Bioresources ; China Fil: Cochard, Hervé. Clermont Université. Université Blaise Pascal. UMR547 PIAF; Francia. Institut National de la Recherche Agronomique; Francia Fil: Delzon, Sylvain. Institut National de la Recherche Agronomique; Francia Fil: Domec, Jean-Christophe. Duke University, Durham. Nicholas School of the Environment; Estados Unidos. Institut National de la Recherche Agronomique; Francia Fil: Fan, Ze-Xin. Chinese Academy of Sciences. Xishuangbanna Tropical Botanical Garden. Key Laboratory of Tropical Forest Ecology; China Fil: Feild, Taylor S.. James Cook University. School of Marine and Tropical Biology; Australia Fil: Jacobsen, Anna L.. California State University. Department of Biology; Estados Unidos Fil: Johnson, Daniel M.. University of Idaho. Rangeland and Fire Sciences. Department of Forest; Estados Unidos Fil: Lens, Frederic. Leiden University. Naturalis Biodiversity Center; Países Bajos Fil: Maherali, Hafiz. University of Guelph. Department of Integrative Biology; Canadá Fil: Martínez-Viralta, Jordi. CREAF; España. Institució Catalana de Recerca i Estudis Avancats; España Fil: Mayr, Stefan. University of Innsbruck. Department of Botany; Austria Fil: McCulloh, Katherine A.. University of Wisconsin-Madison. Department of Botany; Estados Unidos Fil: Mencuccini, Maurizio. University of Edinburgh. School of GeoSciences; Reino Unido. Institució Catalana de Recerca i Estudis Avancats; España Fil: Mitchell, Patrick J.. CSIRO Land and Water Flagship; Australia Fil: Morris, Hugh. Ulm University. Institute of Systematic Botany and Ecology ; Alemania Fil: Nardini, Andrea. Università Trieste. Dipartimento Scienze della Vita ; Italia Fil: Pittermann, Jarmila. University of California. Department of Ecology and Evolutionary Biology; Estados Unidos Fil: Plavcová, Lenka. Ulm University. Institute of Systematic Botany and Ecology; Alemania. University of Alberta. Department of Renewable Resources; Canadá Fil: Schreiber, Stefan G.. University of Alberta. Department of Renewable Resources; Canadá Fil: Sperry, John S.. University of Utah. Department of Biology; Estados Unidos Fil: Wright, Ian J.. Macquarie University. Department of Biological Sciences; Australia Fil: Zanne, Ami E.. George Washington University. Department of Biological Sciences; Estados Unidos

Vessel length is an important but understudied dimension of variation in angiosperm vascular anatomy. Among other traits, vessel length mediates an important tradeoff between hydraulic efficiency and safety that could influence how plants respond to extreme weather with climate change. However, the functional significance of vessel length variation within individual stems is poorly known, in part because existing data analysis methods handle uncertainty in a way that makes vessel length distributions difficult to compare. We provide a solution to this problem through a hierarchical Bayesian framework for estimating vessel lengths and we demonstrate the flexibility of this method by applying it to data from serial cross sections of dye injected stems. Our approach can accelerate data collection and accommodate associated uncertainties by statistically correcting for bias and error that result from subsampling images. We illustrate our analytical framework by estimating and comparing vessel length distributions for 21 woody species characteristic of a North American forest. The best-fit model corrected for both bias due to secondary growth and sampling error within and among species. Vessel length estimates from this model varied by almost an order of magnitude and parameters of these distributions correlated with point estimates derived from a different, commonly used method. Furthermore, we show how key contrasts can be estimated with the Bayesian framework, and in doing so, we show that the shape of the vessel length distribution differed between ring- and diffuse-porous species, suggesting that within-stem vessel length variation corresponds to water stress seasonality and contributes to landscape-level habitat segregation. Our analysis method revealed the importance of within-stem variation in vessel length, and our results complement work on between-species variation in average vessel length, further illuminating how vascular anatomy can influence woody plants’ responses to water stress.

Increasing trade between countries and gains in income have given consumers around the world access to a richer and more diverse set of commercial plant products (i.e., foods and fibers produced by farmers). According to the economic theory of comparative advantage, countries open to trade will be able to consume more-in terms of volume and diversity-if they concentrate production on commodities that they can most cost-effectively produce, while importing goods that are expensive to produce, relative to other countries. Here, we perform a global analysis of traded commercial plant products and find little evidence that increasing globalization has incentivized agricultural specialization. Instead, a country's plant production and consumption patterns are still largely determined by local evolutionary legacies of plant diversification. Because tropical countries harbor a greater diversity of lineages across the tree of life than temperate countries, tropical countries produce and consume a greater diversity of plant products than do temperate countries. In contrast, the richer and more economically advanced temperate countries have the capacity to produce and consume more plant species than the generally poorer tropical countries, yet this collection of plant species is drawn from fewer branches on the tree of life. Why have countries not increasingly specialized in plant production despite the theoretical financial incentive to do so? Potential explanations include the persistence of domestic agricultural subsidies that distort production decisions, cultural preferences for diverse local food production, and that diverse food production protects rural households in developing countries from food price shocks. Less specialized production patterns will make crop systems more resilient to zonal climatic and social perturbations, but this may come at the expense of global crop production efficiency, an important step in making the transition to a hotter and more crowded world.

International audience

Earth is home to a remarkable diversity of plant forms and life histories, yet comparatively few essential trait combinationshave proved evolutionarily viable in today?s terrestrial biosphere. By analysing worldwide variation in six major traitscritical to growth, survival and reproduction within the largest sample of vascular plant species ever compiled, we foundthat occupancy of six-dimensional trait space is strongly concentrated, indicating coordination and trade-offs. Threequartersof trait variation is captured in a two-dimensional global spectrum of plant form and function. One majordimension within this plane reflects the size of whole plants and their parts; the other represents the leaf economicsspectrum, which balances leaf construction costs against growth potential. The global plant trait spectrum provides abackdrop for elucidating constraints on evolution, for functionally qualifying species and ecosystems, and for improvingmodels that predict future vegetation based on continuous variation in plant form and function. Fil: Díaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Kattge, Jens. Max Planck Institute for Biogeochemistry; Alemania Fil: Cornelissen, Johannes H. C.. Vrije Universiteit; Países Bajos Fil: Wright, Ian J.. Macquarie University; Australia Fil: Lavorel, Sandra. Université Grenoble Alpes; Francia Fil: Dray, Stéphane. Université Lyon; Francia Fil: Reu, Björn. University of Leipzig; Francia Fil: Kleyer, Michael. University of Oldenburg; Alemania Fil: Wirth, Christian. Max Planck Institute for Biogeochemistry; Alemania Fil: Prentice, I. Colin. Macquarie University; Australia Fil: Garnier, Eric. Université Paul-Valéry Montpellier; Francia Fil: Bönisch, Gerhard. Max Planck Institute for Biogeochemistry; Alemania Fil: Westoby, Mark. Macquarie University; Australia Fil: Poorter, Hendrik. Forschungszentrum Jülich GmbH; Alemania Fil: Reich, Peter B.. University of Minnesota; Estados Unidos. University of Western Sydney; Australia Fil: Moles, Angela T.. University of New South Wales; Australia Fil: Dickie, John. The Royal Botanic Gardens Kew; Reino Unido Fil: Gillison, Andrew N.. Center for Biodiversity Management; Australia Fil: Zanne, Amy E.. George Washington University; Estados Unidos. Missouri Botanical Garden; Estados Unidos Fil: Chave, Jérôme. Université Paul Sabatier; Francia Fil: Wright, S. Joseph. Smithsonian Tropical Research Institute; Estados Unidos Fil: Sheremetev, Serge N.. Komarov Botanical Institute; Rusia Fil: Jactel, Hervé. Université de Bordeaux; Francia Fil: Baraloto, Christopher. Florida International University; Estados Unidos. Ecologie des Forêts de Guyane; Guayana Francesa Fil: Cerabolini, Bruno. University of Insubria; Italia Fil: Pierce, Simon. University of Milan; Italia Fil: Shipley, Bill. Université de Sherbrooke; Canadá Fil: Kirkup, Donald. The Royal Botanic Gardens Kew; Reino Unido Fil: Casanoves, Fernando. Centro Agronómico Tropical de Investigación y Enseñanza; Costa Rica Fil: Joswig, Julia S.. Max Planck Institute for Biogeochemistry; Alemania Fil: Günther, Angela. Max Planck Institute for Biogeochemistry; Alemania Fil: Falczuk, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Rüger, Nadja. German Centre for Integrative Biodiversity Research; Alemania Fil: Mahecha, Miguel D.. Max Planck Institute for Biogeochemistry; Alemania Fil: Gorne, Lucas Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina

Plant traits – the morphological, anatomical, physiological, biochemical and phenological characteristics of plants and their organs – determine how primary producers respond to environmental factors, affect other trophic levels, influence ecosystem processes and services and provide a link from species richness to ecosystem functional diversity. Trait data thus represent the raw material for a wide range of research from evolutionary biology, community and functional ecology to biogeography. Here we present the global database initiative named TRY, which has united a wide range of the plant trait research community worldwide and gained an unprecedented buy-in of trait data: so far 93 trait databases have been contributed. The data repository currently contains almost three million trait entries for 69 000 out of the world's 300 000 plant species, with a focus on 52 groups of traits characterizing the vegetative and regeneration stages of the plant life cycle, including growth, dispersal, establishment and persistence. A first data analysis shows that most plant traits are approximately log-normally distributed, with widely differing ranges of variation across traits. Most trait variation is between species (interspecific), but significant intraspecific variation is also documented, up to 40% of the overall variation. Plant functional types (PFTs), as commonly used in vegetation models, capture a substantial fraction of the observed variation – but for several traits most variation occurs within PFTs, up to 75% of the overall variation. In the context of vegetation models these traits would better be represented by state variables rather than fixed parameter values. The improved availability of plant trait data in the unified global database is expected to support a paradigm shift from species to trait-based ecology, offer new opportunities for synthetic plant trait research and enable a more realistic and empirically grounded representation of terrestrial vegetation in Earth system models.

Woody stems comprise a large biological carbon fraction and determine water transport between roots and leaves; their structure and function can infl uence both carbon and hydrological cycles. While angiosperm wood anatomy and density determine hydraulic conductivity and mechanical strength, little is known about interrelations across many species. We compiled a global data set comprising two anatomical traits for 3005 woody angiosperms: mean vessel lumen area ( A ) and number per unit area ( N ). From these, we calculated vessel lumen fraction ( F = A N ) and size to number ratio ( S = A / N ), a new vessel composition index. We examined the extent to which F and S infl uenced potential sapwood specifi c stem conductivity ( K S ) and wood density ( D ; dry mass/ fresh volume). F and S varied essentially independently across angiosperms. Variation in K S was driven primarily by S , and variation in D was virtually unrelated to F and S . Tissue density outside vessel lumens (D N ) must predominantly infl uence D . High S should confer faster K S but incur greater freeze – thaw embolism risk. F should also affect K S , and both F and D N should infl uence mechanical strength, capacitance, and construction costs. Improved theory and quantifi cation are needed to better understand ecological costs and benefi ts of these three distinct dimensions.

Summary 1. Plant height is a central part of plant ecological strategy. It is strongly correlated with life span, seed mass and time to maturity, and is a major determinant of a species’ ability to compete for light. Plant height is also related to critical ecosystem variables such as animal diversity and carbon storage capacity. However, remarkably little is known about global patterns in plant height. Here, we use maximum height data for 7084 plant Species · Site combinations to provide the first global, cross-species quantification of the latitudinal gradient in plant height. 2. The mean maximum height of species growing within 15� of the equator (7.8 m) was 29 times greater than the height of species between 60� and 75� N (27 cm), and 31 times greater than the height of species between 45� and 60� S (25 cm). There was no evidence that the latitudinal gradient in plant height was different in the northern hemisphere than in the southern hemisphere (P = 0.29). A 2.4-fold drop in plant height at the edge of the tropics (P = 0.006) supports the idea that there might be a switch in plant strategy between temperate and tropical zones. 3. We investigated 22 environmental variables to determine which factors underlie the latitudinal gradient in plant height. We found that species with a wide range of height strategies were present in cold, dry, low productivity systems, but there was a noticeable lack of very short species in wetter, warmer, more productive sites. Variables that capture information about growing conditions during the harsh times of the year were relatively poor predictors of height. The best model for global patterns in plant height included only one term: precipitation in the wettest month (R 2 =0 .256). 4. Synthesis. We found a remarkably steep relationship between latitude and height, indicating a major difference in plant strategy between high and low latitude systems. We also provide new, surprising information about the correlations between plant height and environmental variables.

The carbon flux from woody debris, a crucial uncertainty within global carbon-climate models, is simultaneously affected by climate, site environment and species-based variation in wood quality. In the first global analysis attempting to explicitly tease out the wood quality contribution to decomposition, we found support for our hypothesis that, under a common climate, interspecific differences in wood traits affect woody debris decomposition patterns. A meta-analysis of 36 studies from all forested continents revealed that nitrogen, phosphorus, and C : N ratio correlate with decomposition rates of angiosperms. In addition, gymnosperm wood consistently decomposes slower than angiosperm wood within common sites, a pattern that correlates with clear divergence in wood traits between the two groups. New empirical studies are needed to test whether this difference is due to a direct effect of wood trait variation on decomposer activity or an indirect effect of wood traits on decomposition microsite environment. The wood trait-decomposition results point to an important role for changes in the wood traits of dominant tree species as a driver of carbon cycling, with likely feedback to atmospheric CO(2) particularly where angiosperm species replace gymnosperms regionally. Truly worldwide upscaling of our results will require further site-based multi-species wood trait and decomposition data, particularly from low-latitude ecosystems.