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14 páginas.- 6 figuras.- 1 tabla.- referencias.- Additional supporting information may be found in the online version of the article at the publisher’s website, 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., This work was supported by the National Natural Science Foundation of China (32071524, 31770514 and 31870711). International research travel by J.H.C.C. was partly funded by the Royal Netherlands Academy of Arts and Sciences (KNAW, CEP grant 12CDP007).

B.J.-A. was funded by the Marie Curie Clarín-COFUND program of the Principality of Asturias-EU (ACB17-26) and the Spanish Research Agency (AEI/10.13039/501100011033)., Testolin, R., Attorre, F., Borchardt, P., Brand, R.F., Bruelheide, H., Chytrý, M., De Sanctis, M., Dolezal, J., Finckh, M., Haider, S., Hemp, A., Jandt, U., Kessler, M., Korolyuk, A.Y., Lenoir, J., Makunina, N., Malanson, G.P., Montesinos-Tubée, D.B., Noroozi, J., Nowak, A., Peet, R.K., Peyre, G., Sabatini, F.M., Šibík, J., Sklenář, P., Sylvester, S.P., Vassilev, K., Virtanen, R., Willner, W., Wiser, S.K., Zibzeev, E.G., Jiménez-Alfaro, B.

Soil bacteria are largely missing from future biodiversity assessments hindering comprehensive forecasts of ecosystem changes. Soil bacterial communities are expected to be more strongly driven by pH and less by other edaphic and climatic factors. Thus, alkalinisation or acidification along with climate change may influence soil bacteria, with subsequent influences for example on nutrient cycling and vegetation. Future forecasts of soil bacteria are therefore needed. We applied species distribution modelling (SDM) to quantify the roles of environmental factors in governing spatial abundance distribution of soil bacterial OTUs and to predict how future changes in these factors may change bacterial communities in a temperate mountain area. Models indicated that factors related to soil (especially pH), climate and/or topography explain and predict part of the abundance distribution of most OTUs. This supports the expectations that microorganisms have specific environmental requirements (i.e., niches/envelopes) and that they should accordingly respond to environmental changes. Our predictions indicate a stronger role of pH over other predictors (e.g. climate) in governing distributions of bacteria, yet the predicted future changes in bacteria communities are smaller than their current variation across space. The extent of bacterial community change predictions varies as a function of elevation, but in general, deviations from neutral soil pH are expected to decrease abundances and diversity of bacteria. Our findings highlight the need to account for edaphic changes, along with climate changes, in future forecasts of soil bacteria.

At broad spatial scales, the factors regulating litter decomposition remain ambiguous, with the understanding of these factors largely based on studies investigating site-specific single litter species, whereas studies using multi litter species mixtures across sites are rare. We exposed in microcosms containing single species and all possible mixtures of four leaf litter species differing widely in initial chemical and physical characteristics from a temperate forest to the climatic conditions of four different forests across the Northern Hemisphere for 1 year. Calcium, magnesium and condensed tannins predicted litter mass loss of single litter species and mixtures across forest types and biomes, regardless of species richness and microarthropod presence. However, relative mixture effects differed among forest types and varied with the access to the litter by microarthropods. Access to the microcosms by microarthropods modified the decomposition of individual litter species within mixtures, which differed among forest types independent of litter species richness and composition of litter mixtures. However, soil microarthropods generally only little affected litter decomposition. Synthesis. We conclude that litter identity is the dominant driver of decomposition across different forest types and the non-additive litter mixture effects vary among biomes despite identical leaf litter chemistry. These results suggest that across large spatial scales the environmental context of decomposing litter mixtures, including microarthropod communities, determine the decomposition of litter mixtures besides strong litter trait-based effects.

14 páginas, 3 figuras, Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that-just like in non-urban areas-plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions., This study was carried out with financial support from the French National Research Agency (ANR) in the frame of the Investments for the Future Programme, within the Cluster of Excellence COTE (Continental To coastal Ecosystems: evolution, adaptability, and governance) (ANR-10-LABX-45) and was further funded by the BNP Paribas Foundation as part of its Climate & Biodiversity Initiative the citizen science project Tree Bodyguards. The authors warmly thank all the young European citizens and their teachers who made this study possible. They also thank the professional scientists who kindly agreed to participate in this study: Alexander Kozel (Belarusian State Technological University and American Psychological Association), Andreas Schuldt (Forest Nature Conservation, Georg-August-University Göttingen, Göttingen, German), Aurélien Sallé (Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRAE, Université d'Orléans), Chloe Mendiondo and Claire Colliaux (Department of Agroecology, Aarhus University, Flakkebjerg Research Centre, DK-4200 Slagelse, Denmark), György Csóka (Department of Forest Protection, NARIC Forest Research Institute, Mátrafüred, Hungary), Lars Opgennoorth (Biodiversity and Conservation Biology, Ecological Genetics, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland), Laurent Augusto (INRAE, Bordeaux Sciences Agro), Marija Popović (Faculty of Forestry, University of Belgrade, Belgrade, Serbia), Mickael Pihain (Research Unit “Ecosystèmes, Biodiversité, Evolution”, University of Rennes 1/CNRS, 35042 Rennes, France), Olivier Bouriaud (Applied Ecology Laboratory, Forestry Faculty, “Ștefan cel Mare, University of Suceava, Suceava, Romania), Stefan K. Müller (Freie evangelische Schule Lörrach), Tomas Roslin (Department of Ecology; Swedish University of Agricultural Sciences), Valentin Queloz (Forest Entomology, Swiss Federal Research Institute WSL), and Vojtech Lanta (Institute of Botany CAS, Dukelská 135, 37901 Třeboň, Czech Republic). They also thank Michael Scherer-Lorenzen (Geobotany, Faculty of Biology, University of Freiburg) for the help during the coordination of the research.

WOS:000731281400001; International audience; The link between biodiversity and ecosystem functioning has been the topic of considerable research, but it remains unclear how biodiversity decline is compromising ecosystem functionality, particularly in the pelagic realm. Here, we explore how pelagic fish species diversity relates to functional diversity by sampling two locations, which, on the basis of biogeography, environmental conditions and human pressures, were expected to host pronounced differences in species composition and abundances and therefore functionality. Strings of five drifting mid-water Baited Remote Underwater Video Systems were used to survey pelagic vertebrate diversity and abundance in two isolated oceanic island systems, the Malpelo Fauna and Flora Sanctuary-a large, 25-year-old marine protected area-and an unprotected area in Cape Verde. Functional diversity, which offers insight into a community's resilience against disturbance, was analysed using six key functional traits of marine fishes. Abundance was recorded as MaxN, the maximum number of individuals of a given species in a single frame during the 2-h deployment time. Cape Verde showed high overall abundance (Total MaxN 873) and low biomass (3559 kg), with a predominance of smaller fishes. Malpelo showed high biomass (7839 kg) but lower abundance (Total MaxN 465), with a predominance of large species. Species and functional diversity were marginally different between locations. Multivariate analysis of species relative abundances showed significant divergence between locations, although community functional traits overlapped strongly, suggesting that both communities share a similar structure and vulnerability. The existence of a common functional 'backbone' in diverging species communities across the oceans, under different productivity regimes, and under different protection levels, suggests that although pelagic communities may differ considerably in terms of species composition, this does not translate into a differing functional structure and resilience potential. Whether this vulnerability is a common feature of pelagic communities and how this contrasts with benthic systems warrants further research.

WOS:000760366500074; International audience; We aim to assess the influence of phylogenetic scale on the relationships of taxonomic and phylogenetic turnovers with environment for angiosperms in China. Specifically, we quantify the effects of contemporary climate on beta-diversity at different phylogenetic scales representing different evolutionary depths of angiosperms. We sampled a latitudinal gradient and a longitudinal gradient of angiosperm assemblages across China (each \textgreater= 3400 km). Species composition in each assemblage was documented. Three metrics of beta-diversity (beta(sim.tax) measuring taxonomic beta-diversity; beta(sim.phy) and D-pw measuring tip- and basal-weighted phylogenetic beta-diversity, respectively) were quantified among assemblages at sequential depths in the evolutionary history of angiosperms from the tips to deeper branches. This was done by slicing the angiosperm phylogenetic tree at six evolutionary depths (0, 15, 30, 45, 60, and 75 million years ago). beta-diversity at each evolutionary depth was related to geographic and climatic distances between assemblages. In general, the relationship between beta-diversity and climatic distance decreased from shallow to deep evolutionary time slice for all the three metrics. The slopes of the decreasing trends for beta(sim.tax) and beta(sim.phy) were much steeper for the latitudinal gradient than for the longitudinal gradient. The decreasing trend of the strength of the relationship was monotonic in all cases except for D-pw across the longitudinal gradient. Geographic distance between assemblages explained little variation in beta-diversity that was not explained by climatic distance. Our study shows that the strength of the relationship between beta-diversity and climatic distance decreases conspicuously from shallow to deep evolutionary depth for the latitudinal gradient, but this decreasing trend is less steep for the longitudinal gradient than for the latitudinal gradient, which likely reflects the influence of historical processes (e.g., the collision of the Indian plate with the Eurasian plate) on beta-diversity.

Aims: Phylogenetic endemism describes the extent to which unique phylogenetic lineages are constrained to restricted geographic areas. Previous studies indicate that species endemism is related to both past and modern climate, but studies of phylogenetic endemism are relatively rare and mainly focused on smaller regions. Here, we provide the first assessment of the patterns of species and phylogenetic endemism in angiosperm trees across the Northern Hemisphere as well as the relative importance of modern climate and glacial–interglacial climate change as drivers of these patterns. Location: Northern Hemisphere. Major taxa: Angiosperm trees. Methods: Using tree assemblages at the scale of 100 km × 100 km grid cells and simultaneous autoregressive (SAR) models, we assessed the relationships between species endemism, phylogenetic endemism and modern climate variables, Last Glacial Maximum (LGM) to present temperature velocity. Results: Species and phylogenetic endemism were associated with both modern climate and glacial–interglacial climate change, with higher values in areas with stable historical climate and warmer and wetter modern conditions. Notably, the multivariate SAR analyses showed that the combinations of variables with highest Akaike’s information criterion (AIC) weight always included both LGM–present climate instability and modern climate, that is, modern precipitation and temperature. Main conclusions: Our results show that high phylogenetic endemism is partially dependent on long-term climate stability, highlighting the threat posed by future climate changes to the preservation of rare, phylogenetically distinct lineages of trees.

Spatial variation in community composition may be driven by a variety of processes, including environmental filtering and dispersal limitation. While work has been conducted on the relative importance of these processes on various taxa and at varying resolutions, tests using high-resolution empirical data across large spatial extents are sparse. Here, we use a dataset on the presence/absence of breeding bird species collected at the 10 km × 10 km scale across the whole of Britain. Pairwise spatial taxonomic and functional beta diversity, and the constituent components of each (turnover and nestedness/richness loss or gain), were calculated alongside two other measures of functional change (mean nearest taxon distance and mean pairwise distance). Predictor variables included climate and land use measures, as well as a measure of elevation, human influence, and habitat diversity. Generalized dissimilarity modeling was used to analyze the contribution of each predictor variable to variation in the different beta diversity metrics. Overall, we found that there was a moderate and unique proportion of the variance explained by geographical distance per se, which could highlight the role of dispersal limitation in community dissimilarity. Climate, land use, and human influence all also contributed to the observed patterns, but a large proportion of the explained variance in beta diversity was shared between these variables and geographical distance. However, both taxonomic nestedness and functional nestedness were uniquely predicted by a combination of land use, human influence, elevation, and climate variables, indicating a key role for environmental filtering. These findings may have important conservation implications in the face of a warming climate and future land use change.

Aim Our understanding of the biological strategies employed by species to cope with challenges posed by aridity is still limited. Despite being sensitive to water loss, bats successfully inhabit a wide range of arid lands. We here investigated how functional traits of bat assemblages vary along the global aridity gradient to identify traits that favour their persistence in arid environments. Location Global. Time period Contemporary. Major taxa studied Bats. Methods We mapped the assemblage-level averages of four key bat traits describing wing morphology, echolocation and body size, based on a grid of 100-km resolution and a pool of 915 bat species, and modelled them against aridity values. To support our results, we conducted analyses also at the species level to control for phylogenetic autocorrelation. Results At the assemblage level, we detected a rise in values of aspect ratio, wing loading and forearm length, and a decrease in echolocation frequency with increasing aridity. These patterns were consistent with trends detected at the species level for all traits. Main conclusions Our findings show that trait variation in bats is associated with the aridity gradient and suggest that greater mobility and larger body size are advantageous features in arid environments. Greater mobility favours bats' ability to track patchy and temporary resources, while the reduced surface-to-volume ratio associated with a larger body size is likely to reduce water stress by limiting cutaneous evaporation. These findings highlight the importance of extending attention from species-specific adaptations to broad scale and multispecies variation in traits when investigating the ability of species to withstand arid conditions.

Combined effects of cumulative nutrient inputs and biogeochemical processes that occur in freshwater under anthropogenic eutrophication could lead to myriad shifts in nitrogen (N):phosphorus (P) stoichiometry in global freshwater ecosystems, but this is not yet well-assessed. Here we evaluated the characteristics of N and P stoichiometries in bodies of freshwater and their herbaceous macrophytes across human-impact levels, regions and periods. Freshwater and its macrophytes had higher N and P concentrations and lower N : P ratios in heavily than lightly human-impacted environments, further evidenced by spatiotemporal comparisons across eutrophication gradients. N and P concentrations in freshwater ecosystems were positively correlated and N : P was negatively correlated with population density in China. These results indicate a faster accumulation of P than N in human-impacted freshwater ecosystems, which could have large effects on the trophic webs and biogeochemical cycles of estuaries and coastal areas by freshwater loadings, and reinforce the importance of rehabilitating these ecosystems.

Mechanisms underlying species richness patterns remain a central yet controversial issue in biology. Climate has been regarded as a major determinant of species richness. However, the relative influences of different evolutionary processes, (i.e. niche conservatism, diversification rate and time for speciation) on species richness–climate relationships remain to be tested. Here, using newly compiled distribution maps for 11 422 woody plant species in eastern Eurasia, we estimated species richness patterns for all species and for families with tropical and temperate affinities separately, and explored the phylogenetic signals in species richness patterns of different families and their relationships with contemporary climate and climate change since the Last Glacial Maximum (LGM). We further compared the effects of niche conservatism (represented by contemporary‐ancestral climatic niches differences), diversification rate and time for speciation (represented by family age) on variation in the slopes of species richness–climate relationships. We found that winter coldness was the best predictor for species richness patterns of most tropical families while Quaternary climate change was the best predictor for those of most temperate families. Species richness patterns of closely‐related families were more similar than those of distantly‐related families within eudicots, and significant phylogenetic signals characterized the slopes of species richness–climate relationships across all angiosperm families. Contemporary‐ancestral climatic niche differences dominated variation in the relationships between family‐level species richness and most climate variables. Our results indicate significant phylogenetic conservatism in family‐level species richness patterns and their relationships with contemporary climate within eudicots. These findings shed light on the mechanisms underlying large‐scale species richness patterns and suggest that ancestral climatic niche may influence the evolution of species richness–climate relationships in plants through niche conservatism. publishedVersion

Aim Biogeographical processes and past environmental conditions are known to constrain current patterns of species, functional and phylogenetic diversity. An unanswered question is whether such constraints to biodiversity also affect ecosystem processes. Location Global. Time period Neogene and Quaternary. Major taxa studied Vascular plants. Methods We propose that evolution, migration-lag in response to environmental changes, and extinction may result in historical legacies in current ecosystem composition (species and functional) that can lead to historical legacies in ecosystem processes - that is, deviations from the potential rates or magnitudes of ecosystem processes, given current environmental conditions and the habitat-suitable native species and trait pools that exist under such circumstances. Results Historical legacies in ecosystem processes may begin with changes in species richness and composition in response to environmental shifts. These changes are mediated by response traits that determine how species react to environmental changes and track suitable environmental conditions. Response traits are often associated with effect traits, which determine the rates and magnitude of ecosystem processes. Via this association, environmentally driven response-trait determined changes in species diversity may cascade to ecosystem processes through effect trait compositional changes. These changes could lead to ecosystem processes deviating from a potential state defined by current environmental conditions and the overall species pool. We populate this conceptual framework with cases that show how historical legacies in biodiversity translate to historical legacies in ecosystem processes, and we discuss the implications of the concept for global change ecology. Main conclusions We need to rethink our expectations of future ecological dynamics as past, and current, environmental changes may push ecosystem processes away from their environmentally and compositionally defined potential state.

Aim: The General Dynamic Model (GDM) links island biogeographical processes to island geological history. A key premise of the GDM implies that environmental factors shaping the ecology and evolution of biota on oceanic islands follow a hump-shaped trend over the island's life span and drive dynamics in carrying capacity, species diversity and endemism. An important component of the GDM is environmental heterogeneity (EH), but its effects on insular diversity remain poorly understood. Here, we first quantified EH, tested whether EH follows the expected hump-shaped trend along island ontogeny and evaluated how EH relates to plant diversity. Location: 135 oceanic islands of volcanic origin. Taxon: Vascular plants. Methods: We calculated 20 EH metrics focusing on topographic and climatic components of EH, and compared whole-island metrics (e.g. range) and moving-window metrics (e.g. roughness). Using linear mixed-effects models, we evaluated the trends of EH with island age and the EH–plant diversity relationship expected based on the GDM. Results: Our analysis revealed some EH components to be collinear, for example, elevation and temperature heterogeneity but also that EH metrics capture different aspects of EH, for example, climatic gradients versus climatic complexity. EH generally followed a hump-shaped trend with island age, peaking early during island ontogeny. Among the EH components, climatic heterogeneity had the strongest effect on plant species richness and elevational heterogeneity on endemism. Lastly, including EH metrics in GDMs (traditionally, only island age and area were included) improved their predictive power. Main conclusions: The EH metrics compared here captured various attributes of the environment that influence insular plant diversity. In line with the GDM, our results strongly support a hump-shaped relationship between EH and island age, suggesting that islands become highly heterogeneous early in their ontogeny. Finally, the contribution of EH to GDM-based models of species richness and endemism suggests that EH is a main driver of the diversity of oceanic island biotas. Refereed/Peer-reviewed

It has been suggested that biogeographic historical legacies in plant diversity may influence ecosystem functioning. This is expected because of known diversity effects on ecosystem functions, and impacts of historical events such as past climatic changes on plant diversity. However, empirical evidence for a link between biogeographic history and present‐day ecosystem functioning is still limited. Here, we explored the relationships between Late‐Quaternary climate instability, species‐pool size, local species and functional diversity, and the net primary productivity (NPP) of Northern Hemisphere forests using structural equation modelling. Our study confirms that past climate instability has negative effects on plant functional diversity and through that on NPP, after controlling for present‐day climate, soil conditions, stand biomass and age. We conclude that global models of terrestrial plant productivity need to consider the biogeographical context to improve predictions of plant productivity and feedbacks with the climate system. ispartof: Ecology Letters vol:23 issue:5 pages:800-810 ispartof: location:England status: published

Aims Glacial-interglacial climate stability and contemporary climate could affect bird diversity through their direct effects on diversification and physiological tolerance, and indirect effects on plant species richness, which could provide more food and ecological niches. This study aims to quantitatively assess the direct and indirect effects of these drivers on species richness, phylogenetic and functional structure of bird assemblages.Location Mainland China.Taxon Birds.Methods Ordinary least squares models and simultaneous autoregressive models were used to test the associations between glacial-interglacial climate anomaly, contemporary climate, plant species richness, elevation range and species richness, phylogenetic structure, functional structure of bird assemblages in mainland China. Structural equation models were used to distinguish between direct and indirect effects of these variables on bird diversity.Results High bird species richness with phylogenetically and functionally clustered structure occurred in regions with more plant species and stable glacial-interglacial climate. Notably, the phylogenetically clustered bird assemblages were composed of young lineages. Contemporary precipitation and elevation range affected bird diversity through their indirect effects on plant species richness.Main Conclusions These findings suggest that more plant species and stable glacial-interglacial climate may promote bird diversity through their effects on in situ diversification and species dispersal rate in southwestern China. Therefore, the well-preserved plant and bird diversity through the long-term climate fluctuations should be of great importance of biodiversity conservation in China.

Background: We aimed to characterise the geographical distribution of Sorensen-based multi-site dissimilarity (beta(sor)) and its underlying true turnover (beta(sim)) and nestedness (beta(sne)) components for Chinese Lauraceae and to analyse their relationships to current climate and past climate change. Methods: We used ensembles of small models (ESMs) to map the current distributions of 353 Lauraceae species in China and calculated beta(sor) and its beta(sim) and beta(sne) components. We tested the relationship between beta(sor), beta s(ne) and beta(sim) with current climate and past climate change related predictors using a series of simultaneous autoregressive (SAR(err)) models. Results: Spatial distribution of beta(sor) of Lauraceae is positively correlated with latitude, showing an inverse relationship to the latitudinal alpha-diversity (species richness) gradient. High beta(sor) occurs at the boundaries of the warm temperate and subtropical zones and at the Qinghai-Tibet Plateau due to high beta(sne). The optimized SAR(err) model explains beta(sor) and beta(sne) well, but not beta(sim). Current mean annual temperature determines beta(sor) and beta(sne) of Lauraceae more than anomalies and velocities of temperature or precipitation since the Last Glacial Maximum. Conclusions: Current low temperatures and high climatic heterogeneity are the main factors explaining the high multi-site beta-diversity of Lauraceae. In contrast to analyses of the beta-diversity of entire species assemblages, studies of single plant families can provide complementary insights into the drivers of beta-diversity of evolutionarily more narrowly defined entities.

Aim: Biological diversity typically varies between climatically different regions, and regions closer to the equator often support higher numbers of taxa than those closer to the poles. However, these trends have been assessed for a few organism groups, and the existing studies have rarely been based on extensive identical surveys in different climatic regions. Location: We conducted standardized surveys of wadeable streams in a boreal (western Finland) and a subtropical (south-eastern Brazil) region, sampling insects identically from 100 streams in each region and measuring the same environmental variables in both regions. Taxon: Aquatic insects. Methods: Comparisons were made at the scales of local stream sites, drainage basins and entire regions. We standardized the spatial extent of the study areas by resampling regional richness based on subsets of sites with similar extents. We examined differences in genus richness and assemblage abundance patterns between the regions using graphical and statistical modelling approaches. Results: We found that while genus accumulation and rank-abundance curves were relatively similar at the regional scale between Finland and Brazil, regional genus richness was higher in the latter but regional abundance much higher in the former region. These regional patterns for richness and abundance were reproduced by basin and local genus richness that were higher in Brazil than in Finland, and assemblage abundance that was much higher in Finland than in Brazil. The magnitude of the difference in genus richness between Brazil and Finland tended to increase from local through basin to regional scales. Main conclusions: Our findings suggest that factors related to evolutionary diversification might explain differences in genus richness between these two climatically different regions, whereas higher nutrient concentrations of stream waters might explain the higher abundance of insects in Finland than in Brazil.

Habitat dynamics interacting with species dispersal abilities could generate gradients in species diversity and prevalence of species traits when the latter are associated with species dispersal potential. Using a process‐based model of diversification constrained by a dispersal parameter, we simulated the interplay between reef habitat dynamics during the past 140 million years and dispersal, shaping lineage diversification history and assemblage composition globally. The emerging patterns from the simulations were compared to current prevalence of species traits related to dispersal for 6315 tropical reef fish species. We found a significant spatial congruence between the prevalence of simulated low dispersal values and areas with a large proportion of species characterized by small adult body size, narrow home range mobility behaviour, pelagic larval duration shorter than 21 days and diurnal activity. Species characterized by such traits were found predominantly in the Indo‐Australian Archipelago and the Caribbean Sea. Furthermore, the frequency distribution of the dispersal parameter was found to match empirical distributions for body size, PLD and home range mobility behaviour. Also, the dispersal parameter in the simulations was associated to diversification rates and resulted in trait frequency matching empirical distributions. Overall, our findings suggest that past habitat dynamics, in conjunction with dispersal processes, influenced diversification in tropical reef fishes, which may explain the present‐day geography of species traits. ISSN:0906-7590 ISSN:1600-0587

Ecosystem processes are driven by both environmental variables and the attributes of component species. The extent to which these effects are independent and/or dependent upon each other has remained unclear. We assess the extent to which climate affects net primary productivity (NPP) both directly and indirectly via its effect on plant size and leaf functional traits. Using species occurrences and functional trait databases for North and South America, we describe the upper limit of woody plant height within 200 × 200 km grid-cells. In addition to maximum tree height, we quantify grid-cell means of three leaf traits (specific leaf area, and leaf nitrogen and phosphorus concentration) also hypothesized to influence productivity. Using structural equation modelling, we test the direct and indirect effects of environment and plant traits on remotely sensed MODIS-derived estimates of NPP, using plant size (satellite-measured canopy height and potential maximum tree height), leaf traits, growing season length, soil nutrients, climate and disturbances as explanatory variables. Our results show that climate affects NPP directly as well as indirectly via plant size in both tropical and temperate forests. In tropical forests NPP further increases with leaf phosphorus concentration, whereas in temperate forests it increases with leaf nitrogen concentration. In boreal forests, NPP most strongly increases with increasing temperature and neither plant size nor leaf traits have a significant influence. Synthesis. Our results suggest that at large spatial scales plant size and leaf nutrient traits can improve predictions of forest productivity over those based on climate alone. However, at higher latitudes their role is overridden by stressful climate. Our results provide independent empirical evidence for where and how global vegetation models predicting carbon fluxes could benefit from including effects of plant size and leaf stoichiometry.

Aim On the basis of multitaxon biogeographical processes related to region-specific geohistory and palaeoclimate, we identified a balanced and area-effective protected area network (PAN) expansion in the East Asian islands, a global biodiversity hotspot. Location Japanese archipelago, Ryukyu archipelago and Izu-Bonin oceanic islands. Methods We modelled the distributions of 6,325 species (amphibians, birds, freshwater fish, mammals, plants and reptiles) using 4,389,489 occurrence data points. We then applied the Zonation software for spatial conservation prioritization. First, we identified environmental drivers underpinning taxon-specific biodiversity patterns. Second, we analysed each taxon individually to understand baseline priority patterns. Third, we combined all taxa into an inclusive analysis to identify the most important PAN expansions. Results Biodiversity patterns were well explained by geographical factors (climate, habitat stability, isolation and area), but their explanatory power differed between the taxa. There was remarkably little overlap between priority areas for the individual higher taxa. The inclusive prioritization analysis across all taxa identified priority regions, in particular in southern subtropical and mountainous areas. Expanding the PAN up to 17% would cover most of the ranges for rare and/or restricted-range species. On average, approximately 30% of the ranges of all species could be covered by the 17% expansion identified here. Main conclusions Our analyses identified top candidates for the expansion of Japan's protected area network. Taxon-specific prioritization was informative for understanding the conservation priority patterns of different taxa associated with unique biogeographical processes. For the basis of PAN expansion, we recommend multi-taxon prioritization as an area-efficient compromise that reflects taxon-specific priority patterns. Spatial prioritization across multiple taxa provides a promising start for the development of conservation plans with the aim of long-term persistence of biodiversity on the East Asian islands.

To accurately capture the impacts of nitrogen (N) on the land carbon (C) sink in Earth system models, model responses to both N limitation and ecosystem N additions (e.g., from atmospheric N deposition and fertilizer) need to be evaluated. The response of the land C sink to N additions depends on the fate of these additions: that is, how much of the added N is lost from the ecosystem through N loss pathways or recovered and used to increase C storage in plants and soils. Here, we evaluate the C–N dynamics of the latest version of a global land model, the Community Land Model version 5 (CLM5), and how they vary when ecosystems have large N inputs and losses (i.e., an open N cycle) or small N inputs and losses (i.e., a closed N cycle). This comparison allows us to identify potential improvements to CLM5 that would apply to simulated N cycles along the open-to-closed spectrum. We also compare the short- (15N tracer addition experiments at eight temperate forest sites. Simulations using both open and closed N cycles overestimated plant N recovery following N additions. In particular, the model configuration with a closed N cycle simulated that plants acquired more than twice the amount of added N recovered in 15N tracer studies on short timescales (CLM5: 46±12 %; observations: 18±12 %; mean across sites ±1 standard deviation) and almost twice as much on longer timescales (CLM5: 23±6 %; observations: 13±5 %). Soil N recoveries in simulations with closed N cycles were closer to observations in the short term (CLM5: 40±10 %; observations: 54±22 %) but smaller than observations in the long term (CLM5: 59±15 %; observations: 69±18 %). Simulations with open N cycles estimated similar patterns in plant and soil N recovery, except that soil N recovery was also smaller than observations in the short term. In both open and closed sets of simulations, soil N recoveries in CLM5 occurred from the cycling of N through plants rather than through direct immobilization in the soil, as is often indicated by tracer studies. Although CLM5 greatly overestimated plant N recovery, the simulated increase in C stocks to recovered N was not much larger than estimated by observations, largely because the model's assumed C:N ratio for wood was nearly half that suggested by measurements at the field sites. Overall, results suggest that simulating accurate ecosystem responses to changes in N additions requires increasing soil competition for N relative to plants and examining model assumptions of C:N stoichiometry, which should also improve model estimates of other terrestrial C–N processes and interactions.

Human activities are accelerating global biodiversity change and have resulted in severely threatened ecosystem services. A large proportion of terrestrial biodiversity is harbored by soil, but soil biodiversity has been omitted from many global biodiversity assessments and conservation actions, and understanding of global patterns of soil biodiversity remains limited. In particular, the extent to which hotspots and coldspots of aboveground and soil biodiversity overlap is not clear. We examined global patterns of these overlaps by mapping indices of aboveground (mammals, birds, amphibians, vascular plants) and soil (bacteria, fungi, macrofauna) biodiversity that we created using previously published data on species richness. Areas of mismatch between aboveground and soil biodiversity covered 27% of Earth's terrestrial surface. The temperate broadleaf and mixed forests biome had the highest proportion of grid cells with high aboveground biodiversity but low soil biodiversity, whereas the boreal and tundra biomes had intermediate soil biodiversity but low aboveground biodiversity. While more data on soil biodiversity are needed, both to cover geographic gaps and to include additional taxa, our results suggest that protecting aboveground biodiversity may not sufficiently reduce threats to soil biodiversity. Given the functional importance of soil biodiversity and the role of soils in human well-being, soil biodiversity should be considered further in policy agendas and conservation actions by adapting management practices to sustain soil biodiversity and considering soil biodiversity when designing protected areas.Disparidades Mundiales entre la Biodiversidad Sobre y Bajo el Suelo Resumen Las actividades humanas están acelerando el cambio en la biodiversidad mundial y han tenido como resultado unos servicios ambientales severamente amenazados. Una gran proporción de la biodiversidad terrestre está albergada en el suelo, pero la biodiversidad de este ha sido omitida de varias evaluaciones mundiales de biodiversidad y de las acciones de conservación, además de que el entendimiento de los patrones mundiales de la biodiversidad del suelo permanece limitado; particularmente, la extensión del traslape entre los puntos fríos y calientes de biodiversidad sobre y bajo suelo no está clara. Examinamos los patrones mundiales de estos traslapes mapeando los índices de biodiversidad sobre el suelo (mamíferos, aves, anfibios y plantas vasculares) y bajo el suelo (bacterias, hongos y macrofauna) que creamos con datos previamente publicados de la riqueza de especies. Las áreas de disparidad entre la biodiversidad sobre y bajo el suelo cubrieron el 27% de la superficie terrestre del planeta. El bioma de los bosques templados de plantas frondosas y mixtas tuvo la proporción más alta de celdas de cuadrícula con una biodiversidad alta sobre el suelo, pero baja para en el subsuelo, mientras que los biomas boreales y de la tundra tuvieron una biodiversidad intermedia bajo el suelo, pero baja para el sobre suelo. Aunque se requieren más datos sobre la biodiversidad del suelo, tanto para cubrir los vacíos geográficos como para incluir a taxones adiciones, nuestros resultados sugieren que la protección a la biodiversidad sobre el suelo puede no reducir suficientemente las amenazas para la biodiversidad del suelo. Dada la importancia funcional de la biodiversidad del suelo y el papel de los suelos en el bienestar humano, se debería considerar a la biodiversidad del suelo mucho más en las agendas políticas y en las acciones de conservación, adaptando a las prácticas de manejo para que mantengan a la biodiversidad del suelo y la consideren cuando designen áreas protegidas.人类活动正在导致全球生物多样性的快速变化, 并已严重影响到生态系统服务功能。陆地生物多样性中很大一部分存在于土壤之中, 然而, 许多全球生物多样性评估和保护行动都没有考虑土壤生物多样性, 人们对全球土壤生物多样性格局的认识也十分有限, 特别是对地表生物多样性和土壤生物多样性的热点地区及贫瘠地区的重叠程度知之甚少。为了研究全球地表生物多样性和土壤生物多样性的重叠情况, 我们利用已发表的物种丰富度数据设计了地表生物多样性 (哺乳动物、鸟类、两栖类、维管植物) 及土壤生物多样性 (细菌、真菌、大型动物群) 指标, 用于绘制相应的地图。结果显示, 地表和土壤生物多样性不匹配的地区占地球陆地面积的 27% 。在温带阔叶林和混交林生物群中, 地表生物多样性高而土壤生物多样性低的栅格占比最高, 而寒带和苔原生物群则是土壤生物多样性中等而地表生物多样性低。虽然还有待增加土壤生物多样性的数据以囊括更多地理区域和生物类群, 但我们的结果已经表明, 保护地表生物多样性可能不足以减少对土壤生物多样性的威胁。鉴于土壤生物多样性的重要功能以及土壤对人类福祉的作用, 应在政策议程和保护行动中更多地考虑土壤生物多样性, 如调整管理实践以保护土壤生物多样性、在保护区设计中纳入土壤生物多样性等等。【翻译: 胡怡思; 审校: 聂永刚】.

International audience; The latitudinal diversity gradient (LDG) is one of the most widely debated patterns in ecology and evolution, associated with hundreds of papers, dozens of hypotheses, and disagreements about its underlying processes. The lack of agreement stems from 1) the verbal nature of existing hypotheses, 2) the failure to mechanistically integrate all relevant ecological and evolutionary processes to the LDG, and 3) the degree to which many empirical patterns are consistent with multiple LDG explanations. We show how mapping LDG hypotheses to a set of key ecological and evolutionary processes leads to a better understanding of the internal logic of those hypotheses. The codification of those processes within a mechanistic eco-evolutionary model is essential for contrasting support for hypotheses and for understanding the relative importance of the processes themselves.

In this intercontinental study of stream diatoms, we asked three important but still unresolved ecological questions: (1) What factors drive the biogeography of species richness and species abundance distribution (SAD)? (2) Are climate-related hypotheses, which have dominated the research on the latitudinal and altitudinal diversity gradients, adequate in explaining spatial biotic variability? and (3) Is the SAD response to the environment independent of richness? We tested a number of climatic theories and hypotheses (i.e., the species-energy theory, the metabolic theory, the energy variability hypothesis, and the climatic tolerance hypothesis) but found no support for any of these concepts, as the relationships of richness with explanatory variables were nonexistent, weak, or unexpected. Instead, we demonstrated that diatom richness and SAD evenness generally increased with temperature seasonality and at mid- to high total phosphorus concentrations. The spatial patterns of diatom richness and the SADmainly longitudinal in the United States but latitudinal in Finlandwere defined primarily by the covariance of climate and water chemistry with space. The SAD was not entirely controlled by richness, emphasizing its utility for ecological research. Thus, we found support for the operation of both climate and water chemistry mechanisms in structuring diatom communities, which underscores their complex response to the environment and the necessity for novel predictive frameworks.

International audience; Aim Biogeographical processes underlying Indo-Pacific biodiversity patterns have been relatively well studied in marine shallow water invertebrates and fishes, but have been explored much less extensively in seaweeds, despite these organisms often displaying markedly different patterns. Using the marine red alga Portieria as a model, we aim to gain understanding of the evolutionary processes generating seaweed biogeographical patterns. Our results will be evaluated and compared with known patterns and processes in animals. Location Indo-Pacific marine region.Methods Species diversity estimates were inferred using DNA-based species delimitation methods. Historical biogeographical patterns were inferred based on a six-gene time-calibrated phylogeny, distribution data of 802 specimens, and probabilistic modelling of geographical range evolution. The importance of geographical isolation for speciation was further evaluated by population genetic analyses at the intraspecific level. Results We delimited 92 candidate species, most with restricted distributions, suggesting low dispersal capacity. Highest species diversity was found in the Indo-Malay Archipelago (IMA). Our phylogeny indicates that Portieria originated during the late Cretaceous in the area that is now the Central Indo-Pacific. The biogeographical history of Portieria includes repeated dispersal events to peripheral regions, followed by long-term persistence and diversification of lineages within those regions, and limited dispersal back to the IMA. Main conclusions Our results suggest that the long geological history of the IMA played an important role in shaping Portieria diversity. High species richness in the IMA resulted from a combination of speciation at small spatial scales, possibly as a result of increased regional habitat diversity from the Eocene onwards, and species accumulation via dispersal and/or island integration through tectonic movement. Our results are consistent with the biodiversity feedback model, in which biodiversity hotspots act as both "centres of origin" and "centres of accumulation," and corroborate previous findings for invertebrates and fish that there is no single unifying model explaining the biological diversity within the IMA.

International audience; AimThis study analyses the places and the scales at which the latitudinal diversity gradient (LDG) for vertebrate species holds or, conversely, fails. Although much empirical support for the LDG at a global scale exists, several marked departures have also been previously reported for some regions, scales and organisms. Here, we aim to test the generality of the LDG by accurately quantifying its variability among regions and scales using a novel analysing approach applied on environmental and species data. LocationGlobal; Vertebrate species (amphibians, mammals and birds). MethodsTo test the LDG, we proceeded in two successive steps. First, we collected environmental and vertebrate species data to summarize the overall environment (likely the LDG). In a second step, we compared the two datasets (environment and species biodiversity index maps) using the Comparison Map and Profile (CMP) method. It computes the correlation between datasets in moving windows, all over both maps (at one scale), and by increasing the size (scale) of the moving windows. Cross-correlations are then spatially computed through all scales in order to map and accurately quantify the relationship between environment and biodiversity on Earth. ResultsThe best environmental variable, explaining almost 70% of the spatial variation in vertebrate species richness, was the temperature seasonality composite (TSC), a good surrogate candidate for the LDG. While the TSC-diversity relationship followed an expected LDG-like pattern in the Southern Hemisphere and in the tropics, it showed significant departures from latitudinal trends in Asia and North America. This observation can be explained by the increase in animal species number with increasing northern latitudes. Main conclusionsWe showed that the LDG (i.e. through the TSC surrogate) relationship fails in many places and at all scales in average. We must then reject the mainstream hypothesis of the overall worldwide LDG pattern. We suggest that it should not be taken for granted in macroecological studies, especially over the Northern Hemisphere. The spatial distribution of vertebrate richness is both area and scale dependent, and this observation is robust to changes in spatial resolution, in data coverage (e.g. ecoregions) and in taxa.

Earth's climate has experienced strong changes on timescales ranging from decades to millions of years. As biodiversity has evolved under these circumstances, dependence on these climate dynamics is expected. In this review, we assess the current state of knowledge on paleoclimatic legacies in biodiversity and ecosystem patterns. Paleoclimate has had strong impacts on past biodiversity dynamics, driving range shifts and extinctions as well as diversification. We outline theory for how these dynamics may have left legacies in contemporary patterns and review the empirical evidence. We report ample evidence that Quaternary glacial–interglacial climate change affects current patterns of species distributions and diversity across a broad range of organisms and regions. We also report emerging evidence for paleoclimate effects on current patterns in phylogenetic and functional diversity and ecosystem functioning and for legacies of deeper-time paleoclimate conditions. Finally, we discuss implications for Anthropocene ecology and outline an agenda to improve our understanding of paleoclimate's role in shaping contemporary biodiversity and ecosystems.

Competitive interactions among species with similar ecological niches are known to regulate the assembly of biological communities. However, it is not clear whether such forms of competition can predict the collapse of communities and associated shifts in ecosystem function in the face of environmental change. Here, we use phylogenetic and functional trait data to test whether communities of two ecologically important guilds of tropical birds (frugivores and insectivores) are structured by species interactions in a fragmented Amazonian forest landscape. In both guilds, we found that forest patch size, quality, and degree of isolation influence the phylogenetic and functional trait structure of communities, with small, degraded, or isolated forest patches having an increased signature of competition (i.e., phylogenetic and functional trait overdispersion in relation to null models). These results suggest that local extinctions in the context of fragmentation are nonrandom, with a consistent bias toward more densely occupied regions of niche space. We conclude that the loss of biodiversity in fragmented landscapes is mediated by niche-based competitive interactions among species, with potentially far-reaching implications for key ecosystem processes, including seed dispersal and plant damage by phytophagous insects.

15 pages; International audience; How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) and their two dominant prey orders (Diptera and Lepidoptera). The resultant web shows a dense link structure and no compartmentalization or modularity across the three predator guilds. Thus, both individual predators and predator guilds tap heavily into the prey community of each other, offering versatile scope for indirect interactions across different parts of the web. The current description of a first but single arctic web may serve as a benchmark toward which to gauge future webs resolved by similar techniques. Targeting an unusual breadth of predator guilds, and relying on techniques with a high resolution, it suggests that species in this web are closely connected. Thus, our findings call for similar explorations of link structure across multiple guilds in both arctic and other webs. From an applied perspective, our description of an arctic web suggests new avenues for understanding how arctic food webs are built and function and of how they respond to current climate change. It suggests that to comprehend the community-level consequences of rapid arctic warming, we should turn from analyses of populations, population pairs, and isolated predator-prey interactions to considering the full set of interacting species.

Body size is related to an extensive number of species traits and ecological processes and has therefore been suggested as an effective metric to assess community changes and ecosystem's state. However, the applicability of body size as an ecological indicator in benthic environments has been hindered by the poor knowledge of the factors influencing the size spectra of organisms. By applying biological trait analysis (BTA) and generalized linear models to a species dataset collected in the German Wadden Sea (53A degrees 41'14'' N, 7A degrees 14'19'' E) between 1999 and 2012, we show that the size structure of the macrobenthic community changes predictably along environmental gradients. Specifically, body size increases with increasing current-induced shear stress and sediment organic matter content. In addition, the presence of oyster-mussel reefs in one of the sampling stations enhanced the survival of species belonging to the smallest size categories in habitats with high hydrodynamic energy. This was probably due to the local sheltering effects, which together with biodeposition also increased organic matter in the sediment, likely favoring large deposit feeders as well. Our results suggest that body size can be a useful trait for estimating effects of anthropogenic stressors, such as organic enrichment or alteration of hydrodynamic regime and could therefore be effectively included in current monitoring programs of intertidal macrobenthic communities.

AimsLong-term climate stability is hypothesized to drive the emergence of species assemblages with large species age differences due to the accumulation of relict species and relatively newly arisen species via reduced extinction and increased speciation. Few studies have addressed these predictions and so far no study has done so for plants across the Northern Hemisphere. Here, we linked Quaternary-scale climate variability to phylogenetic age differences between the oldest and youngest group of species in tree assemblages in 100 km × 100 km grid cells across the Northern Hemisphere to test these predictions.Location: Northern Hemisphere.MethodsLast Glacial Maximum (LGM)-to-present shifts in temperature and precipitation were used as proxies for Quaternary-scale glacial–interglacial climate variability. Simultaneous autoregressive (SAR) models were used to assess the relationships between phylogenetic age differences and Quaternary-scale climate variability.ResultsWe found that phylogenetic age differences overall were largest in China and smallest in Europe, and they declined with increasing temperature instability as predicted, but only in Europe and North America. In China, the relatively mild Quaternary climate changes did not appear to have strongly affected phylogenetic age differences in tree assemblages.Main conclusions Our results show that phylogenetically diverse assemblages with large phylogenetic age differences among species are associated with relatively high long-term climate stability, with intra-regional links between long-term climate variability and phylogenetic composition especially strong in the more unstable regions. These findings point to future climate change as a key risk to the preservation of the phylogenetically diverse assemblages in regions characterized by relatively high paleoclimate stability, with China as a key example.

International audience; AimIn interaction with past climate changes, it is likely that plate tectonics contributed to the shaping of current global species diversity, but so far this has not been statistically quantified at the global level. Here, we tested whether plate tectonics since the breakup of Gondwana left an imprint on current patterns of species richness of amphibians, birds and mammals. LocationGlobal. MethodsWe reconstructed the absolute positions of continental plates since the Early Cretaceous and used this information to derive variables of latitudinal shifts and potential exchanges among landmasses that could have modulated species richness. Using a multi-model inference approach combining both contemporary and historical variables, we quantified the relative importance of variables related to plate tectonics in explaining the spatial variation of the richness of amphibians, birds and mammals. Next, we employed a moving window approach to test whether plate tectonics left a more marked imprint in specific regions. ResultsPlatetectonics left an imprint on current patterns of vertebrate species richness in geologically singular regions, especially in the Indo-Australian Archipelago and the region comprising eastern Africa and Madagascar. For birds and mammals, but not amphibians, we found a marked contrast in species richness across Australia and Southeast Asia and eastern Africa and Madagascar associated with plate tectonics. Moreover, the relationship between species richness and plate tectonics varied across taxonomic orders for birds and mammals. Main conclusionsWhile no general imprint of plate tectonics was detected at the global scale, our regional analysis highlighted a substantial role of geodynamics in shaping current patterns of vertebrate species richness in Southeast Asia and Madagascar. Future studies should integrate the full range of processes associated with plate tectonics, including orogeny, not considered here.

Aims: The 50th anniversary of the publication of the seminal book, The Theory of Island Biogeography, by Robert H. MacArthur and Edward O. Wilson, is a timely moment to review and identify key research foci that could advance island biology. Here, we take a collaborative horizon-scanning approach to identify 50 fundamental questions for the continued development of the field. Location: Worldwide. Methods: We adapted a well-established methodology of horizon scanning to identify priority research questions in island biology, and initiated it during the Island Biology 2016 conference held in the Azores. A multidisciplinary working group prepared an initial pool of 187 questions. A series of online surveys was then used to refine a list of the 50 top priority questions. The final shortlist was restricted to questions with a broad conceptual scope, and which should be answerable through achievable research approaches. Results: Questions were structured around four broad and partially overlapping island topics, including: (Macro)Ecology and Biogeography, (Macro)Evolution, Community Ecology, and Conservation and Management. These topics were then subdivided according to the following subject areas: global diversity patterns (five questions in total); island ontogeny and past climate change (4); island rules and syndromes (3); island biogeography theory (4); immigration–speciation–extinction dynamics (5); speciation and diversification (4); dispersal and colonization (3); community assembly (6); biotic interactions (2); global change (5); conservation and management policies (5); and invasive alien species (4). Main conclusions: Collectively, this cross-disciplinary set of topics covering the 50 fundamental questions has the potential to stimulate and guide future research in island biology. By covering fields ranging from biogeography, community ecology and evolution to global change, this horizon scan may help to foster the formation of interdisciplinary research networks, enhancing joint efforts to better understand the past, present and future of island biotas., B.C.E. was supported by Spanish grant CGL2013-42589-P awarded to B.C.E. by the MINECO and co-financed by FEDER, and Spanish grant S20141203_002597 awarded to B.C.E. by the Organismo Autónomo Parques Nacionales of the MAGRAMA.

Aim: Habitat use and migration strategies of animals are often associated with spatial variation in parasite pressure, but how they relate to one another is not well understood. Here, we use a large dataset on helminth species richness of Charadriiform birds to test whether higher habitat diversity and seasonal migration increase parasite richness in avian hosts. Location: Global. Methods: We compiled a global dataset on helminth species richness, habitat use strategies (marine/freshwater/mixed wintering and osmotic generalist/specialist) and various ecological/life-history traits (migration distance, geographical range size, diet, body mass, sampling latitude) of Charadriiform birds. To test if hosts with different habitat use strategies encounter different parasite pressures, we used comparative methods that correct for shared ancestry and phylogenetic uncertainty. Results: Habitat generalists (mixed wintering habitats and osmotic generalists) harboured more parasite species than habitat specialists; marine- and freshwater-restricted hosts had similar helminth species richness. Contrary to previous results, we found no association between parasite species richness and migration distance. Overall helminth species richness also increased with diet diversity, with no effects of other ecological/life-history traits. Main conclusions: We suggest that birds exploiting diverse habitats and diets are exposed to a more diverse parasite fauna and conclude that distribution patterns and habitat use, rather than migration distance, shape parasite diversity within host populations. Overall, these results demonstrate the significant role of habitat use in explaining how migration may indirectly affect parasite richness in host populations.

Sedimentary pollen offers excellent opportunities to reconstruct vegetation changes over past millennia. Number of different pollen taxa or pollen richness is used to characterise past plant richness. To improve the interpretation of sedimentary pollen richness, it is essential to understand the relationship between pollen and plant richness in contemporary landscapes. This study presents a regional-scale comparison of pollen and plant richness from northern Europe and evaluates the importance of environmental variables on pollen and plant richness. We use a pollen dataset of 511 lake-surface pollen samples ranging through temperate, boreal and tundra biomes. To characterise plant diversity, we use a dataset formulated from the two largest plant atlases available in Europe. We compare pollen and plant richness estimates in different groups of taxa (wind-pollinated vs. non-wind-pollinated, trees and shrubs vs. herbs and grasses) and test their relationships with climate and landscape variables. Pollen richness is significantly positively correlated with plant richness (r = 0.53). The pollen plant richness correlation improves (r = 0.63) when high pollen producers are downweighted prior to estimating richness minimising the influence of pollen production on the pollen richness estimate. This suggests that methods accommodating pollen-production differences in richness estimates deserve further attention and should become more widely used in Quaternary pollen diversity studies. The highest correlations are found between pollen and plant richness of trees and shrubs (r = 0.83) and of wind-pollinated taxa (r = 0.75) suggesting that these are the best measures of broad-scale plant richness over several thousands of square kilometres. Mean annual temperature is the strongest predictor of both pollen and plant richness. Landscape openness is positively associated with pollen richness but not with plant richness. Pollen richness values from extremely open and/or cold areas where pollen production is low should be interpreted with caution because low local pollen production increases the proportion of extra-regional pollen. Synthesis. Our results confirm that pollen data can provide insights into past plant richness changes in northern Europe, and with careful consideration of pollen-production differences and spatial scale represented, pollen data make it possible to investigate vegetation diversity trends over long time-scales and under changing climatic and habitat conditions.

International audience; Species assemblages are shaped by local and continental-scale processes that are seldom investigated together, due to the lack of surveys along independent gradients of latitude and habitat types. Our study investigated changes in the effects of forest composition and structure on bat and bird diversity across Europe. We compared the taxonomic and functional diversity of bat and bird assemblages in 209 mature forest plots spread along gradients of forest composition and vertical structure, replicated in 6 regions spanning from the Mediterranean to the boreal biomes. Species richness and functional evenness of both bat and bird communities were affected by the interactions between latitude and forest composition and structure. Bat and bird species richness increased with broadleaved tree cover in temperate and especially in boreal regions but not in the Mediterranean where they increased with conifer abundance. Bat species richness was lower in forests with smaller trees and denser understorey only in northern regions. Bird species richness was not affected by forest structure. Bird functional evenness increased in younger and denser forests. Bat functional evenness was also influenced by interactions between latitude and understorey structure, increasing in temperate forests but decreasing in the Mediterranean. Covariation between bat and bird abundances also shifted across Europe, from negative in southern forests to positive in northern forests. Our results suggest that community assembly processes in bats and birds of European forests are predominantly driven by abundance and accessibility of feeding resources, i.e., insect prey, and their changes across both forest types and latitudes.

The large variation in the relationships between environmental factors and plant traits observed in natural communities exemplifies the alternative solutions that plants have developed in response to the same environmental limitations. Qualitative attributes, such as growth form, woodiness, and leaf habit can be used to approximate these alternative solutions. Here, we quantified the extent to which these attributes affect leaf trait values at a given resource supply level, using measured plant traits from 105 different species (254 observations) distributed across 50 sites in mesic to wet plant communities in The Netherlands. For each site, soil total N, soil total P, and water supply estimates were obtained by field measurements and modeling. Effects of growth forms, woodiness, and leaf habit on relations between leaf traits (SLA, specific leaf area; LNC, leaf nitrogen concentration; and LPC, leaf phosphorus concentration) vs. nutrient and water supply were quantified using maximum-likelihood methods and Bonferroni post hoc tests. The qualitative attributes explained 8-23% of the variance within sites in leaf traits vs. soil fertility relationships, and therefore they can potentially be used to make better predictions of global patterns of leaf traits in relation to nutrient supply. However, at a given soil fertility, the strength of the effect of each qualitative attribute was not the same for all leaf traits. These differences may imply a differential regulation of the leaf economy traits at a given nutrient supply, in which SLA and LPC seem to be regulated in accordance to changes in plant size and architecture while LNC seems to be primarily regulated at the leaf level by factors related to leaf longevity.

Setting aside overmature planted forests is currently seen as an option for preserving species associated with old-growth forests, such as those with dispersal limitation. Few data exist, however, on the utility of set-aside plantations for this purpose, or the value of this habitat type for biodiversity relative to old-growth semi-natural ecosystems. Here, we evaluate the contribution of forest type relative to habitat characteristics in determining species richness and composition in seven forest blocks, each containing an ancient old-growth stand (> 1000 yrs) paired with a set-aside even-aged planted stand (ca. 180 yrs). We investigated the functionally important yet relatively neglected ectomycorrhizal fungi (EMF), a group for which the importance of forest age has not been assessed in broadleaved forests. We found that forest type was not an important determinant of EMF species richness or composition, demonstrating that set-aside can be an effective option for conserving ancient EMF communities. Species richness of above-ground EMF fruiting bodies was principally related to the basal area of the stand (a correlate of canopy cover) and tree species diversity, whilst richness of below-ground ectomycorrhizae was driven only by tree diversity. Our results suggest that overmature planted forest stands, particularly those that are mixed-woods with high basal area, are an effective means to connect and expand ecological networks of ancient old-growth forests in historically deforested and fragmented landscapes for ectomycorrhizal fungi., Highlights • Ectomycorrhizal fungi richness was similar in ancient and overmature planted forest. • Community composition was also similar across the forest types. • Fungal fruit body richness was positively related to basal area and tree diversity. • Below-ground ectomycorrhizae richness was positively related to tree diversity.

A number of nonlinear models have recently been proposed for simulating soil carbon decomposition. Their predictions of soil carbon responses to fresh litter input and warming differ significantly from conventional linear models. Using both stability analysis and numerical simulations, we showed that two of those nonlinear models (a two-pool model and a three-pool model) exhibit damped oscillatory responses to small perturbations. Stability analysis showed the frequency of oscillation is proportional to √(ϵ−1−1) Ks/Vs in the two-pool model, and to √(ϵ−1−1) Kl/Vl in the three-pool model, where ϵ is microbial growth efficiency, Ks and Kl are the half saturation constants of soil and litter carbon, respectively, and /Vs and /Vl are the maximal rates of carbon decomposition per unit of microbial biomass for soil and litter carbon, respectively. For both models, the oscillation has a period of between 5 and 15 years depending on other parameter values, and has smaller amplitude at soil temperatures between 0 and 15 °C. In addition, the equilibrium pool sizes of litter or soil carbon are insensitive to carbon inputs in the nonlinear model, but are proportional to carbon input in the conventional linear model. Under warming, the microbial biomass and litter carbon pools simulated by the nonlinear models can increase or decrease, depending whether ϵ varies with temperature. In contrast, the conventional linear models always simulate a decrease in both microbial and litter carbon pools with warming. Based on the evidence available, we concluded that the oscillatory behavior and insensitivity of soil carbon to carbon input are notable features in these nonlinear models that are somewhat unrealistic. We recommend that a better model for capturing the soil carbon dynamics over decadal to centennial timescales would combine the sensitivity of the conventional models to carbon influx with the flexible response to warming of the nonlinear model.

Ponds are among the most diverse and yet threatened components of freshwater biodiversity. The conservation of ponds would greatly benefit from the identification of surrogate taxa in preliminary assessments aimed at detecting ponds of potentially high biodiversity value. Here, we used predictive co-correspondence analysis (Co-CA) to quantify the strength of plant species composition and plant community types in predicting multivariate patterns in water beetle assemblages, based on data from 54 farmland ponds in Ireland. The predictive accuracy of a number of environmental variables as well as that of plant diversity (species richness and evenness) was calculated using predictive canonical correspondence analysis (CCA-PLS). The study ponds supported over 30% of the Irish water beetle fauna (76 species), with five species having some form of IUCN Red List Status in Ireland, as well as 67 wetland plant species, including a nationally rare one. Co-CA showed that plant species composition had a positive predictive accuracy, which was significantly higher compared to that of data at the plant community type level. Although environmental variables showed a higher predictive capacity compared to that of plant species composition, the difference was not significant. Explanatory CCA analyses showed that plants and beetles both responded to the same subset of environmental conditions, which explained approximately 18% of the variation in both plant and beetle species composition. Regional differences as well as permanency, substratum, and grazing intensity affected the composition of both plant and beetle assemblages. These findings have important implications in conservation planning. First, wetland plants can be effectively used as a surrogate taxon in the identification of conservation-priority ponds. Second, conservation strategies aimed at maintaining and enhancing pond biodiversity should be based on considerations on plant species composition.

9 páginas, 5 figuras., We have applied a global analytical approach to uncultured Archaea that for the first time reveals well-defined community patterns along broad environmental gradients and habitat types. Phylogenetic patterns and the environmental factors governing the creation and maintenance of these patterns were analyzed for c. 2000 archaeal 16S rRNA gene sequences from 67 globally distributed studies. The sequences were dereplicated at 97% identity, grouped into seven habitat types, and analyzed with both Unifrac (to explore shared phylogenetic history) and multivariate regression tree (that considers the relative abundance of the lineages or taxa) approaches. Both phylogenetic and taxon-based approaches showed salinity and not temperature as one of the principal driving forces at the global scale. Hydrothermal vents and planktonic freshwater habitats emerged as the largest reservoirs of archaeal diversity and consequently are promising environments for the discovery of new archaeal lineages. Conversely, soils were more phylogenetically clustered and archaeal diversity was the result of a high number of closely related phylotypes rather than different lineages. Applying the ecological concept of ‘indicator species’, we detected up to 13 indicator archaeal lineages for the seven habitats prospected. Some of these lineages (that is, hypersaline MSBL1, marine sediment FCG1 and freshwater plSA1), for which ecological importance has remained unseen to date, deserve further attention as they represent potential key archaeal groups in terms of distribution and ecological processes. Hydrothermal vents held the highest number of indicator lineages, suggesting it would be the earliest habitat colonized by Archaea. Overall, our approach provided ecological support for the often arbitrary nomenclature within uncultured Archaea, as well as phylogeographical clues on key ecological and evolutionary aspects of archaeal biology., This research was supported by grant CRENYC CGL2006- 12058 to EOC from the Spanish Ministerio de Educacio´n y Ciencia (MEC), and CONSOLIDER-INGENIO 2010 project GRACCIE CSD2007-00004. JCA benefits from a Juan de la Cierva-MEC postdoctoral fellow, and AB is supported by an FPU-MEC predoctoral scholarship.

Microbial communities respond to a variety of environmental factors related to resources (e.g. plant and soil organic matter), habitat (e.g. soil characteristics) and predation (e.g. nematodes, protozoa and viruses). However, the relative contribution of these factors on microbial community composition is poorly understood. Here, we sampled soils from 30 chalk grassland fields located in three different chalk hill ridges of Southern England, using a spatially explicit sampling scheme. We assessed microbial communities via phospholipid fatty acid (PLFA) analyses and PCR-denaturing gradient gel electrophoresis (DGGE) and measured soil characteristics, as well as nematode and plant community composition. The relative influences of space, soil, vegetation and nematodes on soil microorganisms were contrasted using variation partitioning and path analysis. Results indicate that soil characteristics and plant community composition, representing habitat and resources, shape soil microbial community composition, whereas the influence of nematodes, a potential predation factor, appears to be relatively small. Spatial variation in microbial community structure was detected at broad (between fields) and fine (within fields) scales, suggesting that microbial communities exhibit biogeographic patterns at different scales. Although our analysis included several relevant explanatory data sets, a large part of the variation in microbial communities remained unexplained (up to 92% in some analyses). However, in several analyses, significant parts of the variation in microbial community structure could be explained. The results of this study contribute to our understanding of the relative importance of different environmental and spatial factors in driving the composition of soil-borne microbial communities. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

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