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International audience; The global distribution of exotic species is the result of abiotic, biotic and dispersal filtering processes that shape the movement and success of species outside their native range. In this study we aim to understand how these filtering processes drive the fluxes of grass species among regions, the factors that influence which species establish outside of their native range, and where they do so. We used national and subnational checklists of native and introduced grass species to determine the extent to which each region was a source or recipient of exotic grass species. We asked how species traits may distinguish those grass species that have naturalized outside their native range from those that have not, and how environmental conditions are related to the distribution of exotic grass species. We found that exotic grass establishment is shaped by an array of factors including characteristics of regions, traits of species and their interactions. Regions with a longer history of human occupation and larger numbers of native grass species were generally the most important sources of exotic species. Global flows of species were mostly driven by a climate match between the native and exotic ranges, but were also highly asymmetric, with regions with recent human arrival being the major hosts of exotic grass species. Tall, annual and C4 grass species exhibited particularly high probabilities of establishment outside their native range. Despite the idiosyncrasy and stochasticity characteristic of exotic species establishment, this biogeographical analysis revealed important generalities across this large plant group. Our results suggest that grass species that have co-occurred with humans for a longer time may be better adapted to living in anthropogenic landscapes, explaining the global asymmetry in species introductions.

Trees play a key role in the structure and function of many ecosystems worldwide. In the Mediterranean Basin, forests cover approximately 22% of the total land area hosting a large number of endemics (46 species). Despite its particularities and vulnerability, the biodiversity of Mediterranean trees is not well known at the taxonomic, spatial, functional, and genetic levels required for conservation applications. The WOODIV database fills this gap by providing reliable occurrences, four functional traits (plant height, seed mass, wood density, and specific leaf area), and sequences from three DNA-regions (rbcL, matK, and trnH-psbA), together with modelled occurrences and a phylogeny for all 210 Euro-Mediterranean tree species. We compiled, homogenized, and verified occurrence data from sparse datasets and collated them on an INSPIRE-compliant 10 × 10 km grid. We also gathered functional trait and genetic data, filling existing gaps where possible. The WOODIV database can benefit macroecological studies in the fields of conservation, biogeography, and community ecology.

International audience; Population reinforcement, through translocations of individuals, aims to restore populations of threatened species. The increase in population size or geographic distribution is often used as positive facts when assessing the recovery of a species, making abundance monitoring a major criterion. Based on 8-year monitoring of a reinforced population of North African Houbara bustard (Chlamydotis undulata undulata), over an area of 50,170 km² in the eastern region of Morocco, we assessed the success of management actions by assessing spatial and temporal variation in abundance as well as the factors driving this variation. We used count data to estimate and spatialize population abundance. We then assessed environmental (climate) and management covariates (release effort and hunting management) associated with temporal and spatial variation in abundance. The overall estimate of abundance in the study area was 16,918 individuals (95% CI = 13,629 to 21,027) over our study period, with strong variation between years (range = 10,409-32,401). Our results highlighted strong spatial heterogeneity over the study area, linked to spatial variation in local climate and management conditions. Local abundances were negatively associated with local temperature, were higher in hunting than in non-hunting areas, and were positively influenced by the number of birds released around the focal point. In addition to describing the spatio-temporal variation in the abundance of the species on a large scale, we estimated two major proxies of its conservation status: population size and population trend. The determination of these proxies and the comparison with the counterfactual state of the species confirms the beneficial impact of the restoration and protection programme on the dynamics of the North African Houbara bustard, while underlining the dependence of these dynamics on ongoing management.

International audience; L’informatisation des collections d’histoire naturelle et leur agrégation dans des portails globaux donnent un accès sans précédent à la richesse des collections. De la gestion des collections à l’analyse scientifique, le défi consiste à s’approprier ce changement d’échelle en regard de la quantité et de la nature des données pour répondre à de nouvelles questions dans une dynamique de science ouverte.

Aim: The Mediterranean Basin is a major hotspot of plant biodiversity, including forest trees. Over the past centuries, Mediterranean forests have been fragmented and over-exploited, to which the threats of climate change are now added. Our aim is to better understand patterns and processes of tree biodiversity in the Mediterranean and to provide indicators complementing the traditional approaches to biodiversity conservation based on species counts and occurrences, using georeferenced phylogenetic diversity and endemism analyses in a spatial ecological context. Location: Mediterranean Europe. Methods: Using a dated phylogeny of the 64 Euro-Mediterranean tree genera, we calculated phylogenetic diversity for all 50 × 50 km2 grid cells spanning Mediterranean Europe (n = 643) and compared values with those obtained for genus-level taxonomic diversity. Then, we tested the relative influence of geography, past and present climate, and soil on tree diversity (phylogenetic or taxonomic) and its geographical turnover. Geographical patterns of phylogenetic endemism were inferred using the Categorical Analyses of Neo- and Paleo-Endemism (CANAPE) methodology. Results: We showed that phylogenetic and taxonomic diversity within and among cells are correlated and influenced by soil parameters as well as current, Holocene and Late Glacial Maximum climate. Southern Spain, Cyprus and some Aegean islands contained areas of disproportionately high phylogenetic diversity and a concentration of phylogenetic paleo-endemics, while phylogenetic neo-endemism was high in eastern Sicily. Mixed phylogenetic endemism regions were detected in southern Spain and Portugal, in the Balkans and in Crete. Main conclusions: Our phylogenetic approach provides relevant indicators for better protecting forests of the Mediterranean, encompassing past and present evolutionary processes and factors. We consider areas that show a concentration of evolutionary history manifested by high phylogenetic endemism as high priority targets for the conservation of the European tree flora. Aix-Marseille University ANR-11-LABX-0061

International audience; Scenarios of biodiversity and ecosystem services (BES) are key for decision-makers to understand the consequences of future environmental change on BES. Though a major driver of terrestrial biodiversity loss, land use and land cover changes (LUCC) have been largely overlooked in previous BES assessments. But ecologists lack practical guidance for the general use of LUCC projections. We review the practices in use in LUCC-driven BES assessments and summarize the questions ecologists should address before using LUCC projections. LUCC-driven BES scenarios rely on a substantial set of different socioeconomic storylines (> 200 for 166 papers). Studies explore different futures, but generally concentrate on projections obtained from a single LUCC model. The rationale regarding time horizon, spatial resolution, or the set of storylines used is rarely made explicit. This huge heterogeneity and low transparency regarding the what, why, and how of using LUCC projections for the study of BES futures could discourage researchers from engaging in the design of such biodiversity scenarios. Our results call on those using LUCC projections to more systematically report on the choices they make when designing LUCC-based BES scenarios (e.g. time horizon, spatial and thematic resolutions, scope of contrasted futures). Beyond the improvement of reliability, reproducibility, and comparability of these scenarios, this could also greatly benefit others wanting to use the same LUCC projections, and help land use modellers better meet the needs of their intended audiences. The uncertainties in LUCC-driven BES futures should also be explored more comprehensively, including different socioeconomic storylines and different LUCC models, as recommended in studies dealing with climate-driven BES futures.

International audience; We produced the first time-calibrated phylogeny of all 64 native tree genera occurring on the European side of the Mediterranean Basin. This phylogeny is based on 3 plastid DNA sequences (rbcL matK and trnH-psbA), 4 recognized fossil dates and 10 secondary calibrations. Based on the inferred topology, we then tested whether the investigated tree flora exhibits phylogenetic clustering in both life-history traits known to influence reproduction and species' vulnerability to extinction. Our topology and the estimated dates mostly conform to published partial phylogenies and are highly congruent with the Angiosperm Phylogeny Group classification except for some minor incongruences including the still debated phylogenetic position of Magnoliids. The four strictly endemic genera of the Mediterranean Basin (Chamaerops, Phillyrea, Spartium and Tetraclinis) all showed emergence dates (11-72 Ma) long before the onset of the Mediterranean climate. We did not find any imprints of phylogenetic sorting processes on the life-history traits we studied, except for the mode of seed dispersal, which showed a clustered distribution across our topology. The presence of species at risk of potential extinction within a given genus was randomly distributed along the phylogenetic tree. Species with deficient data were significantly nested within a few of the most recently evolved angiosperm genera. Our analysis closes knowledge gaps and provides a valuable basis for studying the biogeo-graphical and ecological processes that have generated the Mediterranean tree flora. It can also inform conservation planning strategies that aim at broadening traditional taxonomy-focused perspectives with components of evolutionary history and phylogenetic singularity.

International audience

BACKGROUND AND AIMS Earth's climate is dynamic, with strong glacial-interglacial cycles through the Late Quaternary. These climate changes have had major consequences for the distributions of species through time, and may have produced historical legacies in modern ecological patterns. Unstable regions are expected to contain few endemic species, many species with strong dispersal abilities, and to be susceptible to the establishment of exotic species from relatively stable regions. We test these hypotheses with a global dataset of grass species distributions. METHODS We described global patterns of endemism, variation in the potential for rapid population spread, and exotic establishment in grasses. We then examined relationships of these response variables to a suite of predictor variables describing the mean, seasonality and spatial pattern of current climate and the temperature change velocity from the Last Glacial Maximum to the present. KEY RESULTS Grass endemism is strongly concentrated in regions with historically stable climates. It also depends on the spatial pattern of current climate, with many endemic species in areas with regionally unusual climates. There was no association between the proportion of annual species (representing potential population spread rates) and climate change velocity. Rather, the proportion of annual species depended very strongly on current temperature. Among relatively stable regions ( 10 m year-1). Exotic species were most likely to originate from relatively stable regions with climates similar to those found in their exotic range. CONCLUSIONS Long-term climate stability has important influences on global endemism patterns, largely confirming previous work from other groups. Less well recognized is its role in generating patterns of exotic species establishment. This result provides an important historical context for the conjecture that climate change in the near future may promote species invasions.

Questions Research efforts have sought to understand trait–trait relationships among species and trait–environment relationships. However, connections between these two approaches are rare, despite the fact that species-level trait–trait correlations constrain the possible trait–environment correlations. We ask how functional traits of grasses are related to each other and to environmental variation. Location Global, with particular focus on the continental United States. Methods We compiled distribution data for grasses with three spatial grains – TDWG Level 3 ‘botanical countries’, US counties and vegetation plots within the US. We combined these data with trait data compiled from published sources for 14 traits describing physical and chemical features of the leaves, seeds, roots and entire plant. Trait–trait relationships were explored using correlations and PCA, and trait–environment relationships using regression. Finally, we implemented a null model to predict trait–trait correlations at the assemblage level from those at the species level. Results The functional trait composition of grass species varied strongly along environmental gradients. At the species level, there were two main clusters of related traits – one describing general plant size (including height, seed mass, leaf size and rooting depth), and one describing the leaf economics spectrum (including specific leaf area, Nmass and Pmass). Most trait–trait correlations at the assemblage level did not differ significantly from that predicted from the species level, suggesting that the former are strongly constrained by the latter. Trait–trait and trait–environment relationships in grasses were broadly similar to those observed for other groups, with some exceptions related to the particular growth form, physiology and ecology of grass species. Conclusions The unique evolutionary history and ecological role of grasses has led to some unusual trait–climate relationships in the group. Co-variation among traits at the species level is an important template upon which environmental filters act to determine assemblage trait composition.

International audience; Biological invasions are one of the main threats to biodiversity worldwide, and understanding the mechanisms allowing invasive species to colonize their new environments is critical to the management of invasive populations. One particular aspect of invasion biology is to define the environmental conditions within which invasive species can persist (i.e. their ecological niche) to get insights on the potential role of adaptation in successful invasions, as well as to predict future invasion. Here, we use multiple correlative species distribution models and metrics of niche expansion and stability to investigate the worldwide invasion of the spotted-wing drosophila, Drosophila suzukii. By modeling the climatic niche of D. suzukii from occurrence data in its native and invasive ranges, we tested if a shift in the realized niche has occurred during invasion. Furthermore, we use recent population genetics work on the invasion history of the species to test whether invasive populations have preferentially invaded areas with climatic conditions more similar to the ones in their precise area of origin. Overall, our results show that D. suzukii displays a wide climatic niche and suggest that the species' success in the invaded ranges may result from the absence of environmental challenges upon colonization. Furthermore, we show that the use of different geographical backgrounds can impact the outputs of niche comparisons and advice using complementary methods in the study of niche dynamics during biological invasions.

The success of translocation programs aiming to boost the effective population size of a declining species is conditioned by the ability of released individuals to survive and breed effectively while they share the ecological niche of wild individuals. Although ecological niche models are increasingly used as tools for conservation translocations, the realized niche of released and wild populations is seldom compared. In this study, we used data from long-term monitoring of a reinforced population of Houbara Bustards in Morocco. We compared the patterns of use of ecological space in the wild by 446 captive-hatched individuals which settled for breeding with the patterns shown by the wild population from the monitoring of 233 wild-hatched adult breeders. We measured the between-sex similarity of the ecological niches and of the geographical distributions. We found that wild-hatched and captive-hatched individuals shared a large part of the ecological space, suggesting a successful integration of captive-hatched mature individuals. The wild-hatched individuals used a broader range of environmental conditions, driven by females that were, on average, older than captive-hatched females and dispersed toward more arid environments. Although the wild- and captive-hatched males had different geographical distributions, they had statistically equivalent ecological niches. This finding suggests that the released Houbaras succeeded in settling new lekking grounds within a similar ecological niche over a larger spatial extent. Such feedback from post-release monitoring is still rare and appears to be a critical validation step for the subsequent use of ENM in translocation programs to assess the quality of release sites.

International audience; The habitat suitability index, which reflects spatial variability in species occurrence probability, has been shown to exhibit various contrasting relationships with local demographic performances (survival, productivity) in several species. One proposed explanation for these discrepancies is that the link between the habitat suitability index and demography is influenced by density‐dependent, temporally variable processes. Based on the survival rates of more than 3,000 nests monitored over 12 years in the North African Houbara Bustard, we investigated whether the habitat suitability index computed over the species breeding range is related to nest survival throughout the breeding season, accounting for variation in meteorological conditions. We found that the relationship between the habitat suitability index and nest survival progressively changes along the breeding season and that this intra‐annual variation is consistent between years. Our results support the hypothesis that variation in space use occurs intra‐annually and that biotic interactions throughout the breeding season strongly influence the habitat suitability index–demography relationship.

Aim We assessed the temporal trends of taxonomic, functional and phylogenetic diversities in the French avifauna over the last two decades. Additionally, we investigated whether and how this multifaceted approach to biodiversity dynamics can reveal an increasing similarity of local assemblages in terms of species,traits and/or lineages. Location France. Methods We analysed a large-scale dataset that recorded annual changes in the abundance of 116 breeding birds in France between 1989 and 2012. We decomposed and analysed the spatio-temporal dynamics of taxonomic, phylogenetic and functional diversities and each of their α-,β- andγ-components.We also calculated the trend in the mean specialization of bird communities to track the relative success of specialist versus generalist species within communities during the same period. Results We found large variation within and among the temporal trends of each biodiversity facet. On average, we found a marked increase in species and phylogenetic diversity over the period considered, but no particular trend was found for functional diversity. Conversely, changes in β-diversities for the three facets were characterized by independent and nonlinear trends. We also found a general increase in the local occurrence and abundance of generalist species within local communities. Main conclusions These results highlight a relative asynchrony of the different biodiversity facets occurring at large spatial scales. We show why a multifaceted approach to biodiversity dynamics is needed to better describe and understand changes in community composition in macroecology and conservation biogeography.

The field of biodiversity conservation has recently been criticized as relying on a fixist view of the living world in which existing species constitute at the same time targets of conservation efforts and static states of reference, which is in apparent disagreement with evolutionary dynamics. We reviewed the prominent role of species as conservation units and the common benchmark approach to conservation that aims to use past biodiversity as a reference to conserve current biodiversity. We found that the species approach is justified by the discrepancy between the time scales of macroevolution and human influence and that biodiversity benchmarks are based on reference processes rather than fixed reference states. Overall, we argue that the ethical and theoretical frameworks underlying conservation research are based on macroevolutionary processes, such as extinction dynamics. Current species, phylogenetic, community, and functional conservation approaches constitute short-term responses to short-term human effects on these reference processes, and these approaches are consistent with evolutionary principles.

International audience; Despite the increasing use of Species Distribution Models for predicting current or future animal distribution, only a few studies have linked the gradient of habitat suitability (HS) to demographic parameters. While such approaches can improve the reliability of models, they can help to better predict the response of species to changes in HS over space and time, as induced by ongoing global change. Here, we tested whether the spatial variation in HS along the individual movement path is related to survival, using extensive tracking data collected from captive-born individuals translocated to reinforce the wild populations of Houbara bustard. We first modelled and mapped the HS from presence data of wild individuals using niche models in a consensus framework. We further analysed survival of released individuals using capture-recapture modelling and its links to HS, as the trend in suitability from the release sites along movements. We found that the survival of released individuals was related to changes in HS along their movements. For instance, individuals which moved to sites of lower HS than their release sites have lower survival probabilities than the others, independently of the HS of the release sites and daily movement rate. Our results provide an empirical support of the relationship between HS and survival, a major fitness component.

The ectomycorrhizal (ECM) symbiosis connects mutualistic plants and fungal species into bipartite networks. While links between one focal ECM plant and its fungal symbionts have been widely documented, systemic views of ECM networks are lacking, in particular, concerning the ability of fungal species to mediate indirect ecological interactions between ECM plant species (projected-ECM networks). We assembled a large dataset of plant–fungi associations at the species level and at the scale of Corsica using molecular data and unambiguously host-assigned records to: (i) examine the correlation between the number of fungal symbionts of a plant species and the average specialization of these fungal species, (ii) explore the structure of the plant–plant projected network and (iii) compare plant association patterns in regard to their position along the ecological succession. Our analysis reveals no trade-off between specialization of plants and specialization of their partners and a saturation of the plant projected network. Moreover, there is a significantly lower-than-expected sharing of partners between early- and late-successional plant species, with fewer fungal partners for early-successional ones and similar average specialization of symbionts of early- and late-successional plants. Our work paves the way for ecological readings of Mediterranean landscapes that include the astonishing diversity of below-ground interactions.

We produced the first time-calibrated phylogeny of all 64 native tree genera occurring on the European side of the Mediterranean Basin. This phylogeny is based on 3 plastid DNA sequences (rbcL matK and trnH-psbA), 4 recognized fossil dates and 10 secondary calibrations. Based on the inferred topology, we then tested whether the investigated tree flora exhibits phylogenetic clustering in both life-history traits known to influence reproduction and species’ vulnerability to extinction. Our topology and the estimated dates mostly conform to published partial phylogenies and are highly congruent with the Angiosperm Phylogeny Group classification except for some minor incongruences including the still debated phylogenetic position of Magnoliids. The four strictly endemic genera of the Mediterranean Basin (Chamaerops, Phillyrea, Spartium and Tetraclinis) all showed emergence dates (11–72 Ma) long before the onset of the Mediterranean climate. We did not find any imprints of phylogenetic sorting processes on the life-history traits we studied, except for the mode of seed dispersal, which showed a clustered distribution across our topology. The presence of species at risk of potential extinction within a given genus was randomly distributed along the phylogenetic tree. Species with deficient data were significantly nested within a few of the most recently evolved angiosperm genera. Our analysis closes knowledge gaps and provides a valuable basis for studying the biogeographical and ecological processes that have generated the Mediterranean tree flora. It can also inform conservation planning strategies that aim at broadening traditional taxonomy-focused perspectives with components of evolutionary history and phylogenetic singularity.

We produced the first time-calibrated phylogeny of all 64 native tree genera occurring on the European side of the Mediterranean Basin. This phylogeny is based on 3 plastid DNA sequences (rbcL matK and trnH-psbA), 4 recognized fossil dates and 10 secondary calibrations. Based on the inferred topology, we then tested whether the investigated tree flora exhibits phylogenetic clustering in both life-history traits known to influence reproduction and species’ vulnerability to extinction. Our topology and the estimated dates mostly conform to published partial phylogenies and are highly congruent with the Angiosperm Phylogeny Group classification except for some minor incongruences including the still debated phylogenetic position of Magnoliids. The four strictly endemic genera of the Mediterranean Basin (Chamaerops, Phillyrea, Spartium and Tetraclinis) all showed emergence dates (11–72 Ma) long before the onset of the Mediterranean climate. We did not find any imprints of phylogenetic sorting processes on the life-history traits we studied, except for the mode of seed dispersal, which showed a clustered distribution across our topology. The presence of species at risk of potential extinction within a given genus was randomly distributed along the phylogenetic tree. Species with deficient data were significantly nested within a few of the most recently evolved angiosperm genera. Our analysis closes knowledge gaps and provides a valuable basis for studying the biogeographical and ecological processes that have generated the Mediterranean tree flora. It can also inform conservation planning strategies that aim at broadening traditional taxonomy-focused perspectives with components of evolutionary history and phylogenetic singularity.