Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects.We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives. Geosphere-Biosphere Program (IGBP) and DIVERSITAS, the TRY database (TRY-not an acronym, rather a statement of sentiment; https ://www.try-db.org; Kattge et al., 2011) was proposed with the explicit assignment to improve the availability and accessibility of plant trait data for ecology and earth system sciences. The Max Planck Institute for Biogeochemistry (MPI-BGC) offered to host the database and the different groups joined forces for this community-driven program. Two factors were key to the success of TRY: the support and trust of leaders in the field of functional plant ecology submitting large databases and the long-term funding by the Max Planck Society, the MPI-BGC and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, which has enabled the continuous development of the TRY database.

Summary Understanding how rates of reproduction and survival respond to environmental variation across species’ geographical ranges is a key task for both basic and applied ecology. So far, however, environmental drivers of range‐wide demographic variation have only been studied in a few plant species without considering the potentially confounding effects of population density on demographic rates. We present a large‐scale demographic study of 26 shrub species (Proteaceae) from the Cape Floristic Region. All study species have a fire‐dependent life cycle and are serotinous: they exclusively form a canopy seed bank which contains the seeds produced since the last fire. Fire triggers seed release from the canopy so that recruitment is largely limited to a short period after fire. Across the global geographical ranges of the study species, we collected 3454 population‐level records of total fecundity since the last fire (size of individual canopy seed banks), per‐capita recruitment (ratio between post‐fire recruits and pre‐fire adults) and adult fire survival. We used linear regressions to quantify how climate, population density, fire interval and soil nutrients affect demographic variation. A trade‐off between survival and reproduction is evident throughout the geographical ranges of our study species: resprouting species with fire‐protected buds had much higher fire survival than nonsprouters without fire‐protected buds (97% vs. 2%) but they also had substantially lower fecundity and recruitment rates. We found little intraspecific variation in fire survival rates but considerable intraspecific variation in fecundity and recruitment. Range‐wide variation in fecundity was dominated by fire interval whereas recruitment was mostly climate‐driven. Population density and soil nutrients generally had smaller effects but were important for the fecundity and recruitment of several species. Effects of fire interval on fecundity were consistent across species, but other demography–environment relationships showed substantial interspecific differentiation. Synthesis. This study extends demographic research beyond the population to cover the geographical ranges of multiple species. Such large‐scale studies are a necessary first step of a research agenda that aims to understand how range dynamics emerge from first principles of demography, how they are shaped by functional traits and macroevolution and how they will be impacted by global change.

The ecological niche of a species describes the variation in population growth rates along environmental gradients that drives geographic range dynamics. Niches are thus central for understanding and forecasting species’ geographic distributions. However, theory predicts that migration limitation, source–sink dynamics, and time-lagged local extinction can cause mismatches between niches and geographic distributions. It is still unclear how relevant these niche–distribution mismatches are for biodiversity dynamics and how they depend on species life-history traits. This is mainly due to a lack of the comprehensive, range-wide demographic data needed to directly infer ecological niches for multiple species. Here we quantify niches from extensive demographic measurements along environmental gradients across the geographic ranges of 26 plant species (Proteaceae; South Africa). We then test whether life history explains variation in species’ niches and niche–distribution mismatches. Niches are generally wider for species with high seed dispersal or persistence abilities. Life-history traits also explain the considerable interspecific variation in niche–distribution mismatches: poorer dispersers are absent from larger parts of their potential geographic ranges, whereas species with higher persistence ability more frequently occupy environments outside their ecological niche. Our study thus identifies major demographic and functional determinants of species’ niches and geographic distributions. It highlights that the inference of ecological niches from geographical distributions is most problematic for poorly dispersed and highly persistent species. We conclude that the direct quantification of ecological niches from demographic responses to environmental variation is a crucial step toward a better predictive understanding of biodiversity dynamics under environmental change.