Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.

Aim It is not yet clear whether similar mechanisms influence the assembly of ecological communities across different continents. Here, we investigated the functional and phylogenetic diversity of bird assemblages along elevational gradients in two biogeographic regions in order to identify how these are driven by biotic factors, such as food resources and vegetation structure, and abiotic factors, such as ambient temperature and precipitation. Location Two 2,000‐m elevational gradients in the Ecuadorian Andes and on Mount Kilimanjaro, Tanzania. Taxon Forest‐dwelling bird species. Methods We recorded bird species abundances on 18 and 30 plots in the Ecuadorian Andes and on Mount Kilimanjaro respectively. We measured 10 functional morphological traits, related to bird feeding and movement, and utilized bird phylogenies to compare observed values and null‐model corrected effect sizes of functional and phylogenetic diversity along elevational gradients and between biogeographic regions. Furthermore, we assessed how observed values and effect sizes of functional and phylogenetic diversity were associated with the underlying gradients in available food resources, vegetation structure, temperature and precipitation. Results Functional and phylogenetic diversity were generally higher in species assemblages in the Ecuadorian Andes than on Mount Kilimanjaro. Both observed values and effect sizes of functional and phylogenetic diversity decreased significantly with increasing elevation in both biogeographic regions. Functional diversity consistently increased with increasing resource availability, whereas phylogenetic diversity increased with increasing vegetation heterogeneity and canopy closure in both biogeographic regions. Temperature and precipitation were not significantly associated with functional and phylogenetic diversity. Main conclusions Our results suggest that in both mountain systems the diversity of functional traits in bird species assemblages is the result of environmental filtering by available food resources, whereas phylogenetic diversity is primarily limited by vegetation structure. These findings suggest important differences in the main drivers of functional and phylogenetic diversity. We conclude that biotic factors might be more important for driving bird diversity patterns than abiotic factors and that a loss of resource availability and vegetation structure, e.g., through human impacts, is likely to trigger changes in community assembly on tropical mountains.

Aim Trait‐based approaches are increasingly important in ecology and biogeography, but progress is often hampered by the availability of high‐quality quantitative trait data collected in the field. Alternative sources of trait information include scientific floras and taxonomic monographs. Here we test the reliability and usefulness of trait data acquired from scientific floras against trait values measured in the field, and those in TRY, the most comprehensive global plant trait database. Location Tenerife and La Palma, Canary Islands, Spain. Methods We measured leaf area and specific leaf area (SLA) in the field for 451 native vascular plant species and compared them with equivalent trait data digitised from the most recent and comprehensive guide of the Canarian flora, and data sourced from TRY. We regressed the field‐measured traits against their equivalents estimated from the literature and used the regression models from one island to predict the trait values on the other island. Results For leaf area, linear models showed good agreement between values from the scientific flora and those measured in the field (r2 = 0.86). These models were spatially transferable across islands. In contrast, for SLA we found a weak relationship between field‐measured values and the best estimates from the scientific flora (r2 = 0.11). Insufficient data were available in the TRY database for our study area to calculate trait correlations with other data sources. Conclusions Scientific floras can act as useful data sources for quantitative plant trait data for some traits but not others, whilst the TRY database contains many traits, but is incomplete in species coverage for our study region, and oceanic islands in general.

Aim Functional traits can help us to elucidate biogeographical and ecological processes driving assemblage structure. We analysed the functional diversity of plant species of different evolutionary origins across an island archipelago, along environmental gradients and across geological age, to assess functional aspects of island biogeographical theory. Location Canary Islands, Spain. Major taxa studied Spermatophytes. Time period Present day. Methods We collected data for four traits (plant height, leaf length, flower length and fruit length) associated with resource acquisition, competitive ability, reproduction and dispersal ability of 893 endemic, non‐endemic native and alien plant species (c. 43% of the Canary Island flora) from the literature. Linking these traits to species occurrences and composition across a 500 m × 500 m grid, we calculated functional diversity for endemic, non‐endemic native and alien assemblages using multidimensional functional hypervolumes and related the resulting patterns to climatic (humidity) and island biogeographical (geographical isolation, topographic complexity and geological age) gradients. Results Trait space of endemic and non‐endemic native species overlapped considerably, and alien species added novel trait combinations, expanding the overall functional space of the Canary Islands. We found that functional diversity of endemic plant assemblages was highest in geographically isolated and humid grid cells. Functional diversity of non‐endemic native assemblages was highest in less isolated and humid grid cells. In contrast, functional diversity of alien assemblages was highest in arid ecosystems. Topographic complexity and geological age had only a subordinate effect on functional diversity across floristic groups. Main conclusions We found that endemic and non‐endemic native island species possess similar traits, whereas alien species tend to expand functional space in ecosystems where they have been introduced. The spatial distribution of the functional diversity of floristic groups is very distinct across environmental gradients, indicating that species assemblages of different evolutionary origins thrive functionally in dissimilar habitats.

Questions Both species turnover and intraspecific trait variation can affect plant assemblage dynamics along environmental gradients. Here, we asked how community assemblage patterns in relation to species turnover and intraspecific variation differ between endemic and non‐endemic species. We hypothesized that endemic species show lower intraspecific variation than non‐endemic species because they tend to have high rates of in situ speciation, whereas non‐endemic species are expected to have a larger gene pool and higher phenotypic plasticity. Location La Palma, Canary Islands. Methods We established 44 sampling sites along a directional gradient of precipitation, heat load, soil nitrogen, phosphorus and pH. Along this gradient, we estimated species abundances and measured three traits (plant height, leaf area and leaf thickness) on perennial endemic and non‐endemic plant species. In total, we recorded traits for 1,223 plant individuals of 43 species. Subsequently, we calculated community‐weighted mean traits to measure the relative contribution of species turnover, intraspecific variation and their covariation along the analysed gradient. Results The contribution of intraspecific variation to total variation was similar in endemic and non‐endemic assemblages. For plant height, intraspecific variation explained roughly as much variation as species turnover. For leaf area and leaf thickness, intraspecific variation explained almost no variation. Species turnover effects mainly drove trait responses along the environmental gradient, but intraspecific variation was important for responses in leaf area to precipitation. Conclusions Despite their distinct evolutionary history, endemic and non‐endemic plant assemblages show similar patterns in species turnover and intraspecific variation. Our results indicate that species turnover is the main component of trait variation in the underlying study system. However, intraspecific variation can increase individual species’ fitness in response to precipitation. Overall, our study challenges the theory that intraspecific trait variation is more important for the establishment of non‐endemic species compared with endemic species.

AimOceanic islands possess unique floras with high proportions of endemic species. Island floras are expected to be severely affected by changing climatic conditions as species on islands have limited distribution ranges and small population sizes and face the constraints of insularity to track their climatic niches. We aimed to assess how ongoing climate change affects the range sizes of oceanic island plants, identifying species of particular conservation concern.LocationCanary Islands, Spain.MethodsWe combined species occurrence data from single‐island endemic, archipelago endemic and nonendemic native plant species of the Canary Islands with data on current and future climatic conditions. Bayesian Additive Regression Trees were used to assess the effect of climate change on species distributions; 71% (n = 502 species) of the native Canary Island species had models deemed good enough. To further assess how climate change affects plant functional strategies, we collected data on woodiness and succulence.ResultsSingle‐island endemic species were projected to lose a greater proportion of their climatically suitable area (x ̃ = −0.36) than archipelago endemics (x ̃ = −0.28) or nonendemic native species (x ̃ = −0.26), especially on Lanzarote and Fuerteventura, which are expected to experience less annual precipitation in the future. Moreover, herbaceous single‐island endemics were projected to gain less and lose more climatically suitable area than insular woody single‐island endemics. By contrast, we found that succulent single‐island endemics and nonendemic natives gain more and lose less climatically suitable area.Main ConclusionsWhile all native species are of conservation importance, we emphasise single‐island endemic species not characterised by functional strategies associated with water use efficiency. Our results are particularly critical for other oceanic island floras that are not constituted by such a vast diversity of insular woody species as the Canary Islands.

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