BACKGROUND AND AIMS:Photosynthetic tissues of terrestrial plants require a continuous water supply to avoid desiccation while allowing CO2 to diffuse to chloroplasts. This imposes a functional coordination between water-conducting tissues and stomatal regulation. What is the anatomical basis of this coordination? METHODS:We assessed anatomical traits of stomata, trichomes, and xylem vessels as well as branch allocation patterns in 30 olive varieties grown under common environmental conditions in Southern France. Theoretical conductances of leaves and stems were calculated and compared to maximal leaf conductance measured in the field. We also tested whether wood density could serve as a proxy for stem conductance. RESULTS:Stomata, trichomes, and xylem vessels showed positive covariation in size, but not in density. Consequently, no coordination was observed between the total stem vessel area and the total stomatal pore area, nor between the theoretical conductances of stems and leaves. However, we found a positive association between the stomatal pore area and the lumen area when values were scaled at the branch level. Maximal leaf conductance was negatively related to trichome area, but not to theoretical stomatal conductance. Wood density correlated negatively with the lumen fraction in stems, but not with stem conductance. CONCLUSIONS:We conclude that coordination between water transport and loss likely occurs at the branch level, involving allocation patterns beyond anatomy, and that the role of trichomes in water regulation deserves further study in pubescent-leaved species.

ABSTRACT Aim Reliable climate simulations require comparison with robust reconstructions of past climates, often based on fossil pollen assemblages. This is particularly critical in drylands, where climate models frequently diverge. Yet, traditional pollen‐based reconstructions often overlook the mechanistic links between climate and plant functioning, complicating their interpretation. Integrating functional traits into pollen analyses may help identify and reduce biases in climate reconstructions. Location Arid Central Asia. Time Period Present and Holocene. Major Taxa Studied Spermatophytes (pollen‐producing plants). Methods Here, we combine plant functional traits, modern surface pollen assemblages and vegetation plots to test whether assemblage‐level trait–climate relationships are consistent between pollen and vegetation data. Two levels of taxonomic resolution of pollen identification ( fine vs. coarse ) were tested. The biogeographical distributions of plant traits derived from pollen and vegetation were examined, and community‐weighted means of traits were compared between the pollen and vegetation datasets to determine: (1) whether similar trait–climate relationships can be detected in both and (2) which of these relationships are strongest. Results Leaf area, leaf nitrogen content per unit mass, specific leaf area and stem specific density (SSD) showed consistent spatial patterns across pollen and vegetation datasets. The trait–climate relationships were moderately correlated (ca. r of 0.6) between pollen and vegetation data, and the directions of correlations were similar for 85% of the individual relationships. Both fine and coarse taxonomic resolutions capture broad vegetation functional responses to climate, whereas finer pollen identification improves the accuracy of trait–climate relationships. Mean annual precipitation and cold‐quarter temperature and precipitation were the climatic variables most strongly related to traits. Leaf area correlated positively with the three climate parameters, while plant height and SSD correlated positively with annual precipitation. Main Conclusions Our findings support the use of pollen‐derived leaf area, plant height and SSD to track past vegetation structure and improve the reliability of pollen‐based climate reconstructions. Expanding trait databases to better represent water‐stress tolerance traits may strengthen this approach.

Understanding how traits covary and influence growth is key to understanding adaptation in perennial species. In the Mediterranean olive tree (Olea europaea L.), both genetic background and geographical origin (GO) may shape trait variability, covariation patterns, and growth strategies, however these relationships remain largely unexplored. We analysed 100 olive varieties, representing four genetic groups and two GOs (North vs South Mediterranean), by measuring 11 morpho-anatomical and physiological traits, and two growth indicators. We combined multivariate analyses, correlation networks and regression models to explore trait covariation and its impact on growth. Our findings show that trait variation was primarily structured at the varietal level, while both genetic groups and geographic origin significantly shaped covariation patterns and functional integration, with southern-origin varieties tending to exhibit thicker and denser leaves. Trait networks revealed a robust coordination between leaf and stem structural traits, with modularity and connectivity varying across groups. The South group exhibited a more modular network, suggesting more constrained trait integration under arid conditions. At both stem and whole-plant levels, growth was positively associated with leaf area. In contrast, leaf dry matter content showed a positive relationship with stem diameter growth but a negative relationship with whole-plant growth, suggesting that different mechanisms underlie short-term stem expansion and long-term cumulative growth. Overall, genetic factors, environmental context and trait coordination jointly structure olive phenotypic diversity. These findings provide a functional framework for guiding the selection and conservation of olive varieties with growth strategies suited to current and future Mediterranean climates.

This study examines the impact of drought, and by extension potential water scarcity, on the potential of sap conduction in the olive tree, the emblematic fruit tree of the Mediterranean Basin. To understand adaptation of sap conduction potential of varieties concerning drought, we focus on wood anatomical traits in trees cultivated in the conservatory orchard of the 'Conservatoire Botanique National Mediterraneen' (Porquerolles, France) and others from their main cultivation area. Leveraging branch diameter as a key factor influencing anatomical traits, we model density of vessels (DVS) and lumen area of vessels in transverse section (LAV) variation based on branch diameter using regression analyses. Our results show that the pattern of increase in LAV cannot be considered to be dependent on the biogeography and evolutionary history of varieties. But, it is significantly linked to the aridity conditions of the main cultivation area of these varieties. In the perspective of a future drastic increase in aridity, results point to the potential incapacity of varieties from non-irrigated semi-arid zones, to produce vessels large enough to transport sap to the leafy parts of branches, and other varieties from the northern margins of olive distribution area, to modulate conduction in terms of efficiency - safety balance. While some varieties exhibit a robust or moderately plastic phenotype, showing negligible variations in conduction potential with changing aridity in growing conditions, these results concern about the sustainability and future viability of some varieties. More broadly, they raise questions about the olive cultivation sector's resilience in the face of intensifying water stress.

ABSTRACT Aim Pollen assemblages are widely used to infer paleoenvironment features, aiming at reconstructing both past climates and biomes. However, the functional link between environmental conditions and pollen assemblages is not straightforward and requires thorough testing to be used confidently. Here, we use a trait‐based approach to assess the consistency of functional signatures between pollen and plant assemblages. Location Arid Central Asia (ACA). Taxon Spermatophytes (pollen‐producing plants). Methods We assess whether trait values and trait distributions are consistent for surface pollen samples and extant vegetation in the Arid Central Asia biogeographic region. A working plant checklist was compiled for ACA in order to assign trait values to pollen types and vegetation taxa. This was done for two widely used methods of pollen aggregation schemes (coarse and fine pollen type depend on the level of pollen identification). The functional signatures of pollen and vegetation samples were compared both at the taxon and community levels, using large‐scale trait and vegetation databases, for the six traits of the global spectrum of plant form and function (i.e., plant height, seed mass, leaf area, specific leaf area, nitrogen content per leaf mass, and stem‐specific density). Results Trait distributions and bivariate trait relationships were broadly similar for pollen types and vegetation taxa, which is also the case for the multivariate spaces of the global spectrum of plant form and function. At the community scale, the trait values weighted by taxon abundance significantly differed among biomes, and these differences were consistent for both pollen aggregation schemes and extant. Main Conclusions The pollen aggregation scheme does not impact the organisation of the functional space of the global spectrum of plant form and function, which compares well with that based on species actually present in the vegetation plots. This is also true at the community scale. These findings are very promising for improving climate and biome reconstructions from pollen assemblages and pave the way to a “pollen functional biogeography”.

Although phenology has long been recognized as a critical feature for the adaptation of organisms to their local environment, until recently, phenological events have seldom been considered in the broader context of trait‐based ecology. Here, we assess the association between phenology and two key traits structuring the phenotype: (i) leaf longevity, or leaf life span, which is a pivotal trait for plant resource use through its role in the so‐called ‘leaf economics spectrum’, and (ii) fruit mass, which contributes to a syndrome evolved by plants to promote seed dispersal. Leaf—production and loss—and reproductive—flowering and fruiting phases—phenology was followed during 4 years on 52 cultivated varieties and wild accessions of olive ( Olea europaea L. subsp. europaea ) maintained in an ex situ varietal collection located in the Mediterranean Region of southern France. Leaf life span was derived from leaf phenology censuses. Leaf mass per area and leaf nitrogen content were measured to test whether leaf life span and phenology were associated with these two other central traits of the leaf economics spectrum. Fruit fresh mass at harvest was determined to assess the association between reproductive phenology and reproductive output. There was a twofold variation in average leaf life span across varieties, which was related to both the time of peak loss of leaves and the duration of the leaf loss period. We found no evidence that leaf life span and leaf phenology were related to the two other traits of the leaf economics spectrum. Fruit fresh mass, which varied 10‐fold across varieties, was twice as large in cultivated olives than in wild olives. It was related to several phases of reproductive phenology, including fruit development time. Leaf and reproductive phenologies were found to be largely uncoupled. Leaf phenology emerges as a functional dimension largely independent of plant resource use, while reproductive phenology appears as a minor determinant of fruit mass. Overall, these results demonstrate weak associations between phenology and traits describing other aspects of plant form and function within the olive species. Read the free Plain Language Summary for this article on the Journal blog.

Trait-based approaches have proven, and continue to offer strong potential to tackle key issues in ecology, including: (i) understanding the functioning of organisms and how it relates to the environment, (ii) identifying the rules governing the assembly of communities and the coexistence of species, (iii) understanding how the functioning of organisms scales up to that of ecosystems and controls some of the services they deliver to humans. We present FAIRTraits, a data set of plant traits assembled from a set of studies designed to address these issues in the pedo-climatic context of the Northern Mediterranean Basin, considered both a biodiversity and a climatic hotspot. The FAIR (Findable, Accessible, Interoperable and Reusable) guiding principles were followed to ensure maximum visibility and reusability of these data. FAIRTraits compiles and standardizes trait data collected over the 1997-2023 period on six sites by the same research group, ensuring that a consistent methodology was followed. These data were obtained on individuals from 1,955 populations of 240 species belonging to 155 genera and 48 families (172 herbaceous and 39 woody species). It contains 189,452 records for 183 quantitative traits from the different plant organs (leaves, stems, roots, and reproductive parts), which have been grouped into 10 categories: allocation ratio, architecture, chemistry, dynamics, mechanics, microbial associations, morphology, phenology, physiology and plant size. Trait values are given at the level of individual measurements. Species-level values of height and phenology taken from a Mediterranean flora are also given. Species are characterized by plant family, life cycle, Raunkiaer lifeform, photosynthetic pathway and by an original successional stage indicator value. As trait values strongly depend on environmental conditions, we also provide information on the climatic conditions and soil properties of the sites, as well as on disturbance regimes of the plots in which sampled individuals were collected. The following steps were taken to ensure the FAIRness of the data set. Findable: metadata are described using the Ecological Metadata Language, and are deposited both on the InDoRES (CNRS/MNHN) metadata catalogue and on the GBIF data portal (see below); Accessible: FAIRTraits is available on the InDoRES repository, with a subset available on the GBIF data portal (see below); Interoperable: recognized taxonomical and terminological resources to qualify taxa and attributes have been used whenever possible, and fully described sampling protocols and measurement methods are given both for traits and environmental data. A subset of the data could be mapped onto the Darwin Core biodiversity standard, making it possible to display part of the data set on the GBIF portal, more traditionally used for taxonomic occurrence data. Reusable: (meta)data are thoroughly described using domain-relevant community standards, and the full data set is released under the CC-BY 4.0 license. We believe that these multiple efforts, spanning from the very content of the data set to its careful formatting, will make of FAIRTraits a highly valuable resource for trait-based research, both in terms of data analysis and reusability. ### Competing Interest Statement The authors have declared no competing interest.

Background and Aims Intraspecific trait variations in response to nutrient availability are expected to depend on (1) the category of traits considered, and (2) species ecology, with species requiring high nutrient levels expected to be more plastic. However, there are few comparisons of trait responses considering simultaneously (a) above-ground traits approximating ecological strategies, (b) root traits involved in nutrient acquisition, and (c) traits integrating the whole plant, and including multiple species.Methods We studied 17 annual species coming from two contrasted environments in the same rangeland of southern France. Plants were grown in a common garden under two fertilization treatments.Key Results We evidenced no effect of origin on trait values, suggesting little or no differentiation according to the environment of origin. Among the 14 traits measured, whole-plant traits, in particular plant nitrogen content, plant dry mass and root mass fraction, showed strong plastic responses to fertilization, whereas the response was weak or even absent for above- and below-ground organ-level traits related to ecological strategies, suggesting that they play a secondary role in plant responses to nutrient availability. Finally, species' ecological preferences (i.e. their nutrient requirements), predicted the plasticity in plant nitrogen content per mass, whereas species position along the acquisition-conservation trade-off (approximated by leaf traits) predicted plasticity in plant dry mass. This cautions against the systematic use of leaf traits as a proxy of species ecology and functioning.Conclusions Our results challenge the assumption that leaf traits universally reflect plant responses to nutrient availability. They advocate a better characterization of traits directly involved in nutrient acquisition and underscore the importance of considering how trait-trait and trait-environment relationships may depend on the group of species considered. These findings offer an avenue for more accurate predictions of plant responses to nutrient gradients in natural and managed ecosystems.

Trait-based ecology relies on high-quality, well-documented data to explore how plant traits relate to environmental conditions, community assembly, and ecosystem functioning. However, the reuse and synthesis of trait data across studies remain limited by several constraints: a lack of detailed metadata, heterogeneous protocols, absence of individual-level measurements, and underrepresentation of certain trait types-particularly below-ground traits. Many existing datasets also lack the environmental details necessary to investigate trait-environment relationships at local scales. Here, we present FAIRTraits, a comprehensive dataset that addresses these limitations by compiling 189,452 records of quantitative trait measurements collected between 1997 and 2023 from 1955 populations of 240 vascular plant species in the Northern Mediterranean Basin, a region known both for its exceptional biodiversity and as a climate change hotspot. All data were collected by a single research group using consistent and well-documented field and laboratory protocols, ensuring internal consistency across traits, species, sites, and years. FAIRTraits includes 180 traits measured at the individual or replicate level, with no aggregation. It features an unprecedented diversity of traits spanning all major plant organs-leaves, stems, roots, and reproductive parts. These include widely used traits such as specific leaf area and plant height, but also traits that are rarely reported, especially below-ground traits related to root morphology, as well as mechanical properties, phenology, and microbial associations. In addition to raw measurements, species are annotated with categorical descriptors (e.g., life form, photosynthetic pathway, and successional status), and species-level values taken from a Mediterranean flora, for key traits such as reproductive phenology and maximum height. To support analyses that account for environmental variability, each observation is linked to detailed descriptors of the plot where the individual was sampled, including climate data, soil physicochemical properties, and disturbance regime. Full metadata on sampling protocols and measurement methods are provided for every trait and environmental variable. FAIRTraits was built in compliance with the FAIR principles of data management (Findable, Accessible, Interoperable, and Reusable). Metadata are described using the Ecological Metadata Language (EML); trait definitions are standardized using community-endorsed semantic resources. The data are archived across two interoperable repositories: GBIF (via Darwin Core and trait-specific extensions) for taxon-trait associations and InDoRES for environmental and contextual data. These efforts ensure long-term preservation, data traceability, and seamless integration with plant trait databases such as BROT or TRY, and cross-organism initiatives such as the Open Traits Network or the Encyclopedia of Life. FAIRTraits offers a robust, richly documented, and reusable resource for investigating plant functional strategies, trait-environment relationships, and scaling from individuals to communities and ecosystems. It also provides a concrete example of how trait datasets can meet the highest standards of data quality and interoperability-serving as a model for future community-led initiatives in functional ecology. The FAIRTraits database is released under the CC-BY Attribution 4.0 International license.

Assessing the extent of genotypic and phenotypic trait variation within a genetically diversified species is crucial to understanding how plants cope with environmental differences. We examine these components in Olea europaea L. europaea, one of the most widespread and diverse tree crops cultivated in the Mediterranean Basin, a region facing rapid climatic shifts with increasing summer drought. We compared trait values of 83 olive varieties from different Mediterranean countries, grown in two ex situ varietal collections with contrasting environments: subhumid and semi-arid climates. Ten leaf-, stem- and branch traits related to resource and water use were compared across 50 varieties within each site, and phenotypic plasticity was assessed for the 17 varieties common to them. Trait plasticity was assessed with the phenotypic dissimilarity index while varietal plasticity was assessed in multidimensional trait space with the multivariate plasticity index. Our results showed considerable phenotypic variability within (up to 59.54%) and between (up to 39.17%) sites. Varieties grown in semi-arid conditions were more conservative, showing denser leaves and wood, and thicker bark. Common varieties exhibited contrasting degrees of plasticity across traits, demonstrating that high plasticity for some traits does not necessarily imply overall plasticity. Additionally, varieties with conservative trait values were not less plastic than more acquisitive varieties. Varieties showed distinct phenotypic adjustments across sites, with trait variations indicating acclimation strategies to reduce water loss in the arid environment. Our results also suggest that acclimation to different environments occurs through the adjustment of multiple traits, complicating plasticity comparisons across varieties.

The traditional ecological risk assessment (ERA) approach for chemicals in terrestrial ecosystems primarily focuses on the protection of individual species, populations, or community.However, it often overlooks the aboveground and belowground processes and functions that underpin essential ecosystem services (ES).ERA aims to protect biodiversity, which constitutes or supports the service-providing units (SPUs) driving ES.However, not all species contribute equally to ecosystem functions due to functional redundancy.While every species is important, especially in specialized ecosystem with small number of species or low redundancy, focusing on functional groups rather than individual species responses might provide a better measure of how chemicals affect ecosystem functions and services.Integrating biodiversity measures into soil ERA is recommended, but current approaches tend to emphasize species protection over functional diversity or groups (Fajana et al., 2024).To address this, grouping species into functional groups such as litter feeders, fungal feeders, saprotrophs, and predators for soil invertebrates, or graminoids and forbs for terrestrial plants has been suggested to evaluate chemical risks on ES (Fajana et al., 2024).

Trait‐based ecology, a prominent research field identifying traits linked to the distribution and interactions of organisms and their impact on ecosystem functioning, has flourished in the last three decades. Yet, the field still grapples with critical challenges, broadly framed as Raunkiæran shortfalls. Recognizing and interconnecting these limitations is vital for designing and prioritizing research objectives and mainstreaming trait‐based approaches across a variety of organisms, trophic levels, and biomes. This strategic review scrutinizes eight major limitations within trait‐based ecology, spanning scales from organisms to the entire biosphere. Challenges range from defining and measuring traits (SF 1), exploring intraspecific variability within and across individuals and populations (SF 2), understanding the complex relationships between trait variation and fitness (SF 3), and discerning trait variations with underlying evolutionary patterns (SF 4). This review extends to community assembly (SF 5), ecosystem functioning and multitrophic relationships (SFs 6 and 7), and global repositories and scaling (SF 8). At the core of trait‐based ecology lies the ambition of scaling up processes from individuals to ecosystems by exploring the ecological strategies of organisms and connecting them to ecosystem functions across multiple trophic levels. Achieving this goal necessitates addressing key limitations embedded in the foundations of trait‐based ecology. After identifying key SFs, we propose pathways for advancing trait‐based ecology, fortifying its robustness, and unlocking its full potential to significantly contribute to ecological understanding and biodiversity conservation. This review underscores the significance of systematically evaluating the performance of organisms in standardized conditions, encompassing their responses to environmental variation and effects on ecosystems. This approach aims to bridge the gap between easily measurable traits, species ecological strategies, their demography, and their combined impacts on ecosystems.

Within individuals and/or species of trees, the structure and gas exchange of sun-exposed leaves from the outer part of the canopy have been found to relate to sampling height. Across species, the gas exchange of such leaves has been shown to relate to their structure and biochemical composition, but not to canopy height. Why are leaf traits related to height within tree species but not across a broader range of species? And what are the components of leaf structure involved in leaf-level carbon, water and nitrogen economies? Plant height, leaf mass per area (LMA) and its underlying components, gas exchange, leaf nitrogen and carbon isotopic discrimination were assessed for 60 species from different life and growth forms growing in the Mediterranean, spanning a wide range of height and LMA values. Contrary to previous comparisons across species, our study shows that leaves of tall plants had a high LMA, a high leaf dry matter content (LDMC) and were slightly thicker; their stomatal conductance and photosynthetic rate were low, while their intrinsic water-use efficiency (iWUE) was high. LMA was related to all gas exchange variables as well as to leaf nitrogen. These effects were mostly mediated through LDMC, with limited effects of leaf thickness. These conclusions were hardly modified when phylogeny was account for. Across species of varying life and growth forms, leaf functioning relates to both plant height and leaf structure. These results provide a generalization of previous conclusions found in trees at the intra-individual and/or intraspecific levels. Inconsistencies among previous studies with respect to plant height are likely an issue of context-dependency, which should be explicitly taken into account for a better understanding of plant form and function.Read the free Plain Language Summary for this article on the Journal blog. Au sein des individus et/ou des esp & egrave;ces d'arbres, il a & eacute;t & eacute; montr & eacute; que la structure et les & eacute;changes gazeux des feuilles expos & eacute;es au soleil dans la partie ext & eacute;rieure de la canop & eacute;e & eacute;taient li & eacute;s & agrave; la hauteur d'& eacute;chantillonnage. Entre esp & egrave;ces, il a & eacute;t & eacute; d & eacute;montr & eacute; que les & eacute;changes gazeux de ces feuilles & eacute;taient li & eacute;s & agrave; leur structure et & agrave; leur composition chimique, mais pas & agrave; la hauteur de la plante. Pourquoi les caract & eacute;ristiques des feuilles sont-elles li & eacute;es & agrave; la hauteur au sein d'une m & ecirc;me esp & egrave;ce d'arbre, alors que ce n'est pas le cas lorsque l'on compare des esp & egrave;ces diff & eacute;rentes ? Et quelles sont les composantes de la structure foliaire impliqu & eacute;es dans les & eacute;conomies du carbone, de l'eau et de l'azote des feuilles ? La hauteur des plantes, la masse surfacique des feuilles (MSF) et ses composantes sous-jacentes, les & eacute;changes gazeux, la teneur en azote et la discrimination isotopique du carbone des feuilles ont & eacute;t & eacute; & eacute;valu & eacute;s pour 60 esp & egrave;ces de diff & eacute;rentes formes de vie et de croissance se trouvant dans la r & eacute;gion m & eacute;diterran & eacute;enne, et couvrant une large gamme de valeurs de hauteur et de MSF. Contrairement aux comparaisons pr & eacute;c & eacute;dentes effectu & eacute;es entre esp & egrave;ces, notre & eacute;tude montre que les feuilles des plantes de haute stature ont une MSF & eacute;lev & eacute;e, une teneur en mati & egrave;re s & egrave;che foliaire & eacute;lev & eacute;e et sont l & eacute;g & egrave;rement plus & eacute;paisses ; leur conductance stomatique et leur vitesse de photosynth & egrave;se sont faibles, alors que leur efficacit & eacute; intrins & egrave;que d'utilisation de l'eau est & eacute;lev & eacute;e. La MSF est reli & eacute;e & agrave; toutes les variables relatives aux & eacute;changes gazeux ainsi qu'& agrave; l'azote foliaire. Ces effets sont principalement expliqu & eacute;s par des diff & eacute;rences de teneur en mati & egrave;re s & egrave;che, avec des effets limit & eacute;s de l'& eacute;paisseur des feuilles. Ces conclusions ne sont pas significativement modifi & eacute;es lorsque la phylog & eacute;nie est prise en compte. Pour des esp & egrave;ces appartenant & agrave; diff & eacute;rentes formes de vie et de croissance, nous avons montr & eacute; que le fonctionnement des feuilles & eacute;tait reli & eacute; & agrave; la fois & agrave; la structure de celles-ci et & agrave; hauteur de la plante. Ces r & eacute;sultats constituent une g & eacute;n & eacute;ralisation des conclusions obtenues sur des arbres aux niveaux intra-individuel et/ou intrasp & eacute;cifique, mais contrastent avec les & eacute;tudes pr & eacute;c & eacute;dentes conduites entre esp & egrave;ces pour ce qui est de la hauteur. Ces diff & eacute;rences pourraient s'expliquer par des effets de d & eacute;pendance au contexte, qui devraient & ecirc;tre explicitement pris en compte pour une meilleure compr & eacute;hension de la forme et de la fonction des plantes.

Studying modern pollen rain in Middle Asia is crucial for understanding past climate and vegetation changes. This study presents the first dataset of pollen surface samples and vegetation plots from Tajikistan and Uzbekistan, known as the Tajikistan and Uzbekistan Surface Data Base (TUSDB), to enhance our understanding of past climate and vegetation changes in Arid Central Asia (ACA). Multivariate analysis methods, including TWINSPAN and CONISS, are used to review the primary vegetation types in Central Asia and assess pollen distribution across these types. Linear relationships, Davis indices, and R-values are applied to evaluate vegetation representativeness based on pollen abundances. Redundancy Analysis is used to compare pollen and climate parameters, and the reliability of TUSDB for local climate reconstructions is tested using transfer functions and machine learning approaches.The TWINSPAN analysis identifies vegetation types consistent with the Uzbek classification, such as desert, steppe, and cryophilous open woodlands. Nine vegetation subtypes are revealed by the pollen samples, with key contributions from trees like Juniperus spp. and Juglans regia, and non-arboreal plants like Cyperaceae and Poaceae. The study also highlights biases in pollen representation, with some tree taxa overrepresented and certain vegetation-important taxa underrepresented, which can be corrected using pollen R-values.Finally, functional trait aggregation for past pollen sequences shows similarities between modern pollen and vegetation plots. Climate reconstructions validated through transfer functions highlight the complementary role of local and global calibration datasets. These findings confirm the reliability of pollen signals for inferring Holocene climate and vegetation trends, enabling future Uzbek pollen-based reconstructions.

It is crucial to document biodiversity data and to take actions to halt the ongoing massive loss of biodiversity. Yet, these data are poorly defined. We propose a definition of biodiversity data and discuss its implications for data management, enabling enhanced data mobilization for integrated research and efficient conservation strategies.

Estimating the sign and strength of interactions among plants is central to understand the dynamics and functioning of communities, but is challenging to do for species-rich communities. Instead, spatial relationships between plants (clustering or spatial segregation) are sometimes used as a surrogate for the net effect of interactions ocurring between plants (positive or negative, respectively). However, this approach remains poorly tested outside of arid and alpine ecosystems, the ecological settings it originated from. In experimental rangelands, we explored how management intensification, sheep exclusion and a natural soil depth gradient control the level of plant spatial segregation, or 'negative co-occurrence', usually considered as a measurement of competition intensity. We link these spatial patterns to classical broad plant strategies defined by 11 locally measured functional traits, and to the realized vegetation height and cover. Plant segregation was highest when both grazing and fertilization were applied. Unexpectedly, general plant strategies (competitive, and acquisitive strategies) had little relationship with plant spatial patterns. Instead, spatial constraints increased segregation wherever cover was high and free bare ground was limited, or where plant growth is restricted by grazing to a few centimeters above ground. These results show that fine-scale spatial patterns appear to capture competition for space, rather than for light or resources, as suggested by broad plant strategies. This may explain discrepancies in conclusions drawn from spatial patterns in grasslands, and clarifies the way towards a mechanistic understanding of spatial patterns. Synthesis: The fine scale spatial organization of plant communities has been thought to reflect the intensity of competition among plants, but this approach has struggled to provide consistent results in grasslands. We show here that spatial patterns reflect competition for space rather than broad plant strategies captured by plant functional traits, helping us read observed plant spatial patterns to map interactions among plants in the field. ### Competing Interest Statement The authors have declared no competing interest.

Question: Predicting the functional response of vegetation to environmental variations remains highly challenging. A first reason is that trait-environment relationships result from joint intraspecific and interspecific responses. A second reason is that most plant communities host sets of species that are expected to display different environmental responses according to their ecophysiological strategies.Location: Mediterranean rangeland, Larzac Plateau, France ("La Fage" INRAE experimental station: 43(degrees)55' N, 3(degrees)05'E).Methods: In a Mediterranean rangeland, we tested whether changes in trait values in response to management intensification (increased resource availability and grazing intensity) differ between annuals and perennials that coexist locally. To capture the multiple facets of plant phenotypes, we studied nine traits related to carbon acquisition and conservation, plant size, water-use efficiency, phenology and reproduction.Results: For most traits, we evidenced a significant interaction between environment and life history. In particular, changes in trait values were higher in perennials for leaf traits related to tissue density and growth. These differences were explained by: (a) a lower species turnover in annuals, and (b) the presence of species with more distinct trait values across environments in perennials. For most traits, these changes were not accompanied by differential intraspecific variations between annuals and perennials, which invalidates previous theoretical predictions. In addition, the contribution of intraspecific trait variation to among-communities trait variance was higher for annuals than perennials for most traits.Conclusion: Altogether, our findings highlight that changes in trait values with the environment can depend on functional groups (here, life history), which can further critically impact the assessment of the functional response of communities. They challenge the mean field approaches to communities in which trait aggregation is most often blindly applied, without considering potential different trajectories in response to environmental changes at various nested organizational levels.

QuestionAlthough leaf biomechanical properties have been identified as critical traits for plant-herbivore interactions, their responses to grazing pressure have been poorly investigated. Intensification of rangeland management, associated with fertilization and an increase in grazing pressure, has been shown to favour fast-growing species that can compensate for biomass losses due to grazing. According to the postulated trade-off between resource acquisition and defence, it is often expected that acquisitive traits should be associated with low leaf mechanical resistance. Here we investigated the responses of two leaf biomechanical traits, and their underlying traits, to management intensification.LocationWe used a long-term experiment in a rangeland located in the Mediterranean region of Southern France, in which three treatments corresponding to different fertilizer inputs and sheep grazing pressures were established.MethodsWe sampled 24 abundant graminoid and forb species. The responses of work to shear and force to tear to the treatments were tested together with those of growth-related leaf traits (leaf mass per area, dry matter content). To better understand the observed patterns, we tested whether the difference between species' leaf biomechanics could be explained by morpho-anatomical characteristics such as leaf thickness and density.ResultsConsistent with the acquisition-defence trade-off hypothesis, we found that graminoids from fertilized and intensely grazed areas had lower leaf resistance than those in ungrazed areas. However, no difference in leaf biomechanics was found in forbs despite a significant decrease in leaf mass per area and leaf dry matter content with management intensification. Consistent with this, we found no significant effect of morpho-anatomical traits on either biomechanical trait in forbs.ConclusionsOur results suggest that the observed responses in graminoids result from phenotypic constraints between resource acquisition and biomechanical defence. However, these phenotypic constraints appeared to be released in forbs, questioning the idea of a universal relationship between these two functions. We investigated how leaf biomechanics responds to grazing and fertilization, and its coordination with resource acquisition traits. Management intensification favoured species with lower leaf toughness in graminoids, but not in forbs. In graminoids, low toughness was related to fast acquisition, while this was not the case in forbs. Variations in leaf anatomy are hypothesized to explain these differences.image

In the last three decades, quantitative approaches that rely on organism traits instead of taxonomy have advanced different fields of ecological research through establishing the mechanistic links between environmental drivers, functional traits, and ecosystem functions. A research subfield where trait-based approaches have been frequently used but poorly synthesized is the ecology of seagrasses; marine angiosperms that colonized the ocean 100M YA and today make up productive yet threatened coastal ecosystems globally. Here, we compiled a comprehensive trait-based response-effect framework (TBF) which builds on previous concepts and ideas, including the use of traits for the study of community assembly processes, from dispersal and response to abiotic and biotic factors, to ecosystem function and service provision. We then apply this framework to the global seagrass literature, using a systematic review to identify the strengths, gaps, and opportunities of the field. Seagrass trait research has mostly focused on the effect of environmental drivers on traits, i.e., “environmental filtering” (72%), whereas links between traits and functions are less common (26.9%). Despite the richness of trait-based data available, concepts related to TBFs are rare in the seagrass literature (15% of studies), including the relative importance of neutral and niche assembly processes, or the influence of trait dominance or complementarity in ecosystem function provision. These knowledge gaps indicate ample potential for further research, highlighting the need to understand the links between the unique traits of seagrasses and the ecosystem services they provide.