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13 páginas.- 4 figuras.- 1 tabla.- referencias., 1. Many studies have quantified the functional variation of fine root traits to understand the overarching trade-off between maximizing resource acquisition or conservation (root economics spectrum [RES]). However, we know remarkably less on how plant strategies along the RES are actually constrained by the amount of photosynthates required to construct roots (i.e. construction costs, CC) or how below-ground interactions with symbiotic organisms modify root trait patterns and their relationships with CC. 2. Our main aim was to quantify CC of fine roots (, This work was financially supported by the Spanish Ministry of Science and Innovation (grants no. CGL2017-82254-R-INTARSU and ECO-MEDIT (CGL2014-53236-R)), the project Ecología funcional de los bosques andaluces y predicciones sobre sus cambios futuros (For-Change; UCO-27943), the project Funcionalidad y servicios ecosistémicos de los bosques andaluces y no rmarroquíes: relaciones con la diversidad vegetal y edáfica ante el cambio climático by Junta de Andalucía (Spain) and the Seneca Foundation (project 20654/JLI/18), all co-funded with European FEDER funds. We thank C. Navarro-Fernández and C. Padilla-Díaz for helping during field work, as well as to the IRNAS Analytical Service for chemical analysis of plants and soils. Open Access funding enabled and organized by Projekt DEAL. WOA Institution: BRANDENBURGISCHE TECHNISCHE UNIVERSITAET COTTBUS-SENFTENBERG, Blended DEAL: Projekt DEAL.

International audience; Plant functional traits are useful in tracking changes in the environment, and play an important role in determining ecosystem functioning. The relationship between plant functional traits and ecosystem functioning remains unclear, although there is growing evidence on this relationship. In this study, we tested whether the functional structure of vegetation has significant effects on the provision of ecosystem services. We analysed plant trait composition (specific leaf area, leaf carbon and nitrogen ratio, isotopic carbon fraction, stem dry matter content, seed mass and plant height), soil parameters (nutrients, pH, bulk density) and proxies of ecosystem services (carbon stock, decomposition rate, invertebrate activity) in twenty-four plots in three tropical ecosystems (active restored and natural forests and an agroforestry system) in Ghana. For each plot, we measured above-ground biomass, decomposition rates of leaves and invertebrate activity as proxies for the provision of ecosystem services to evaluate (i) whether there were differences in functional composition and soil properties and their magnitude between ecosystem types. We further aimed to (ii) determine whether the functional structure and/or soil parameters drove ecosystem functions and multifunctionality in the three ecosystem types. For functional composition, both the leaf economic spectrum and seed mass dimension clearly separated the ecosystem types. The natural forest was more dominated by acquisitive plants than the other two ecosystem types, while the non-natural forests (agroforest and restored forest) showed higher variation in the functional space. The natural forest had higher values of soil properties than the restored forest and the agroforestry system, with the differences between the restored and agroforestry systems driven by bulk density. Levels of ecosystem service proxies and multifunctionality were positively related to the functional richness of forest plots and were mainly explained by the differences in site conditions. Our study demonstrated the effects of functional forest structure on ecosystem services in different forest ecosystems located in the semi-deciduous forest zone of Ghana.

[EN] A major aim in invasion ecology is to understand the role of exotic species in plant communities. Whereas most studies have explored the traits of exotic species in the context of the introduced community, functional comparisons of entire assemblages of species in their native and introduced communities have rarely been analysed. Taking advantage of the unidirectional invasion of plant species of European origin (i.e. colonizers) into California, this study aims to investigate the relative importance of plant traits, environmental factors and invasion status in biological invasions. We compared the functional structure (i.e. trait composition and diversity) along resource availability gradients in recipient and native Mediterranean grassland communities in California and Spain, respectively. Traits were related to resource use in above-ground and below-ground organs and reproductive strategy. We also investigated how niche differences vary along environmental gradients between coexisting colonizer and native species assemblages within communities. There were clear differences in the functional structure of Mediterranean grassland communities between regions, which were associated with the resource availability gradient. Paradoxically, the most acquisitive communities occurred in resource-poor sites, highlighting that rapid acquisition and use of resources permit species to cope with environmental stress through stress avoidance. In Spain, colonizer species had greater specific leaf area than non-colonizers. Yet, differences between colonizer and non-colonizer species in Spain for other traits were mostly absent and did not change along the gradient. This might be a result of the greater native species richness as a consequence of the agricultural practices that have taken place in Europe for millennia and reflect that the entire species pool of grasslands is adapted to agricultural landscapes. In comparison, in California, colonizer species were more acquisitive in their use of resources than natives under favourable conditions, but functionally converged in resource-limited sites. Synthesis. These results underscore that the importance of niche differences between native and colonizer species as a community assembly mechanism is strongly subjected to the influence of habitat filtering. Trait comparisons are context dependent, and a correct interpretation of filtering processes in community assembly requires a regional perspective. SI

10 páginas.- 3 figuras.- 1 tabla.- referencias.- The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpls.2021.773118/full#supplementary-material, Extensive research efforts are devoted to understand fine root trait variation and to confirm the existence of a belowground root economics spectrum (RES) from acquisitive to conservative root strategies that is analogous to the leaf economics spectrum (LES). The economics spectrum implies a trade-off between maximizing resource acquisition and productivity or maximizing resource conservation and longevity; however, this theoretical framework still remains controversial for roots. We compiled a database of 320 Mediterranean woody and herbaceous species to critically assess if the classic economics spectrum theory can be broadly extended to roots. Fine roots displayed a wide diversity of forms and properties in Mediterranean vegetation, resulting in a multidimensional trait space. The main trend of variation in this multidimensional root space is analogous to the main axis of LES, while the second trend of variation is partially determined by an anatomical trade-off between tissue density and diameter. Specific root area (SRA) is the main trait explaining species distribution along the RES, regardless of the selected traits. We advocate for the need to unify and standardize the criteria and approaches used within the economics framework between leaves and roots, for the sake of theoretical consistency., This work was financially supported by the German Research Foundation (ECOFUMER, GZ: GA 2899/3-1), Spanish Ministry of Science and Innovation (grant no. CGL2017-82254-R-INTARSU), ECO-MEDIT (CGL2014-53236-R), the projects “Ecología Funcional de los Bosques Andaluces y Predicciones Sobre sus Cambios Futuros (For-Change; UCO-FEDER 18 REF 27943 MOD B; Spain) and Funcionalidad y Servicios Ecosistémicos de los Bosques Andaluces y Normarroquíes: Relaciones con la Diversidad Vegetal y Edáfica Ante el Cambio Climático” (P18-RT-3455) by Junta de Andalucía (Spain), and the Seneca Foundation (project 20654/JLI/18), all cofinanced by European FEDER funds.

Oaks (Quercus) are a dominant woody plant genus in the northern hemisphere, which occupy a wide range of habitats and are ecologically diverse. We analysed the wood anatomical traits, the variables derived and the relative hydraulic conductivity of 21 oak species to identify their performance according to abiotic factors, leaf phenological patterns and phylogenetic restrictions by analysing the interspecific variation along an environmental gradient. First, we determine the causes of anatomical trait variation in the oaks, analysing the functional trade-offs related to distribution along the environmental gradient. We measure the phenotypic plasticity of the anatomical traits to determine the role of environment and geographic distance in the range of phenotypic plasticity. Second, we examined if oaks co-occurred along the environmental gradient. Then we analysed if wood anatomical traits reflect differences among their phylogenetic section, leaf habit and a phylogenetic section/leaf habit category. Last, we tested the phylogenetic signal. Our results showed that vessel diameter, vessel frequency, wood density and relative hydraulic conductivity are the main axes of trait variation in the species analysed among leaf habit categories. The aridity index and seasonal precipitation drive the variation in the analysed traits. Higher environmental distance resulted in a higher relative distance plasticity index among traits. Co-occurrence of oak species with different leaf habits and phylogenetic trajectories may promote complementary resource acquisition. The phylogenetic signal in the oak species studied was low, which implies labile wood traits., Wood anatomical traits reflect the adaptations along an aridity gradient in oak species. We found that high temperatures combined with periodic water deficits lead to narrower vessels, high-density wood occupied by smaller fibres. On the contrary, on humid sites, tall oaks invest in widest vessels to conduct water with great efficiency. Oak species in the study site showed an adaptive response of wood traits to climate, but there is also evidence of a low phylogenetic signal. Co-occurrence of oak species with different leaf habits and phylogenetic trajectories may promote complementary resource acquisition.

de la Riva, E.G., Arenas, M., Villar, R., Garcia-Oliva, F., Oyama, K. 2019. The role of evapotranspiration on the foliar functional distribution of 28 Quercus species from Mexico and Spain. Ecosistemas 28(3):199-207. Doi.: 10.7818/ECOS.1803 Quercus species represent the most important woody genus in the northern hemisphere, with broad environmental distribution in Spain and Mexico. Functional plant traits are commonly used as indicators of species diversification and environmental adaptations, and they allow us to better understand the morphological and physiological limitations of the species that restrict its evolution. The main objective of this study is to explore the spectrum of variation of Quercus genus, by analyzing the variation in five functional leaf traits of 28 Quercus species from Spain and Mexico along an environmental gradient of potential evapotranspiration. We found two major dimensions of functional variation: on one hand, the species are segregating along the humidity gradient according with the leaf economics spectrum. Therefore, we found species associated to a conservative use of resources in areas with higher evapotranspiration rate and acquisitive species in the areas with lower evapotranspiration. On the other hand, the leaf size is mainly determined by the geographical origin of the species. These results suggest that the evolutionary modifications within the same genus are related with the leaf traits variation, being humidity a key factor of functional trait variation within the Quercus genus. In addition, we would like to highlight that we do not find relationship between leaf longevity and leaf economic spectrum, which may be explained by the different evolutionary histories of the leaf habit in oaks between both countries.

Given the importance of carbon allocation for plant performance and fitness, it is expected that competition and abiotic stress influence respiratory costs associated with stem wood biomass production and maintenance. In this study, stem respiration (R) was measured together with stem diameter increment in adult trees of eight co-occurring species in a sub-Mediterranean forest stand for 2 years. We estimated growth R (Rg), maintenance R (Rm) and the growth respiration coefficient (GRC) using two gas exchange methods: (i) estimating Rg as the product of growth and GRC (then Rm as R minus Rg) and (ii) estimating Rm from temperature-dependent kinetics of basal Rm at the dormant season (then Rg as R minus Rm). In both cases, stem basal-area growth rates governed intra-annual variation in R, Rg and Rm. Maximum annual Rm occurred slightly before or after maximum Rg. The mean contribution of Rm to R during the growing season ranged from 56% to 88% across species using method 1 and from 23% to 66% using method 2. An analysis accounting for the phylogenetic distance among species indicated that more shade-tolerant, faster growing species exhibited higher Rm and Rg than less shade-tolerant, slower growing ones, suggesting a balance between carbon supply and demand mediated by growth. However, GRC was not related to species growth rate, wood density, or drought and shade tolerance across the surveyed species nor across 27 tree species for which GRC was compiled. The GRC estimates based on wood chemical analysis were lower (0.19) than those based on gas exchange methods (0.35). These results give partial support to the hypothesis that wood production and maintenance costs are related to species ecology and highlight the divergence of respiratory parameters widely used in plant models according to the methodological approach applied to derive them.

1 Pág. Correción errata., In the version of this Article originally published, the surname of author Tina Parkhurst was incorrectly written as Schroeder. This has now been corrected.

Functional segregation among species in a community depends on their mean trait values (i.e. functional distinctiveness), and the range of trait attributes exhibited by each species (i.e. functional diversity). Previous evidence suggests that invasive plants tend to display traits related to a more acquisitive resource-use strategy than natives. However, the contribution of intraspecific trait variation to functional diversity has received little attention in community ecology, and might provide interesting information about community processes. In this study, we used eight plant traits related to carbon and nutrient acquisition of coexisting dominant native and invasive plants in eight communities across the Mediterranean-climate biome to determine sources of functional segregation between native and invasive species. We found three major axes of functional variation, related to leaf economics, resource-use efficiency, and plant height. Invasive species across communities had leaf traits related to an acquisitive resource-use strategy in contrast to native species, whereas differences in the second and third axes were community dependent. Invasive species were more functionally diverse than native species across the dataset and in four out of the eight communities. Intraspecific variance accounted for 11%–27% of total trait variation and was on average greater in invasive species, and especially important in the axis related to resource use efficiency. These results, although dependent on the trait and community considered, offer interesting insights to the sources of functional trait diversity of native and invasive species within communities, indicating that intraspecific variation might not be equally distributed between native and invasive species.

Plant functional traits are highly plastic to changes in climatic factors and nutrient availability. However, the intraspecific plant response to abiotic factors and the overall effect on tree growth and productivity is still under debate. We studied forest productivity for 30 Quercus ilex subsp. ballota forests in Spain along a broad climatic gradient of aridity (mean annual precipitation from 321 to 858 mm). We used linear mixed models to quantify the effect of climatic and edaphic (soil nutrients, topography, and texture) factors on tree functional traits (leaf and branch traits), and subsequently, the effect of such functional traits and abiotic factors on the relative growth rate (RGR) of adult trees. We used piecewise structural equation models (SEMs) to determine the causal effect of intrinsic and extrinsic factors on forest productivity. Our results showed that tree functional traits were mainly explained by climatic and edaphic factors. Functional traits and tree biomass explained forest biomass and RGR, respectively, which ultimately explained forest productivity. In conclusion, intraspecific variability of functional traits has a significant effect on plant biomass and growth, which ultimately may explain forest productivity in Quercus ilex forests., Fondo Europeo de Desarrollo Regional-FEDER, Junta de Andalucía, Ministerio de Educación y Ciencia, Gobierno de España

14 páginas.-- 5 figuras.-- 2 tablas.-- 83 referencias.-- Electronic supplementary material The online version of this article https://doi.org/10.1007/s00468-017-1646-z) contains supplementary material, which is available to authorized users, Key message This study reinforces the existence of the leaf economics spectrum in Mediterranean woody species, and demonstrates the strong influence of phylogeny, leaf habit and environmental context as main drivers of variability in structural and nutrient traits of leaves. Abstract Leaf structural and nutrient traits are key attributes of plant ecological strategies, as these traits are related to resource-use strategies and plant growth. However, leaf structure and nutrient composition can vary among different habitats, leaf habits or phylogenetic groups. In this study, we measured 13 leaf traits (one structural—leaf mass per area, LMA—and 12 nutrient traits) in 98 Mediterranean woody species growing over a wide range of environmental conditions, with the final aim of discerning the main causes of leaf trait variability. The variance decomposition results show that phylogeny, leaf habit and habitat type affected in several ways the structural and nutrient traits studied. Leaf nutrient concentrations are strongly positively correlated amongst themselves, and negatively correlated with LMA, in accordance with the “leaf economics spectrum”. We found that leaf habit and phylogeny were important causes of variation in LMA and in a broad number of leaf nutrients (i.e., C, N, Mg, S, K), while other micronutrients seemed to be more dependent on the environment (i.e., Cu and Mn). In summary, our study reinforces the existence of the leaf economics spectrum in a broad pool of Mediterranean woody species, and demonstrates the strong influence of phylogeny, leaf habit and environmental context as the main drivers of variability in some leaf structural and nutrient traits., This study was funded by the Spanish MEC coordinated project DIVERBOS (CGL2011-30285-C02-01 and C02-02), the Andalusian ANASINQUE project (PGC2010-RNM-5782), the Life+Biodehesa Project (11/BIO/ES/000726), ECO-MEDIT (CGL2014-53236-R), RESTECO (CGL2014-52858-R) and European FEDER funds.

11 páginas.-- 2 figuras.-- 2 tablas.-- 49 referencias.-- Supporting Information Additional Supporting Information may be found in the online version of this article: Appendix S1. Sampling site locations and soil characterization. Appendix S2. Studied woody plant species and their abundances (%) by site. Appendix S3. Mean ( SE) of mycorrhizal traits by plant species. Appendix S4. Estimation of plant species turnover vs intraspecific component on community mycorrhizal trait variability. Appendix S5. Community-weighted mean values per site for each functional trait. Appendix S6. Relationships between mycorrhizal and other plant traits at the species level with hylogenetically independent contrasts. Appendix S7. Correlations among soil variables by Pearson coefficient. Appendix S8. Plant species richness and abundance by mycorrhizal type and site., This study was funded by the Spanish MEC coordinated project DIVERBOS (CGL2011-30285-C02-01 and C02-02), RESTECO (CGL2014-52858-R), ECO-MEDIT (CGL2014-53236-R), the Andalusian ANASINQUE project (PGC2010-RNM-5782), the Life + Biodehesa Project (11/BIO/ES/000726) and European FEDER funds.

12 páginas..- 4 figuras.-- 70 referencias.--Supporting Information: Additional Supporting Information may be found in the online version of this article: Appendix S1. Species list.--Appendix S2. Functional traits list.--Appendix S3. Phylogenetic tree.-- Appendix S4. Pearson correlation coefficients between traits.-- Appendix S5. Relationships between morphologicaltraits, carbon isotope fraction and leaf chlorophyll.-- Appendix S6. Phylogenetic generalized least square analysis.-- Appendix S7. Non-metric multidimensional scaling analysis.-- Appendix S8. Illustration of the scale effects., Questions: Is there any evidence of coordination among leaf, stem and root traits, and thereby of the existence of a plant economics spectrum at the species and community level in Mediterranean forests? Are these traits related to plant size and seed mass? Location: Mediterranean forests and shrublands, Sierra Morena mountains, Córdoba, southern Spain. Methods: We selected nine woody plant communities along a natural local gradient of soil water and nutrient availability. We measured key leaf, stem, root and whole-plant traits for 38 dominant woody plant species. The variation across species of 15 functional traits (of the leaf, stem and root) was analysed and coordination among them was tested. We explored the relationships between these traits (hereafter 'resource-use traits' due to their close association with the acquisition-conservation trade-off) and plant height and seed mass. Finally, we compared results at species level with those calculated at community level, considering community-weighted means (CWMs). Results: We found a significant coordination between traits belonging to different plant organs, and propose the existence of a plant economics spectrum in Mediterranean forests along the environmental gradient. However, weaker relationships were found within groups of species under similar environmental conditions. We did not find the expected orthogonal relationships between plant height, seed mass and resource-use traits. Relationships among functional traits were stronger at the community level than at the species level. Conclusions: This study reveals a high degree of functional coordination between traits belonging to different plant organs at both species and community level, and suggests the existence of a plant economics spectrum across 38 Mediterranean woody plant species. However, this general trend of functional coordination between organs became weaker or disappeared when considering restricted groups of species belonging to environmentally similar sites (e.g. dry vs wet sites), suggesting that the diversification of strategies within communities is not related to the economics spectrum at a lower spatial scale. Interestingly, the high degree of coordination between resource-use traits and seed mass at the community level seems to support the tolerance-fecundity model, which predicts an inverse relationship between fecundity and stress tolerance. © 2015 International Association for Vegetation Science., We thank Miguel Verdú for help with the phylogenetic tree and analyses and Jose Rafael Vera for plant trait analyses. We also thank Jard ın Botánico de Córdoba (Francisca Herrera) and the Semillas Cantueso Company (José Angel Cantueso) for providing seedmass data. We are very grateful to Francesco de Bello for interesting comments on previous versions of the manuscript. This study was funded by the Spanish MEC coordinated project DIVERBOS (CGL2011-30285-C02-01 and C02-02), the Andalusian ANASINQUE project (PGC2010-RNM-5782), the Life + Biodehesa Project (11/BIO/ES/000726), ECO-MEDIT (CGL2014-53236-R) and European FEDER funds. Dr. DavidWalker revised the English

10 páginas.-- 4 figuras.-- 3 tablas.-- 77 referencias.-- Supplementary material (available online as Appendix oik.01875 at (www.oikosjournal.org/readers/appendix). Appendix 1–5. http://www.ecography.org/appendix/oik-01875, Understanding which factors and rules govern the process of assembly in communities constitutes one of the main challenges of plant community ecology. The presence of certain functional strategies along broad environmental gradients can help to understand the patterns observed in community assembly and the filtering mechanisms that take place. We used a trait-based approach, quantifying variations in aboveground (leaf and stem) and belowground (root) functional traits along environmental gradients in Mediterranean forest communities (south Spain). We proposed a new practical method to quantify the relative importance of species turnover (distinguishing between species occurrence and abundance) versus intraspecific variation, which allowed us to better understand the assemblage rules of these plant communities along environmental gradients. Our results showed that the functional structure of the studied plant communities was highly determined by soil environment. Results from our modelling approach based on maximum likelihood estimators showed a predominant influence of soil water storage on most of the community functional traits. We found that changes in community functional structure along environmental gradients were mainly promoted by species turnover rather than by intraspecific variability. Specifically, our new method of variance decomposition demonstrated that between-site trait variation was the result of changes in species occurrence rather than in the abundance of certain dominant species. In conclusion, this study showed that water availability promoted the predominance of specific trait values (both in above and belowground fractions) associated to a resource acquisition or conservation strategy. In addition, we provided evidence that changes on community functional structure along the environmental gradient were mainly promoted by a process of species replacement, which represent a crucial step towards a more general understanding of the relative importance of intraspecific versus interspecific trait variation in these woody Mediterranean communities. © 2015 The Authors., This study was funded by the Spanish MEC coordinated project DIVERBOS (CGL2011–30285-C02-01 and C02-02), the Andalusian ANASINQUE project (PGC2010-RNM-5782), and European FEDER funds. Isotopic analysis was carried out in the LIE of EBD, CSIC, multielemental analysis of soil and plant samples in the IRNAS Analysis Service and N and C of leaves in the SCAI of University of Córdoba.

15 páginas.-- 6 figuras.-- 1 tabla.-- referencias.-- The online version of this article (doi:10.1007/s10021-017-0147-7) contains supplementary material, which is available to authorized users., Water availability is one of the most important factors determining species distribution, plant community structure and ecosystem functioning. We explore how the functional structure of Mediterranean woody plant communities varies along a regional gradient of aridity in the Andalusian region (south Spain). We question whether communities located in more arid sites show more similarity in their functional structure when compared with communities located in wetter sites or whether, instead, there is divergence in their functional spaces. We selected five aridity zones (three sampling sites per zone) and measured 13 traits of different functional dimensions (including leaf, stem and root traits) in 74 woody plant species. We quantified functional space differences using the n-dimensional niche space approach (hypervolume). We found a larger functional space for the wetter communities compared with the more arid communities, which showed greater overlap of the trait space occupation. Our results indicate that aridity acts as a key abiotic filter affecting various metrics of the community trait structure, in accordance with the plant economics spectrum. We have also documented consistent variation in the functional space, supporting lower functional diversity under more harsh climatic conditions. The trend of functional space variation along the aridity gradient was different when considering traits from only one plant organ. Thus, the filtering process driving the functional structure of the communities studied here largely depends on the trait axis considered; for example, the root dimension showed considerable variation in wet environments, whereas the leaf dimension exhibited a larger functional space in the drier habitats., This study was funded by the Spanish MEC Projects DIVERBOS (CGL2011-30285-C02-01 and C02-02), ECO-MEDIT (CGL2014-53236-R), RESTECO (CGL2014-52858-R) and DECAFUN (CGL2015-70123-R), the Andalusian ANASINQUE project (PGC2010-RNM-5782), the Life + Biodehesa Project (11/BIO/ES/000726), and the European FEDER funds. CV was supported by the European Research Council (ERC) Starting Grant Project ‘Ecophysiological and biophysical constraints on domestication in crop plants’ (Grant ERC-StG-2014-639706-CONSTRAINTS).

12 páginas.-- 4 figuras.-- 93 referencias.-- Details of electronic Supporting Information are provided below.-- The whole dataset of this study is publicly available in the Dryad Digital Repository: https://doi.org/10.5061/dryad.qc90d (Pérez-Ramos et al. 2017). http://hdl.handle.net/10261/278268, 1 Understanding how different factors mediate the resistance of communities to climatic variability is a question of considerable ecological interest that remains mostly unresolved. This is particularly remarkable to improve predictions about the impact of climate change on vegetation. 2 Here, we used a trait-based approach to analyse the sensitivity to climatic variability over 9 years of 19 Mediterranean shrubland communities located in southwest Spain. We evaluated the role of functional diversity (FD) and soil environment as drivers of community stability (assessed as changes in plant cover, species diversity and composition). 3 The studied shrubland communities were strongly sensitive to inter-annual variability in climate. First, colder and drier conditions caused remarkable decreases in total plant cover but increased FD, likely because the reduction of plant cover after harsh climatic conditions promoted the expansion of functionally dissimilar species in the new open microsites; although communities returned to their initial values of plant cover after nine years, changes in FD and structure persisted over time. Second, drier and colder conditions favoured the predominance of shrubs with a conservative resource-use strategy (i.e. with higher dry matter content in leaves, stems and roots), bigger seeds and a more efficient use of water. 4 The most functionally diverse communities were the most stable over time in terms of species diversity, likely because a higher number of functionally dissimilar species allowed compensatory dynamics among them. 5 Communities inhabiting more acidic and resource-limited environments were less variable over time, probably because they were mainly constituted by slow-growth, stress-tolerant species that are potentially better adapted to harsh climatic conditions. 6 Synthesis. This study highlights the utility of a trait-based approach to evaluate how plant communities respond to climatic variability. We could infer that the increased frequency of extreme climatic events predicted by climatic models will alter the functional structure of shrubland communities, with potential repercussions for ecosystem functioning. Our results also provide new insights into the role of FD and soil environment as buffers of the climate impact on woody communities, as well as potentially useful information to be applied in ecologically based management and restoration strategies., This study was supported by the “Ramón y Cajal” Research Programme to IMPR (RYC-2013- 13937), by the Spanish MEC projects DIVERBOS (CGL2011-30285-C02-01 and C02-02), DECAFUN (CGL2015-70123-R), SECADIN (CGL2012-32965), ECO-MEDIT (CGL2014-53236-R), BIOCLIM (CGL2015-67419-R) and ECOMETAS (CGL2014-53840-REDT), by the European projects Env Europe (LIFE08 ENV/IT/000399) and eLTER (GA 654359), by the Generalitat de Catalunya (AGAUR, 2014 SGR 453) and FEDER Funds.

14 páginas.-- 4 figuras.-- 1 tablas.-- 38 referencias.-- Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11104-017-3433-4), Background and aims: Root traits play a critical role in plant resource-use strategies and ecosystem functioning, but there is great controversy regarding their identity and functionality in different dimensions of belowground functional variation. Here, we explored the level of covariation among a suite of key root traits (i.e. specific root length, root dry matter content, diameter and density) as well as between them and two aboveground traits related with plant function (leaf nutrient concentration and specific leaf area). We also evaluated whether these patterns of trait covariation were consistent at different spatial scales and organisational levels. Methods: We collected fine root (< 2 mm) samples of 534 individuals (of 80 woody species) along a wide regional range of environmental conditions in southern Spain. Results: In general, strong correlations among most of the root morphological traits were found, supporting the existence of a ‘root economics spectrum’, as well as between root traits and the aboveground traits. However, root diameter was not completely aligned along this ecological axis, supporting the idea of a multidimensional spectrum of root traits. The main syndrome of root trait covariation was consistent at the different spatial scales and organisational levels. Soil nutrients and water availability were the main drivers of root trait variation. Conclusions: Our results indicate that root trait variation is primarily aligned along a leading dimension related to resource economics. However, the distinct pattern of root diameter may indicate a multidimensionality of belowground traits that needs to be explored in greater depth., This study was funded by the Spanish MEC coordinated project DIVERBOS (CGL2011-30285-C02- 01 and C02-02), ECO-MEDIT (CGL2014-53236-R), RESTECO (CGL2014-52858-R), ECOMETAS (CGL2014-53840-REDT), the Life + Biodehesa Project (11/BIO/ES/000726) and European FEDER funds.

1.Ecosystem functioning relies heavily on belowground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and environmental variation. 2.We compiled a worldwide fine-root trait dataset, featuring 1115 species from contrasting climatic areas, phylogeny and growth forms to test a series of hypotheses pertaining to the influence of plant functional types, soil and climate variables, and the degree of manipulation of plant growing conditions on species fine-root trait variation. Most particularly, we tested the competing hypotheses that fine-root traits typical of faster return on investment would be most strongly associated with conditions of limiting versus favourable soil resource availability. We accounted for both data source and species phylogenetic relatedness. 3.We demonstrate that (1) Climate conditions promoting soil fertility relate negatively to fine-root traits favouring fast soil resource acquisition, with a particularly strong positive effect of temperature on fine-root diameter and negative effect on specific root length (SRL), and a negative effect of rainfall on root nitrogen concentration; (2) Soil bulk density strongly influences species fine-root morphology, by favouring thicker, denser fine-roots; (3) Fine-roots from herbaceous species are on average finer and have higher SRL than those of woody species, and N2-fixing capacity positively relates to root nitrogen; (4) Plants growing in pots have higher SRL than those grown in the field. 4.Synthesis. This study reveals both the large variation in fine-root traits encountered globally and the relevance of several key plant functional types and soil and climate variables for explaining a substantial part of this variation. Climate, particularly temperature, and plant functional types were the two strongest predictors of fine-root trait variation. High trait variation occurred at local scales, suggesting that wide-ranging belowground resource economics strategies are viable within most climatic areas and soil conditions. This is the peer reviewed version of an article, which has been published in final form at [http://dx.doi.org/10.1111/1365-2745.12769]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

13 páginas.-- 5 figuras.-- 1 tabla.-- referencias.-- Supplementary material is available at Journal of Plant Ecology online. https://doi.org/10.1093/jpe/rtw027, Aims Extreme climatic events may have important consequences for plant community structure and composition. In 2005, a severe drought together with a cold winter promoted extensive damage and mortality in shrubland communities of southwest Spain (Doñana National Park). Here, we aim to identify the mechanisms underlying community stability (resistance and resilience) in response to this extreme climatic event, considering changes in the functional structure of these communities. Methods We used a trait-based approach, quantifying variations in 10 functional traits at the community level (community weighted means, CWM) and the functional diversity (functional richness, evenness and divergence) in 18 plots at three different times: predating the climatic event (estimated from the sum of the live and dead volume of each species in 2007), and 2 and 8 years after the 2005 episode. We also quantified the differences in functional traits and functional diversity between adult and recruit stages, which allowed us to better understand the contribution of the recruitment to the maintenance of the functional structure and diversity of the community. Important Findings Communities with higher functional divergence before the climatic event maintained nearly constant their levels of functional divergence 8 years after, but they were more prone to changes in species composition. Community resistance in terms of vegetation cover was positively correlated with root dry matter content, whereas community resilience was positively correlated with leaf chlorophyll (LChl). We also found that some values (weighted means) of functional community traits (such as root dry matter content and LChl) had increased 2 years after the event, returning to the pre-event conditions after 8 years. In addition, there was hardly any establishment of new species in the community and the recruits did not make substantial differences to the community functional structure. Only seed mass differed significantly between the adult and seedling stages. In summary, the extreme climatic event induced rapid vegetation changes, modifying several functional properties of the community, but, in spite of the occurrence of changes in species composition, a rapid convergence of these shrubland communities took place due to the replacement of species with functional redundancy, thus recovering the initial conditions and supporting the existence of strong mechanisms of functional resilience., This study was funded by the Spanish MEC projects DIVERBOS (CGL2011-30285-C02-01 and C02-02), SECADIN (CGL2012-32965) and ECO-MEDIT (CGL2014-53236-R), the Catalonian 2014-SGR-453 grant, the ICTS-Reserva Biológica de Doñana projects 38/2007, 27/2009 and 11/2013 and European FEDER funds. Isotopic analysis was carried out in the LIE of EBD(CSIC), multielemental analysis of soil and plant samples in the IRNAS Analysis Service and leaf N analysis in the SCAI of the University of Córdoba.

Question: Does community assembly on roadsides differ between two contrasting habitats along a stress–productivity gradient? Is establishment success determined by the regional pool, environmental filters or historical events? Location: Highway roadcuts and embankments in central Spain (401290N, 031340W). Methods: Species composition was recorded annually in 45 plots distributed on steep slopes with newly exposed surfaces (roadcuts) or newly built topsoiled substrates (embankments), for 4 years following hydroseeding with standard or native seed mixture. Frequency of appearance and local colonization and extinction rates of individual species were clustered in establishment success groups. We examined the correspondence between descriptive plant traits and species performance on both roadslope types. Results: Roadslope species richness showed a sustained increase over time, although at consistently lower levels and rates on the more productive embankments. Sixty per cent of the colonization events involved species from the surrounding vegetation. Hydroseeded species persisted through time, but did not modify community composition or dynamics. A higher establishment success rate was found in wind-pollinated species with large seeds and in exotic species. Those species growing on embankments showed an equal or higher establishment success rate on roadcuts and, conversely, species from roadcuts exhibited an equal or lower success rate on embankments. Conclusions: At the initial stages of community assemblage on unproductive newly created areas, species richness was shaped by the regional species pool. Communities on less harsh topsoiled embankments were subjected, however, to the filtering effect of competitive exclusion. In a reclamation context, efforts to increase site productivity may have detrimental consequences for in situ conservation of local diversity.

13 páginas.-- 5 figuras.-- 3 tablas.-- 74 referencias.-- Electronic supplementary material The online version of this article (doi:10.1007/s00442-016-3550-4) contains supplementary material, which is available to authorized users., Extreme climatic episodes, likely associated with climate change, often result in profound alterations of ecosystems and, particularly, in drastic events of vegetation die-off. Species attributes are expected to explain different biological responses to these environmental alterations. Here we explored how changes in plant cover and recruitment in response to an extreme climatic episode of drought and low temperatures were related to a set of functional traits (of leaves, roots and seeds) in Mediterranean shrubland species of south-west Spain. Remaining aerial green cover 2 years after the climatic event was positively related to specific leaf area (SLA), and negatively to leaf water potential, stable carbon isotope ratio and leaf proline content. However, plant cover resilience, i.e. the ability to attain pre-event values, was positively related to a syndrome of traits distinguished by a higher efficiency of water use and uptake. Thus, higher SLA and lower water-use efficiency characterized species that were able to maintain green biomass for a longer period of time but were less resilient in the medium term. There was a negative relationship between such syndromes and the number of emerging seedlings. Species with small seeds produced more seedlings per adult. Overall, recruitment was positively correlated with species die-off. This study demonstrates the relationship between plant traits and strong environmental pulses related to climate change, providing a functional interpretation of the recently reported episodes of climate-induced vegetation die-off. Our findings reveal the importance of selecting meaningful traits to interpret post-event resilience processes, particularly when combined with demographic attributes., This study was supported by the projects CGL2009-08101, CGL2010-16373, CGL2012-32965, DIVERBOS (CGL2011-30285-C02-01 and C02-02), AGAUR 2009-SGR-00247 and 2014-SGR-00453, ICTS-RBD 38/2007, 27/2009 and 11/2013, ECO-MEDIT (CGL2014-53236-R), and by European FEDER funds. Personnel from the ICTS-RBD kindly supported the fieldwork.

Leaf mass per area (LMA) is a morphological trait widely used as a good indicator of plant functioning (i.e. photosynthetic and respiratory rates, chemical composition, resistance to herbivory, etc.). The LMA can be broken down into the leaf density (LD) and leaf volume to area ratio (LVA or thickness), which in turn are determined by anatomical tissues and chemical composition. The aim of this study is to understand the anatomical and chemical characteristics related to LMA variation in species growing in the field along a water availability gradient. We determined LMA and its components (LD, LVA and anatomical tissues) for 34 Mediterranean (20 evergreen and 14 deciduous) woody species. Variation in LMA was due to variation in both LD and LVA. For both deciduous and evergreen species LVA variation was strongly and positively related with mesophyll volume per area (VA or thickness), but for evergreen species positive relationships of LVA with the VA of epidermis, vascular plus sclerenchyma tissues and air spaces were found as well. The leaf carbon concentration was positively related with mesophyll VA in deciduous species, and with VA of vascular plus sclerenchymatic tissues in evergreens. Species occurring at the sites with lower water availability were generally characterised by a high LMA and LD