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Global trait–environment relationships of plant communities

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Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs because different strategies can facilitate co-existence within communities. A key remaining question is to what extent community-level trait composition is globally filtered and how well it is related to global vs. local environmental drivers. Here, we perform a global, plot-level analysis of trait-environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support communities differing greatly in mean trait values. The two main community trait axes which capture half of the global trait variation (plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale.Similarly, within-plot trait variation does not vary systematically with macro-environment. Our results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be predominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning or biotic interactions.
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Articles
https://doi.org/10.1038/s41559-018-0699-8
How climate drives the functional characteristics of veg-
etation across the globe has been a key question in eco-
logical research for more than a century1. While functional
information is available for a large portion of the global pool of
plant species, we do not know how functional traits of the different
species that co-occur in a community are combined, which is what
Global trait–environment relationships of plant
communities
HelgeBruelheide   1,2*, JürgenDengler  2,3,4, OliverPurschke1,2, JonathanLenoir5,
BorjaJiménez-Alfaro6,1,2, StephanM.Hennekens  7, ZoltánBotta-Dukát8, MilanChytrý  9,
RichardField  10, FlorianJansen  11, JensKattge  2,12, ValérioD.Pillar  13, FranziskaSchrodt  10,12,
MiguelD.Mahecha  2,12, RobertK.Peet  14, BrodySandel15, PetervanBodegom16, JanAltman  17,
EstebanAlvarez-Dávila18, MohammedA.S.Arfin Khan  19,20, FabioAttorre  21, IsabelleAubin  22,
ChristopherBaraloto  23, JorcelyG.Barroso24, MarijnBauters  25, ErwinBergmeier26, IdoiaBiurrun  27,
AnneD.Bjorkman  28, BenjaminBlonder29,30, AndražČarni  31,32, LuisCayuela  33, TomášČerný34,
J.HansC.Cornelissen35, DylanCraven  2,36, MatteoDainese  37, GéraldineDerroire  38,
MicheleDe Sanctis  21, SandraDíaz39, JiříDoležal17, WilliamFarfan-Rios40,41, TedR.Feldpausch  42,
NicoleJ.Fenton43, EricGarnier  44, GregR.Guerin  45, AlvaroG.Gutiérrez  46, SylviaHaider1,2,
TarekHattab47, GregHenry48, BrunoHérault  49,50, PedroHiguchi51, NorbertHölzel52,
JürgenHomeier  53, AnkeJentsch  20, NorbertJürgens54, ZygmuntKącki55, DirkN.Karger56,57,
MichaelKessler56, MichaelKleyer  58, IlonaKnollo9, AndreyY.Korolyuk59, IngolfKühn  36,1,2,
DanielC.Laughlin60,61, FredericLens  62, JacquelineLoos63, FrédériqueLouault64,
MariyanaI.Lyubenova65, YadvinderMalhi66, CorradoMarcenò  27, MaurizioMencuccini67, 68,
JonasV.Müller69, JérômeMunzinger  70, IslaH.Myers-Smith  71, DavidA.Neill72, ÜloNiinemets73,
KateH.Orwin74, WimA.Ozinga  7,75, JosepPenuelas  68,73,76, AaronPérez-Haase  77,78 , PetrPetřík  17,
OliverL.Phillips  79, MeelisPärtel80, PeterB.Reich81,82, ChristineRömermann  2,83,
ArthurV.Rodrigues  84, FrancescoMariaSabatini  1,2, JordiSardans68,76, MarcoSchmidt  85,
GunnarSeidler1, JavierEduardoSilva Espejo86, MarcosSilveira87, AnitaSmyth45, MariaSporbert1,2,
Jens-ChristianSvenning28, ZhiyaoTang88, RaquelThomas89, IoannisTsiripidis90, KirilVassilev91,
CyrilleViolle44, RistoVirtanen  2,92,93, EvanWeiher94, ErikWelk  1,2, KarstenWesche  2,95,96,
MartenWinter2, ChristianWirth2,12,97 and UteJandt  1,2
Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing
different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs
because different strategies can facilitate co-existence within communities. A key question is to what extent community-level trait
composition is globally filtered and how well it is related to global versus local environmental drivers. Here, we perform a global,
plot-level analysis of trait–environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant
species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support
communities differing greatly in mean trait values. The two main community trait axes that capture half of the global trait variation
(plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and
soil conditions at the global scale. Similarly, within-plot trait variation does not vary systematically with macro-environment. Our
results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than
has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be pre-
dominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning and biotic interactions.
A full list of affiliations appears at the end of the paper.
NATURE ECOLOGY & EVOLUTION | VOL 2 | DECEMBER 2018 | 1906–1917 | www.nature.com/natecolevol
1906
Content courtesy of Springer Nature, terms of use apply. Rights reserved
... Accordingly, Diaz et al. [38] demonstrated that most of the global plant trait variation is expressed in a two-dimensional space, where one dimension is related to the size of the whole plant, while the other represents the variation in leaf economics traits. Together, size and leaf economics traits can express how the plants cope with the growth limitations occurring in their habitats [39][40][41]. ...
... Taxonomically, such a distinctiveness was well expressed in the sample of species considered for functional analyses, as only 8 out of 83 taxa (<10%) occurred in both the communities. However, because variations in climate and soil fertility exert relevant effects on plant traits at global and local scales (e.g., [37,41]), the community-level effects of the xerophile/mesophile ecological transition should also reflect the relationships between species traits and growth conditions. In our data, the species' ordination over the functional space and their ecological preferences fitted such an expectation, suggesting that the considered functional traits provide services with respect to specific environmental conditions [46]. ...
... Plant size and leaf economics traits are closely related to the productivity challenges that plants experience in the wild [18,37,39,40]. In particular, local environmental variations are expected to enhance filtering processes that promote the segregation of species with different trait combinations into different communities [41]. Accordingly, the observed relationships between functional and productivity proxies indicate that the measured traits were relevant modulators of plant productivity in the two analyzed communities. ...
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Understanding how functional traits influence community assemblage and functioning is crucial for assessing the effects of global change on vegetation composition. We studied the functional composition (i.e., plant size (SIZE), leaf area (LA), specific leaf area (SLA), and leaf dry matter content (LDMC)) of a xerophile pasture and a mesophile grassland in southern Italy, and recorded species richness (SR), plant cover (COV) and flowering rates (FLOW) over a 7-year period. Both communities revealed the dominance of stress-tolerators, probably reflecting an adaptation to the Mediterranean climate. The functional classification of species distinguished three groups. Species from the mesophile community had larger SIZE and LA, while those from the xerophile pasture showed higher LDMC; SLA was not connected to the source community. Community-level analyses confirmed such patterns, but with higher SLA in the mesophile grassland. While SR was comparable, COV and FLOW varied between the communities. At the species level, LDMC was positively related to FLOW and the inter-annual variability of COV and FLOW. At the community level, SIZE, LA and SLA were positively related to COV, while LDMC was positively related to FLOW. Trait variations can significantly contribute to the xerophile–mesophile shift in Mediterranean mountain vegetation, by regulating the productivity of species and communities in the two contexts and, possibly, their responsiveness to global change.
... Current theories differ about how inter-and intraspecific trait variation should track climate. On the one hand, current evidence based on community-wide trait variation at the interspecific level suggests low trait variation in extreme and fluctuating environments owing to strong selection or trait sorting (Bruelheide et al., 2018;Šímová et al., 2018;Wieczynski et al., 2019). On the other hand, previous research also indicates that plasticity should be higher in stressful or extreme environments, which should lead to higher trait variation at the intraspecific level in these environments (Chevin & Hoffmann, 2017;Valladares et al., 2014). ...
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Quantifying trait‐environment associations can help elucidate the processes underpinning the structure of species assemblages. However, most work has focused on trait variation across rather than within species, meaning that processes operating at the intraspecific levels cannot be detected. Incorporating intraspecific trait variation in community‐wide analyses can provide valuable insights about the role of morphological adaptation and plasticity on species persistence and the composition of ecological communities. Here, we assessed geographic variation in the direction (i.e., adaptation) and strength of selection, and the magnitude of plasticity, by examining community‐wide trait variation in ant communities along an environmental gradient spanning 9° latitude in Quebec, Canada. Specifically, we measured 9 morphological traits related to foraging strategies, resource use and thermal regulation at 20 locations across temperate and boreal forests. We then examined how the mean and variance of these traits varied along temperature and precipitation gradients. Moreover, we examined how these trait‐environment relationships varied across levels of organization, from individual workers (intraspecific) to colonies (intraspecific) and species (interspecific). We observed changes in mean trait values along environmental gradients, but very little change in variance. Specifically, we observed a decrease in the mean length of antennae and an increase in the mean eye length from mild (warm and wet) to more extreme environments (cold and dry). These shifts in trait means were mostly coordinated across organizational levels (i.e., worker, colony, and species). We also observed a general increase in trait variance from mild to extreme environments, but only at the species level. Our findings suggest that stressful environmental conditions exert a strong selection pressure on ant morphology causing shifts in optimal trait values. These adaptations may enable persistence at the northern edge of the boreal forest and therefore influence the composition of these ant communities. Specifically, ants with large eyes and short antennae are overrepresented at the transition zone between the boreal forest and the tundra, possibly representing an adaptation to these more open habitats. Our study demonstrates that combining spatial and community‐wide intraspecific functional trait data provides a promising way forward to gain new insights on trait adaptations and processes underpinning community structure along environmental gradients.
... To compare the effects of different response variables on the detection of ecological processes, we used 11 response variables, including multivariable, single functional, and phylogenetic variables. First, we calculated the community-weighted mean (CWM;Bruelheide et al., 2018) taking the relative importance value of tree species within each subplot as the weight. The formula used is as follows: Trait c = ΣP i × trait i , where Trait c represents the CWM of i functional trait of leaf. ...
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Neutral‐theory‐based stochastic and niche‐theory‐based determinative processes are commonly used to explain the mechanisms of natural community assembly. However, considerable uncertainty remains regarding the relative importance of different ecological processes in shaping forest communities. Functional traits and phylogeny provide important information about plant environmental adaptation strategies and evolutionary history and promise a better mechanistic and predictive understanding of community assembly. Based on nine leaf functional traits and phylogenetic data of 18 dominant species in a Lithocarpus glaber–Cyclobalanopsis glauca evergreen broad‐leaved forest, we analyzed the variation in traits, explored the influence of phylogeny and environment on leaf traits, and distinguished the relative effects of spatial and environmental variables on functional traits and phylogenetic compositions. The results showed the following: (i) Leaf traits had moderate intraspecific variation, and significant interspecific variation existed especially among life forms. (ii) Significant phylogenetic signals were detected only in leaf thickness and leaf area. The correlations among traits both supported “the leaf economics spectrum” at the species and community levels, and the relationships significantly increased or only a little change after removing the phylogenetic influence, which showed a lack of consistency between the leaf functional trait patterns and phylogenetic patterns. We infer the coexistent species tended to adopt “realism” to adapt to their habitats. (iii) Soil total potassium and phosphorus content, altitude, aspect, and convexity were the most critical environmental factors affecting functional traits and phylogenetic composition. Total environmental and spatial variables explained 63.38% of the variation in functional trait composition and 47.96% of the variation in phylogenetic structures. Meanwhile, the contribution of pure spatial factors was significantly higher than that of the pure environment. Stochastic processes played dominant roles in driving community functional trait assembly, but determinative processes such as environmental filtering had a stronger effect on shaping community phylogenetic structure at a fine scale. We infer the coexistent species tended to adopt “realism” to adapt to their habitats.Neutral‐ theory‐based stochastic processes played dominant roles in driving community functional trait assembly, but niche‐theory‐based determinative processes such as environmental filtering had a stronger effect on shaping community phylogenetic structure at a fine scale.
... Plants can respond specifically and actively to environmental changes rather than only passively withstand external stresses [21]. According to the community functional ecology theories [22][23][24], plant seed germination, seedling growth, and individual development and survival, along with environmental gradients, are mainly regulated by functional traits at species and community levels [25][26][27][28][29][30]. Plant individuals can modify their water requirements by reducing leaf size, stomatal conductance, and photosynthetic rates in response to droughts [3,31,32]. ...
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Widespread niche convergence suggests that species can be organized according to functional trait combinations to create a framework analogous to a periodic table. We compiled ecological data for lizards to examine patterns of global and regional niche diversification, and we used multivariate statistical approaches to develop the beginnings for a periodic table of niches. Data (50+ variables) for five major niche dimensions (habitat, diet, life history, metabolism, defense) were compiled for 134 species of lizards representing 24 of the 38 extant families. Principal coordinates analyses were performed on niche dimensional data sets, and species scores for the first three axes were used as input for a principal components analysis to ordinate species in continuous niche space and for a regression tree analysis to separate species into discrete niche categories. Three-dimensional models facilitate exploration of species positions in relation to major gradients within the niche hypervolume. The first gradient loads on body size, foraging mode, and clutch size. The second was influenced by metabolism and terrestrial versus arboreal microhabitat. The third was influenced by activity time, life history, and diet. Natural dichotomies are activity time, foraging mode, parity mode, and habitat. Regression tree analysis identified 103 cases of extreme niche conservatism within clades and 100 convergences between clades. Extending this approach to other taxa should lead to a wider understanding of niche evolution.
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The dipteran family Chironomidae is the most widely distributed and frequently the most abundant group of insects in freshwater, with rep­ resentatives in both terrestrial and marine environments. A very wide range of gradients of temperature, pH, oxygen concentration, salinity, current velocity, depth, productivity, altitude and latitude have been exploited, by at least some chironomid species, and in grossly polluted environments chironomids may be the only insects present. The ability to exist in such a wide range of conditions has been achieved largely by behavioural and physiological adaptations with relatively slight morphological changes. It has been estimated that the number of species world-wide may be as high as 15000. This high species diversity has been attributed to the antiquity of the family, relatively low vagility leading to isolation, and evolutionary plasticity. In many aquatic ecosystems the number of chironomid species present may account for at least 50% of the total macroinvertebrate species recorded. This species richness, wide distribution and tolerance to adverse conditions has meant that the group is frequently recorded in ecological studies but taxonomic difficulties have in the past prevented non-specialist identification beyond family or subfamily level. Recent works, including genetic studies, have meant that the family is receiving much more attention globally.
Article
Hutchinson's n-dimensional hypervolume concept for the interpretation of niches as geometric shapes has provided a foundation for research across different fields of ecology and evolution. There is now an expanding set of applications for hypervolume concepts, as well as a growing set of statistical methods available to operationalize this concept with data. The concept has been applied to environmental, resource, functional trait, and morphometric axes and to different scales, i.e. from individuals, species, to communities and clades. Further, these shapes have been variously interpreted as niches, ecological or evolutionary strategy spaces, or proxies for community structure. This paper highlights these applications’ shared mathematical framework, surveys uses of the hypervolume concept across fields, discusses key limitations and assumptions of hypervolume concepts in general, provides a critical guide to available statistical estimation methods, and delineates the situations where hypervolume concepts can be useful.
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Leaf traits strongly impact biogeochemical cycles in terrestrial ecosystems. Understanding leaf trait variation along environmental gradients is thus essential to improve the representation of vegetation in Earth system models. Our aims were to quantify relationships between leaf traits and climate in permanent grasslands at a biogeographical scale and to test whether these relationships were sensitive to (a) the level of nitrogen inputs and (b) the inclusion of information pertaining to plant community organization.
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Trade-offs maintain diversity and structure communities along environmental gradients. Theory indicates that if covariance among functional traits sets a limit on the number of viable trait combinations in a given environment, then communities with strong multidimensional trait constraints should exhibit low species diversity. We tested this prediction in winter annual plant assemblages along an aridity gradient using multilevel structural equation modelling. Univariate and multivariate functional diversity measures were poorly explained by aridity, and were surprisingly poor predictors of community richness. By contrast, the covariance between maximum height and seed mass strengthened along the aridity gradient, and was strongly associated with richness declines. Community richness had a positive effect on local neighbourhood richness, indicating that climate effects on trait covariance indirectly influence diversity at local scales. We present clear empirical evidence that declines in species richness along gradients of environmental stress can be due to increasing constraints on multidimensional phenotypes.