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1. Trait coordination reveals the fast–slow plant economics spectrum along the vertical canopy profile in central Amazonian forests

   https://doi.org/10.1111/1365-2435.70213  

   Ziccardi, Leonardo G; Taylor, Tyeen C; Smith, Marielle N; Gonçalves, Nathan B; Kramer, David; Campos, Kleber Silva; Prohaska, Neill; Restrepo‐Coupe, Natalia; Saleska, Scott R; Siqueira‐Silva, Advanio Inácio; et al (December 2025, Functional Ecology)

   Abstract Understanding how environmental drivers affect tree functioning is essential to improve predictions of tropical forests' response to climate change. While functional traits directly influence tree performance, our understanding of how canopy environments shape their coordination and variation along the vertical forest profile remains limited.We quantified annual growth rates in terms of above‐ground biomass (AGB), the maximum efficiency of photosystem II (Fv/Fm) and six tree functional traits related to water transport (xylem density and Huber value), leaf morphology (leaf size, angle and stomatal density) and photosynthesis (specific leaf area) along the vertical forest profile in an old‐growth central Amazonian forest.To investigate the influence of canopy environments and ontogenetic stages on the variation of these traits, we divided the forest into three vertical strata defined by height from the ground (S1: 0–20 m; S2: 20–40 m; S3: >40 m). We sampled 162 branches and 486 leaves from 54 trees of 10 species, encompassing at least five of the most abundant species per stratum. Path analysis and correlation matrices were used to explore the links between canopy environments, traits and the ‘fast–slow’ plant economics spectrum.We found significant effects of height on relative tree growth, leaf size and specific leaf area. Trait correlations varied across strata suggesting an ecological stratification of canopy functional niches. Trait–growth correlations increased in number and strength with increasing height, suggesting greater trait‐mediated growth control in large trees.Our results reveal how traits and strategies on the ‘fast–slow’ plant economics spectrum are vertically distributed and coordinated along the forest profile. Our findings highlight important interactions between species and canopy environments in determining plant traits, with emergent species showing adaptive strategies at different stages of their development. Read the freePlain Language Summaryfor this article on the Journal blog. 

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2. Ontogenetic shifts in wood anatomy and leaf traits in tropical dry forests

   https://doi.org/10.1111/nph.70725  

   Williams, Peter J; Zipkin, Elise F; González‐Melo, Andrés; Salgado‐Negret, Beatriz; González‐M, Roy; Norden, Natalia; Benavides‐Tocarruncho, Juan Pablo; Cely, Juan Manuel; Ferrer, Julio Abad; García‐Villalobos, Daniel; et al (January 2026, New Phytologist)

   Summary Trees experience changes in environmental conditions and biophysical constraints as they grow that may lead to shifts in functional traits. While ontogenetic shifts in leaf traits are relatively well understood, changes in wood anatomy traits from seedlings to adults are less clear, especially in tropical dry forests where drought strongly influences adult wood traits.We collected wood and leaf functional trait data for seedlings and adult trees in four dry forest sites along a rainfall gradient in Colombia. Using a Bayesian framework, we quantified intraspecific trait shifts between seedlings and adults, and we compared functional axes and trait correlations between these stages.Leaf traits shifted along a clear functional axis from more acquisitive seedlings to more conservative adults, but changes in vessel traits were more complicated. Vessel diameter increased across ontogeny as plant height increased. Wood anatomy traits were less tightly coupled for seedlings than for adults, such that the hydraulic safety–efficiency trade‐off observed in adults appeared to be weaker.Our results indicate that wood anatomy traits do not show coordinated ontogenetic shifts among traits because traits associated with hydraulic safety and efficiency are less integrated in seedlings. In dry forests, hydraulic trade‐offs become stronger as trees grow taller. 

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3. Shifting trait coordination along a soil‐moisture‐nutrient gradient in tropical forests

   https://doi.org/10.1111/1365-2435.14679  

   Boisseaux, Marion; Nemetschek, Daniela; Baraloto, Christopher; Burban, Benoit; Casado‐Garcia, Angela; Cazal, Jocelyn; Clément, Jeanne; Derroire, Géraldine; Fortunel, Claire; Goret, Jean‐Yves; et al (January 2025, Functional Ecology)

   Abstract Soil nutrients and water availability are strong drivers of tropical tree species distribution across scales. However, the physiological mechanisms underlying environmental filtering along these gradients remain incompletely understood. Previous studies mostly focused on univariate variation in structural traits, but a more integrative approach combining multiple physiological traits is needed to fully portray species functional strategies.We measured nine leaf functional traits related to trees' resource capture and hydraulic strategies for 552 individuals belonging to 21 tropical tree species across an environmental gradient in Amazonian forests. Our sampling included generalist and specialist species fromterra firme(TF) and seasonally flooded (SF) forests. We tested the influence of the topographic wetness index, a proxy for soil moisture and nutrient gradients, on each trait separately and on the trait integration through multivariate indices computed from the eigenvalues of a principal component analysis on the traits of the species. Finally, we evaluated intraspecific trait variability (ITV) for generalists and specialists by calculating the coefficient of variation for each trait.Results showed that (1) the environment had a greater influence on trait syndromes than single trait variation. Moreover, (2) SF specialist species expressed a stronger leaf trait coordination than TF specialist species. Furthermore, (3) the ability of generalist species to occupy a broader range of environments was not reflected by a larger ITV than specialist species but by the capacity to change trait coordination across environments.Our work highlights the need to investigate functional strategies as multidimensional syndromes in physiological trait space to fully understand and predict species distribution along environmental gradients. Read the freePlain Language Summaryfor this article on the Journal blog. 

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4. The ontogenetic dimension of plant functional ecology

   https://doi.org/10.1111/1365-2435.14464  

   Barton, Kasey E. (November 2023, Functional Ecology)

   Abstract Plant functional strategies change considerably as plants develop, driven by intraindividual variability in anatomical, morphological, physiological and architectural traits.Developmental trait variation arises through the complex interplay among genetically regulated phase change (i.e. ontogeny), increases in plant age and size, and phenotypic plasticity to changing environmental conditions. Although spatial drivers of intraspecific trait variation have received extensive research attention, developmentally driven intraspecific trait variation is largely overlooked, despite widespread occurrence.Ontogenetic trait variation is genetically regulated, leads to dramatic changes in plant phenotypes and evolves in response to predictable changes in environmental conditions as plants develop.Evidence has accumulated to support a general shift from fast to slow relative growth rates and from shade to sun leaves as plants develop from the highly competitive but shady juvenile niche to the stressful adult niche in the systems studied to date.Nonetheless, there are major gaps in our knowledge due to examination of only a few environmental factors selecting for the evolution of ontogenetic trajectories, variability in how ontogeny is assigned, biogeographic sampling biases on trees in temperate biomes, dependencies on a few broadly sampled leaf morphological traits and a lack of longitudinal studies that track ontogeny within individuals. Filling these gaps will enhance our understanding of plant functional ecology and provide a framework for predicting the effects of global change threats that target specific ontogenetic stages. Read the freePlain Language Summaryfor this article on the Journal blog. 

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5. Functional traits and ecological niches as correlates of the interspecific growth–mortality trade‐off among seedlings of 14 tropical tree species

   https://doi.org/10.1111/1365-2435.14624  

   Zhang, Caicai; Gu, Rong; Lin, Luxiang; Russo, Sabrina E (July 2024, Functional Ecology)

   The interspecific trade‐off between growth versus mortality rates of tree species is thought to be driven by functional biology and to contribute to species ecological niche differentiation. Yet, functional trait variation is often not strongly correlated with growth and mortality, and few studies have investigated the relationships of both traits and niches, specifically encompassing above and belowground resources, to the trade‐off itself. These relationships are particularly relevant for seedlings, which must often survive resource limitation to reach larger size classes.We investigated the functional basis of the interspecific growth–mortality trade‐off and its relationship with ecological niches for seedlings of 14 tree species in a tropical forest in southwest China.We found evidence for an interspecific growth–mortality trade‐off at the seedling stage using 15 functional traits and 15 ecological niche variables. None of the organ‐level traits correlated with growth, mortality, nor the trade‐off, whereas specific stem length (SSL), a biomass allocation trait, was the only trait to have a significant correlation (positive). Moreover, light‐defined niches were not correlated with growth, mortality or the trade‐off, but soil‐defined niches did. Species at the faster growth/higher mortality end of the trade‐off were associated with higher fertility defined by lower soil bulk density and slope, and higher soil organic matter concentration and soil total nitrogen.Our findings indicate the importance of stem elongation and soil fertility for growth, mortality and their trade‐off at the seedling stage in this Asian tropical forest. Our findings contrast with analogous studies in neotropical forests showing the importance of photosynthesis‐related leaf traits related to insolation. Therefore, the functional drivers of demographic rates and trade‐offs, as well as their consequences for ecological niches, can vary among forests, likely owing to differences in biogeography, canopy disturbance rates, topography and soil properties. Moreover, the effects of functional trait variation on demographic rates and trade‐offs may be better revealed when biomass allocation is accounted for in a whole‐plant context. Read the freePlain Language Summaryfor this article on the Journal blog. 

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