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opencc-zeroFeb 2023View details →

Nutrient-based species selection is a prevalent driver of community assembly and functional trait space in tropical forests

1. Soil nutrient availability and functional traits interact in complex ways during the assembly of tree communities hindering our understanding of the implications that this may have for their phylogenetic and functional diversity. 2. We combined abundance, taxonomic, phylogenetic and functional trait data of 222 tree species distributed along nutrient concentration gradients at twenty-four plots in two tropical forest study sites. We analysed micro and macronutrient concentration in organic and topsoil horizons and tested for: (1) nutrient-based species sorting due to contrasting trait-environment relationships; (2) whether nutrient filtering has consequences for phylogenetic and functional diversity, and functional space size and occupancy; and (3) we mapped trait distributions across the phylogeny of tree species to track the evolutionary signature of nutrient availability. 3. We found that total nitrogen (N), available phosphorus and total potassium in soil accounted for 68% of the variation in tropical tree species community composition, with strong associations with nutrient concentration for 89% of the tree species included in the analysis. This nutrient-based species selection was mediated by interactions between the three soil nutrient concentrations with leaf nitrogen, leaf thickness and wood density. Soil N concentration was positively associated with the functional space at the site level. At a plot level soil N concentration positively correlated with functional evenness and it was negatively associated with the functional space not occupied by any species in the tree community. Despite the phylogenetic conservatism of leaf N across tree lineages even when not considering legumes, many sister-species pairs show contrasting values which match with their habitat preferences thus indicating the evolutionary lability of this trait, particularly within recently diversified clades. 4. Synthesis. Our results demonstrate that soil nutrient-based species selection is a prevalent driver of community assembly in tropical forests, a process mediated by key functional traits within the leaf and wood economics spectrum. Functional space size and its filling increase with soil nutrient concentration, whereas niche vacancy decreases. This selection process has likely influenced tropical tree species diversification patterns via habitat specialization.

opencc-zeroMar 2023View details →

Global intraspecific trait-climate relationships for grasses are linked to a species' typical form and function

Plant traits are useful for predicting how species may respond to environmental change and/or influence ecosystem properties. Understanding the extent to which traits vary within species and across climatic gradients is particularly important for understanding how species may respond to climate change. We explored whether climate drives spatial patterns of intraspecific trait variation for three traits (specific leaf area (SLA), plant height, and leaf nitrogen content (Nmass)) across 122 grass species (family: Poaceae) with a combined distribution across six continents. We tested the hypothesis that the sensitivity (i.e., slope) of intraspecific trait responses to climate across space would be related to the species' typical form and function (e.g., leaf economics, stature, and lifespan). We observed both positive and negative intraspecific trait responses to climate with the distribution of slope coefficients across species straddling zero for precipitation, temperature, and climate seasonality. As hypothesized, variation in slope coefficients across species was partially explained by leaf economics and lifespan. For example, acquisitive species with nitrogen-rich leaves grew taller and produced leaves with higher SLA in warmer regions compared to species with low Nmass. Compared to perennials, annual grasses invested in leaves with higher SLA yet decreased height and Nmass in regions with high precipitation seasonality. Thus, while the influence of climate on trait expression may at first appear idiosyncratic, variation in trait-climate slope coefficients is at least partially explained by the species' typical form and function. Overall, our results suggest that a species' mean location along one axis of trait variation (e.g., leaf economics) could influence how traits along a separate axis of variation (e.g., plant size) respond to spatial variation in climate.

opencc-zeroMar 2023View details →

High functional diversity in deep-sea fish communities and increasing intra-specific trait variation with increasing latitude

Variation in both inter- and intra-specific traits affect community dynamics, yet we know little regarding the relative importance of external environmental filters vs internal biotic interactions that shape the functional space of communities along broad-scale environmental gradients, such as latitude, elevation or depth. We examined changes in several key aspects of functional alpha-diversity for marine fishes along depth and latitude gradients by quantifying intra- and inter-specific richness, dispersion and regularity in functional trait space. We derived eight functional traits related to food acquisition and locomotion, and calculated seven complementary indices of functional diversity for 144 species of marine ray-finned fishes along large-scale depth (50 m – 1200 m) and latitudinal gradients (29° – 51° S) in New Zealand waters. Traits were derived from morphological measurements taken directly from footage obtained using Baited Remote Underwater Stereo-Video systems and museum specimens. We partitioned functional variation into intra- and inter-specific components for the first time using a PERMANOVA approach. We also implemented two tree-based diversity metrics in a functional distance-based context for the first time: namely, the variance in pairwise functional distance, and the variance in nearest-neighbour distance. Functional alpha diversity increased with increasing depth, and decreased with increasing latitude. More specifically, the dispersion and mean nearest-neighbour distances among species in trait space, and intra-specific trait variability all increased with depth, whereas functional hypervolume (richness) was stable across depth. In contrast, functional hypervolume, dispersion and regularity indices all decreased with increasing latitude; however, intra-specific trait variation increased with latitude, suggesting that intra-specific trait variability becomes increasingly important at higher latitudes. These results suggest that competition within and among species are key processes shaping functional multi-dimensional space for fishes in the deep sea. Increasing morphological dissimilarity with increasing depth may facilitate niche partitioning to promote coexistence, whereas abiotic filtering may be the dominant process structuring communities with increasing latitude.

opencc-by-4.0Jan 2023View details →

Plant functional traits and corresponding satellite multispectral data for two sites in the Czech Republic

This data set contains measurements of plant functional traits and corresponding satellite multispectral data for two sites in the Czech Republic – Lanžhot and &Scaron;títná throughout multiple campaigns. Plant functional traits were collected from representative trees selected at both study sites. At the Lanžhot site, a total of 16 trees of the following species were sampled: Quercus robur (4 trees), Quercus cerris L. (2 trees), Carpinus betulus (4 trees), Fraxinus angustifolia (4 trees), Tilia cordata (2 trees). At &Scaron;títná, a total of 10 Fagus sylvatica trees were sampled. Field campaigns were timed to cover different phenological stages of deciduous tree leaf development, from fresh leaf emergence, through full leaf development at the peak of the growing season, to autumn leaf senescence. In total, six field campaigns at Lanžhot during 2019 and 2020 and five field campaigns at &Scaron;títná during 2020 and 2021 were conducted.

Beyond trait distances: Functional distinctiveness captures the outcome of plant competition

Functional trait distances between coexisting organisms reflect not only complementarity in the way they use resources, but also differences in their competitive abilities. Accordingly, absolute and relative trait distances have been widely used to capture the effects of niche dissimilarity and competitive hierarchies, respectively, on the performance of plants in competition. However, multiple dimensions of the plant phenotype are involved in these plant-plant interactions (PPI), challenging the use of relative trait distances to predict their outcomes. Furthermore, estimating the effects of competitive hierarchy on the performance of a group of coexisting plants remains particularly difficult since relative trait distances relate to the effects of a focal plant on another. We argue that trait distinctiveness, an emerging facet of functional diversity that characterizes the eccentric position of a species (or genotype) in a phenotypic space, can reveal the unique role played by a given individual plant in a group of competing plants . We used the model crop species Oryza sativa spp. japonica to evaluate the ability of trait distances and trait distinctiveness to predict the outcome of intraspecific PPI on the performance of single genotype and genotype mixtures. We performed a screening experiment to characterize the phenotypic space of 49 rice genotypes based on 11 aboveground and root traits. We selected nine genotypes with contrasting positions in the phenotypic space and grew them in pots following a complete pairwise interaction design. Relative distances and distinctiveness based on traits associated with light competition were by far the best predictors of the performance of single genotypes - taller genotypes that acquired resource faster being the best competitors - while absolute trait distances had no effect. These results indicate that competitive hierarchy for light dominates PPI in this experiment. Consistently, trait distinctiveness in plant height and age at flowering had the strongest, positive effects on mixture performance, confirming that functional distinctiveness captures the effects of trait hierarchies and asymmetric PPI at this scale. Our findings shed new light on the role of trait diversity in regulating PPI and ecosystem processes and call for a greater consideration of functional distinctiveness in studies of coexistence mechanisms.

Data from: Leaf metabolic traits reveal hidden dimensions of plant form and function

In this study, we interpreted leaf metabolome variation among 457 tropical and 339 temperate plant species to understand how the metabolome contributes to macroecological variation in plant functioning. Metabolome data were generated using liquid chromatography mass spectrometry, annotated with compound names (where possible), and cross-referenced against chemoinformatics databases to derive metabolite chemical properties. We then compared variation in leaf metabolite chemical properties among species with variation in classical plant functional traits.

FIG. 4 in Lichen community assemblages and functional traits as indicators of vegetation types in central Mexico, based on herbarium specimens

FIG. 4. — Community weighted mean proportions of functional traits for each vegetation type: A, growth forms; B, substrate; C, reproductive structure types; D, photobionts.

FIG. 3 in Lichen community assemblages and functional traits as indicators of vegetation types in central Mexico, based on herbarium specimens

FIG. 3. — Ordination and clustering of lichen communities from the different vegetation types: A, non-parametric multidimensional scaling (NDMS); B, cluster analysis dendrogram. The sites Cerro el Capulín and Cerro Juan el Grande show different affinities in both analyses (part of the xerophytic shrubland in the NDMS, but more similar to the Quercus L. forest in the dendrogram, labeled as the Xerophytic-Quercus group in the latter).

FIG. 5 in Lichen community assemblages and functional traits as indicators of vegetation types in central Mexico, based on herbarium specimens

FIG. 5. — Non-metric Multidimensional Scaling analysis of lichen community functional traits and environmental variables in three vegetation types. * (p <0.05) and ** (p <0.005) represent the significance of functional traits related to the Xerophytic shrubland (X), Subtropical shrubland (S), and Quercus L. forest (Q).

FIG. 1 in Lichen community assemblages and functional traits as indicators of vegetation types in central Mexico, based on herbarium specimens

FIG. 1. — Amplitude and mean values of alpha diversity (species richness) per vegetation type. Symbols: black dot, outlier; white dots, mean values.

FIG. 6 in Lichen community assemblages and functional traits as indicators of vegetation types in central Mexico, based on herbarium specimens

FIG. 6. — Correlation of lichen community functional traits and environmental variables in three vegetation types.

FIG. 2 in Lichen community assemblages and functional traits as indicators of vegetation types in central Mexico, based on herbarium specimens

FIG. 2. — Beta diversity and shared species per vegetation type: A, pairwise comparisons of the different elements of beta diversity (Xerophytic, xerophytic shrubland; Quercus, Quercus forest; Subtropical, subtropical shrubland); B, Venn diagram showing exclusive and shared species among the vegetation types included in this study.

opencc-by-3.0-usAug 2023View details →

Foliar functional trait maps for six sites along the Western Ghats of India

Maps of seven key foliar functional traits for six sites along the Western Ghats of India, derived using field-sampled data and hyperspectral images acquired by NASA's Airborne Visible/ Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG). Traits in this dataset include:  Leaf mass per area (LMA) in g/m2, foliar nitrogen in % dry mass (%dm), foliar fiber (%dm), foliar lignin (%dm), foliar sugars (%dm), foliar calcium (%dm), and total phenolics (%dm).

opencc-zeroAug 2023View details →

Geology constrains biomineralization expression and functional trait distribution in the Mountainsnails (Oreohelix)

Aim: Geographic variation in metabolic resources necessary for functional trait expression can set limits on species distributions. For species that need to produce and maintain biomineralized traits for survival, spatial variation in mineral macronutrients may constrain species' distributions by limiting the expression of biomineralized traits. Here, we examine whether threatened, heavily biomineralized Oreohelix land snails are restricted to CaCO3 rock regions, if they incorporate greater amounts of CaCO3 rock carbon in their shell than less biomineralized smooth forms, and if ornamentation increases shell strength. Location: Western United States Methods: We used random forest (RF) classification models at multiple spatial resolutions to evaluate the contribution of topographic, vegetation, climate, and geologic variables in predicting the presence of heavily biomineralized shell ornaments. We then measured and compared shell biometric variables, 14C/12C ratios, and peak force for fracture for ornamented and smooth forms from calcareous and non-calcareous substrates. Results: Distance to CaCO3 rock was the most important variable in all trait distribution models and was highly associated with local ornamentation classification and forecasted distribution. Pairwise comparisons of 14C/12C ratios in closely occurring ornamented vs. smooth population pairs revealed ornamented forms incorporate greater CaCO3 rock carbon than smooth forms. Ornamented types measured in this study were generally heavier and required greater peak force for fracture than smooth snails, except when compared to smooth forms sampled from CaCO3 rock. Main conclusions: Biomineralization expression, species distribution, and trait function appear to be constrained by mineral supply in a highly diverse group of land snails. This trait-environment relationship suggests similar CaCO3 macronutrient constraints may modulate biomineralization expression and restrict species distribution in other terrestrial molluscs and has a direct impact on the management of Oreohelix species.

opencc-zeroSep 2023View details →

Functional traits of young seedlings predict trade-offs in seedling performance in three neotropical forests

<ol> <li>Understanding the mechanisms that promote the coexistence of hundreds of species over small areas in tropical forest remains a challenge. Many tropical tree species are presumed to be functionally equivalent shade-tolerant species that differ in performance trade-offs between survival in shade and the ability to quickly grow in sunlight.</li> <li>Variation in plant functional traits related to resource acquisition is thought to predict variation in performance among species, perhaps explaining community assembly across habitats with gradients in resource availability. Many studies have found low predictive power, however, when linking trait measurements to species demographic rates.</li> <li>Seedlings face different challenges recruiting on the forest floor and may exhibit different traits and/or performance trade-offs than older individuals face in the eventual adult niche. Seed mass is the typical proxy for seedling success, but species also differ in cotyledon strategy (reserve vs photosynthetic) or other seedling traits. These can cause species with the same average seed mass to have divergent performance in the same habitat.</li> <li>We combined long-term studies of seedling dynamics with functional trait data collected at a standard developmental stage in three diverse neotropical forests to ask whether variation in coordinated suites of traits predicts variation among species in demographic performance.</li> <li>Across hundreds of species in Ecuador, Panama, and Puerto Rico, we found seedlings displayed correlated suites of leaf, stem, and root traits, which strongly correlated with seed mass and cotyledon strategy. Variation among species in seedling functional traits, seed mass, and cotyledon strategy were strong predictors of trade-offs in seedling growth and survival.</li> <li>Our findings highlight the importance of cotyledon strategy in addition to seed mass as a key component of seed and seedling biology. These results also underscore the importance of matching the ontogenetic stage of the trait measurement to the stage of demographic dynamics.</li> <li> Synthesis: With strikingly consistent patterns across three tropical forests, we find strong evidence for the promise of functional traits to provide mechanistic links between seedling form and demographic performance. </li> </ol>