Find research datasets worth reusing

opencc-zeroDec 2017View details →

Data from: A trait-based framework for discerning drivers of species co-occurrence across heterogeneous landscapes

Null model analysis of species co-occurrence patterns has long been used to gain insight into community assembly but is often limited to identifying non-random patterns without providing clarity about underlying ecological mechanisms. This challenge is especially apparent when sampling units are spread across a heterogeneous landscape or along an environmental gradient because multiple mechanisms can produce similar co-occurrence patterns. We developed a trait-based approach for discriminating between environmental filtering and biotic interactions as the probable driver of co-occurrence patterns across environmentally heterogeneous sites. We demonstrate our framework by analyzing the co-occurrence of small mammals over elevation in three independent mountain ranges in the Great Basin of the western United States. Our sampling design accounts for landscape scale environmental variability and within-site habitat heterogeneity. We identified 52 non-random species pairs, of which 36 were aggregated and 16 were segregated. For each pair, we determined which mechanism was the likely ecological explanation using a hypothesis-testing framework based on functional trait similarity. Expectations of biotic interactions were based on similarity of diet and body size whereas habitat affinity and geographic range were used for environmental filtering. Only four pairs were consistent with expectations under biotic interactions, including pairs for which competitive exclusion has previously been documented. In addition to analyzing individual pairs, we used binomial tests of observed versus expected totals of intra- and inter-guild pairs to determine assemblage-wide deviations from random community structure. Signatures of environmental filtering were consistent across mountain ranges and scales. Despite differences in species composition and significant pairs among data sets, our approach revealed consistent mechanistic conclusions, emphasizing the value of trait-based methods to co-occurrence and community assembly.

opencc-zeroMar 2020View details →

Phenological responses to climate warming in temperate moths and butterflies: species traits predict future changes in voltinism

Changes in the number of generations per year (voltinism) have been among the most common phenological responses to climate warming in insects inhabiting seasonal environments. Nevertheless, numerous species have maintained univoltine (one generation per year) phenology with increasing temperatures, indicating the involvement of phylogenetic, ecological or some other constraints on phenological change. I examined geographic variation in voltinism in moths and butterflies of Northern Europe to identify species traits that might predispose species to univoltine/multivoltine phenology. I focused on species with a wide latitudinal distribution range (15 degrees as a minimum) which makes it unlikely that constraints imposed by season length could preclude multivoltinism across their distribution. Almost half of the 731 moth and butterfly species considered appear to have a single generation throughout their entire European range. A univoltine life-cycle across a wide latitudinal gradient suggests the presence of some constraint that makes additional generations either impossible or at least strongly disadvantageous, which will unlikely change with future climate warming. The scattered distribution of univoltine and multivoltine species across the lepidopteran phylogeny indicates that phylogenetic constraints are not strongly limiting changes in voltinism, and the trait is open to ecologically-driven adaptive evolution. My data show that species with one generation per year are generally larger than multivoltine species, but size forms no absolute constraint to having multiple generations per year. Obligately univoltine species dominate among egg and adult overwinterers (life-histories typical of so-called spring-feeders), whereas species with capacity for multiple generations prevail among pupal overwinterers. Multivoltinism is also infrequent among species feeding on grasses, particularly in endophagous grass-feeders. Larval diet breadth has no discernible effect on voltinism. Given the diverse ecological consequences of voltinism and its changes, accounting for the species' capacity for multivoltinism may be a key to address future challenges in biodiversity conservation and pest management.

opencc-by-4.0May 2024View details →

Data and scripts for "Joint species-trait distribution modelling: The role of intraspecific trait variation in community assembly"

The README explains how to reproduce the analyses presented in the paper "Joint species-trait distribution modelling: The role of intraspecific trait variation in community assembly" by Abrego et al. The input data for the script pipeline is the file “Kilpisjarvi_plant_data.csv”. This file includes the data on the plants and their traits in the long format. Hence, each row of the data matrix corresponds to measurements on one plant species in one study plot. The joint species-trait distribution modelling (JSTDM) pipeline that analyses these data consists of the following R-scripts. ·        S1_define_JSTDM_models.R. This script defines the JSDTM models (null model and environmental model) that include five response types for each species: the presence-absence, abundance conditional on presence, and the plot-level trait values of specific leaf area (SLA), leaf area (LA) and mean height (MH). The model is defined in the Hierarchical Modelling of Species Communities (HMSC) framework utilizing the R-package Hmsc. The models are saved in the file “unfitted_models.RData”. ·        S2_fit_models.R. This script loads the unfitted models and fits them using the posterior sampling methods implemented in the R-package Hmsc. The models are fitted with increasing thinning until thin=100, which value was used to generate the results of the paper. The fitted models are saved in the file "models_thin_100_samples_250_chains_4.Rdata". ·        S3_plot_Omega_matrices.R. This script loads the fitted models and plots the association matrices (Fig. 2 of the paper). The csv file containing the values used to construct Fig. 2 is also given (figure2Cdata.csv and figure2Ddata.csv). ·        S4_show_VP_Beta_Gamma.R. This script loads the fitted models and extracts information on the variance partitionings (VP; Figs. S3 and S4 of the paper), the relationships between response types and environmental predictors (beta; Fig. S2 of the paper), and the relationships between response types and species-level traits (gamma; Fig. S5 of the paper). The csv file containing the values used to construct Fig. S2 (figureS2Adata.csv and figureS2Bdata.csv), Fig. S3 (figureS3data.csv), Fig. S4 (figureS4data.csv) and Fig S5 (figureS5data.csv) are also given. ·        S5_conditional_cross_validation.R. This script performs 10-fold cross validation to the data to test the predictive power related to the modelled plant traits. The script performs both regular (unconditional) cross-validation where all data are masked for the test fold, and conditional cross-validation where only the trait data (but not the abundance data) are masked for the test fold. ·        S6_show_conditional_cross_validation_results.R. This script plots the results of cross-validation (Fig. 3 of the paper). The csv file containing the values used to construct Fig. 3 is also given (figure3Adata.csv and figure3Bdata.csv). ·        S7_scenario_predictions.R. This script performs the scenario simulations described and shown in Fig. 4 of the paper. The csv file containing the values used to construct Fig. 4 is also given (figure4Bdata.csv and figure4Cdata.csv).

opencc-zeroOct 2023View details →

The effects of water-stress, temperature, and plant traits on the outbreak potential of a specialist and generalist spider mite species (Acari: Tetranychidae)

The host-generalist two-spotted spider mite [Tetranychus urticae (Acari: Tetranychidae); TSM] and host-specialist Banks grass mite [Oligonychus pratensis (Acari: Tetranychidae); BGM] are common pests of corn (Zea mays L.) in the arid western United States. Climate warming and decreased precipitation may promote conditions favored by these spider mites. However, rapid evolution of spider mite resistance to commercially available acaricides is driving the need for alternative solutions for managing outbreaks. Planting of drought-tolerant corn hybrids has been proposed to be a dual-purpose strategy for mitigating water deficits for irrigation and reducing leaf conditions favorable for BGM outbreaks. However, understanding of the mechanisms responsible for reducing the BGM in the field is lacking, and determining whether outbreaks of the TSM can also be averted using drought-tolerant corn is a pressing concern. We conducted a two-year field study testing a drought-tolerant corn hybrid and an analogous drought-susceptible hybrid under water-stress with artificially-infested spider mite populations. Drought-tolerant corn had larger stem diameter, more massive cobs, and greater leaf water mass compared to the drought-susceptible corn under water stress. We also found that the BGM populations were reduced on drought-tolerant plants under water-stress, as expected, but we found an opposite trend in the TSM. Lastly, water-stressed leaves were warmer, transpired less, and had higher carbon concentration, which contributed to larger investment in eggs and growth in the BGM. We anticipate that further evaluation of irrigation and crop drought-tolerance in management of agriculture systems for multiple pest species will be increasingly impactful in arid regions.

opencc-zeroDec 2023View details →

Morphological, ecological and territorial traits for 525 Hylinae frog species

This dataset includes data on 15 morphological, ecological and territorial variables (columns) for 525 Hylinae frog species (rows), as well as cites of the references from which data were retrieved, complete references and description of variables

opencc-by-4.0Dec 2023View details →

Data and code for: Regional and local variability in the morphometric traits of two emblematic seagrass species (Zostera marina and Zostera noltei) along the French coast

We present here the raw data and scripts to reproduce the results presented in the preprint "Regional and local variability in the morphometric traits of two emblematic seagrass species (Zostera marina and Zostera noltei) along the French coast" available on Zenodo.    Preprin abstract: Zostera marina and Zostera noltei are two foundation species that play a crucial role in the functioning of coastal ecosystems. They occur in a wide range of environmental conditions over a large geographical area in the northern hemisphere. The aim of this study was to investigate the scales of variability in the dynamics of these two species in relation to environmental conditions in four sites along the French coasts. We used community trajectory analysis, a multivariate statistical approach that allows quantitative measures and comparisons of ecosystem temporal trajectories. We found a significant effect of latitude and tidal regime on the seasonal dynamics of the two species. Populations from the southernmost microtidal site showed a seasonal stability in their morphometric traits and a good resistance to present-day climatic conditions. In the meso- and macrotidal regime sites, hydrodynamics and light have led to very different ecological strategies. On the one hand, high tidal currents increased shoot density and root biomass, while on the other hand, low light and less current favoured the development of long leaves to optimise photosynthesis. Finally, significant variation in meadow development was also observed at the local scale, which requires further investigation to identify the specific drivers. Our discussion suggests that special attention should be paid to interpreting the dynamics of these species according to the scale of observation, and that this diversity of variation scales should be taken into account in conservation measures. In a global context of seagrass bed decline, our study suggests some avenues of research to improve our understanding of seagrass species ecology in order to properly assess the state of coastal waters.

High sexual display trait diversity without measured genetic divergence in a montane hybrid zone involving young species (Habronattus americanus subgroup, Araneae, Salticidae)

Genetic introgression, allele exchange across species boundaries, is a commonly recognized feature of animal evolution. Under such a paradigm contemporary contact zones provide first-hand and complementary insight into the geographic, phenotypic, and genetic details of introgression. Also, when mate choice phenotypes are conspicuous and variable in hybrids, contact zones provide potential insight into how sexual selection interacts with species boundary maintenance, particularly when postzygotic reproductive isolation is weak. The Habronattus americanus subgroup includes several recently evolved jumping spider species, with an estimated age of about 200,000 years, and substantial evidence for hybridization and introgression. We explored a contact zone involving H. americanus (Keyserling, 1885) and H. kubai (Griswold, 1979) on Mount Shasta, California, in alpine habitats that would have been unavailable (under ice) at the Last Glacial Maximum. We characterized morphological diversity within the contact zone, including the fine-scale geographic distribution of hybrid and parental individuals, and assessed genetic variation using ddRADseq data. Combined results indicate a lack of measured genomic differentiation between specimens with distinct morphologies, including individuals with phenotypes of the parental species. We identified a diverse array of hybrid morphologies, with phenotypic evidence for backcrossing, essentially forming a phenotypic bridge between parental taxa. The study area is characterized by more hybrid than parental individuals, with a significantly larger number of red-palped morphologies than white and/or yellow-palped morphologies; the novel, white-palped phenotype is perhaps transgressive. Overall, these results contribute to a better understanding of the expected ebb and flow of lineage interactions during the early stages of speciation.

Decoupling of uptake and transport-related traits in absorptive roots across coexisting herbaceous species in alpine meadows

<div>The anatomical structure of roots determines their function. Coexisting species complementarily forage nutrients by roots themselves (e.g., root strategy) and their fungal partners (e.g., mycorrhizal strategy), leading to a tradeoff between root strategy and mycorrhizal strategy. However, few studies have specifically evaluated whether and how the root anatomical structures are involved in this tradeoff, especially for species in alpine ecosystems limited by extreme climate.Here, absorptive root anatomical and chemical traits and three key root traits commonly associated with nutrient foraging strategies, i.e., root strategy indicated by first-order root length and root branching intensity and mycorrhizal strategy indicated by arbuscular mycorrhizal fungal colonization, were examined across 68 herbaceous species in alpine meadows of the Tibetan Plateau.We observed that absorptive roots with higher branching intensity had more protoxylem poles, thinner cortices and smaller cortical cells, whereas absorptive roots with higher mycorrhizal colonization and longer first-order roots consistently had thicker cortices and larger cortical cells. Unexpectedly, root cortical traits responsible for nutrient uptake were decoupled from stelar traits specialized in water and nutrient transportation. The decoupling may be related to the non-coordinated changes in soil water and nutrient availability in the meadows of the Tibetan Plateau. In addition, we found that root cortical thickness and stelar radius increased at a similar rate rather than well-reported different rates with increasing root diameter. Our results demonstrate that root internal makeup plays an integral role in forming the diverse nutrient foraging strategies in belowground. These findings provide new insights into our understanding of plant coexistence and responses of alpine meadows to climate change on the Tibetan Plateau.</div>

Phylogeny and climate explain contrasting hydraulic traits in different life forms of 150 woody Fabaceae species

<ol> <li>The contrasting hydraulic traits observed among different plant life forms are shaped by entangled environmental and evolutionary processes. However, we lack an understanding of the relative importance of life form, climate and phylogeny in explaining the variance of hydraulic traits.</li> <li>We analyzed seven hydraulic traits and eleven climatic variables of 150 Fabaceae species representing three life forms from 62 sites worldwide, using phylogenetic comparative analyses and variance partitioning.</li> <li>The phylogenetic signal found in most traits disappeared after considering life form, indicating that phylogenetic conservatism in traits originated from the divergence among life forms. The trait-climate relationships were also phylogenetically dependent, implying that trait responses are driven by climate and phylogeny together. Variance partitioning showed that phylogeny and climate explained greater trait variation than life form did.</li> <li> Synthesis. The climate-driven hydraulic trait responses in Fabaceae still existed with phylogeny being considered, suggesting that this large family may be particularly sensitive to climate change. Our results emphasize the need to include phylogeny in plant hydraulic adaptation studies under future climate change.</li> </ol>

SquamBase 1.0 – a dataset of squamate species traits

Motivation: I present a database that contains information on multiple key traits for all 11,744 recognized species of squamates worldwide. The database encompasses key traits and hopefully a reasonably comprehensive picture of available public knowledge. I present a comprehensive description of the sources and rationale leading to the assignment of each particular trait state for each species. Hopefully, the dataset can serve the scientific community and promote research and understanding of the group, comparisons with other taxa, and assessment of conservation needs. Furthermore, gaps in our knowledge of squamate traits become readily apparent and will hopefully lead to further study and even better knowledge. Main types of variables contained: morphological, ecological, life history, geographic and conservation-related traits Spatial location: Global Time period: Late Holocene to recent Major taxa and level of measurement: Squamata, species Software format: .xlsx

opencc-zeroFeb 2024View details →

The effect of neighbor species' phylogenetic and trait difference on tree growth in subtropical forests

To comprehensively understand ecological dynamics within a forest ecosystem, it is vital to explore how surrounding trees influence the growth of individual trees in a community. Biotic interactions have a significant potential impacts on individual tree growth and their effects can be evaluated through trait and phylogenetic-based approaches. This study investigates the relative importance of biotic interactions on tree growth by examining several metrics and considering three classes of intrinsic growth rates among the focal individuals: slower, intermediate and faster-growing trees. The metrics include hierarchical and absolute trait differences of focal trees to neighbors, neighborhood crowding index, phylogenetic distance, and trait community metrics. Our results indicated that the phylogenetic distance between the focal tree and its neighbors positively impacted the growth of all classes, whereas different traits have distinct effects on slower and faster-growing trees. Specific leaf area (SLA) and leaf area (LA) showed hierarchical importance to tree growth. Trees surrounded by neighbors with higher SLA and LA than themselves grow better, particularly for slower-growing trees. Higher levels of wood density difference between the focal trees and their neighbors positively impacts slower and faster-growing trees, while height difference negatively impacts faster-growing trees. We conclude that the interactions between trees are mediated by their ecological differences, but the performance and responses to surrounding competitors vary along with their growth class within a community. This study has revealed that the tree's intrinsic growth rate mediates the effect of traits and phylogeny of surrounding trees on individual tree growth.

opencc-zeroMar 2024View details →

Fifteen physiological traits related to osmoregulation and reactive oxygen species metabolism in two life form aquatic plants under a natural water salinity gradient on the Tibetan Plateau and Northwest China

Aquatic plants, as the primary producers, determine the community structure and ecological function of freshwater ecosystems. However, salinization threatens inland freshwater wetlands and thus the survival of aquatic plants. Exploring the plant physiological responses to increasing water salinity could enhance our understandings of plant adaptive strategies under future climate change regimes in wetlands. We measured 15 physiological traits of 49 aquatic plant species along a large environmental gradient in alpine and arid regions of western China, to explore the physiological adaptions and compare the similarities and differences in adaptive strategies between the two life forms to natural water salinity. We found that both water salinity and low temperature were key factors affecting aquatic plants in alpine and arid regions. Aquatic plants adapt to saline habitats by accumulating proline and sulfur (S) concentrations, and to cold habitats by increasing ascorbate peroxidase activity. Plant trait network analysis showed that the hub trait in emergent plants was S, but in submerged plants was proline, suggesting that emergent plants balanced osmoregulation and reactive oxygen metabolism via S-containing compounds, while submerged plants prioritizing the regulation of osmotic balance via proline.

opencc-zeroDec 2023View details →

Stem decomposition of temperate tree species is determined by stem traits and fungal community composition during early stem decay

Dead trees are vital structural elements in forests playing key roles in the carbon and nutrient cycle. Stem traits and fungal community composition are both important drivers of stem decay, and thereby affect ecosystem functioning, but their relative importance for stem decomposition over time remains unclear. To address this issue, we used a common garden decomposition experiment in a Dutch larch forest hosting fresh logs from 13 common temperate tree species. In total 25 fresh wood and bark traits were measured as indicators of wood accessibility for decomposers, nutritional quality, and chemical or physical defense mechanisms. After one and four years of decay, we assessed the richness and composition of wood-inhabiting fungi using amplicon sequencing and determined the proportional wood density loss. Average proportional wood density loss for the first year was 18.5%, with further decomposition occurring at a rate of 4.3% yr-1 for the subsequent three years across tree species. Proportional wood density loss varied widely across tree species in the first year (8.7-24.8% yr-1) and subsequent years (0-11.3% yr-1). The variation was directly driven by initial wood traits during the first decay year, then later directly driven by bark traits and fungal community composition. Moreover, bark traits affected the composition of wood-inhabiting fungi and thereby indirectly affected decomposition rates. Specifically, traits promoting resource acquisition of the living tree, such as wide conduits that increase accessibility and high nutrient concentration, increased initial wood decomposition rates. Fungal community composition, but not fungal richness explained differences in wood decomposition after four years of exposure in the field, where fungal communities dominated by brown-rot and white-rot Basidiomycetes were linked to higher wood decomposition rate. Synthesis. Understanding what drives deadwood decomposition through time is important to understand the dynamics of carbon stocks. Here, using a tailor-made experimental design in a temperate forest setting, we have shown that stem trait variation is key to understanding the roles of these drivers; Initially, wood traits explained decomposition rates while subsequently, bark traits and fungal decomposer composition drove decomposition rates. These findings inform forest management with a view to selecting tree species to promote carbon storage.

opencc-zeroMar 2024View details →

Data from: Relationships between rhizosphere microbial communities, soil abiotic properties and root trait variation within a pine species

Rhizosphere microbes play important roles in plant performance and ecosystem functioning. It is becoming increasingly clear that rhizosphere communities vary with soil properties and variation in root traits among plant species. However, less is known about whether and how variation in root traits within plant species influences the rhizosphere microbial communities. We evaluated the intraspecific root traits variation and explored their associations with bacterial and fungal communities in rhizosphere by focusing on an ectomycorrhizal tree species, i.e., Pinus massoniana, in 22 sites in subtropical China. The first dimension of the principal component analysis on root traits revealed evidence for the 'conservation' gradient of the root economics space. Overall, root traits explained more variation in fungal communities than in bacterial communities in the rhizosphere. Functional composition of rhizosphere microbial communities changed significantly along the 'conservation' gradient, with fast-growing copiotrophic bacteria and symbiotic ectomycorrhizal fungi were significantly enriched on the 'acquisition' side, while slow-growing oligotrophic bacteria were significantly enriched on the 'conservation' side of the gradient. Synthesis: Our study demonstrates that intraspecific variation in plant roots significantly influence rhizosphere microbial communities, which in turn can influence plant nutrition and therefore plant performance within the community.

opencc-zeroMar 2024View details →

Data and code from: Similar trait-based successional assembly in native and introduced plants despite species pool differences

What drives the composition of invaded communities and the local abundance of introduced species are key questions in ecology. Community-assembly theory provides a useful framework for addressing these questions. Specifically, the environmental filtering model of community assembly predicts that a species' presence and abundance in a community depends on the interaction between its functional traits and the local environmental filters. However, for introduced species, larger-scale dispersal and introduction-related filters may restrict their regional trait pool. Here we tested this framework using long-term data from 50+ years of old-field vegetation succession. We asked whether native and introduced plant assemblages followed the same trait-based assembly rules. We also asked whether local functional dissimilarities between the two can be explained by regional species pool differences, a possibility that has rarely been addressed. We found strong similarities in the assembly processes of native and introduced plants. Average height and seed mass of both groups increased over time, consistent with previous studies of old-field succession. Moreover, the two showed similar trait-abundance relationships. While there were also some differences, particularly in their trait-incidence relationships, these differences appeared to be minor.Further, we identified species pool constraints on introduced species, and found that the exotic species pool was biased towards early successional traits. Lastly, we found that highly invasive exotic species were also likely to deviate from the expected trait-abundance relationship, suggesting a link between the two. These results suggest that introduced species generally follow the same assembly rules as native species. They also indicate that species pool differences can result in local functional composition differences, even when the two groups follow the same assembly rules. Moreover, there may be a link between species invasiveness and deviation from assembly rules, which, if further confirmed, provides a potential method of identifying strong invaders.

opencc-by-4.0Apr 2024View details →

Data on soil variables (with plot IDs) and grassland species traits used for the analysis of grassland vegetation data by Pillar, V.D. (2024) Trait divergence in plant community assembly is generated by environmental factor interactions. Journal of Vegetation Science, 35, e13259. Available from: https://doi.org/10.1111/jvs.13259

File <a href="../api/records/10983049/draft/files/Plot_IDs_990ua.txt/content" target="_blank" rel="noopener noreferrer">Plot_IDs_990ua.txt</a> contains the IDs of the 1-m2 plots used for the analysis of grassland vegetation data by Pillar, V.D. (2024) Trait divergence in plant community assembly is generated by environmental factor interactions. The plot data are stored in the sPlot database (PPBio South Brazilian Grassland Database). File <a href="../api/records/10983049/draft/files/E_990ua_21SoilVar.txt/content" target="_blank" rel="noopener noreferrer">E_990ua_21SoilVar.txt</a> contains data on soil variables evaluated in the 250 m transects, but here expanded to the 990 1-m2 plots (each transect was sampled using 10 1-m2 pots). File <a href="../api/records/10983049/draft/files/B_769spp_4t.txt/content" target="_blank" rel="noopener noreferrer">B_769spp_4t.txt</a> is the species trait database collected in the framework of several research projects in the Quantitative Ecology Lab (EcoQua) and Grassland Vegetation Studies Lab (LevCamp) of Universidade Federal do Rio Grande do Sul (UFRGS). Data gaps were filled by compiled from the TRY database and data imputation.

opencc-by-4.0Oct 2024View details →

OctocoralTraits: a global database of trait information for octocoral species

The OctocoralTraits_v2_2 ZIP file contains structured data and code to create all figures from the manuscript: “The Octocoral Trait Database: a global database of trait information for octocoral species”. The folder also contains the code used to validate the data descriptor. Specifically, the folder contains the following files: ·       Code.R – This is the annotated code used to create all figures in R.  (v R studio; 2023.06.0+421) ·       OctocoralTraits_v2_2.csv – This is the first data realase of the octocoral trait database, used to create all figures of the manuscript. ·       sp_id.csv – This is a file containing the list of accepted octocoral species contained in the database ·       iqtree.tre – This is a tree object used to create a family-resolved tree of octocorals. It has been downloaded from McFadden et al. 2022. Revisionary systematics of Octocorallia (Cnidaria: Anthozoa) guided by phylogenomics ·       MEOW folder – A folder containing regional information from Spalding et al. 2007. Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas ·       Provinces_coord.csv: A file containing the coordinates of marine provinces, also derived from Spalding et al. 2007 ·       Table_ids folder - A folder containing tables with information of the corresponding ids that appear in the file database. ·      Validation folder: A folder containing a Technical_validation.R file that was used to flag outliers and extreme outliers, duplicated rows and potential structural errors in the data (e.g., a given observation_id linked to more than one resource, species or location).

opencc-zeroNov 2021View details →

Directional selection shifts trait distributions of planted species in dryland restoration

1. The match between species trait values and local abiotic filters can restrict community membership. An often-implicit assumption of this relationship is that abiotic filters select for a single locally optimal strategy, though difficulty in isolating effects of the abiotic environment from those of dispersal limitation and biotic interactions has resulted in few empirical tests of this assumption. Similar constraints have made it difficult to assess whether the type and intensity of abiotic filters shift along gradients of environmental harshness, as predicted by the stress dominance hypothesis. 2. We planted 9,216 plants of perennial grass and forb species that had a range of functional trait values and were assigned to a warm, intermediate, or cool temperature tolerance pools across eight sites on the Colorado Plateau. We compared the distributions of traits of surviving individuals to null distributions to evaluate whether there were shifts in trait means and variation. Borrowing from phenotypic selection concepts in evolutionary biology, we assessed support for stabilizing, directional, and disruptive abiotic filtering of trait distributions and whether these types of filtering varied with initial species pool. 3. Functional composition was significantly different from null distributions for nearly all traits at all sites, with trait variation more restricted in harsher abiotic conditions, supporting the stress-dominance hypothesis. Contrary to expectations, we primarily found evidence for directional selection, which increased in frequency in warm species pools while disruptive selection was found more often in cool and intermediate species pools. 4. Synthesis: This study provides a controlled experimental approach to test the effect of the abiotic environment on plant trait filtering. We found that opportunistic strategies allowing for rapid water acquisition during favorable periods improved survival at warmer sites. Species with these strategies may be expected to benefit from increasing aridity and may be selected for active management efforts. More generally, the prevalence of directional selection may have important implications for dynamic vegetation models that rely on trait distributions for translating environmental variation into ecosystem processes.

opencc-zeroFeb 2022View details →

Data from: Plant life history traits rather than soil legacies determine colonisation of soil patches in a multi-species grassland

Interactions between plants and soil biota are increasingly shown to play critical roles in plant species co-existence processes. Plant species co-existence is thought to be promoted via biotic legacies that plant species leave behind in the soil after a plant disappears. These soil legacies are hypothesised to supress colonisation success when the preceding plant is of the same species, that is, when a plant species encounters its own, species-specific soil antagonists. However, colonisation of vacant spots in plant communities is in the first place determined by the ability of plants to reach such vacant locations. We currently lack an understanding of the explicit role of soil legacy effects and their relative contribution to colonisation processes in plant communities consisting of plant species inherently differing in colonisation ability. In experimental, outdoor plant communities consisting of eight grassland species, we tested the effect of five differently conditioned soil patches on plant species colonisation success over three consecutive growing seasons. We found that colonisation success was largely determined by the species' reproductive strategy, lateral spread and growth rate, and not by the plant species that conditioned the soil patch. Fast spreading, clonal plant species reached the soil patches first and initially attained the highest biomass inside the patch. One year later, slower spreading plant species colonised the patch via seedlings. Species with intrinsically high growth rates attained the highest biomass, decreasing biomass of the initial colonisers. While subtle differences between conditioned soil patches did occur, these were not strong enough to overcome the inherent differences in colonisation ability between the various plant species. Synthesis: Our results reject the hypothesis that colonisation of vacant soil patches in plant communities is strongly affected by the legacy that is left behind by the preceding plant species. Instead, plant species life history strategy plays a prominent role, driving sequential plant species replacements. Based on our results and recent accounts in literature we present a conceptual model for local cyclic dynamics in grassland communities, where soil legacy plays a role in affecting the performance of established plant species rather than colonisation of vacant patches.