Find research datasets worth reusing

Changes in plant community assembly from patchy degradation of grasslands and grazing by different-sized herbivores

Grassland degradation caused by increases in livestock grazing threatens a variety of ecosystem services. Understanding changes in plant community assembly during the process of grassland degradation in the presence of grazing is important to help restore degraded grasslands worldwide but has received little attention thus far. The grassland degradation process is typified by heterogeneous degradation, i.e., gradual formation of degraded patches (hereafter "patchy degradation"). Here, we experimentally examined the effects of herbivore grazing and patchy degradation on plant community assembly using nine pairs of non-degraded (intact) and patch-degraded (fragmented) grasslands subject to grazing by different-sized herbivores (i.e., NG, no grazing; SG, sheep grazing; CG, cattle grazing) over four years. Using a null-model approach, we estimated the relative magnitude of deterministic processes of community assembly by comparing the observed and expected β-diversity. We found that in the absence of herbivore grazing, deterministic processes played a greater role in community assembly, regardless of whether patchy degradation had occurred. However, the deterministic processes resulted in plant communities being more spatially similar in non-degraded grasslands while being more dissimilar in patchy degraded grasslands. Compared with non-degraded grasslands, species with strong competitive abilities (i.e., Leymus chinensis) were less dominant in patchy degraded grasslands, indicating relaxed competition and a reduced role of species interactions over plant communities. Instead, patchy degradation added the role of environmental variables over plant communities. Sheep grazing consistently promoted more stochastic plant community assembly in both non-degraded and patch-degraded grasslands, while cattle grazing promoted more stochastic plant community assembly only in the non-degraded state, having no effect in the patch-degraded state. Our study offers important insights into changes in plant community assembly during ongoing patch-degradation of grasslands, indicating the role of increased environmental filtering of soil and reduced species interactions in driving plant community dynamics with increasing grassland patchy degradation. We also uncovered an herbivore species-specific effect on plant community assembly during the process of grassland degradation, which will better inform and improve future grassland restoration planning efforts.

opencc-by-4.0Dec 2022View details →

Historical Plant Collections Card Catalog

TREC began operations in 1930 with development of the land and planting of the first crops. The digitized card catalog documents the earliest plants collected and cultivated at TREC including ornamental and fruit crops. Native and rare plants are also included with conservation focus. Most of the cards document activity from the 1930's to the 1960's with fewer entries from the 1970's and 1980's. The catalog for this collection is contained as `_CardCatalogFiles2021.xlsx` with the collection as the accompanying 468 image files that digitize 4,170 cards.

opencc-by-4.0Dec 2022View details →

Plant virus SNP prediction artificial dataset Performance Study

Recent developments in high-throughput sequencing (HTS) technologies and bioinformatics have drastically changed research on viral pathogens, especially for virus discovery and monitoring. Indeed, proper monitoring of the viral population requires information on the different isolates circulating in the studied area. For this purpose, HTS technologies have greatly facilitated the generation of new genomes of the detected viruses and their comparison. Nevertheless, the bioinformatics analyses allowing the reconstruction of genomes and the detection of Single Nucleotide Polymorphisms (SNPs) can potentially create bias, although it has not been widely addressed so far.   Therefore, more knowledge is required on the limitation and possibility of predicting SNPs based on HTS-generated sequence datasets. To address this issue, we compared the ability of 14 plant virology laboratories, each employing a different bioinformatics pipeline, to detect 21 variants of pepino mosaic virus (PepMV) through large-scale Performance Testing (PT) using three artificially designed datasets. The bioinformatics analyses were divided into three key steps: reads pre-processing (quality trimming, merging …), virus identification (assembly, alignment, mapping …) and variant calling. Each step was evaluated independently through an original, step-by-step PT design with iteration between participants.    Overall, this work underlines key parameters in SNP detection and proposes recommendations for reliable variant calling for plant viruses. The identification of the closest reference, mapping parameters and manual validation of the prediction were the most impactful analysis step for the success or failure of the predictions. Strategies to improve SNPs prediction are also discussed.

Data from the fungal phyllosphere of Mediterranean plant species

The phyllosphere is a wide and complex ecosystem that provides key support for microbial diversity. Fungal communities inhabiting the leaf are functionally variable and play important roles on plant performance. Factors conditioning the arrival and colonization of fungal communities will determine the phyllosphere fungal composition. Plant identity, leaf functional traits and host plant phylogeny have been shown to be regulators of the microbial colonization of the leaves and can be considered as biotic filters determining the assembly of phyllosphere fungal communities. By high-throughput sequencing, we analysed the phyllosphere fungal communities from 38 Mediterranean woody plant species in two forests of the south-eastern Iberian Peninsula. We analysed the effect of plant species and site on fungal community composition. We also tested the effect of leaf functional traits and plant phylogeny on plant species differences in their fungal communities, and on the structure of the plant-fungus interaction network. Plant species account for a larger proportion than site in the variability of the composition of phyllosphere fungal communities. Leaf traits and host phylogeny influence the arrival and colonization of phyllosphere fungal communities across plant species. Plants with pubescent leaves and phylogenetically closer harbour more similar communities of decomposers, pathogens and epiphytes. Leaf habit (i.e., evergreen vs. deciduous) also influences the community composition of decomposer and epiphytic fungi. Leaf carbon, leaf water content and leaf mass per area affect differentially each functional guild. Plant-fungus interaction networks present a modular structure in which plants belonging to the same module share more fungal species and are phylogenetically closer. We provide evidence that even though phyllosphere fungal communities are complex ecosystems, fungi with contrasting relationships with the plant (decomposers, epiphytes and pathogens) respond similarly to a common subset of leaf traits that impose physical limitations to the assembly of phyllosphere fungal communities.

Mycorrhizal fungi alter root exudation to cultivate a beneficial microbiome for plant growth

Arbuscular mycorrhizal (AM) fungi traditionally form symbioses with most plant species. Although AM fungi have critical effects on microbial communities, the pathways showing how AM fungi shape rhizosphere bacterial communities and their functions are rarely explored. Through three systematic experiments, AM fungi-bacteria interactions were first investigated in the rhizosphere of Lotus japonicus, then the interactions were confirmed by a second experiment with wild-type and a mycorrhiza-defective mutant ljcbx of L. japonicus. The mechanisms were presented by adding core bacteria and AM fungi to the plant rhizosphere with the third experiment. We found that AM fungi-bacteria interactions enhanced host plant growth and identified a core bacterial group that uniquely enhanced host plant growth. Adding core bacteria and AM fungi promoted host growth and nutrient acquisition compared to adding AM fungi or core bacteria independently. Allelopathic substances secreted by AM fungal colonizing host roots to recruit the rhizosphere bacteria were detected by the multi-omics joint analysis, showing that arachidonic acid was the main allelopathic substance that affected AM fungi–bacteria interactions. Our findings provide direct evidence that mycorrhizal infection simulated root exudation, such as arachidonic acid, recruited a beneficial microbiome to the host rhizosphere, increasing plant growth and soil nutrient turnover.

Mapping trait versus species turnover reveals spatiotemporal variation in functional redundancy and network robustness in a plant‐pollinator community

1. Functional overlap among species (redundancy) is considered important in shaping competitive and mutualistic interactions that determine how communities respond to environmental change. Most studies view functional redundancy as static, yet traits within species – which ultimately shape functional redundancy – can vary over seasonal or spatial gradients. We therefore have limited understanding of how trait turnover within and between species could lead to changes in functional redundancy or how loss of traits could differentially impact mutualistic interactions depending on where and when the interactions occur in space and time. 2. Using an Arctic bumblebee community as a case study, and 1,277 individual measures from 14 species over three annual seasons, we quantified how inter- and intraspecific body-size turnover compared to species turnover with elevation and over the season. Coupling every individual and their trait with a plant visitation, we investigated how grouping individuals by a morphological trait or by species identity altered our assessment of network structure and how this differed in space and time. Finally, we tested how the sensitivity of the network in space and time differed when simulating extinction of nodes representing either morphological trait similarity or traditional species groups. This allowed us to explore the degree to which trait-based groups increase or decrease interaction redundancy relative to species-based nodes. 3. We found that i) groups of taxonomically and morphologically similar bees turn over in space and time independently from each other, with trait turnover being larger over the season; ii) networks composed of nodes representing species versus morphologically similar bees were structured differently; and iii) simulated loss of bee trait groups caused faster coextinction of bumblebee species and flowering plants than when bee taxonomic groups were lost. Crucially, the magnitude of these effects varied in space and time, highlighting the importance of considering spatiotemporal context when studying the relative importance of taxonomic and trait contributions to interaction network architecture. 4. Our finding that functional redundancy varies spatiotemporally demonstrates how considering the traits of individuals within networks is needed to understand the impacts of environmental variation and extinction on ecosystem functioning and resilience.

Polymer nanoparticles pass the plant interface

As agriculture strives to feed an ever-increasing number of people, it must also adapt to increasing exposure to minute plastic particles. To learn about the accumulation of nanoplastics by plants, we prepared well-defined block copolymer nanoparticles by aqueous dispersion polymerisation. A fluorophore was incorporated via hydrazone formation and uptake into roots and protoplasts of Arabidopsis thaliana was investigated using confocal microscopy. Here we show that uptake is inversely proportional to nanoparticle size. Positively charged particles accumulate around root surfaces and are not taken up by roots or protoplasts, whereas negatively charged nanoparticles accumulate slowly and become prominent over time in the xylem of intact roots. Neutral nanoparticles penetrate rapidly into intact cells at the surfaces of plant roots and into protoplasts, but xylem loading is lower than for negative nanoparticles. These behaviours differ from those of animal cells and our results show that despite the protection of rigid cell walls, plants are accessible to nanoplastics in soil and water.

opencc-by-4.0Dec 2022View details →

Plant responses to hypergravity: a comprehensive review [Dataset]

These are the datasets used to generate the keyword co-occurrence network and the mapping of hypergravity treatments in the literature for the review article titled "Plant responses to hypergravity: a comprehensive review".  Article Citation: Hosamani, R., Swamy, B.K., Dsouza, A. et al. Plant responses to hypergravity: a comprehensive review. Planta 257, 17 (2023). <a href="https://doi.org/10.1007/s00425-022-04051-6">https://doi.org/10.1007/s00425-022-04051-6</a>

Data for: Plant roots fuel tropical soil animal communities

Belowground life relies on plant litter, while its linkage to living roots had long been understudied, and remains unknown in the tropics. Here, we analysed the response of 30 soil animal groups to root trenching and litter removal in rainforest and plantations in Sumatra, and found that roots are similarly important to soil fauna as litter. Trenching effects were stronger in soil than in litter, with an overall decrease in animal abundance in rainforest by 42% and in plantations by 30%. Litter removal little affected animals in soil layers, but decreased the total abundance by 60% in rainforest and rubber plantations but not in oil palm plantations. Litter and root effects on animal group abundances were explained by body size or vertical distribution. Our study quantifies principle carbon pathways in soil food webs under tropical land use, providing the basis for mechanistic modelling and ecosystem-friendly management of tropical soils.

Isotopic evidence for increased carbon and nitrogen exchanges between peatland plants and their symbiotic microbes with rising atmospheric CO2 concentrations since 15000 cal. yr BP

Whether nitrogen (N) availability will limit plant growth and removal of atmospheric CO2 this century is controversial. Studies have suggested that N could progressively limit plant growth, as trees and soils accumulate N in slowly cycling biomass pools in response to increases in carbon sequestration. However, a question remains over the longer-term (decadal to century) feedbacks between climate, CO2 and plant N uptake. The symbiosis between plants and microbes can help plants with mycorrhizal N uptake or biological N2 fixation – the pathway through which N can be rapidly brought into ecosystems and thereby partially or completely alleviate N limitation on plant productivity. Here we present results for plant N isotope composition (δ15N) in a peat core that dates to 15000 cal. yr BP to ascertain ecosystem-level N cycling responses to rising atmospheric CO2 concentrations in the past. We found that an increase in atmospheric CO2 concentration happened with a decrease in δ15N values of both Sphagnum moss and Ericaceae over this time period when constrained for climatic factors. A modern experiment demonstrated that δ15N of Sphagnum mosses decreased with increasing N2 fixation rates. These findings suggested that N2 fixation in Sphagnum moss by symbiosis with cyanobacteria and N uptake in Ericaceae by symbiosis with mycorrhizal fungi both likely increased with rising atmospheric CO2 concentrations, highlighting a longer-term feedback mechanism whereby N constraints on terrestrial carbon storage can be overcome.

Data from: Savanna resilience to droughts increases with proportion of browsing wild herbivores and plant functional diversity

1. Maintaining the resilience and functionality of savannas is key to sustaining the ecosystem services they provide. This maintenance is largely dependent on the resilience of savannas to stressors, such as prolonged droughts. The resilience to drought is largely determined by the interaction of herbivores and the functional composition of vegetation. So far, our understanding and ability to predict the response of savannas to drought under different types of rangeland use and as a function of vegetation composition are still limited. 2. In this study, we used the ecohydrological, spatially-explicit savanna model EcoHyD to determine if the resilience of a savanna rangeland towards prolonged droughts can be enhanced by the choice of rangeland use type (grazer-dominated, mixed-feeders or browser-dominated) and animal density. We evaluated the ability of a Namibian savanna system to withstand droughts and to recover from droughts based on its perennial grass cover and the overall species composition. 3. Generally, we determined a low resilience under high grazer densities. Most importantly, we found that functional diversification of herbivores and plants acted as resilience insurance against droughts, leading to greater resistance and recovery of perennial grasses. In particular, a higher proportion of herbivores allowed for higher resilience, probably also due to a short-term switch to more drought-resistant or unpalatable species. 4. In this case, herbivore diversification was of high self-regulatory value by reestablishing trophic complexity, reducing the need for additional management interventions. 5. Synthesis and applications. Savanna systems will be more resistant to drought if (i) a dense perennial grass cover is maintained, protecting the topsoil from heat-induced water losses and erosion, encompassing functionally important species that are particularly well adapted to water stress and that are palatable, if (ii) the grazing pressure is adjusted to the productivity of the system, and (iii) the herbivore community includes browsers.

Data from: Does the reduction of seed dormancy during ex situ cultivation affect the germination and establishment of plants reintroduced into the wild?

1. Plants or seeds produced in botanic gardens or nurseries have become an important source of plant material for reintroductions or population reinforcements. However, recent research has shown that these living collections bear the risk of being genetically impoverished and adapted to the artificial habitat. In particular, many studies have reported a decline of seed dormancy during ex situ cultivation, which may compromise their suitability for reintroduction programs. However, the impact of those ex situ-derived changes on the germination and establishment of reintroduced plant populations is still unclear. 2. We studied the germination behaviour, population establishment and plant fitness over three years of reintroduced plants of the short-lived perennial Digitalis lutea, comparing plants grown from (1) a 30-year botanic garden population, (2) seeds from a seed bank representing the initial starting point of the botanic garden culture, and (3) a re-sampled corresponding wild population. 3. Under laboratory conditions, wild-collected seeds required cold stratification to germinate, whereas seeds from the garden population germinated without stratification. This pattern was strongly reduced in an outdoor pot experiment, where only a few garden seeds germinated before winter, and all seeds remained dormant when seeded in the natural area of origin. In a transplant experiment, reintroduced plants from the wild population outperformed both, the garden and the seed bank plants, in their fitness in the first 3 years after reintroduction suggesting adaptation to current climatic conditions. 4. Synthesis and Applications: Our study demonstrates that trait changes that occurred during ex situ cultivation can negatively impact the establishment of reintroduced plants. We conclude that wild plant material collected from contemporary populations is best suited for reintroduction and should be preferred over ex situ-cultivated and seed bank stored material, especially when the cultivation spanned multiple generations. However, our study also shows that germination requirements change in complex ways, and the loss of dormancy observed under laboratory conditions may not always be directly transferable to natural conditions. When established standards are respected, ex situ propagated material may thus still be a valuable resource, especially when wild material is not available in sufficient quantities.

A direct comparison of ecological theories for predicting the relationship between plant traits and growth

Despite long-standing theory for classifying plant ecological strategies, limited data directly links organismal traits to whole-plant growth rates. We compared trait-growth relationships based on three prominent theories: growth analysis, Grime's competitive-stress tolerant-ruderal (CSR) triangle, and the leaf economics spectrum (LES). Under these schemes, growth is hypothesized to be predicted by traits related to relative biomass investment, leaf structure or gas exchange, respectively. We also considered traits not included in these theories, but that might provide potential alternative best predictors of growth. In phylogenetic analyses of 30 diverse milkweeds (Asclepias spp.) and 21 morphological and physiological traits, growth rate (total biomass produced per day) varied 50-fold and was best predicted by biomass allocation to leaves (as predicted by growth analysis) and the CSR traits of leaf size and leaf dry matter content. Total leaf area and plant height were also excellent predictors of whole-plant growth rate. Despite two LES traits correlating with growth (mass-based leaf nitrogen and area-based leaf phosphorus contents), these were in the opposite direction predicted by LES, such that higher N and P contents corresponded to slower growth. The remaining LES traits (e.g., leaf gas exchange) were not predictive of plant growth rates. Overall, differences in growth rate were driven more by whole-plant characteristics such as biomass fractions and total leaf area than individual leaf-level traits such as photosynthetic rate or specific leaf area. Our results are most consistent with classical growth analysis - combining leaf traits with whole-plant allocation to best predict growth. However, given that destructive biomass measures are often not feasible, applying easy-to-measure leaf traits associated with the CSR classification appear more predictive of whole plant growth than LES traits. Testing the generality of this result across additional taxa would further improve our ability to predict whole-plant growth from functional traits across scales.

Data from: Use of an exotic host plant reduces viral burden in a native insect herbivore

Incorporation of exotic plants into the diets of native herbivores is a common phenomenon, influencing interactions with natural enemies and providing insight into the tritrophic costs and benefits of dietary expansion. We evaluated how use of an exotic plant, Plantago lanceolata, impacted immune performance, development, and susceptibility to pathogen infection in the neotropical herbivore Anartia jatrophae (Lepidoptera: Nymphalidae). Caterpillars were reared on P. lanceolata or a native plant, Bacopa monnieri, and experimentally infected with a pathogenic virus, Junonia coenia densovirus. We found that virus-challenged herbivores exhibited higher survival rates and lower viral burdens when reared on P. lanceolata compared to B. monnieri, though immune performance and development time were largely similar on the two plants. These findings reveal that use of an exotic plant can impact the vulnerability of a native herbivore to pathogen infection, suggesting diet-mediated protection against disease as a potential mechanism facilitating the incorporation of novel resources.

opencc-by-4.0Jan 2023View details →

Resampling alpine herbarium records reveals changes in plant traits over space and time - dataset

Data overview: These data correspond to the analyses conducted for the article "Resampling alpine herbarium records reveals changes in plant traits over space and time" by Francesca Jaroszynska, Christian Rixen, Sarah Woodin, Jonathan Lenoir and Sonja Wipf, in Journal of Ecology Metadata for jaroszynska_herbarium_traits_data.csv: date = date; date of collection time = factor; time of collection (historical or recent) elevation = numerical; elevation in metres above sea level of the sample collection site selevation = numerical; scaled elevation selevation2 = numerical; elevation in metres above sea level of sample collection site (elevation/1000). sSlope = numerical; scaled slope (slope/10) slope = numerical; computed slope based on elevation trait = string; name of the measured trait <ul> <li> crFlowerN = numerical; Cardamine resedifolia; number of flowers </li> <li> crHeight = numerical; Cardamine resedifolia; plant height </li> <li> crLeafL = numerical; Cardamine resedifolia; length of longest leaf </li> <li> crRosetteLeafN = numerical; Cardamine resedifolia; number of leaves in rosette </li> <li> paBasalLeafL = numerical; Poa alpina; basal leaf length </li> <li> paInflorescenceL = numerical; Poa alpina; inflorescence length </li> <li> paHeight = numerical; Poa alpina; plant height </li> <li> pvInfL = numerical; Polygonum viviparum; length of inflorescence </li> <li> pvLA = numerical; Polygonum viviparum; leaf area (length x width) </li> <li> pvLeafL = numerical; Polygonum viviparum; leaf length </li> <li> pvRepH= numerical; Polygonum viviparum; plant height </li> <li> rgFlowerStemL = numerical; Ranunculus glacialis; flowering stem length </li> <li> rgLeafStemL = numerical; Ranunculus glacialis; petiole length </li> <li> rgLeafW = numerical; Ranunculus glacialis; leaf width </li> <li> rgFlowerN = integer; Ranunculus glacialis; number of flowers </li> </ul>   traitGroup = factor; the group to which each trait belongs (VegHeight = vegetative height, ReprHeight = reproductive height, ReprOut = reproductive output, PhotoCap = photosynthetic capacity) value = numerical; value of the trait measured species = factor; species code (car_res = Cardamine resedifolia, ran_glac = Ranunculus glacialis, pol_viv = Polygonum viviparum, poa_alp = Poa alpina) transect = string; transect along which the herbarium sample was taken confidence = factor; reliability of the metadata associated with the herbarium sample, assigned by the authors Jaroszynska and Wipf (low, medium, high) northness = numerical; northness eastness = numerical; eastness observer = string; botanist who conducted the collection sheet = string; unique identifier for the collection sheet   Metadata for jaroszynska_climate_traits_data.csv: year = year; year of sample collection Month = integer; month of sample colection Temperature = numerical; monthly average temperature (ºC) Precipitation = numerical; monthly total precipitation (mm) yearMonth = string; year.month season = factor; season associated to the corresponding month (spring, summer, autumn, winter) timePeriod = factor; climate period referring to the time before, after, or during the baseline reference period (see article for further details) meanAnnTemp = numerical; mean annual temperature (ºC) sumAnnPrecip = numerical; total annual precipitation (mm) meanSeaTemp = numerical; mean seasonal temperature (ªC) sumSeaPrecip = numerical; total seasonal precipitation (mm) meanRefTemp = numerical; mean seasonal temperature for reference period (ªC) temp_anomaly = numerical; temerature anomaly from the reference period (ªC) lagMonths = string; used in seasonal calculation seasonal_precip = numerical; seasonal precipitation (mm) precip_anomaly = numerical; seasonal precipitation anomaly (mm)

Data from: Plant attributes interact with fungal pathogens and nitrogen addition to drive soil enzymatic activities and their temporal variation

Nitrogen enrichment can alter soil communities and their functioning directly, via changes in nutrient availability and stoichiometry, or indirectly, by changing plant communities or the abundance of consumers. However, most studies have only focused on one of these potential drivers and we know little about the relative importance of the different mechanisms (changes in nutrient availability, in plant diversity or functional composition, or in consumer abundance) by which nitrogen enrichment affects soil functioning. In addition, soil functions could vary dramatically between seasons, however, they are typically measured only once during the peak growing season. We therefore know little about the drivers of intra-annual stability in soil functioning. In this study, we measured activities of β-glucosidase and acid phosphatase, two extracellular enzymes that indicate soil functioning. We did so in a large grassland experiment which tested the effects, and relative importance, of nitrogen enrichment, plant functional composition and diversity, and foliar pathogen presence (controlled by fungicide) on soil functioning. We measured the activity of the two enzymes across seasons and years to assess the stability and temporal dynamics of soil functioning. Overall β-glucosidase activity was slightly increased by nitrogen enrichment over time but did not respond to the other experimental treatments. Conversely, plant functional diversity, and interactions between plant attributes and fungicide application, were important drivers of mean acid phosphatase activity. The temporal stability of both soil enzymes was differently affected by two facets of plant diversity: species richness increased temporal stability and functional diversity decreased it; however, these effects were dampened when nitrogen and fungicide were added. Synthesis: The fungicide effects on soil enzyme activities suggest that foliar pathogens can also affect belowground processes and the interacting effect of fungicide and plant diversity suggests that these plant enemies can modulate the relationship between plant diversity and ecosystem functioning. The contrasting effects of our treatments on the mean versus stability of soil enzyme activities clearly show the need to consider temporal dynamics in belowground processes, to better understand the responses of soil microbes to environmental changes such as nutrient enrichment.

Data for: Using environmental DNA to investigate avian interactions with flowering plant

Animal pollination is an important and highly valued ecosystem function and the role of birds as pollinators is increasingly acknowledged. However, such interactions can be challenging to document and often require extensive field programs. Over the last decade, environmental DNA (eDNA) has been analysed from several different contemporary sample types such as water, soil, flowers, and air. The applications of these studies include biodiversity monitoring, detection of endangered species, community compositions, and, more recently, flower-arthropod interactions. However, it remains unknown whether flower-eDNA is applicable to other taxonomic groups interacting with plants, as well as the deposition and degradation of eDNA on flowers. Here, we test whether eDNA from flowers can be used for detecting bird pollinators. In a controlled environment (an aviary with great tits [Parus major]), we show that birds leave significant traces of DNA on the flowers without observed visits (airborne eDNA). We further show that when birds had been in contact with the flowers, DNA concentrations increased to levels significantly higher than airborne background DNA. Subsequently, we sampled five clusters of wild flowers in Papua New Guinea and detected four species of birds, two of which are nectar-feeders, and one that is an insectivorous species known to visit flowers. These four bird species were regularly seen in the area and caught in mist-nets in the days prior to sampling of the flowers. In total, 29 bird species were recorded (18 mist-netted) in the area and of these eight are nectarivorous. Our quantitative approach suggests that it is possible to distinguish airborne background bird DNA deposited on flowers from actual flower visits of birds in the wild, although this might be highly context specific. Our findings are of broad interest within research on ecosystem functioning, biotic interactions, and plant-animal mutualism.

Dataset: A three-dimensional approach to general plant fire syndromes

1. Plant fire syndromes are usually defined as combinations of fire response traits, the most common being resprouting (R) and seeding (S). Plant flammability (F), on the other hand, refers to a plant's effects on communities and ecosystems. Despite its important ecological and evolutionary implications, F has rarely been considered to define plant fire syndromes and, if so, usually separated from response syndromes. 2. We propose a three-dimensional model that combines R, S and F, encapsulating both plant response to fire regimes and the capacity to promote them. Each axis is divided into three possible standardized categories, reflecting low, medium and high values of each variable, with a total of 27 possible combinations of R, S and F. 3. We hypothesized that different fire histories should be reflected in the position of species within the three-dimensional space and that this should help assess the importance of fire as an evolutionary force in determining R-S-F syndromes. 4. To illustrate our approach we compiled information on the fire syndromes of 24 dominant species of different growth forms from the Chaco seasonally-dry forest of central Argentina, and we compared them to 33 species from different Mediterranean-type climate ecosystems (MTCEs) of the world. 5. Chaco and MTCEs species differed in the range (seven syndromes vs. thirteen syndromes, respectively) and proportion of extreme syndromes (i.e. species with extreme values of R, S and/or F) representing 29% of species in the Chaco vs. 45% in the MTCEs. 6. Additionally, we explored the patterns of R, S and F of 4032 species from seven regions with contrasting fire histories, and found significantly higher frequencies of extreme values (predominantly high) of all three variables in MTCEs compared to the other regions, where intermediate and low values predominated, broadly supporting our general hypothesis. 7. The proposed three-dimensional approach should help standardize comparisons of fire syndromes across taxa, growth forms and regions with different fire histories. This will contribute to the understanding of the role of fire in the evolution of plant traits and assist vegetation modelling in the face of changes in fire regimes.

Plant-soil feedbacks in sympatric Asclepias species

Plants affect associated biotic and abiotic edaphic factors, with reciprocal feedbacks from soil characteristics affecting plants. These two-way interactions between plants and soils are collectively known as plant-soil feedbacks (PSFs). The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of PSFs, although the strength and direction of feedbacks among sympatric congeners is not well understood. We examined plant-soil feedback responses of Asclepias syriaca, a common clonal milkweed species, with several sympatric congeners across a gradient of increasing phylogenetic distances (A. tuberosa, A. viridis, A. sullivantii, and A. verticillata, respectively). Plant-soil feedbacks were measured through productivity and colonization by arbuscular mycorrhizal (AM) fungi. Asclepias syriaca produced less biomass in soils conditioned by the most phylogenetically distant species (A. verticillata), relative to conspecific-conditioned soils. Similarly, arbuscular mycorrhizal (AM) fungal colonization of A. syriaca roots was reduced when grown in soils conditioned by A. verticillata, compared to colonization in plants grown in soil conditioned by any of the other three Asclepias species, indicating mycorrhizal associations are a potential mechanism of observed positive PSFs. This display of differences between the most phylogenetically distant, but not close or intermediate, paring(s) suggest a potential phylogenetic threshold, although other exogenous factors cannot be ruled out. Overall, these results highlight the potential role of phylogenetic distance in influencing positive PSFs through mutualists.

Can species naming drive scientific attention? A perspective from plant-feeding arthropods

How do researchers choose their study species? Some choices are based on ecological or economic importance, some on ease of study, some on tradition – but could the name of a species influence researcher decisions? We asked whether phytophagous arthropod species named after their host plants were more likely to be assayed for host-associated genetic differentiation (or 'HAD'; the evolution of cryptic, genetically isolated host specialists within an apparently more generalist lineage). We chose 30 arthropod species (from a Google Scholar search) for which a HAD hypothesis has been tested. We traced the etymologies of species names in the 30 corresponding genera, and asked whether HAD tests were more frequent among species whose etymologies were based on host-plant names (e.g., Eurosta solidaginis, which attacks Solidago) vs. those with other etymologies (e.g., Eurosta fenestrata, from Latin fenestra, or window). Species with host-derived etymologies were more likely to feature in studies of HAD than those with other etymologies. We speculate that the etymology of a scientific name can draw a researcher's attention to aspects of life-history and thus influence the direction of our scientific gaze.