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opencc-by-4.0Sep 2021View details →

Nickel and chromium stable isotopic composition of ureilites: implications for the Earth's core formation and differentiation of the ureilite parent body

We report the first Ni and Cr stable isotope data for ureilite meteorites that are the mantle residue of a carbon-rich differentiated planet. Ureilites have similar Ni stable isotope compositions as chondrites, suggesting the core-mantle differentiation of ureilite parent body did not fractionate Ni isotopes. Since the size of Earth is potentially larger than that of ureilite parent body (UPB; with diameter > 690 km), resulting in higher temperatures at the core-mantle boundary of Earth, it can be predicted that the terrestrial core formation may not directly cause Ni stable isotope fractionation. On the other hand, we also report high-precision Cr stable isotope composition of ureilites, including one ureilitic trachyandesite (ALM-A) that is enriched in lighter Cr stable isotopes relative to the main-group ureilites, which suggests the partial melting occurred on UPB. The globally heavy Cr in the UPB compared to chondrites can be caused by sulfur-rich core formation processes.

Figure 4 in Structure and composition of the insect community associated with flower buds and inflorescences of Byrsonima verbascifolia (Malpighiaceae)

Figure 4. Similarity of the abundance of floral visitors collected in the two flowering stages of B. verbascifolia. BUD = flower buds; IFL: inflorescences. (From ten plants sampled during 2 hours: 1 h in the morning and 1 h in the afternoon).

Figure 3 in Structure and composition of the insect community associated with flower buds and inflorescences of Byrsonima verbascifolia (Malpighiaceae)

Figure 3. Abundance, richness and diversity of flower visitors and ants collected in B. verbascifolia. BUD = flower buds; IFL: inflorescences. Error bars represent SE. (From ten plants sampled during 2 hours: 1 h in the morning and 1 h in the afternoon).

Figure 2 in Structure and composition of the insect community associated with flower buds and inflorescences of Byrsonima verbascifolia (Malpighiaceae)

Figure 2. (a) Venn diagram for specimens of flower visitors collected in B. verbascifolia. (b) Venn diagram for ant specimens collected in B. verbascifolia BUD = flower buds; IFL: inflorescences. (From ten plants sampled during 2 hours: 1 h in the morning and 1 h in the afternoon).

Figure 1 in Structure and composition of the insect community associated with flower buds and inflorescences of Byrsonima verbascifolia (Malpighiaceae)

Figure 1. Phenology of B. verbascifolia during 12 months. The number of leaves, flower buds, inflorescences and infructescences.

Figure 5 in Structure and composition of the insect community associated with flower buds and inflorescences of Byrsonima verbascifolia (Malpighiaceae)

Figure 5. Similarity of the abundance of ants collected in the two flowering stages of B. verbascifolia. BUD = flower buds; IFL: inflorescences. (From ten plants sampled during 2 hours: 1 h in the morning and 1 h in the afternoon).

opennotspecifiedJan 2012View details →

Figure 7. Composite figure with a in Early eusuchia crocodylomorpha from the vertebrate-rich Plattenkalk of Pietraroia (Lower Albian, southern Apennines, Italy)

Figure 7. Composite figure with a mounted photograph of the mandible and illustration of Pietraroiasuchus ormezzanoi.

opennotspecifiedAug 2016View details →

Figure 12. Pinnichthys aimoriensis papillae pattern, composite from AMNH 265020 and CIUFES 2414 in Molecular phylogeny, analysis of character evolution, and submersible collections enable a new classification of a diverse group of gobies (Teleostei: Gobiidae: Nes subgroup), including nine new species and four new genera

Figure 12. Pinnichthys aimoriensis papillae pattern, composite from AMNH 265020 and CIUFES 2414. Illustration by J.L. Van Tassell.

We are what we eat, plus some per mill: Using stable isotopes to estimate diet composition in Gyps vultures over space and time

1. Dietary studies in birds of prey involve direct observation and examination of food remains at resting and nesting sites. Although these methods accurately identify diet in raptors, they are time consuming, resource intensive and associated with biases that stem from the feeding ecology of raptors like Gyps vultures (Gyps africanus and Gyps rueppelli). Our study set out to estimate diet composition in Gyps vultures informed by stable isotopes that provide a good representation of assimilated diet from carrion resources in local systems. 2. We hypothesized that differences in Gyps vulture diet composition is a function of sampling location, and that these vultures move between Serengeti National Park and Selous Game Reserve to forage. We also, theorized that grazing ungulates are the principal items in Gyps vulture diet. 3. Through a combination of linear and Bayesian models, diet derived from d13C in Gyps vultures consisted of grazing herbivores across study areas, with those in Serengeti National Park consuming higher proportions of grazing herbivores (> 87%). d13C differences in vulture feather subsets per site did not indicate vulture diet change, and in combination with blood d13C, vultures fed largely on grazers for ~159 days before they were sampled in both sites. Similarly, d15N values implied that Gyps vultures fed largely on herbivores across space and time. d34S ratios separated prey source for vultures between the two sites. d34S variation in vultures across sites resulted from differences in baseline (plant) d34S values, though it is not possible to match d34S to specific locations. 4. Our findings highlight the relevance of repeated sampling that considers tissues with varying isotopic turnover and emerging Bayesian techniques for dietary studies using stable isotopes. Findings also suggested limited vulture movement between the two local systems. However, more sampling coupled with telemetry is required to fully comprehend this observation and its implications to Gyps vulture ecology and conservation.

opencc-by-4.0Sep 2021View details →

Tutorial videos on the application of XPS inelastic background for characterization of composition and morphology of nano-structures with QUASES software

The tutorial videos illustrate the application of XPS inelastic background analysis for characterization of composition and morphology of nano-structures with QUASES software. For an introduction to the method, see: S. Tougaard "Practical guide to the use of backgrounds in quantitative XPS." J Vac Sci Technol A. 2021;39:011201. doi:10.1116/6.0000661 S. Tougaard "Accuracy of the non-destructive surface nanostructure quantification technique based on analysis of the XPS or AES peak shape". Surf Interface Anal. 1998;26(4):249-269. doi:<a href="https://doi-org.proxy1-bib.sdu.dk/10.1002/(SICI)1096-9918(199804)26:4%3C249::AID-SIA368%3E3.0.CO;2-A">https://doi-org.proxy1-bib.sdu.dk/10.1002/(SICI)1096-9918(199804)26:4<249::AID-SIA368>3.0.CO;2-A</a>   The inelastic background analysis was done with the QUASES-Tougaard software . See www. quases.com. It is recommended to read first the short description in the pdf file: Guide to the 14 posted videos.pdf. This explains briefly the purpose of each video.  To best understand what is done in Video 9  ("9.Practical procedure to correct for elastic electron scattering.mp4") you should first watch Video 8, then Video 6 and then Video 9.

Unaltered soil microbial community composition, but decreased metabolic activity in a semi-arid grassland after two years of passive experimental warming

Soil microbial communities regulate soil carbon feedbacks to climate warming through microbial respiration (i.e. metabolic rate). A thorough understanding of the responses of composition, biomass and metabolic rate of soil microbial community to warming is crucial to predict soil carbon stocks in a future warmer climate. Therefore, we conducted a field manipulative experiment in a semi-arid grassland on the Loess Plateau of China to evaluate the responses of the soil microbial community to increased temperature from April 2015 to December 2017. Soil temperature was 2.0 oC higher relative to the ambient when open-top chambers (OTCs) were used. Warming did not affect microbial biomass or the composition of microbial functional groups. However, warming significantly decreased microbial respiration, directly resulting from soil pH decrease driven by the co-mediation of aboveground biomass increase, inorganic nitrogen increase and moisture decrease. These findings highlight that the soil microbial community structure of semi-arid grasslands resisted the short-term warming by 2 oC, although its metabolic rate declined.

Species composition and functional trait data for wet pine savannas

Trait differences among plant species can favor species coexistence. The role that such differences play in the assembly of diverse plant communities maintained by frequent fires remains unresolved. This lack of resolution results in part from the possibility that species with similar traits may coexist because none has a significant fitness advantage and in part from the difficulty of experimental manipulation of highly diverse assemblages dominated by perennial species. We examined a 65-year chronosequence of losses of herbaceous species following fire suppression (and subsequent encroachment by Pinus elliottii) in three wet longleaf pine savannas. We used cluster analysis, similarity profile permutation tests and k-R cluster analysis to identify statistically significant functional groups. We then used randomization tests to determine if the absence of functional groups near pines was greater (or less) than expected by chance. We also tested whether tolerant and sensitive species were less (or more) likely to co-occur by chance in areas in savannas away from pines in accordance with predictions of modern coexistence theory. Functional group richness near pines was lower than expected from random species extirpations. Wetland perennials with thick rhizomes and high leaf water content, spring-flowering wetland forbs (including Drosera tracyi), orchids, Polygala spp., and club mosses were more likely to be absent near pines than expected by chance. C3 grasses and sedges with seed banks and tall, fall-flowering C4 grasses were less likely to be absent near pines than expected by chance. Species sensitive to pine encroachment were more likely to co-occur with other such species away from pines at two of the three sites. Results suggest that herb species diversity in frequently-burned wet savannas is maintained in part by a weak fitness (e.g., competitive) hierarchy among herbs, and not as a result of trait differences among co-occurring species.

Seasonal variation in community composition and distributional ranges of birds along a subtropical elevation gradient in China

Aim Seasonal variation in community composition and species distributional ranges along elevational gradients remain poorly known but are essential to inform conservation. In this study, we aim to understand how species richness, community composition, and elevational ranges of montane birds change between the breeding and the non-breeding season. Location The east slope of the southern Gaoligong Mountains, Yunnan, southwestern China, elevational range: 700 - 3400 m a.s.l.; latitudinal range: 24°56´- 26°09´ N. Methods We compared bird species richness and community composition in nine 300-m elevational bands in the breeding (April - May) and non-breeding (December - January) seasons. We also calculated seasonal elevational shifts of 97 species with sufficient data recorded in both seasons and assessed how species' traits influenced these shifts. Results Species richness declined in high and low elevations between the breeding and non-breeding season. The temporal beta diversity shift from the breeding to the non-breeding season was mainly caused by species losses rather than species gains in high- and low- elevation communities. Communities in middle elevations showed a contrasting pattern, with seasonal composition change resulting mainly from species gains. We also found that species' seasonal distribution shifts were mainly associated with breeding elevation and diet. Notably, high- and middle-elevation breeders and insectivores significantly shifted their elevational ranges downslope in the non-breeding season. In addition, species that participate in mixed-species flocks and that rely on forests also showed significant downslope shifts in the non-breeding season. Main Conclusions These results show complex patterns of the interconnectedness of bird communities along the elevational gradient. Keeping forests at middle elevations intact appears especially important as they are used in winter by species that breed at both high and middle elevations. Furthermore, our results suggested conservation actions maintaining connectedness in low and middle elevations are urgently needed to conserve regional biodiversity and highlight the importance of seasonality in montane ecosystem research.

opencc-by-4.0Sep 2021View details →

COMPOSITIONAL SPATIO-TEMPORAL PM2.5 MODELLING IN WILDFIRES (R SCRIPT AND DATASET)

The present R script and dataset were used in the assessment of a spatio-temporal PM2.5 model in wildfire events with a limited number of monitoring stations using a compositional approach (CoDa).

Climate overrides the effects of land use on the functional composition and diversity of mediterranean reptile assemblages.

Aim: To test the hypothesis that spatial variations in climate and land use explain the distribution and diversity of reptiles' ecological traits in a biodiversity hotspot of the Mediterranean basin. Location: French Mediterranean region Taxon: Reptiles (25 species) Methods: We defined 288 species assemblages from 27858 opportunistic occurrence records within 10 x 10 km square grid cells. Using a RLQ analysis, we investigated the distribution of nine ecological traits describing reptiles' reproductive, dietary and behavioural strategies along environmental gradients formed by 10 climatic, topographic and land-use descriptors. After homogenizing survey effort through rarefaction, we used generalized additive models to assess variations in species richness and several measures of functional diversity and composition along these gradients. Results: Although ecological traits were not structured by environmental gradients at a species level, species richness and all measures of functional diversity varied non-linearly with climate, elevation and secondarily land use. Species richness and body size peaked at intermediate altitudes, indicating a climatic transition zone between Mediterranean and medio-european herpetofaunas. Conversely, functional diversity increased from Mediterranean plains, dominated by urbanization and agriculture, to higher elevations. These changes were associated with shifts towards less productive, more diurnal and more forest-related species. Main conclusions: Species-scale patterns are insufficient to assess regional variations in ecological traits in space. Our results support the hypothesis that climatic limitations in species' distributions, rather than environmental filtering, explain the taxonomic and ecological diversity of reptiles at a regional scale. Although secondary to climate, land abandonment has a strong structuring effect which may contribute to homogenize the composition of reptile assemblages.

Is the age of plant communities predicted by the age, stability and soil composition of the underlying landscapes? An investigation of OCBILs

Old, climatically buffered, infertile landscapes (OCBILs) have been hypothesized to harbour an elevated number of persistent plant lineages and are predicted to occur across different parts of the globe, interspersed with other types of landscapes. We tested whether the mean age of a plant community is associated with occurrence on OCBILs, as predicted by climatic stability and poor soil environments. Using digitized occurrence data for seed plants occurring in Australia (7033 species), sub-Saharan Africa (3990 species) and South America (44 482 species), regions that comprise commonly investigated OCBILs (Southwestern Australian Floristic Region, Greater Cape Floristic Region and campos rupestres), and phylogenies pruned to match the species occurrences, we tested for associations between environmental data (current climate, soil composition, elevation and climatic stability) and two novel metrics developed here that capture the age of a community (mean tip length and mean node height). Our results indicate that plant community ages are influenced by a combination of multiple environmental predictors that vary globally; we did not find statistically strong associations between the environments of OCBIL areas and community age, in contrast to the prediction for these landscapes. The Cape Floristic Region was the only OCBIL that showed a significant, although not strong, overlap with old communities.

Third and fourth trophic level composition shift in an aphid-parasitoid-hyperparasitoid food web limits aphid control in an intercropping system

1. Understanding how resource diversification affects ecological interactions, food web structure and ecosystem functioning is essential in both fundamental and applied ecology. While plant diversification strategies (either in- or around-field) are often proposed in agricultural landscapes as practices to improve the biological control of herbivores by natural enemies, results remain variable and unsure. 2. Here, we studied the effect of an in-field diversification practice (the intercropping of leguminous crops within cereal fields, an increasingly common practice but with inconsistent results on biological control) on cereal aphid control and the structure of a cereal-aphid-parasitoid-hyperparasitoid food web for two years. 3. We report that aphid control was not increased in mixed fields, nor was cereal parasitoid diversity and food web complexity. Nevertheless, the provision of alternative hosts in mixed fields led to a functional community composition shift, favouring generalist parasitoid species over specialist ones. 4. Moreover, we observed a higher hyperparasitism rate in mixed fields, suggesting that secondary parasitoids were favoured by alternative resources, which may have disrupted aphid control by primary parasitoids. 5. Synthesis and applications. This study demonstrates that parasitoid community composition shift and increased top-down control by the fourth trophic level can impact parasitoid efficiency to control herbivores. These results highlight the necessity to study fine-scale mechanisms within food webs to be able to set-up efficient methods to support biodiversity and associated ecosystem services in agricultural landscapes.

Data for: Plant-soil biota interactions explain shifts in plant community composition under global change

1. Plant-soil biota interactions play a crucial role in the assembly of plant communities and the maintenance of plant species diversity. However, few studies have tested how the effect of soil biota on plant species and communities depend on environmental context and whether shifts in plant community composition caused by environmental change are associated with variation in plant-soil biota interactions. 2. We combined a field experiment in a Tibetan alpine meadow and a greenhouse experiment with factorial combinations of nitrogen (N) enrichment and warming to examine the role of plant-soil biota interactions in plant community dynamics. 3. The results showed that plant relative abundances were negatively correlated with the net effects of soil biota on plant growth but only under ambient field conditions. Warming and N-enrichment alleviated the negative soil biota effects in the greenhouse, and changed plant community composition and reduced species diversity in the field. Importantly, changes in soil biota effects on plant growth were positively correlated with changes in plant relative abundances caused by warming and N-enrichment in field. In a parallel field experiment, the diversity of mycorrhizal fungi increased while the diversity of fungal pathogens remained unchanged under warming and N-enrichment, indicating that soil biodiversity may play a critical role in plant responses to environmental change. 4. This study empirically demonstrates that altered plant-soil biota interactions explain shifts in plant community composition under global change, providing new insights into the mechanisms of diversity loss in a changing world.

Road salt inputs alter biogeochemistry but not plant community composition in exurban forested wetlands

Forested wetlands of the temperate north are increasingly exposed to deicing salts, but it is unclear how this may alter wetland biogeochemistry and plant community composition. To investigate potential effects of deicing salts on exurban forested wetlands in southern New England, we employed a multi-site field study to describe spatiotemporal patterns of soil physiochemical, water quality, and vegetation characteristics with distance from road deicing salt source. We surveyed nine road-adjacent, red maple-dominated wetlands to quantify a suite of soil parameters (Na+, K+, Mg2+, Ca2+, pH, electrical conductivity (EC), heavy metals, N, P, soil moisture), as well as surface and groundwater salinity, and vegetation communities. With increasing distance from roads along 165-m transects penetrating into each wetland, soil salinity (EC, Na+) decreased, while soil base cation concentrations (Mg2+, Ca2+) increased, likely due to cation exchange (Na+ displacing other base cations). <a name="_Hlk73441264">We also measured foliar chemistry and observed elevated Na+ and reduced Mg2+ of dominant species leaf tissue near roads, suggesting plant nutrient uptake responds to road-salt related changes in soil physicochemical variables. </a>Despite this, we did not detect differences in plant community composition (ground, shrub layers) along road-salt induced soil chemistry gradients in the field, likely because surface and ground water salinities were relatively low (maximum: 0.64 ppt). To determine at which field salinities we could potentially expect changes in wetland plant communities, we conducted a full-factorial, manipulative seed bank experiment to examine how NaCl concentration (0, 0.5, 1, 2, 4, 8 parts per thousand (ppt)), frequency of salt exposure (pulse, constant) and water level (surface, 2-cm below surface) affected soil seed bank responses. Seedling richness was reduced at salinities exceeding 1 ppt, and seedling density was reduced above 2 ppt, but pulsing tended to alleviate salt-induced reductions in seed bank responses. As salinization of freshwater ecosystems continues to increase, our results suggest that field salinity levels of exurban New England forested wetlands are nearing yet still typically below the threshold for which we expect to see strong plant community responses.