Sampling Occasions Research Articles

Urbanization driving Ocypode quadrata burrow density, depth, and width across Caribbean beaches

Globally, sandy beaches support local economies and are the most commonly-used type of coastline. This importance is perhaps most striking in the Caribbean; however, no study has assessed the morphological features of the U.S. Virgin Islands (USVI) sandy beaches or evaluated how their biodiversity is influenced by human activities. We addressed these gaps by sampling eight St. Thomas, USVI, beaches with different urbanization levels (Stumpy Bay, Santa Maria Bay, Caret Bay, Neltjeberg Bay, Lindberg Bay, Magens Bay, Coki Point Beach, and Sapphire Beach) multiple times during high- and low-tourist season. At each sampling site and occasion, we measured environmental features (i.e., grain size, waves, and slope), urbanization variables (e.g., solid waste, traffic of vehicles, and beach cleaning) and ghost crab (Ocypode quadrata) population parameters (i.e., burrow density, depth, and width). We found that all studied beaches have similar morphodynamic features, being generally characterized as wave dominated reflective. Urbanization variables were the main drivers of ghost crab populations, with visitor frequency, distance to urban center, and evidence of vehicles on sand exerting stronger roles than variations in physical beach characteristics. Overall, our results provide important information on the morphology of USVI beaches and the impact of beach use. We expect these results will increase understanding of the drivers and threats to local sandy beach biodiversity, inform future management decisions for the territory, while creating a baseline for ghost crab studies in the U.S. Virgin Islands.

Vacuum degassing impact on non-metallic inclusions during clean steelmaking

ABSTRACT The objective of this article was to study the impact of duration of vacuum degassing process on the type and morphology of non-metallic inclusions which are undesired & unavoidable by product of steelmaking process. During the vacuum degassing stage five top slag and steel samples were taken. All sample occasions measured chemical composition of the molten steel and top slag, and SEM analysis of the non-metallic inclusions. It was seen that during vacuum degassing process the chemistry, dispersions as well as the morphology of the non-metallic inclusions is constantly changing. The Alumina content of the top slag is increased while CaO content is reduced. The percentage share of calcium aluminate type of inclusions verses spinel is increased. In the beginning of the vacuum degassing wt-% of Al in non-metallic inclusions is the highest however as the time passes this wt-% is reduced at the same time inclusions with larger ECDs appear.

Endemicity and diversification of carbapenem-resistant Acinetobacter baumannii in an intensive care unit

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a major public health concern globally. Often studied in the context of hospital outbreaks, little is known about the persistence and evolutionary dynamics of endemic CRAB populations. A three-month cross-sectional observational study was conducted in a 28-bed intensive care unit (ICU) in Hangzhou, China. A total of 5068 samples were collected from the hospital environment (n=3985), patients (n=964) and staff (n=119). CRAB isolates were obtained from 10.5% of these samples (n=532). All of these isolates, plus an additional 19 from clinical infections, were characterised through whole-genome sequencing. The ICU CRAB population was dominated by OXA-23-producing global clone 2 isolates (99.3% of all isolates) that could be divided into 20 distinct clusters, defined through genome sequencing. CRAB was persistently present in the ICU, driven by regular introductions of distinct clusters. The hospital environment was heavily contaminated, with CRAB isolated from bed units on 183/335 (54.6%) sampling occasions but from patients on only 72/299 (24.1%) occasions. CRAB was spread to adjacent bed units and rooms, and following re-location of patients within the ICU. We also observed three horizontal gene transfer events between CRAB strains in the ICU, involving three different plasmids. The epidemiology of CRAB in this setting contrasted with previously described clonal outbreaks in high-income countries, highlighting the importance of environmental CRAB reservoirs in ICU epidemiology and the unique challenges in containing the spread of CRAB in ICUs where this important multidrug-resistant pathogen is endemic. This work was undertaken as part of the DETECTIVE research project funded by the Medical Research Council (MR/S013660/1), National Natural Science Foundation of China (81861138054, 32011530116, 31970128, 31770142), Zhejiang Province Medical Platform Backbone Talent Plan (2020RC075), and the National Key Research and Development Program of China grant (2018YFE0102100). W.v.S was also supported by a Wolfson Research Merit Award (WM160092).

Bumblebee flower constancy and pollen diversity over time.

Bees often focus their foraging effort on a few or even a single flower species, even if other equally rewarding flower species are present. Although this phenomenon-called flower constancy-has been widely documented during single foraging trips, it is largely unknown if the behavior persists over longer time periods, especially under field conditions with large temporal variations of resources. We studied the pollen diet of individuals from nine different Bombus terrestris colonies for up to 6 weeks, to investigate flower constancy and pollen diversity of individuals and colonies, and how these change over time. We expected high degrees of flower constancy and foraging consistency over time, based on foraging theory and previous studies. Instead, we found that only 23% of the pollen foraging trips were flower constant. The fraction of constant pollen samples did not change over the study period, although repeatedly sampled individuals that were flower constant once often showed different preferences at other sampling occasions. The similarity of pollen composition in samples collected by the same individuals at different occasions dropped with time. This suggests that the flower preferences change in response to shifting floral resources. The average diversity of pollen from single foraging trips was around 2.5 pollen types, while the colony-level pollen diversity was about three times higher. How rapidly preferences change in response to shifting resources, and if this differs between and within bee species depending on factors such as size, should be the focus of future research.

Estimating parasite infrapopulation size given imperfect detection: Proof-of-concept with ectoparasitic fleas on prairie dogs.

Parasite infrapopulation size - the population of parasites affecting a single host - is a central metric in parasitology. However, parasites are small and elusive such that imperfect detection is expected. Repeated sampling of parasites during primary sampling occasions (e.g., each host capture) informs the detection process. Here, we estimate flea (Siphonaptera) infrapopulation size on black-tailed prairie dogs (Cynomys ludovicianus, BTPDs) as a proof-of-concept for estimating parasite infrapopulations given imperfect detection. From Jun-Aug 2011, we live-trapped 299 BTPDs for a total of 573 captures on 20 plots distributed among 13 colonies at the Vermejo Park Ranch, New Mexico, USA. During each capture, an anesthetized BTPD was combed 3 times consecutively, 15s each, to remove and count fleas. Each flea (n=4846) was linked to the BTPD from which it was collected and assigned an encounter history ('100', '010', '001'). We analyzed the encounter histories using Huggins closed captures models, setting recapture probabilities to 0, thereby accounting for flea removal from hosts. The probability of detecting an individual flea (p) increased with Julian date; field personnel may have become more efficient at combing fleas as the field season progressed. Combined p across 3 combings equaled 0.99. Estimates of flea infrapopulation size were reasonable and followed the negative binomial distribution. Our general approach may be broadly applicable to estimating infrapopulation sizes for parasites. The utility of this approach increases as p declines but, if p is very low, inference is likely limited.

Role of Chironomus plumosus (Diptera, Chironomidae) Population in the Central Zone of the Shallow Lake Trasimeno (Italy)

Adult swarms of non-biting pestiferous midges (Chironomidae: Diptera), primarily Chironomus plumosus, prevail over and around Lake Trasimeno (Italy) during the summer season. The current field survey (2018–2021, 33 sampling occasions) was carried out in the central area of the lake. It revealed a macrobenthic community consisting of Chironomidae (40.72%) and Oligochaeta (59.23%). Chironomus plumosus was the dominant chironomid species (98.84%). A previous survey (2000–2002, 11 sampling occasions) had highlighted a similar community, although C. plumosus had a lower density, comprising a maximum of 295.0 ind. m−2. This density was five times lower than the maximum densities of 2018–2021. A survey (2018–2021, 58 sampling occasions) conducted in the littoral zone revealed much greater chironomid biodiversity, with C. plumosus abundance of only 24.35% among all chironomids. This species showed an average density (88.1 ind. m−2) five times lower than its density (467.9 ind. m−2) in the central zone (2018–2021). Therefore, the central area of the lake, constituting about 90% of its total surface area, is the main region for the origin of C. plumosus adults and, consequently, during the summer months, it is the primary source of the annoying swarms that affect residents and tourists of the lake vicinity.

Fish Biozonation in the Balkan Peninsula, Especially in Bulgaria: A Challenge

Fish are important elements of aquatic ecosystems. Their communities naturally follow the river continuum and have been well described in the western European freshwater watersheds. In regions of higher endemism, such as the Balkan Peninsula, the widely accepted fish zonation of Illies is doubtfully relevant. In this study, a more suitable categorization of lotic and lentic freshwater ecosystems in Bulgaria is proposed, based on 389 multimethodological and multihabitat fish sampling occasions. Referent-type communities have been determined for 33 types of recognized water bodies. Adapted zonation of Illies is a rough estimation of the real distribution of fish assemblances in the country; moreover, sensitive and/or endemic species are generally of restricted distribution and abundance. In view of the lentic ecosystems, they can be divided into salmonid and cyprinid, at approximately 1500 m above sea level.

Longitudinal Study of Dynamic Epidemiology of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Pigs and Humans Living and/or Working on Pig Farms.

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales have been increasingly isolated from pigs, highlighting their potential for transmission to humans living and/or working within pig farms. As longitudinal data on the prevalence and the molecular characteristics of such isolates from the high-risk farming population remain scarce, we performed a long-term study on 39 Dutch pig farms. Fecal samples from pigs, farmers, family members, and employees were collected during four sampling occasions with a 6-month period. The presence of ESBL-producing Enterobacterales and their molecular characteristics (ESBL gene, plasmid, and sequence types) were determined by standard methods. Data on personal and farm characteristics were collected using questionnaires. ESBL-producing Escherichia coli was present in pigs at least once for 18 of 39 farms and in 17 of 146 farmers, family members, and/or employees. Among these 417 E. coli isolates, blaCTX-M-1 was the most frequently observed ESBL gene in pigs (n = 261) and humans (n = 25). Despite the great variety in plasmid (sub)types and E. coli sequence types (STs), we observed genetic similarity between human- and pig-derived isolates in (i) ESBL gene, plasmid (sub)type, and ST, suggesting potential clonal transmission in seven farms, and (ii) only ESBL gene and plasmid (sub)type, highlighting the possibility of horizontal transfer in four farms. Five pig farmers carried ESBL producers repeatedly, of whom two carried an identical combination of gene, plasmid (sub)type, and ST over time. Human ESBL carriage was associated with both presence of ESBL producers in pigs and average number of hours working on the pig farm per week, while prolonged human carriage was observed only incidentally. IMPORTANCE Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli represents a public health hazard due to reduced therapeutic options for the treatment of infections. Although direct contact with pigs is considered a risk factor for human ESBL-producing E. coli carriage through occupational exposure, nationwide data regarding the occurrence of such isolates among pigs and humans living and/or working on farms remain scarce. Therefore, we determined (i) the longitudinal dynamics in prevalence and molecular characteristics of ESBL-producing E. coli in Dutch pig farmers and their pigs over time and (ii) the potential transmission events between these reservoirs based on genetic relatedness and epidemiological associations in longitudinal data. Our data suggesting the possibility of clonal and horizontal dissemination of ESBL-producing Escherichia coli between pigs and pig farmers can be used to inform targeted intervention strategies to decrease the within-farm human exposure to ESBL-producing E. coli.

New records of Trichodactylus fluviatilis Latreille, 1828 (Decapoda: Brachyura: Trichodactylidae) in Southeastern Brazil

Freshwater crabs play important ecological roles in lotic ecosystems, occupying different trophic levels and participating in the detritus food chain. Trichodactylus fluviatilis is a freshwater crab that occurs along the Brazilian coast and inland portions of southeastern Brazil. This species occurs in rivers and in coastal and mountain streams up to more than 1,100 m above sea level. Herein we report the occurrence of T. fluviatilis in one of the largest Atlantic Forest remnants located on flat terrain, which contains one of the most threatened vegetation types found within this biodiversity hotspot. We collected one adult female and 15 juveniles over four sampling occasions between February and September 2015. These records extend the number of locations where the presence of T. fluviatilis was confirmed and contribute to the knowledge about the geographical distribution of this species in Espírito Santo state and in the Atlantic Forest. This information will prove valuable in refining distribution maps and assessing the species' threatened status, aiding in the formulation of wildlife conservation strategies for streams in the Atlantic Forest.

Temporal stability in beta diversity does not guarantee surrogacy or compositional stability in a micro-phytoplankton metacommunity

Temporal stability in beta diversity does not guarantee surrogacy or compositional stability in a micro-phytoplankton meta¬community. In this study, we evaluated phytoplankton community organization (i.e., microalgae filtered in 20 μm mesh-sized plankton net) in a highly dynamic subtropical tidal river over three years. Specifically, we assessed temporal stability in the spatial organization of phytoplankton, the diatoms’ efficiency as an indicator (surrogate group) of ecological patterns of other phytoplankton groups, the temporal variation in species composition, and the beta diversity of a metacommunity. We performed six sampling occasions at the end of the summers and winters from 2017 to 2019 at 16 sampling points comprising a strong en¬vironmental gradient in the Guaraguaçu River, South Brazil. We tested for correlations of community structures from different periods and for correlations between diatoms species and those from other phytoplankton groups using Mantel tests. Species compositions were compared among periods using a permutational multivariate analysis of variance, and temporal variation in metacommunity beta diversity was evaluated using null models. There was temporal stability in the spatial dissimilarities of communities. Diatoms were poorly correlated with the other phytoplankton groups. The temporal stability in spatial structure, a facet of beta diversity, was in line with the temporal stability in compositional variation – a measurement of metacommuni¬ty beta diversity. Our results also showed that such stability was not static, since community compositions varied over time, mainly between seasons. We conclude that even in a highly dynamic tidal river, the temporal stability of spatial organization may indicate that the spatial gradient is so strong that it maintains spatial structuring over time. Such patterns were maintained even with the dynamic species changes over seasons. The fact that different phytoplankton groups do not respond similarly to the spatial gradient reinforces that microalgae should be analyzed separately in ecological studies, and long-term monitoring should consider different algal groups for a complete assessment of ecological patterns.

Volumetric Spore Traps Are a Viable Alternative Tool for Estimating Heterobasidion Infection Risk

Prophylactic stump treatments against the conifer root rot fungus Heterobasidion annosum s.l. should take into account the airborne inoculum density of the pathogen, in order to be economically feasible. Our objective was to test if an automatic volumetric spore trap (AVST) could be used as a sensitive alternative of passive traps for quantifying Heterobasidion airspora in forest stands. The routinely used wood disc exposure method (WDE) was implemented simultaneously with AVST in five coniferous monocultures and three near-natural stands without silvicultural management in Czechia. Air sampling took place for 24-h intervals in five months of the main sporulation period. The atmospheric concentration of H. annosum s.l. spores (cHa) was determined by qPCR with generic and species-specific primers. AVST detected more target species than WDE on 77% of sampling occasions. When comparing the relative abundance of the three European H. annosum s.l. species detected by AVST and WDE, H. parviporum and H. abietinum were found to be overrepresented on wood discs. cHa in November was significantly higher than in May and June, confirming the seasonal pattern typical for temperate Europe. For an accurate and rapid estimation of Heterobasidion primary infection risk, the usage of AVST is highly recommended.

Inferring predator-prey interactions from camera traps: ABayesian co-abundance modeling approach.

Predator-prey dynamics are a fundamental part of ecology, but directly studying interactions has proven difficult. The proliferation of camera trapping has enabled the collection of large datasets on wildlife, but researchers face hurdles inferring interactions from observational data. Recent advances in hierarchical co-abundance models infer species interactions while accounting for two species' detection probabilities, shared responses to environmental covariates, and propagate uncertainty throughout the entire modeling process. However, current approaches remain unsuitable for interacting species whose natural densities differ by an order of magnitude and have contrasting detection probabilities, such as predator-prey interactions, which introduce zero inflation and overdispersion in count histories. Here, we developed a Bayesian hierarchical N-mixture co-abundance model that is suitable for inferring predator-prey interactions. We accounted for excessive zeros in count histories using an informed zero-inflated Poisson distribution in the abundance formula and accounted for overdispersion in count histories by including a random effect per sampling unit and sampling occasion in the detection probability formula. We demonstrate that models with these modifications outperform alternative approaches, improve model goodness-of-fit, and overcome parameter convergence failures. We highlight its utility using 20 camera trapping datasets from 10 tropical forest landscapes in Southeast Asia and estimate four predator-prey relationships between tigers, clouded leopards, and muntjac and sambar deer. Tigers had a negative effect on muntjac abundance, providing support for top-down regulation, while clouded leopards had a positive effect on muntjac and sambar deer, likely driven by shared responses to unmodelled covariates like hunting. This Bayesian co-abundance modeling approach to quantify predator-prey relationships is widely applicable across species, ecosystems, and sampling approaches and may be useful in forecasting cascading impacts following widespread predator declines. Taken together, this approach facilitates a nuanced and mechanistic understanding of food-web ecology.

Seasonally variable interactions between dissolved organic matter and mineral particles in an agricultural river

Streams and rivers form an important link in the global carbon cycle by transporting and transforming large amounts of carbon imported from terrestrial ecosystems to the oceans. Since streams in agricultural areas often experience increased concentrations of suspended mineral particles from soil erosion, they are important sites where dissolved organic carbon (DOC) may be adsorbed to particles and retained in the sediment. As the extent of adsorption varies with the molecular composition of dissolved organic matter (DOM), which is seasonally variable, we expect also the fraction of organic material that adsorbs to mineral particles to fluctuate over time. We sampled the agriculturally impacted River Fyrisån (Sweden) monthly during 1 year, and measured DOC concentration and DOM composition based on several optical properties. At each sampling occasion, we estimated the potential for adsorption by exposing the samples to a reference clay. The potential for adsorption was greatest when riverine DOM had the most terrestrial character, as this fraction of the DOM pool was selectively adsorbed to clay surfaces. The extent of adsorption was negatively related to the concentration of base cations, most notably calcium. We suggest that the observed relationships between the potential for adsorption, DOM composition and base cations are linked by discharge. A bioavailability test at one sampling occasion suggested that DOM remaining after exposure to clay particles was more biodegradable. This implies that adsorption may alter the degradation potential of DOM remaining in solution, which could have far reaching effects on the fate of organic carbon.

Environmental microbiology going computational-Predictive ecology and unpredicted discoveries.

Environmental microbiology going computational-Predictive ecology and unpredicted discoveries.

Empirical food webs of 12 tropical reservoirs in Singapore.

Food webs summarise trophic interactions of the biotic components within an ecosystem, which can influence nutrient dynamics and energy flows, ultimately affecting ecosystem functions and services. Food webs represent the hypothesised trophic links between predators and prey and can be presented as empirical food webs, in which the relative strength/importance of the respective links are quantified. Some common methods used in food web research include gut content analysis (GCA) and stable isotope analysis (SIA). We combine both methods to construct empirical food web models as a basis for monitoring and studying ecosystem-level outcomes of natural (e.g. species turnover in fish assemblage) and intentional environmental change (e.g. biomanipulation). We present 12 food webs from tropical reservoir communities in Singapore and summarise the topology of each with widely-used network indices (e.g. connectance, link density). Each reservoir was surveyed over 4-6 sampling occasions, during which, representative animal groups (i.e. fish species and taxonomic/functional groups of zooplankton and benthic macroinvertebrates) and all likely sources of primary production (i.e. macrophytes, periphyton, phytoplankton and riparian terrestrial plants) were collected. We analysed gut content in fishes and bulk isotope (d13C and d15N) profiles of all animals (i.e. fishes and invertebrates) and plants collected. Both sets of information were used to estimate the relative strength of trophic relationships using Bayesian mixing models. We document our protocol here, alongside a script in the R programming language for executing data management/analyses/visualisation procedures used in our study. These data can be used to glean insights into trends in inter- and intra-specific or guild interactions in analogous freshwater lake habitats.

Contact varroacidal efficacy of lithium citrate and its influence on viral loads, immune parameters and oxidative stress of honey bees in a field experiment.

With an almost global distribution, Varroa destuctor is the leading cause of weakening and loss of honey bee colonies. New substances are constantly being tested in order to find those that will exhibit high anti-Varroa efficacy at low doses/concentrations, without unwanted effects on bees. Lithium (Li) salts stood out as candidates based on previous research. The aims of this study were to evaluate Li citrate hydrate (Li-cit) for its contact efficacy against Varroa, but also the effect of Li-cit on honey bees by estimating loads of honey bee viruses, expression levels of immune-related genes and genes for antioxidative enzymes and oxidative stress parameters on two sampling occasions, before the treatment and after the treatment. Our experiment was performed on four groups, each consisting of seven colonies. Two groups were treated with the test compound, one receiving 5 mM and the other 10 mM of Li-cit; the third received oxalic acid treatment (OA group) and served as positive control, and the fourth was negative control (C group), treated with 50% w/v pure sucrose-water syrup. Single trickling treatment was applied in all groups. Both tested concentrations of Li-cit, 5 and 10 mM, expressed high varroacidal efficacy, 96.85% and 96.80%, respectively. Load of Chronic Bee Paralysis Virus significantly decreased (p < 0.01) after the treatment in group treated with 5 mM of Li-cit. In OA group, loads of Acute Bee Paralysis Virus and Deformed Wing Virus significantly (p < 0.05) increased, and in C group, loads of all viruses significantly (p < 0.01 or p < 0.001) increased. Transcript levels of genes for abaecin, apidaecin, defensin and vitellogenin were significantly higher (p < 0.05—p < 0.001), while all oxidative stress parameters were significantly lower (p < 0.05—p < 0.001) after the treatment in both groups treated with Li-cit. All presented results along with easy application indicate benefits of topical Li-cit treatment and complete the mosaic of evidence on the advantages of this salt in the control of Varroa.

A general modeling framework for open wildlife populations based on the Polya tree prior.

Wildlife monitoring for open populations can be performed using a number of different survey methods. Each survey method gives rise to a type of data and, in the last five decades, a large number of associated statistical models have been developed for analyzing these data. Although these models have been parameterized and fitted using different approaches, they have all been designed to either model the pattern with which individuals enter and/or exit the population, or to estimate the population size by accounting for the corresponding observation process, or both. However, existing approaches rely on a predefined model structure and complexity, either by assuming that parameters linked to the entry and exit pattern (EEP) are specific to sampling occasions, or by employing parametric curves to describe the EEP. Instead, we propose a novel Bayesian nonparametric framework for modeling EEPs based on the Polya tree (PT) prior for densities. Our Bayesian nonparametric approach avoids overfitting when inferring EEPs, while simultaneously allowing more flexibility than is possible using parametric curves. Finally, we introduce the replicate PT prior for defining classes of models for these data allowing us to impose constraints on the EEPs, when required. We demonstrate our new approach using capture-recapture, count, and ring-recovery data for two different casestudies.

Nematode Community of a Natural Grassland Responds Sensitively to the Broad‐Spectrum Fungicide Mancozeb in Soil Microcosms

Fungicides make up the largest part of total pesticide use, with the dithiocarbamate mancozeb being widely applied as a nonsystemic contact pesticide to protect a wide range of field crops against fungal diseases. Although nematodes are key drivers of soil functioning, data on effects of fungicides, and especially mancozeb, on these nontarget organisms are scarce. Therefore, the effects of mancozeb on a soil nematode community from a natural grassland were assessed in small-scale soil microcosms. Nematodes were exposed to mancozeb-spiked soil in six nominal concentrations (7-133 mg/kg dry soil) and analyzed after 14, 56, and 84 days in terms of densities, genus composition, and functional traits. Because this fungicide is known to quickly degrade in soils (50% degradation time <1 day), mancozeb concentrations were analyzed for all sampling occasions. Chemical analysis revealed considerably lower measured concentrations compared with the aimed nominal soil concentrations at the beginning of the exposure (1-18 mg/kg dry soil), suggesting fast degradation during the spiking process. Nevertheless, the native nematode community responded sensitively to the fungicide mancozeb, revealing lower no-observed-effect concentration and 10% effect concentration (EC10) values than reported for other soil invertebrates such as springtails and earthworms. Using the EC10 for the most sensitive nematode community endpoint (percentage of predators and omnivores: 1.2 mg/kg dry soil), the risk assessment exhibited a toxicity exposure ratio of 0.66 and, thus, a high risk of mancozeb for soil nematodes. Keeping in mind their abundance and their central roles in soil food-web functioning, the demonstrated sensitivity to a widely applied fungicide underscores the relevance of the inclusion of nematodes into routine risk-assessment programs for pesticides. Environ Toxicol Chem 2022;41:2420-2430. © 2022 SETAC.

Modeling habitat use and potential distribution of kit fox in the Trans‐Pecos, Texas

AbstractManagement of a species requires knowledge of their distribution and the environmental factors that influence their use of an area. The kit fox (Vulpes macrotis) is a small fox species endemic to the threatened desert grasslands of the western United States and northern Mexico. Little information exists on the status and distribution of kit fox in Texas, USA; however, researchers have documented population declines in the closely related swift fox (Vuples velox) in the Texas Panhandle. Therefore, our objectives were to survey areas of potential kit fox habitat using remote trail cameras to determine use and detection rates for kit fox, evaluate and quantify environmental effects on habitat use, and map potential distribution of kit fox habitat throughout the Trans‐Pecos using results from the preceding occupancy analysis. We conducted camera surveys at 732 baited sites from March 2018 to March 2020, with each survey lasting 14 days on average (~10,248 camera‐days). We detected kit fox at 99 of 732 camera survey sites. We divided surveys into 3‐day sampling occasions and fit single‐season occupancy models to test for an effect of sampling occasion and season on detection and for effects of slope, elevation, shrub height, shrub canopy cover, percent litter, percent herbaceous cover, and bare ground on habitat use. Overall detection was 0.31 ± 0.001 (SE) and was influenced by sampling occasion and season, with detection being highest during November to February and earlier in the survey. Mean probability of use for sites was 0.17 ± 0.01 (range = 0.00–0.85) and was influenced by 4 environmental covariates, with the greatest probability of use in areas with gentler slopes, lower elevations, shorter shrubs, and a greater percentage bare ground. We used the most supported model to make a map of predicted habitat use across the Trans‐Pecos region and showed evidence of model fit. Our work provides detailed baseline information on the distribution and environmental relationships of kit fox in the region and can be used to assist with future research and monitoring efforts.

Plastic pollution on Durance riverbank: First quantification and possible environmental measures to reduce it

Plastic pollution is one of the most pressing issues of our time, with negative impacts on natural ecosystems, human health, and the climate system. The identification of top litter items discarded in the environment is essential to prioritize environmental policies to prevent plastic leakage and promote a circular economy. Here, we present the first quantification of macrolitter on three sites along Durance riverbank and one site on Lake Serre-Ponçon's beach, in the Région SUD–Provence-Alpes-Côte d'Azur, southeastern France. Data were collected through citizen science between 2019 and 2020 in three sampling occasions (autumn, winter, spring) on Durance riverbank and in 22 occasions on Lake Serre-Ponçon. A total of 25'423 litter items were categorized, of which 82% were plastics. Single-use plastic items correspond to 8.13% of total, while single-use plastic bottles are among the top 10 litter items at each site. Median litter abundance across all samples is 2,081 items/100 m survey, two orders of magnitude higher than European precautionary threshold value for marine litter (20 items/100 m survey). The majority of items (74.83%) were small and non-identifiable. Pieces of polystyrene, soft plastics and rigid plastics represented the majority of litter items in total (56.63%) and at S1 (89.28%), S2 (58.95%) and S3 (79.60%). Glass pieces corresponded to 15.83% of total litter items. Soft plastic pieces are the most abundant litter category overall and correspond to 58.85% of litter items at sampling site along Durance riverbank located in an agricultural zone, suggesting their source from agricultural plastic mulch films. Among the identifiable items, the most abundant were plastic biomedia used in waste water treatment plants and single-use beverage bottles in plastic and in glass. The development of extended producer responsibility schemes for plastic mulch films and plastic biomedia and of deposit return schemes for single-use beverage bottles is suggested as a way to prevent leakage in the environment. This work confirms the opportunity to use citizen science to gather relevant data on macrolitter items and to monitor the effectiveness of environmental regulations to reduce plastic pollution.