Variation In Resource Use Research Articles

Dietary Niche Variation in an Invasive Omnivore: The Effects of Habitat on Feral Pig Resource Use in Hawai'i.

Invasive omnivores may have profound impacts on ecological communities through diet selection, particularly when their functional roles differ from those in their native range. While the threat of feral pigs (Sus scrofa) to native plant communities in Hawai'i is well known, their trophic dynamics and the drivers of variation in their diet remain understudied. We investigated the feral pig trophic niche on Hawai'i Island using stable isotopes (13C and 15N) and Bayesian mixing models to identify drivers of variation in resource use. We also reconstructed intra-individual variability for six subsampled individuals to understand temporal variation in resource use and individual diet specialization. Our results revealed that feral pigs on Hawai'i Island exhibit a broad trophic niche characterized by diverse diets, with substantial overlap in resource use across districts and habitats. Differences in dietary composition in the transition from forest to open habitat were driven primarily by a decline in invertebrates and an increasing reliance on resources enriched in 15N, which may reflect a shift in protein sources with habitat. Pigs in forested areas exhibited a smaller trophic niche than those in open habitats, largely driven by differences in feeding strategies and resource availability. Diets for subsampled individuals varied little, suggesting feral pig resource-use strategies in Hawai'i tend to be relatively stable through time. Individual niche width was relatively narrow compared to that of feral pigs in Hawai'i at large, indicating the relatively wide feral pig dietary niche is characterized by substantial intraspecific diet specialization, likely as a result of strong intraspecific competition. Understanding the drivers of feral pig resource use offers key information for management strategies aimed at mitigating their ecological impacts in imperiled systems like Hawai'i.

Incorporating ecological heterogeneity and intraspecific variation differentiates complex interactions between apex predators and stocked fish

Ecological heterogeneity and intraspecific variation can impact energy flow from the base of the food web to top predators. We evaluated the effect of intraspecific variation on estimates of lake trout (Salvelinus namaycush) consumption of stocked kokanee (lacustrine sockeye salmon, Oncorhynchus nerka) in a 390 ha oligotrophic lake with two distinct basins. Lake trout stomach content analyses, stable isotope niche space, and catch rates indicated high intraspecific variation in resource use across habitats and basins. Intraspecific variation and ecological heterogeneity were incorporated into two bioenergetics modeling approaches; one lake-wide model, and one partitioned model that accounted for differences in lake trout diet composition and population size across habitats. The ecologically partitioned model highlighted that lake trout consumption was primarily in the epilimnion of one basin, while the lake-wide, unpartitioned model performed similarly but failed to provide ecological context for where that consumption occurred. Incorporating ecological heterogeneity and intraspecific variation into bioenergetic models can more accurately represent top predators foraging patterns across habitats and inform management actions to mitigate impacts to stocked fish.

Assessment of the Environmental Footprint of Various Food Production Systems

Purpose: This study sought to assess the environmental footprint of various food production systems. Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library. Findings: The findings reveal that there exists a contextual and methodological gap relating to the environmental footprint of various food production systems. Preliminary empirical review revealed that with a call for transformative changes to mitigate ecological impacts while ensuring food security and human well-being. Through a comprehensive analysis, significant variations in resource use and emissions were highlighted across different production methods. The study emphasized the interconnectedness between dietary choices, agricultural practices, and environmental outcomes, urging policymakers to enact evidence-based policies and agricultural stakeholders to adopt regenerative farming practices. Ultimately, the study served as a call to action for concerted efforts to transition towards a more sustainable and resilient food system, integrating ecological principles, social equity, and economic viability to promote harmony between human activities and the natural environment. Unique Contribution to Theory, Practice and Policy: The Systems theory, Ecological Economics and Agroecology models may be used to anchor future studies on the environmental footprint of various food production systems. The study made significant contributions to theory, practice, and policy in the realm of sustainable food production and environmental conservation. It advanced theoretical understanding by advocating for a systems-based approach to assessing environmental impacts and highlighting the importance of considering multiple dimensions of sustainability. In practice, the study recommended the adoption of agroecological approaches and the promotion of sustainable farming practices to mitigate environmental harm. Policy recommendations included the implementation of regulatory interventions and incentives to promote sustainability, while consumer education and international collaboration were emphasized for driving demand for sustainable food products and facilitating knowledge sharing. Lastly, the study underscored the importance of investment in research and innovation to drive continuous improvements in sustainable food production systems.

Floral resource partitioning of coexisting bumble bees: Distinguishing species-, colony-, and individual-level effects.

Resource partitioning is considered a key factor in alleviating competitive interactions, enabling coexistence among consumer species. However, most studies have focused on resource partitioning between species, ignoring the potentially critical role of intraspecific variation in resource use. We investigated floral resource partitioning across species, colonies, and individuals in a species-rich bumblebee community in the diversification center of bumblebees. We used a total of 10,598 bumblebees belonging to 13 species across 5 years in the Hengduan Mountains of southwest China. First, we evaluated the influence of a comprehensive set of floral traits, including both those related to attractiveness (flower color and shape) and rewards (pollen, sugar ratio, nectar volume, sugar concentration, and amino acid content) on resource partitioning at the species level in bumblebee-plant networks. Then, we explored intraspecific resource partitioning on the colony and individual levels. Our results suggest that bumblebee species differ substantially in their use of the available floral resources, and that this mainly depends on flower attractiveness (floral color and shape). Interestingly, we also detected floral resource partitioning at the colony level within all commonest bumblebee species evaluated. In general, floral resource partitioning between bumblebee individuals decreased with species- and individual-level variation in body size (intertegular span). These results suggest that bumblebee species may coexist via the flexibility in their preferences for specific floral traits, which filters up to support the co-occurrence of high numbers of species and individuals in this global hotspot of species richness.

Trophic downgrading of an adaptable carnivore in an urbanising landscape

Urbanisation critically alters wildlife habitat and resource distribution, leading to shifts in trophic dynamics. The loss of apex predators in human-transformed landscapes can result in changes in the ecological roles of the remaining mesocarnivores. Decreased top–down control together with increased bottom–up forcing through greater availability of anthropogenic foods can result in a predation paradox. Understanding these changes is important for conserving ecological function and biodiversity in rapidly urbanising systems. Here, we use stable isotope analysis to provide insight into longer term changes in trophic position, niche width and overlap of an elusive, medium-sized urban adapter, the caracal (Caracal caracal) in and around the city of Cape Town, South Africa. Using fur samples (n = 168) from individuals along a gradient of urbanisation we find that overall caracals have a broad isotopic dietary niche that reflects their large variation in resource use. When accounting for underlying environmental differences, the intensity of anthropogenic pressure, measured using the Human Footprint Index (HFI), explained variation in both food subsidy use (δ13C values) and trophic status (δ15N values). The significantly higher δ13C values (P < 0.01) and lower δ15N values (P < 0.001) of caracals in more urbanised areas suggest that predator subsidy consumption occurs via predictable, anthropogenic resource subsidies to synanthropic prey. These prey species are predominantly primary consumers, resulting in shifts in diet composition towards lower trophic levels. Further, caracals using areas with higher HFI had narrower isotope niches than those in less impacted areas, likely due to their hyperfocus on a few lower trophic level prey species. This pattern of niche contraction in urban areas is retained when accounting for caracal demographics, including sex and age. The removal of apex predators in human-transformed landscapes together with reliable resource availability, including abundant prey, may paradoxically limit the ecological influence of the remaining predators, and bring about a degree of predator trophic downgrading. The dampening of top–down control, and thus ecosystem regulation, likely points to widespread disruption of trophic dynamics in rapidly developing areas globally.

Variations in the costs of atrial fibrillation: a longitudinal study across 27 European and Central Asian countries

Abstract Background/Introduction For many conditions, disease complications are the main driver of care costs. Atrial fibrillation (AF) – the commonest manifestation of cardiac arrhythmia – increases the risk of stroke and coronary heart disease, both of which are costly. Although the clinical burden of AF is widely documented, it is unknown to what extent AF-related complications contribute to healthcare costs and if these costs vary across countries. Purpose To assess the individual patient healthcare costs associated with AF-related complications and their variation across 27 European and Central Asian countries. Methods We used data from the European Society of Cardiology’s Atrial Fibrillation General Registry, a prospective, multinational registry of 10,249 atrial fibrillation patients from 27 countries with two-years of annual follow-up. Information on patients’ clinical characteristics, healthcare visits, as well as diagnostic and interventional procedures were collected at each visit. Atrial fibrillation related complications were angina, non-ST-elevation myocardial infarction (NSTEMI), ST-elevation myocardial infarction (STEMI), thromboembolic events, haemorrhagic events, and new onset or worsening heart failure. All healthcare resource use (inpatient stays, outpatient visits, and medications) were costed using 2019 UK unit costs to better assess variations in overall resource use across countries. We used panel data methods to assess the association of AF-related complications and healthcare costs and resource use. The models were adjusted for patients’ clinical and sociodemographic characteristics, prior medication use and geographical location. Results Over the follow-up period, 745 (8%) patients had an AF-related complication at 12-months and 477 (6%) at 24-months. Of the total 1,222 complications, the most common AF-related complication was new onset or worsening heart failure which occurred in 567 (3%) patients with complications. Overall, angina (£2,629, 95% CI: 1869 to 3361) and haemorrhagic events (£2,549, £2,199 to £2,900) incurred the highest cost, whereas non-stable myocardial infarction (£1,367, £687 to £2,048) incurred the least additional cost. We found significant regional variation. Costs of angina in Eastern EU and in non-EU former Soviet republics were, respectively, £1,362 (-£2,262 to -£461) and £1,416 (-£2,571 to -£261) lower than in Western Europe. Whereas costs in Southern EU and Northern EU countries were £721 (-£2,629 to £1,186) and £344 (-£1,460 to £ 674) lower than in Western Europe. Conclusions Although disease complications are costly in all countries, notable differences were observed across countries. These differences were driven by fewer investigations, clinic visits, and ER admissions. Our results, therefore, highlight the regional variations in resource use patterns across countries, limiting the generalisability of country-specific economic evaluations to other jurisdictions.

Differential patterns of taxonomic and functional diversity for two groups of canopy arthropods across spatial scales

AbstractArthropod diversity is often linked to variation in resource use, dispersal ability, habitat connectivity, and climate factors that differ across spatial scales. The aim of this research was to examine how species richness, functional diversity, and community composition of two taxa differing in functional roles and dispersal ability are structured across spatial scales and to identify the importance of vegetation, climate, and landscape in explaining these patterns at different scales. Organisms were collected from tree canopies using insecticidal fogging in the summer of 2000 from 96 trees in 24 stands of 6 deciduous forest sites in 2 ecoregions of the eastern United States. Taxonomic and functional beta diversity of ants (Hymenoptera: Formicidae) and spiders (Araneae) were partitioned across four hierarchical spatial scales (individual tree, forest stand, site, and ecoregion). The contributions of climatic, landscape, and vegetation variables were determined using model selection. Ant and spider species richness, functional diversity, and community composition differed between taxa and across spatial scales. Alpha diversity (within trees) was lower than expected for both taxa and types of diversity, with host tree species supporting different species of ants and spiders. While the beta components of species diversity among trees and forest stands were greater than expected for both taxa, spiders also showed significant levels of beta diversity among sites. Functional beta diversity was less scale‐dependent than taxonomic beta diversity. Stand‐level patterns of beta diversity were significantly predicted by variation in climate and landscape connectivity. The effects of climate and landscape fragmentation on the diversity and community structure of both taxa indicate that anthropogenic climate change and land use change will alter canopy arthropod communities. Results also suggest that patterns of diversity among fragmentation metrics are influenced by differences in dispersal ability.

Individual contribution to niche expansion in amphibians: a test of the niche variation hypothesis

The niche variation hypothesis (NVH) suggests that populations released from competition are able to expand their realized ecological niche. This increase in total niche width (TNW) can arise by 1) increasing heterogeneity among individuals' niche through individual specialization, i.e. inter‐individual variation in resource use, (IS) occurring when different individuals of a population use a subset of the population's resource pool, or 2) by expanding the niche of all individuals within the population. Although several morphological and phenotypical studies have confuted the NVH, there is generally strong support for this hypothesis when behavioural or ecological traits are considered, and in particular when the trophic niche is measured at the individual level. In this study our primary aim is to corroborate the NVH, providing robust evidence for a significant and positive relationship between population TNW and IS in amphibian populations, at a global scale.

Ecologically driven differences in individual diet specialization across three populations of Guiana dolphin.

Populations usually considered foraging generalists may include specialized individuals that feed on a restricted subset of the prey spectrum consumed by the population. By analyzing the time series of δ13C and δ15N values in sequential growth layer groups within tooth dentin, we measured population- and individual-level variation in resource use of three populations of Guiana dolphins (Sotalia guianensis)-Caravelas River, Babitonga Bay, and Norte Bay-along a latitudinal gradient in the southwestern Atlantic Ocean. We show that the Guiana dolphin at Caravelas River is a generalist population consisting of individual dietary specialists, likely due to the absence of other resident dolphin populations thus allowing individuals to target prey across a wide range of habitats. The Babitonga Bay population is also composed of individual specialists potentially due to the selective foraging behavior of some individuals on high-quality prey sources within and near the bay. In contrast, the Norte Bay population comprises individual generalists, which likely reflects its distinctive cohesive social organization, coexistence with two other dolphin species, and an opportunistic foraging strategy in response to resource fluctuations inherent to the southern limit of the species distribution. Although the Guiana dolphin is generally considered to be a dietary generalist at the population level, our findings reveal that the total niche width of populations and the degree of individual diet specialization are highly context dependent, suggesting dietary plasticity that may be related to a latitudinal gradient in resource availability and environmental conditions.

Variation in resource use between adult and juvenile Semipalmated Sandpipers (Calidris pusilla) and use of physiological indicators for movement decisions highlights the importance of small staging sites during southbound migration in Atlantic Canada

Semipalmated Sandpipers (Calidris pusilla) are Arctic-breeding shorebirds that use staging sites in Atlantic Canada during their annual migration to South America. The Bay of Fundy has long been recognized as a critical staging site for migrating Semipalmated Sandpipers and supports a large prey base. The diet of adult sandpipers in the Bay is flexible but the diet of juveniles, which arrive later, is not well documented. Comparatively little is known about the prey base and how it is utilized by sandpipers at sites in Atlantic Canada outside the Bay. Plasma metabolite measures can provide useful insight to assess habitat quality for sandpipers and have not yet been measured in Semipalmated Sandpipers in Atlantic Canada. To address these knowledge gaps we sampled shorebird habitat to estimate invertebrate availability in the Bay of Fundy and the Northumberland Strait. Concurrently, we collected blood samples from adult and juvenile sandpipers for analysis of plasma metabolite levels and isotopic estimates of dietary niche in both regions. We found that sites on the Northumberland Strait hosted a more diverse and variable prey base than sites within the Bay of Fundy, and that sandpipers were selective when foraging there, appearing to prefer bivalves. Juveniles may occupy a broader dietary niche than adults along the Northumberland Strait, though appear to gain weight as efficiently. Sandpipers sampled along the Northumberland Strait had higher plasma triglyceride concentrations than those within the Bay of Fundy, which may suggest differences in fattening rate or dietary fat intake. Sandpipers that had lower triglyceride concentrations on the Northumberland Strait were more likely to move into the Bay of Fundy, while sandpipers with high triglyceride values tended to remain on the Strait. These data suggest that sandpipers made movement decisions within the region depending on their physiological state. Our results suggest adult and juvenile Semipalmated Sandpipers successfully use a variety of staging habitats in Atlantic Canada. This is an encouraging finding for sandpiper conservation in the region, but also indicates that maintaining access to a broad variety of staging habitats is critical, supporting calls for stronger conservation measures throughout the region.

Impacts of river fragmentation on limiting individual dietary specialization of Amazonian predatory fish.

Individual dietary specialization is one of the factors that promotes variation in resource use at the individual level. Here we used stable isotope analysis of multiple tissues with different turnover rates to examine the degree of individual specialization in two sub-populations of the predator Cichla temensis inhabiting both fragmented and undammed rivers within the Uatumã River basin of the Amazon. Our results showed that the undammed river provides better conditions to promote individual dietary specialization than the fragmented river. This study contributes to the understanding of how specific life history characteristics of populations of generalist predators are impacted by fragmentation within megadiverse environments such as the Amazon basin.

Size reduction and skull shape parallelism following the evolutionary forest-to-savanna transition in Platyrrhini monkeys.

There are strong physiological and behavioral differences that allow animals to live in forests versus savannas. For example, terrestrial forest-dwelling mammals tend to be small compared to species living in savannas. Robust capuchin monkeys (genus Sapajus) are widespread in tropical South America, occurring in both forest and savanna environments, with forest species considered basal in an evolutionary context. Whether or not skull shape and size variations are associated with variation in resource use remains unknown, particularly for the two species living in savanna (Sapajuslibidinosus and S. cay). Here we show that savanna species present convergent size and skull characteristics that may facilitate living in this new environment. Geometric morphometric methods were used to assess skull size and shape variation for 184 Sapajus specimens distributed across South America. We used phylogenetic generalized least squares to test size against environmental variables and multivariate morphological trajectories/partial least square analyses on the skull shape to detect shape differences in specimens between forest and savanna biomes. Our findings reveal Sapajus size reduction in the evolutionary transition from forest to savanna, a process related to increasing seasonality. Moreover, we found morphological parallelism in the skull (e.g., muzzle shortening) and (large) molars in the two savanna species, features that may facilitate the processing of harder food such as fallback resources. We associate these phenotypic differences to the evolutionary process of colonizing the savannas by primates (including early hominins), leading to morphological adaptations to tolerate stressful, seasonal environments, such as body size reduction and ingestion and mastication of tough foods.

Individual Dietary Specialization in a Generalist Bee Varies across Populations but Has No Effect on the Richness of Associated Microbial Communities.

AbstractDespite the increasingly documented occurrence of individual specialization, the relationship between individual consumer interactions and diet-related microbial communities in wild populations is still unclear. Using data from nests of Ceratina australensis from three different wild bee populations, we combine metabarcoding and network approaches to explore the existence of individual variation in resource use within and across populations and whether dietary specialization affects the richness of pollen-associated microbes. We reveal the existence of marked dietary specialization. In the most specialized population, we also show that individuals' diet breadth was positively related to the richness of fungi but not bacteria. Overall, individual specialization appeared to have a weak or negligible effect on the microbial richness of nests, suggesting that different mechanisms beyond environmental transmission may be at play regarding microbial acquisition in wild bees.

Energetic consequences of resource use diversity in a marine carnivore.

Understanding how intraspecific variation in the use of prey resources impacts energy metabolism has strong implications for predicting long-term fitness and is critical for predicting population-to-community level responses to environmental change. Here, we examine the energetic consequences of variable prey resource use in a widely distributed marine carnivore, juvenile sand tiger sharks (Carcharias taurus). We used carbon and nitrogen isotope analysis to identify three primary prey resource pools-demersal omnivores, pelagic forage, and benthic detritivores and estimated the proportional assimilation of each resource using Bayesian mixing models. We then quantified how the utilization of these resource pools impacted the concentrations of six plasma lipids and how this varied by ontogeny. Sharks exhibited variable reliance on two of three predominant prey resource pools: demersal omnivores and pelagic forage. Resource use variation was a strong predictor of energetic condition, whereby individuals more reliant upon pelagic forage exhibited higher blood plasma concentrations of very low-density lipoproteins, cholesterol, and triglycerides. These findings underscore how intraspecific variation inresource use may impact the energy metabolism of animals, and more broadly, that natural and anthropogenically driven fluctuations in prey resources could have longer term energetic consequences.

Association of Self-reported Primary Care Physician Tolerance for Uncertainty With Variations in Resource Use and Patient Experience

Inappropriate variations in clinical practice are a known cause of poor quality and safety, with variations often associated with nonclinical factors, such as individual differences in cognitive processing. The differential response of physicians to uncertainty may explain some of the variations in resource use and patient experience. To examine the association of physician tolerance for uncertainty with variations in resource use and patient experience. This survey study linked physician survey data (May to June 2019), patient experience survey data (January 2016 to December 2019), and billing data (January 2019 to December 2019) among primary care physicians (PCPs) at Massachusetts General Hospital with at least 10 visits in 2019. The statistical analysis was performed in 2021. The analysis examined associations of PCP tolerance for uncertainty with the tendency to order diagnostic tests, the frequency of outpatient visits, hospital admissions, emergency department visits, and patient experience data (focused on physician communication and overall rating). A 2-stage hierarchical framework was used to account for clustering of patients under PCPs. Binary outcomes were modeled using a hierarchical logistic model, and count outcomes were modeled using hierarchical Poisson or negative binomial models. The analysis was adjusted for patient demographic variables (age, sex, and race and ethnicity), socioeconomic factors (payer and neighborhood income), and clinical comorbidities. Of 217 included physicians, 137 (63.1%) were women, and 174 (80.2%) were adult PCPs. A total of 62 physicians (28.6%) reported low tolerance, 59 (27.2%) reported medium tolerance, and 96 (44.2%) reported high tolerance for uncertainty. Physicians with a low tolerance for uncertainty were less likely to order complete blood cell counts (odds ratio [OR], 0.66; 95% CI, 0.50-0.88), thyroid tests (OR, 0.67; 95% CI, 0.52-0.88), a basic metabolic profile (OR, 0.78; 95% CI, 0.60-1.00), and liver function tests (OR, 0.72; 95% CI, 0.53-0.99) than physicians with a high tolerance for uncertainty. Physicians who reported higher tolerance for uncertainty were more likely to receive higher patient experience scores for listening to patients carefully (OR, 0.65; 95% CI, 0.50-0.83) and higher overall ratings (OR, 0.80; 95% CI, 0.66-0.98) than physicians with medium tolerance. Conversely, no association was found between physician tolerance for uncertainty and patient outpatient visits, hospital admissions, or emergency department visits. In clinical practice, identifying and effectively managing inappropriate variations and improving patient experience have proven to be difficult, despite increased attention to these issues. This study supports the hypothesis that physicians' tolerance for uncertainty is associated with differences in resource use and patient experience. Whether enhancing physicians' tolerance for uncertainty could help reduce unwarranted practice variations, improve quality and patient safety, and improve patient's experience remains to be established.

Comparative trophic ecology of microhabitat-associated guilds of reef fishes in the Adriatic Sea.

Reef ecosystems are characterized by highly heterogenous habitats and functionally diverse fish communities. Few studies have examined how functional diversity differs among habitats within these communities, i.e., species associated with a specific habitat may have similar trophic ecologies meaning that the functional diversity within the community is driven by habitat diversity or, conversely, high functional diversity within each habitat would indicate that resource segregation also occurs at the habitat level. We used stable isotope ratios of carbon and nitrogen to estimate trophic position, resource use and ontogenetic niche shifts of 15 reef fishes associated with four distinct habitat types (cryptobenthic, epibenthic sand, epibenthic rock and hyperbenthic) on the Croatian coast of the Adriatic Sea. Trophic ecology was quite similar across fish assemblages, but there was strong evidence of niche segregation among fish species within each assemblage showing high functional diversity within each microhabitat. The sampled fish community contained benthic and pelagic resource users, along with multiple intermediate generalists. Consumer stable isotope ratios revealed considerable interspecific variation in resource use among fishes within each habitat type. The cryptobenthic fishes were a notable exception to this trend with the narrow range of resource use values, indicating reliance of these species on a single resource. The greatest diversity of trophic positions within a guild was observed in cryptobenthic and rock-associated epibenthic fishes. The majority of observed ontogenetic variation in studied fish species reflected an increase in benthic resource use and trophic position. However, the degree of ontogenetic variation in trophic ecology of studied species, if present, was generally low, showing no dramatic change in the ecology of any species. The size structuring among guilds was considerable, with cryptobenthic fishes the smallest on average and hyperbenthic fishes the largest, despite guilds having similar ranges of trophic positions.

What a few hairs can tell us about the resource use of giant armadillos.

Understanding of resource requirements of vulnerable species is key for conservation planning. Here, we used stable carbon (δ13 C) and nitrogen isotopes (δ15 N) of hair from giant armadillos (Priodontes maximus) to understand individual resource use. We collected hair from 19 giant armadillos analyzing 34 samples from the Brazilian Pantanal and compared the resource use between sexes and age classes. We also assessed the relationship of isotopic values with individuals' body mass and the habitat type used. We observed a wide variation in resource use by giant armadillos, showing that individuals consume prey that feeds on distinct resources and occupies different habitat types, indicating that there is individual variation in foraging behavior. Most giant armadillos presented a mixed diet (C3 /C4 resources, forests/open areas), but a quarter of individuals had strictly C4 diets (open areas). Males are more prone to forage on C4 resources, presenting an isotopic niche 2.6-times larger than that of females. Subadults presented diets more associated with habitats with high arboreal cover (C3 resources, forests), while adults foraged more in open areas (C4 resources). This result is mirrored by the positive relationship between δ13 C values and body mass, suggesting that larger giant armadillos tend to feed more in open areas. We observed that δ13 C values decreased as individuals increased the use of habitats with high arboreal cover. We stress the importance of conserving the natural mosaic in the Pantanal landscape for the species persistence, given that giant armadillos require all habitat types to fulfill their dietary, spatial, and developmental needs.

Intensity of hospital resource use following traumatic brain injury: a multicentre cohort study, 2013-2016.

Background:The knowledge gap regarding acute care resource use for patients with traumatic brain injury (TBI) impedes efforts to improve the efficiency and quality of the care of these patients. Our objective was to evaluate interhospital variation in resource use for patients with TBI, identify determinants of high resource use and assess the association between hospital resource use and clinical outcomes.Methods:We conducted a multicentre retrospective cohort study including patients aged 16 years and older admitted to the inclusive trauma system of Quebec following TBI, between 2013 and 2016. We estimated resource use using activity-based costs. Clinical outcomes included mortality, complications and unplanned hospital readmission. Interhospital variation was evaluated using intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs). Correlations between hospital resource use and clinical outcomes were evaluated using correlation coefficients on weighted, risk-adjusted estimates with 95% CIs.Results:We included 6319 patients. We observed significant interhospital variation in resource use for patients discharged alive, which was not explained by patient case mix (ICC 0.052, 95% CI 0.043 to 0.061). Adjusted mean resource use for patients discharged to long-term care was more than twice that of patients discharged home. Hospitals with higher resource use tended to have a lower incidence of mortality (r −0.347, 95% CI −0.559 to −0.087) and unplanned readmission (r −0.249, 95% CI −0.481 to 0.020) but a higher incidence of complications (r 0.491, 95% CI 0.255 to 0.666).Conclusion:Resource use for TBI varies significantly among hospitals and may be associated with differences in mortality and morbidity. Negative associations with mortality and positive associations with complications should be interpreted with caution but suggest there may be a trade-off between adverse events and survival that should be evaluated further.

Limited resources shape home range patterns of an insular ungulate in a semi-arid ecosystem

Understanding patterns of home range size and selection are critical to protect vulnerable wild populations, particularly in semi-arid regions with increasing land use pressures. Using movement data from 64 GPS-collared southern mule deer (Odocoileus hemionus fulinginatus), monitored over two years in San Diego County, we assessed patterns and drivers of home range following a two-step approach. First, we implemented seasonal home range selection functions to examine variation in selection and avoidance of environmental factors. We then used these results to evaluate the relative impact of environmental factors in combination with intrinsic factors on home range size. We found that deer use of high-quality forage and water sources varied seasonally. These variations in resource use, along with sex and age, played a role in determining home range size of the southern mule deer. Home range size was larger for male deer, and smaller among older females. Home ranges for both sexes were smaller when forage quality increased and larger with greater variability in water proximity. The limited resources of semi-arid environments, like water and forage, affect southern mule deer populations and highlight the importance of evaluating combined intrinsic and extrinsic factors of home range size and composition to inform management practices.

Utilization patterns, outcomes and costs of a simplified acute malnutrition treatment programme in Burkina Faso.

Access to treatment for acute malnutrition remains a challenge, in part due to the fragmentation of treatment programmes based on case severity. This paper evaluates utilization patterns, outcomes and associated costs for treating acute malnutrition cases among a cohort of children in Burkina Faso. This study is a secondary analysis of a proof‐of‐concept trial, called Optimizing treatment for acute Malnutrition (OptiMA), conducted in Burkina Faso in 2016. A total of 4958 eligible children whose mid‐upper arm circumference (MUAC) was less than 125 mm or with oedema were followed weekly and given ready‐to‐use therapeutic foods (RUTF). We evaluated the service utilization and outcomes among patients and estimated resource use and variable cost per patient, and examined factors driving variation in resource use. Children with lower initial MUAC level grew faster but required more time to recover than those with higher initial MUAC level. They also had higher rates of death, default and nonresponse. The simplified OptiMA approach for treating acute malnutrition achieved high rates of recovery overall (84%), especially among less severe cases, with modest quantities of RUTF. The average overall variable cost per child admitted was US$38.0 (SD: 20.5) half of which was accounted for by the cost of RUTF. Cost per recovered case was correlated with case severity, ranging from US$35.1 to US$132.8. If simplified integrated programmes using severity‐based RUTF dosing can increase access to treatment at earlier, less severe stages of acute malnutrition, they can help avoid more serious and costlier cases.