A circumpolar study unveils a positive non-linear effect of temperature on arctic arthropod availability that may reduce the risk of warming-induced trophic mismatch for breeding shorebirds.

Seasonally abundant arthropods are a crucial food source for many migratory birds that breed in the Arctic. In cold environments, the growth and emergence of arthropods are particularly tied to temperature. Thus, the phenology of arthropods is anticipated to undergo a rapid change in response to a warming climate, potentially leading to a trophic mismatch between migratory insectivorous birds and their prey. Using data from 19 sites spanning a wide temperature gradient from the Subarctic to the High Arctic, we investigated the effects of temperature on the phenology and biomass of arthropods available to shorebirds during their short breeding season at high latitudes. We hypothesized that prolonged exposure to warmer summer temperatures would generate earlier peaks in arthropod biomass, as well as higher peak and seasonal biomass. Across the temperature gradient encompassed by our study sites (>10°C in average summer temperatures), we found a 3-day shift in average peak date for every increment of 80 cumulative thawing degree-days. Interestingly, we found a linear relationship between temperature and arthropod biomass only below temperature thresholds. Higher temperatures were associated with higher peak and seasonal biomass below 106 and 177 cumulative thawing degree-days, respectively, between June 5 and July 15. Beyond these thresholds, no relationship was observed between temperature and arthropod biomass. Our results suggest that prolonged exposure to elevated temperatures can positively influence prey availability for some arctic birds. This positive effect could, in part, stem from changes in arthropod assemblages and may reduce the risk of trophic mismatch.

Space-use behaviour of woodland caribou based on a cognitive movement model.

Movement patterns offer a rich source of information on animal behaviour and the ecological significance of landscape attributes. This is especially useful for species occupying remote landscapes where direct behavioural observations are limited. In this study, we fit a mechanistic model of animal cognition and movement to GPS positional data of woodland caribou (Rangifer tarandus caribou; Gmelin 1788) collected over a wide range of ecological conditions. The model explicitly tracks individual animal informational state over space and time, with resulting parameter estimates that have direct cognitive and ecological meaning. Three biotic landscape attributes were hypothesized to motivate caribou movement: forage abundance (dietary digestible biomass), wolf (Canis lupus; Linnaeus, 1758) density and moose (Alces alces; Linnaeus, 1758) habitat. Wolves are the main predator of caribou in this system and moose are their primary prey. Resulting parameter estimates clearly indicated that forage abundance is an important driver of caribou movement patterns, with predator and moose avoidance often having a strong effect, but not for all individuals. From the cognitive perspective, our results support the notion that caribou rely on limited sensory inputs from their surroundings, as well as on long-term spatial memory, to make informed movement decisions. Our study demonstrates how sensory, memory and motion capacities may interact with ecological fitness covariates to influence movement decisions by free-ranging animals.

Wolves adapt territory size, not pack size to local habitat quality.

1. Although local variation in territorial predator density is often correlated with habitat quality, the causal mechanism underlying this frequently observed association is poorly understood and could stem from facultative adjustment in either group size or territory size. 2. To test between these alternative hypotheses, we used a novel statistical framework to construct a winter population-level utilization distribution for wolves (Canis lupus) in northern Ontario, which we then linked to a suite of environmental variables to determine factors influencing wolf space use. Next, we compared habitat quality metrics emerging from this analysis as well as an independent measure of prey abundance, with pack size and territory size to investigate which hypothesis was most supported by the data. 3. We show that wolf space use patterns were concentrated near deciduous, mixed deciduous/coniferous and disturbed forest stands favoured by moose (Alces alces), the predominant prey species in the diet of wolves in northern Ontario, and in proximity to linear corridors, including shorelines and road networks remaining from commercial forestry activities. 4. We then demonstrate that landscape metrics of wolf habitat quality - projected wolf use, probability of moose occupancy and proportion of preferred land cover classes - were inversely related to territory size but unrelated to pack size. 5. These results suggest that wolves in boreal ecosystems alter territory size, but not pack size, in response to local variation in habitat quality. This could be an adaptive strategy to balance trade-offs between territorial defence costs and energetic gains due to resource acquisition. That pack size was not responsive to habitat quality suggests that variation in group size is influenced by other factors such as intraspecific competition between wolf packs.

Towards an energetic landscape: broad-scale accelerometry in woodland caribou.

Energetic balance is a central driver of individual survival and population change, yet estimating energetic costs in free- and wide-ranging animals presents a significant challenge. Animal-borne activity monitors (using accelerometer technology) present a promising method of meeting this challenge and open new avenues for exploring energetics in natural settings. To determine the behaviours and estimated energetic costs associated with a given activity level, three captive reindeer (Rangifer tarandus tarandus) at the Toronto Zoo were fitted with collars and observed for 53 h. Activity patterns were then measured over 13 months for 131 free-ranging woodland caribou (R. t. caribou) spanning 450,000 km(2) in northern Ontario. The captive study revealed a positive but decelerating relationship between activity level and energetic costs inferred from previous behavioural studies. Field-based measures of activity were modelled against individual displacement, vegetation abundance (Normalized Difference Vegetation Index), snow depth and temperature, and the best fit model included all parameters and explained over half of the variation in the data. Individual displacement was positively related to activity levels, suggesting that broad differences in energetic demands are influenced by variation in movement rates. After accounting for displacement, activity was highest at intermediate levels of vegetation abundance, presumably due to foraging behaviour. Snow depth, probably associated with digging for winter forage, moderately increased activity. Activity levels increased significantly at the coldest winter temperatures, suggesting the use of behavioural thermoregulation by caribou. These interpretations of proximate causal factors should be regarded as hypotheses subject to validation under normal field conditions. These results illustrate the landscape characteristics that increase energetic demands for caribou and confirm the great potential for the use of accelerometry in studies of animal energetics.

Environmental and individual drivers of animal movement patterns across a wide geographical gradient.

Within the rapidly developing field of movement ecology, much attention has been given to studying the movement of individuals within a subset of their population's occupied range. Our understanding of the effects of landscape heterogeneity on animal movement is still fairly limited as it requires studying the movement of multiple individuals across a variety of environmental conditions. Gaining deeper understanding of the environmental drivers of movement is a crucial component of predictive models of population spread and habitat selection and may help inform management and conservation. In Ontario, woodland caribou (Rangifer tarandus caribou) occur along a wide geographical gradient ranging from the boreal forest to the Hudson Bay floodplains. We used high-resolution GPS data, collected from 114 individuals across a 450000 km(2) area in northern Ontario, to link movement behaviour to underlying local environmental variables associated with habitat permeability, predation risk and forage availability. We show that a great deal of observed variability in movement patterns across space and time can be attributed to local environmental conditions, with residual individual differences that may reflect spatial population structure. We discuss our results in the context of current knowledge of movement and caribou ecology and highlight potential applications of our approach to the study of wide-ranging animals.

Patterns and causes of demographic variation in a harvested moose population: evidence for the effects of climate and density-dependent drivers.

1. Better understanding of the mechanisms affecting demographic variation in ungulate populations is needed to support sustainable management of harvested populations. While studies of moose Alces alces L. populations have previously explored temporal variation in demographic processes, managers responsible for populations that span large heterogeneous landscapes would benefit from an understanding of how demography varies across biogeographical gradients in climate and other population drivers. Evidence of thresholds in population response to manageable and un-manageable drivers could aid resource managers in identifying limits to the magnitude of sustainable change. 2. Generalized additive models (GAMs) were used to evaluate the relative importance of population density, habitat abundance, summer and winter climatic conditions, primary production, and harvest intensity in explaining spatial variation in moose vital rates in Ontario, Canada. Tree regression was used to test for thresholds in the magnitudes of environmental predictor variables that significantly affected population vital rates. 3. Moose population growth rate was negatively related to moose density and positively related to the abundance of mixed deciduous habitat abundant in forage. Calf recruitment was negatively related to a later start of the growing season and calf harvest. The ratio of bulls to cows was related to male harvest and hunter access, and thresholds were evident in predictor variables for all vital rate models. 4. Findings indicate that the contributions of density-dependent and independent factors can vary depending on the scale of population process. The importance of density dependence and habitat supply to low-density ungulate populations was evident, and management strategies for ungulates may be improved by explicitly linking forest management and harvest. Findings emphasize the importance of considering summer climatic influences to ungulate populations, as recruitment in moose was more sensitive to the timing of vegetation green-up than winter severity. The efficacy of management decisions for harvested ungulates may require regional shifts in targets where populations span bioclimatic gradients. The use of GAMs in combination with recursive partitioning was demonstrated to be an informative analytical framework that captured nonlinear relationships common in natural processes and thresholds that are relevant to population management in diverse systems.

Behavioural responses of breeding arctic sandpipers to ground-surface temperature and primary productivity.

Most birds incubate their eggs, which requires time and energy at the expense of other activities. Birds generally have two incubation strategies: biparental where both mates cooperate in incubating eggs, and uniparental where a single parent incubates. In harsh and unpredictable environments, incubation is challenging due to high energetic demands and variable resource availability. We studied the relationships between the incubation behaviour of sandpipers (genus Calidris) and two environmental variables: temperature and a proxy of primary productivity (i.e. NDVI). We investigated how these relationships vary between incubation strategies and across species among strategies. We also studied how the relationship between current temperature and incubation behaviour varies with previous day's temperature. We monitored the incubation behaviour of nine sandpiper species using thermologgers at 15 arctic sites between 2016 and 2019. We also used thermologgers to record the ground surface temperature at conspecific nest sites and extracted NDVI values from a remote sensing product. We found no relationship between either environmental variables and biparental incubation behaviour. Conversely, as ground-surface temperature increased, uniparental species decreased total duration of recesses (TDR) and mean duration of recesses (MDR), but increased number of recesses (NR). Moreover, small species showed stronger relationships with ground-surface temperature than large species. When all uniparental species were combined, an increase in NDVI was correlated with higher mean duration, total duration and number of recesses, but relationships varied widely across species. Finally, some uniparental species showed a lag effect with a higher nest attentiveness after a warm day while more recesses occurred after a cold day than was predicted based on current temperatures. We demonstrate the complex interplay between shorebird incubation strategies, incubation behaviour, and environmental conditions. Understanding how species respond to changes in their environment during incubation helps predict their future reproductive success.

Appropriateness of adrenocorticotropic hormone stimulation test for critically ill patients.

BACKGROUND: In earlier work, it was shown that patients with septic shock who also have adrenal insufficiency experience a benefit in terms of lower mortality rates with hydrocortisone supplementation. As such, the adrenocorticotropic hormone (ACTH) stimulation test has been used frequently to identify these patients. However, recent evidence has suggested that the identification and treatment of adrenal insufficiency in patients with septic shock does not reduce mortality. These results call into question the utility of the ACTH stimulation test in this patient population. OBJECTIVES: To determine the indications for ordering the ACTH stimulation test for critically ill patients at a tertiary care hospital and to classify the indications as either appropriate (e.g., primary adrenal insufficiency or medication-induced suppression of the hypothalamus-pituitary-adrenal axis) or inappropriate (e.g., patients with septic shock, prior etomidate exposure, or absence of steroid use). METHODS: A retrospective analysis of health care records was conducted for all patients who had been admitted to the intensive care unit and who had undergone an ACTH stimulation test during 2007. For each patient, the indication for the test was identified and classified as appropriate or inappropriate. RESULTS: A total of 35 ACTH stimulation tests were performed during the study period, of which 8 (23%) were classified as having an appropriate indication and 27 (77%) as having an inappropriate indication. Of the tests with an inappropriate indication, 15 (56%) were ordered for patients with septic shock. However, the number of ACTH tests ordered for this indication declined as the year progressed. CONCLUSIONS: The ACTH stimulation test was often used inappropriately for patients with septic shock. Over time, there appeared to be a trend away from use of this test in this patient population, perhaps reflecting increasing awareness of the lack of benefit.

Dosing Recommendations for Continuous Venovenous Hemodiafiltration with AN69 Filter Membranes and Prismaflex Dialyzers.

BACKGROUND: Continuous renal replacement therapy is used to manage fluid and solute imbalances in critically ill patients but may affect the clearance of concurrently administered drugs. The impact of continuous renal replacement therapy on pharmacokinetics has been summarized, but previous reports have included studies involving various modes of therapy, filter membranes, and brands of dialyzers, which makes it difficult to apply the recommendations to individual patients. In Canada, continuous venovenous hemodiafiltration (CVVHDF) with a Prismaflex dialyzer machine (Gambro, Saint-Léonard, Quebec) and AN69 filter membranes is the most common mode of continuous renal replacement therapy for critically ill patients. OBJECTIVE: To develop a set of dosage recommendations for commonly encountered medications used in treating critically ill patients who are undergoing CVVHDF with a Prismaflex dialyzer and AN69 filter membranes. METHODS: A literature search was conducted to identify studies of the pharmacokinetics and disposition of drugs in patients undergoing CVVHDF via a Prismaflex dialyzer (sold under 3 brand names: Gambro, Hospal, and Prima) equipped with polyacrylonitrile (AN69) filter membranes. From each study, the mean total clearance of each study medication during CVVHDF was extracted and compared with clearance of the drug in patients not undergoing CVVHDF, to produce dosage guidelines for patients undergoing CVVHDF. RESULTS: A total of 22 studies of 14 medications were included in the final review. For most of the drugs, the total clearance during CVVHDF was less than clearance in patients whose renal function was presumed to be normal. Fluconazole and moxifloxacin had greater total clearance during CVVHDF, but a dose adjustment during CVVHDF was deemed necessary only for fluconazole. CONCLUSIONS: Dosing recommendations were created for concurrently administered drugs for patients undergoing treatment with this particular CVVHDF equipment. Patient-specific factors and clinical judgement should also be taken into account.

Real-Life Frequency of New-Onset Thrombocytopenia during Linezolid Treatment.

BACKGROUND: Thrombocytopenia is a well-recognized adverse effect of linezolid; however, the frequency of this adverse effect during therapy has been variable across previous studies, and the associated risk factors are unclear. OBJECTIVES: To identify the real-life frequency of new-onset thrombocytopenia due to linezolid and to determine the associated risk factors. METHODS: A retrospective observational cohort study was conducted among consecutive inpatients at a tertiary care hospital who received linezolid for a minimum of 5 days between January 2013 and August 2017. Data were extracted from electronic medical records obtained from a hospital database. Thrombocytopenia was defined as platelet count less than 100 × 109/L or a 50% reduction from baseline (i.e., before linezolid initiation). Risk factors were identified by comparing the characteristics of patients who experienced the adverse effect during linezolid therapy with those of patients who did not experience the adverse effect. Continuous data were analyzed with the t test and categorical data with the χ2 test. RESULTS: A total of 102 patients were included (38 women, 64 men; overall mean age 50 years, standard deviation [SD] 21). The mean duration of linezolid therapy was 14 (SD 10) days. Thrombocytopenia occurred in 18 patients (17.6%). Risk factors for the development of thrombocytopenia included mean duration of therapy (22 [SD 18] days versus 12 [SD 7] days; p = 0.023), renal replacement therapy (17% versus 4%; p = 0.032), renal impairment (61% versus 32%; p = 0.021), and concomitant administration of unfractionated heparin (50% versus 21%; p = 0.013). CONCLUSIONS: The real-life frequency of new-onset of thrombocytopenia in patients receiving linezolid for a minimum of 5 days was 17.6%. Risk factors for linezolid-induced thrombocytopenia included prolonged duration of therapy, renal impairment, and concomitant unfractionated heparin.

CONTEXTE: La thrombopénie est une réaction indésirable bien connue, induite par le linézolide; cependant, la fréquence de cette réaction indésirable pendant le traitement hvariait d'une étude à l'autre et on ignore quels sont les facteurs de risque associés à cet antibiotique. OBJECTIFS: Découvrir la fréquence réelle des nouveaux cas de thrombopénie causés par le linézolide et déterminer les facteurs de risque qui lui sont associés. MÉTHODES: Une étude de cohorte observationnelle rétrospective a été menée auprès de patients hospitalisés consécutivement dans un hôpital de soins tertiaires, qui ont reçu du linézolide pendant au moins cinq jours entre janvier 2013 et août 2017. Les données ont été tirées des dossiers médicaux électroniques provenant d'une base de données d'un hôpital. La thrombopénie a été définie comme un taux de plaquettes de moins de 100 × 109/L ou comme une réduction de 50 % de leur valeur initiale (c'est-à-dire, avant l'amorce du traitement au linézolide). Les chercheurs ont établi les facteurs de risque en comparant les caractéristiques des patients ayant subi la réaction indésirable pendant leur traitement au linézolide avec les caractéristiques des patients n'ayant pas subi cet effet indésirable. Les données continues ont été analysées à l'aide d'un test t et les données catégoriques à l'aide d'un test de χ2. RÉSULTATS: Au total, 102 patients ont été admis (38 femmes, 64 hommes; âge moyen de 50 ans, écart-type de 21). La durée du traitement au linézolide était de 14 jours (écart-type de 10). Dix-huit patients (17,6 %) ont souffert de thrombopénie. Parmi les facteurs de risque de thrombopénie, on comptait la durée moyenne du traitement (22 jours [écart-type de 18] contre 12 jours [écart-type de 7]; p = 0,023), le traitement de suppléance rénale (17 % contre 4 %; p = 0,032), l'insuffisance rénale (61 % contre 32 %; p = 0,021) et l'administration concomitante d'héparine non fractionnée (50 % contre 21 %; p = 0,013). CONCLUSIONS: La fréquence réelle de nouveaux cas de thrombopénie parmi les patients recevant du linézolide pendant un minimum de 5 jours était de 17,6 %. Parmi les facteurs de risque de thrombopénie associés au linézolide, on mentionne l'allongement de la durée du traitement, l'insuffisance rénale et l'administration concomitante d'héparine non fractionnée.

Moral distress in intensive care unit personnel is not consistently associated with adverse medication events and other adverse events.

PURPOSE: To examine the association between moral distress in ICU personnel, and medication errors and adverse events, and other adverse events. MATERIALS AND METHODS: In 13 ICUs, we measured moral distress once in all ICU staff, and incidence of five explicity-defined adverse safety events over 2 years. In 10 of the ICUs, pharmacists tabulated medication errors and adverse events during 1 day in the 2-year period. Average moral distress scores for each professional group were correlated with each safety measure. RESULTS: In the pharmacy study, there were almost no significant correlations between moral distress and measures of medication safety. However, higher moral distress in nurses was associated with more interceptions of near misses per administration error (r = 0.68, p = 0.04), and higher moral distress in physicians was associated with more incorrect measurements for medication monitoring per recommended action for monitoring (r = 0.68, p = 0.03). For the other adverse events, the only significant association was a positive association between moral distress in physicians and bleeding while on anticoagulants (OR: 1.1; 95% CI: 1.0-1.3). CONCLUSION: Moral distress in ICU personnel is generally not associated with medication errors or adverse events, or other adverse events, but it may be associated with both hyper-vigilance and distraction.

Comment on "Global pattern of nest predation is disrupted by climate change in shorebirds".

Kubelka et al (Reports, 9 November 2018, p. 680) claim that climate change has disrupted patterns of nest predation in shorebirds. They report that predation rates have increased since the 1950s, especially in the Arctic. We describe methodological problems with their analyses and argue that there is no solid statistical support for their claims.

Woodland caribou habitat selection patterns in relation to predation risk and forage abundance depend on reproductive state.

The ideal free distribution assumes that animals select habitats that are beneficial to their fitness. When the needs of dependent offspring differ from those of the parent, ideal habitat selection patterns could vary with the presence or absence of offspring. We test whether habitat selection depends on reproductive state due to top-down or bottom-up influences on the fitness of woodland caribou (Rangifer tarandus caribou), a threatened, wide-ranging herbivore. We combined established methods of fitting resource and step selection functions derived from locations of collared animals in Ontario with newer techniques, including identifying calf status from video collar footage and seasonal habitat selection analysis through latent selection difference functions. We found that females with calves avoided predation risk and proximity to roads more strongly than females without calves within their seasonal ranges. At the local scale, females with calves avoided predation more strongly than females without calves. Females with calves increased predation avoidance but not selection for food availability upon calving, whereas females without calves increased selection for food availability across the same season. These behavioral responses suggest that habitat selection by woodland caribou is influenced by reproductive state, such that females with calves at heel use habitat selection to offset the increased vulnerability of their offspring to predation risk.

The impacts of forest management strategies for woodland caribou vary across biogeographic gradients.

Loss or alteration of forest ecosystems due to anthropogenic activities has prompted the need for mitigation measures aimed at protecting habitat for forest-dependent wildlife. Understanding how wildlife respond to such management efforts is essential for achieving conservation targets. Boreal caribou are a species of conservation concern due to the impacts of human induced habitat alteration; however the effects of habitat management activities are poorly understood. We assessed the relationship between large scale patterns in forest harvesting and caribou spatial behaviours over a 20-year period, spanning a change in forest management intended to protect caribou habitat. Caribou range size, fidelity, and proximity to forest harvests were assessed in relation to change in harvest patterns through time and across two landscapes that varied widely in natural disturbance and community dynamics. We observed up to 89% declines in total area harvested within our study areas, with declining harvest size and aggregation. These landscape outcomes were coincident with caribou exhibiting greater fidelity and spacing farther away from disturbances at smaller scales, hypothesized to be beneficial for acquiring food and avoiding predators. Contrary to our expectation that the large scale maintenance of habitat patches would permit caribou to space away from disturbance, their proximity to harvest blocks at the population range scale did not decrease through time, suggesting that movement toward landscape recovery for caribou in previously harvested regions will likely stretch over multiple decades. Caribou spatial behaviours varied across the two landscapes independently of forest management. Our study underlines the importance of understanding both changes in industry demands, as well as natural landscape variation in habitat when managing wildlife.

5-Aminosalicylic Acid-Associated Myocarditis and Pericarditis: A Narrative Review.

BACKGROUND: Use of medications containing the 5-aminosalicylic acid (5-ASA) moiety may cause a rare but potentially lethal side effect involving inflammation of the heart (myocarditis) or pericardium (pericarditis) or both (myopericarditis). Early recognition of 5-ASA as the cause is important to prevent progression of the inflammation. OBJECTIVE: To provide clinicians with information to assist in recognizing the signs and symptoms of 5-ASA-induced cardiac inflammation and the characteristics of the suspected therapy, and in determining the appropriate approach to treatment. DATA SOURCES STUDY SELECTION AND DATA EXTRACTION: The Embase database was searched, for the period 1974 to July 17, 2015, for published descriptions of cases of cardiac inflammation caused by 5-ASA-containing medications. The search terms included the names of specific agents, as well as terms for different types of cardiac inflammation. Articles in any language were retained for inclusion in this narrative review. FINDINGS: There is no symptom, sign, laboratory test, or constellation of symptoms and signs that is pathognomonic for 5-ASA-induced myocardial-pericardial toxicity. Similarly, there is no single laboratory, electrocardiographic, or echocardiographic finding or combination of findings that implicates 5-ASA as the cause of nonspecific symptoms. However, most patients present with chest pain, shortness of breath, and fever within the first 28 days after initiating 5-ASA. Physical examination, electrocardiography, and diagnostic imaging will yield findings consistent with myocarditis, with or without accompanying pericarditis. Prompt discontinuation of the 5-ASA will result in resolution of symptoms within days, without the need for any adjunctive therapies. Rechallenge with any 5-ASA-containing compound carries a high risk for recurrence of the inflammation. CONCLUSIONS: Any patient presenting with chest pain, shortness of breath, or fever within 28 days after initiating a 5-ASA-containing drug should be considered as exhibiting drug-induced inflammation. The 5-ASA-containing drug should be stopped immediately until other causes can be proven (or excluded); if no other cause is discovered, the 5-ASA should not be restarted.

L'emploi de médicaments à base d'acide 5-aminosalicylique (5-AAS) peut causer un effet indésirable rare, mais potentiellement mortel qui se traduit par l'inflammation du myocarde (myocardite) ou du péricarde (péricardite) ou de ces deux éléments du système cardiaque (myopéricardite). Il est important d'établir rapidement que l'inflammation est imputable à l'AAS afin de prévenir la progression de cet effet indésirable.