RESUMEN
AbstractMany animals follow annual cycles wherein physiology and behavior change seasonally. Hibernating mammals undergo one of the most drastic seasonal alterations of physiology and behavior, the timing of which can have significant fitness consequences. The environmental cues regulating these profound phenotypic changes will heavily influence whether hibernators acclimate and ultimately adapt to climate change. Hence, identifying the cues and proximate mechanisms responsible for hibernation termination timing is critical. Northern Idaho ground squirrels (Urocitellus brunneus)-a rare, endemic species threatened with extinction-exhibit substantial variation in hibernation termination phenology, but it is unclear what causes this variation. We attached geolocators to free-ranging squirrels to test the hypothesis that squirrels assess surface conditions in spring before deciding whether to terminate seasonal heterothermy or reenter torpor. Northern Idaho ground squirrels frequently reentered torpor following a brief initial emergence from hibernacula and were more likely to do so earlier in spring or when challenged by residual snowpack. Female squirrels reentered torpor when confronted with relatively shallow snowpack upon emergence, whereas male squirrels reentered torpor in response to deeper spring snowpack. This novel behavior was previously assumed to be physiologically constrained in male ground squirrels by testosterone production required for spermatogenesis and activated by the circannual clock. Assessing surface conditions to decide when to terminate hibernation may help buffer these threatened squirrels against climate change. Documenting the extent to which other hibernators can facultatively alter emergence timing by reentering torpor after emergence will help identify which species are most likely to persist under climate change.
Asunto(s)
Hibernación , Sciuridae , Estaciones del Año , Nieve , Animales , Sciuridae/fisiología , Hibernación/fisiología , Femenino , Masculino , Letargo/fisiologíaRESUMEN
Human-bat interactions are now the source of the majority of locally acquired human lyssavirus infections in many high-income countries without hematophagous or 'vampire' bat species. This study aims to identify the most common types and circumstances of bat exposures occurring among members of the general public in high-income countries with no hematophagous bats, and to describe the health-seeking behaviours associated with exposures in these settings. We conducted a scoping review of relevant academic and grey literature on bat exposures and confirmed bat lyssavirus infections among members of the general public in Australia, Canada, the United States and high-income European countries from 1996 to 2019. Case studies and population-based studies were included for analysis, and findings were extracted and synthesized by the literature type and geographic region. A total of 63 publications were identified, including: 47 case studies and 16 population-based studies. Overall, most exposures in Australia and Europe were intentionally initiated by humans and involved attempts to handle, touch or help a bat. In North America, however, household exposures were more common and predominantly involved a bat being found in a room or area where a person had slept. Studies also showed that a proportion of bat exposures in high-income countries go unreported in the absence of a public health investigation and are therefore unlikely to receive prompt treatment. The results of this review suggest that the most effective strategies for preventing bat exposures vary between regions and that health-seeking behaviours following bat exposures could be improved in high-income settings.
Asunto(s)
Quirópteros , Lyssavirus , Infecciones por Rhabdoviridae , Animales , Países Desarrollados , Humanos , Aceptación de la Atención de Salud , Infecciones por Rhabdoviridae/veterinaria , ZoonosisRESUMEN
Whale-watching is a global tourism industry whose annual revenue exceeds two billion dollars. Australia is a key player in this industry, especially on the east and west coast where humpback whales migrate each year between their breeding and feeding grounds. However, the global whale-watching industry faces uncertainty from changing whale migration patterns, with whales progressively 'arriving' at the traditional whale-watching areas earlier than in previous years/decades. If the whale-watching industry cannot evolve with these changing dynamics then the arrival of the whales might be missed resulting in a potential loss of revenue. This social-ecological issue has suddenly been exacerbated by the disruption to tourism caused by the global pandemic COVID-19. In this study, we use a systems modelling framework, which combines qualitative and quantitative processes, to evaluate the social-ecological system behaviour of the whale-watching industry. We apply this systems approach to the Gold Coast, one of Australia's premier tourist destinations and home to a vibrant whale-watching industry. The outcome of this systems assessment is that the efficacy of the whale-watching industry is affected through determinants of both supply (ability to respond to changes in whale behaviour) and demand (attractiveness of whale-watching). Furthermore, the recovery time of all tourism after COVID-19 will take years if not decades.
Asunto(s)
COVID-19 , Cambio Climático , Animales , Humanos , Australia , SARS-CoV-2 , IncertidumbreRESUMEN
Bioaccumulation models are an important and widely-used tool for assessing ecosystem health with regards to heavy metal contamination. However, these models do not usually account for the potentially significant effect of temperature-dependency in metal uptake. In this study, we explored the role of temperature-dependency in heavy metal bioaccumulation by developing and comparing two kinetic-based copper bioaccumulation models for a common estuarine oyster (Saccostrea glomerata): (i) a standard first-order model that ignores temperature effects; and (ii) a modified first-order model that uses a standard temperature function to account for the temperature-dependency of the uptake rate constant. The models were calibrated within a Bayesian framework so that parameters could be treated as random variables and any uncertainty propagated through to the model output. A 12-month biomonitoring study was carried out within Moreton Bay, Queensland, Australia to provide time-series data for the modelling. Results of the modelling showed that the two bioaccumulation models provided comparable fits of the biomonitoring field data. However, dependent on the time of year and monitoring period selected, the copper uptake rate would vary dramatically due to temperature effects, which could result in an overestimation or underestimation of the copper uptake rate. Finally by calibrating the bioaccumulation models within a Bayesian framework, these models were able to utilize prior knowledge of the model parameters as part of the calibration process and also account for the uncertainty and variability in the bioaccumulation predictions. The ability to account for uncertainty and variability is an important consideration when undertaking environmental risk assessments especially in coastal waterways where there are strong seasonal variations.