Conservation Physiology最新文献

As a relatively nascent discipline, conservation physiology has struggled to deliver science that is relevant to decision-makers or directly useful to practitioners. A growing body of literature has revealed that co-produced research is more likely to generate knowledge that is not only relevant, but that is also embraced and actionable. Co-production broadly involves conducting research collaboratively, inclusively, and in a respectful and engaged manner-spanning all stages from identifying research needs to study design, data collection, interpretation and application. This approach aims to create actionable science and deliver meaningful benefits to all partners involved. Knowledge can be co-produced with practitioners/managers working for regulators or stewardship bodies, Indigenous communities and governments, industry (e.g. fishers, foresters, farmers) and other relevant actors. Using diverse case studies spanning issues, taxa and regions from around the globe, we explore examples of co-produced research related to conservation physiology. In doing so, we highlight benefits and challenges while also identifying lessons for others considering such an approach. Although co-production cannot guarantee the ultimate success of a project, for applied research (such as what conservation physiology purports to deliver), embracing co-production is increasingly regarded as the single-most important approach for generating actionable science to inform conservation. In that sense, the conservation physiology community would be more impactful and relevant if it became commonplace to embrace co-production as demonstrated by the case studies presented here.

Turbidity is increasing in freshwaters globally due to human activities and is known to affect visually mediated behaviours in fish. As anthropogenic impacts continue to degrade aquatic environments, it is critical to determine how sensory systems are affected and what this might mean for population persistence. We investigated the effect of turbidity on visual detection thresholds in an African cichlid fish (Pseudocrenilabrus multicolor) that experiences environmental extremes across its East African range. We tested the visual abilities of adult wild-caught fish from two sites representing the extremes of turbidity and oxygen (a high turbidity, high dissolved oxygen river and a low turbidity, low dissolved oxygen swamp). Further, we reared offspring of wild-caught parents from each population in a full-factorial high/low oxygen, high/low turbidity design to tease apart the influence of each stressor on visual detection thresholds. We used an optomotor response test to determine detection thresholds under increasing levels of turbidity for both wild-caught and lab-reared fish. Detection thresholds were higher in the wild-caught river population compared to the swamp population, and there was a strong sex difference, such that wild-caught males had higher detection thresholds than females regardless of population of origin. Our results suggest that there are sex-based differences in contrast detection abilities that could play a critical role in visual ecology for populations experiencing divergent turbidity regimes. In the rearing experiment, sex-based differences in detection thresholds were influenced by different aspects of the rearing treatment. Detection threshold varied significantly by oxygen-rearing treatment for males and by the interactive effects of oxygen and turbidity for females. This research improves our understanding of the effect of elevated turbidity on African cichlid vision and contributes to growing knowledge of how animals respond to environmental change.

Gulls (Laridae) use natural and urban environments and are useful 'biomonitors' of coastal ecosystem health. Here, we assessed physiological health of glaucous-winged gulls (Larus glaucescens, GWGU) wintering in the Salish Sea, British Columbia, Canada, a biodiverse region undergoing rapid anthropogenic change. We measured six physiological health biomarkers (blood glucose, triglycerides, haemoglobin, haematocrit, reactive oxygen metabolites and total antioxidants). Gulls sampled on the west coast of Vancouver Island had higher blood δ ¹³C and δ ¹⁵N values likely reflecting more marine diets compared with birds sampled in the Lower Mainland of Vancouver and in associated urban habitats such as landfills but terrestrial isotopic inputs are confounding. We found few differences in any of the six physiological markers in relation to region and habitat, or in overall indices of 'health' and 'nutritional state' using principal components analysis, even though these were characterized by varying levels of urban development and anthropogenic activity. Furthermore, individual variation in physiological traits was independent of individual variation in blood δ ¹³C and δ ¹⁵N values. This likely reflects the fact that we sampled 'physiologically homeostatic' individuals at all locations and habitats. Our study establishes reference values for six putative 'health' biomarkers, highlighting important covariates that need to be considered (e.g. sex, location) and provides a foundation for long-term physiological monitoring in relation to future anthropogenic impacts in this region.

Much progress has been made in understanding the pathophysiology of white-nose syndrome (WNS), a devastating disease that has impacted North American hibernating bats for nearly two decades. Growth of the causative fungal pathogen, Pseudogymnoascus destructans, on exposed epidermal tissue of bats creates an immune reaction that disrupts natural hibernation physiology and leads to premature expenditure of energy reserves and often death. Past work has highlighted the similarities between WNS and immune reconstitution inflammatory syndrome, but other conditions that have not been considered yet may also be relevant. We performed a transcriptomic analysis of wing tissue from naïve and exposed bats to further investigate the implications of observed differential gene expression patterns. For this analysis, we collected wing biopsy samples from 41 individuals prior to WNS emergence and 58 individuals 2-5 years after WNS emergence. We generated poly-A enriched tag-Seq libraries to compare gene expression between these groups. We then linked our findings and those of past studies to other disease systems to build hypotheses regarding mechanisms of WNS pathophysiology. We found an overrepresentation of functions related to programmed cell death and cytokine activity among upregulated genes. Importantly, we also identified upregulation of three S100 damage-associated molecular patterns (DAMPs) in exposed populations. Taken together, our findings and those of past studies suggest that infected bats experience a feedback loop of cell death among immune cells, the release of DAMPs and the stimulation of cytokine release that may act to maintain pathological immune activity. This feedback loop likely relates to cytokine storms in individuals with severe infection and possibly deteriorates into sepsis over time. Given the pathophysiology of sepsis, multiple organ dysfunction potentially contributes to the physiological disruption associated with WNS.

Changes in ocean temperature are expected to have a considerable effect on fishes through the impact of temperature on physiological performance, vital energetic processes (i.e. metabolism, foraging and swimming style) and reproductive fitness. To understand the sensitivity of an exploited population of Chrysoblephus laticeps in to temperature variability, intermittent-flow respirometry was used to quantify and compare changes in metabolic rate and aerobic scope under different temperatures (10, 16, 21 and 24°C) mimicking thermal variations experienced in the home range of this species. A total performance score was developed to represent aerobic performance across the range of test temperatures. This score was calculated for each temperature from the lower (25%), mid (50%) and upper (75%) percentiles of the aerobic scope range available for the species. The results of this study identified heterogeneity in physiological performance phenotypes amongst individuals of the exploited population. There was significant variation in the aerobic performance of high, intermediate and low performers at higher temperatures. However, differences in performance were not significant at low temperatures, where several intermediate performers maintained high performance. High performers maintained high rates of physiological performance across a broad range of temperatures, whereas low performers were physiologically limited outside of their optimal thermal range. These results suggest that individuals with a broad aerobic scope (i.e. high aerobic scope (AS) values across a range of temperatures) may likely be the most resilient to short-term thermal variability caused by marine heat waves and upwelling events in temperate coastal environments. Since the shape of thermal performance curves differs between individuals and reflects the range at which individuals can function above specified performance thresholds, individual thermal performance must be measured repeatedly in the same individual over a thermal gradient. An understanding of physiological phenotypic diversity amongst individuals is critical to understand the impacts of thermal variability on fished populations.

Rewilding and species reintroductions are increasingly important conservation strategies, involving both captive-bred and wild-rescued animals, with the goal of restoring ecosystems and supporting populations of threatened species. Over the past 30 years, the Elephant Transit Home in Sri Lanka has rescued and rehabilitated more than 150 orphaned elephant calves that were subsequently released back into the wild. Understanding how rehabilitation and release processes affect the welfare status of these calves can provide valuable information on factors affecting release outcomes. This study evaluated patterns of faecal glucocorticoid metabolite (fGCM) concentrations as a physiological indicator of stress in 10 orphaned elephants (six males, four females) rescued at ≤1 year of age and released back into Udawalawe National Park after rehabilitation at the Elephant Transit Home (release age, 6 to 8 years). Faecal samples (~2/week) were collected for 9 months pre- (n = 53 samples) and 16 months post- (n = 153 samples) release. Mean fGCM concentrations during the early post-release period (first 17 days) were significantly higher than in pre- and later post-release periods, with no differences between males and females. Results indicate elephants adapted quickly after release, likely aided by being released in a small group (n = 10) of socialized cohorts. In fact, fGCM normalized to concentrations lower on average than at the Elephant Transit Home in the months preceding release. Understanding the stress response of elephants during and after translocations is crucial for well-being and successful integration into the wild. Minimizing stress through appropriate protocols, such as selecting strong social units, is essential. Hormonal monitoring is a valuable tool that should be considered long-term to assess the adaptation, survival and eventual reproductive success of rewilded elephants.

Fishes can acclimate to a range of temperatures. However, the signalling factors controlling thermal acclimation are not well understood. Here, in two experiments, we examined the putative roles of plasma-borne factors (e.g. hormones) and skin thermoreception in the acclimation process. In experiment 1, 16°C-acclimated Atlantic cod (Gadus morhua) were subjected to a transfusion treatment by injecting plasma from 8°C (cold), 16°C (control) or 21°C (warm) acclimated cod, 10 times over four days. Plasma was collected from donor cod that were 24 h into their acclimation. In experiment 2, 16°C-acclimated goldsinny wrasse (Ctenolabrus rupestris) were exposed to an immersion treatment consisting of 10 s immersions in an 8°C (cold), 16°C (control) or 24°C (warm) water bath, repeated five times daily for five days. These brief immersions allowed for changes to skin temperature but not deeper tissues. Following these treatments, we measured the critical thermal maximum (CT_max) of all fish and the standard metabolic rate (SMR) in cod. Neither the immersions nor transfusions affected fish CT_max. However, the SMR was elevated in cod receiving plasma from cold-acclimated donors, suggesting that circulating molecules transferred from donors had initiated metabolic compensation in recipients. Thyroid hormone plasma levels were not different amongst acclimated donors and thus appear not to have been involved in the metabolic compensation. Our experiments found no evidence that brief, repeated cutaneous exposures to temperature changes can trigger acclimation, but do demonstrate a potential role of haematological endocrine control in metabolic acclimation, although further experiments will be required to investigate this process.

Artificial light at night (ALAN) is an emergent yet already global form of sensory pollution. However, its effects on marine environments remain poorly understood compared to those on terrestrial ecosystems. Low-latitude ecosystems such as shallow coral reefs might be at greater risk as they experience little change in annual day length and reef organisms rely on moonlight illumination as a zeitgeber for critical biological processes. Moreover, many coral reef fish are demersal spawners, making them vulnerable to the effects of ALAN from early life. We performed a field experiment to determine whether artificial light affects the quality of fish embryos and newly hatched larvae by exposing wild nests of the orange-fin anemonefish (Amphiprion chrysopterus) to white light emitting diode (LED) light (22 ± 2.0 lx; 4000 K) throughout the 6-day embryonic development period. We also explored whether light pollution indirectly influences offspring traits by measuring parental care investment. Exposure to ALAN altered embryo quality, leading to a reduction in egg volume (2.40%) and yolk reserves (6.11%) alongside an increase in heart rate (7.42%) a few hours before hatching. These changes reflect higher metabolic demands of embryos developing under light-polluted conditions. As parental care investment was unaffected by light pollution, our results suggest that these effects are more likely the consequence of a direct effect of ALAN on embryogenesis. In contrast, there was no influence of artificial light on the larval morphology or swimming performance, suggesting that the direct effects of ALAN on fish embryos do not cascade onto the larval stage immediately after hatching. These results may suggest that embryos compensated for ALAN exposure to maintain their early post-hatching larval performance. Further studies are needed to investigate whether light pollution exposure during embryonic development has delayed effects on larval performance during the dispersal phase or on larval survival.