Conservation Physiology最新文献

The presence of chemical contaminants in freshwater systems poses a threat to many aquatic organisms, and understanding the extent and nature of this threat can facilitate conservation management actions. Sturgeon are considered threatened worldwide and they differ in many important ways from other fishes. Two sturgeon species, green sturgeon (Acipenser medirostris) and white sturgeon (A. transmontanus), are found in California and utilize anthropogenically impacted freshwater habitats of the Central Valley. This study evaluated the behavioural effects in endogenously feeding larvae (3-7 days post hatch) of both sturgeon species following an acute exposure (96 hours) to the pyrethroid pesticide bifenthrin at aqueous concentrations ranging from 10 to 2000 ng/l, with selected levels based on previous environmental monitoring. Sturgeon had high survival at all concentrations tested (~95%), yet at higher concentrations (>1000 ng/l) they displayed altered behavioural patterns, including reduced activity, increased meander of the movement path and reduced thigmotaxis. While these higher concentrations of bifenthrin have been observed within water samples from the sturgeon habitats of California, they appear uncommon. The present study suggests that sturgeon larvae are not highly sensitive to acute aqueous exposure under environmentally relevant concentrations of bifenthrin (1-10 ng/l), yet these aqueous concentrations do have behavioural effects that may be of concern for the conservation of these declining species. Additionally, impacts to these species may also occur through exposure to sediment-bound bifenthrin or dietary bioaccumulation, and more work needs to be done to understand the implications of these exposure routes.

The northern bobwhite (Colinus virginianus) is an economically and ecologically vital gamebird in North America experiencing vast population declines. With the recent validation of an enzyme immunoassay to detect corticosterone metabolites in faeces, there are many opportunities for its scientific application. Corticosterone, a key avian stress-related hormone, has many beneficial functions that support a quail's immune response, primarily by suppressing inflammation, allowing cells to function more efficiently. However, chronic levels of elevated corticosterone in Aves have been shown to cause metabolic disruption and suppressed reproduction and growth. Determining root causes of chronically elevated corticosterone levels is vital for bobwhite conservation efforts. Proposed research investigating causes of bobwhite stress includes examining the effects of pesticides, climate, disease and management strategies. However, the various methodologies exploring these relationships may result in different ways the faeces are stored and processed, especially in studies on wild bobwhite. These differences may impact research outcomes leading to incorrect conclusions. This study was conducted to determine if enzyme immunoassay results from faecal samples frozen or left in the environment before extraction of faecal corticosterone metabolites differ from those where extraction is immediate. Faeces treatments affected the corticosterone metabolite measurements differently depending on whether the faeces were from males or females, so the effects of treatments were analysed within each sex. No significant difference was found in female faecal corticosterone metabolite concentrations between the frozen and environmentally exposed faeces (P = 0.853); however, concentrations in the immediately extracted faecal corticosterone metabolites were significantly lower (P < 0.001). Male bobwhite faecal samples that were immediately frozen had significantly lower faecal corticosterone metabolite concentrations compared to environmentally exposed male samples and frozen female samples (P = 0.039). These results indicate that faecal corticosterone metabolite concentrations are comparable between environmentally exposed samples from both sexes and frozen samples from females.

Wildlife health assessments including haematology and biochemistry parameters are essential to evaluating the well-being of free-living species. In Galapagos, the iconic giant tortoises still thrive in the archipelago despite anthropogenic pressures, with up to 13 extant species distributed across most islands and ecosystems. In previous work conducted by our research group, we described for the first-time reference intervals of haematology and plasma biochemistry in four Galapagos tortoise species. With the aim of continuing to provide cutting-edge health data for Galapagos tortoises, here we report haematology and plasma biochemistry descriptive statistics, reference intervals and cell morphology of tortoises from four different tortoise populations (i.e. Alcedo Volcano, Cerro Azul Volcano, Cinco Cerros and Sierra Negra Volcano). Additionally, we compared values between sexes and applied a principal component analysis to explore differences in haematology and biochemistry parameters between tortoise populations, including those previously published by our research group. Females presented higher calcium, phosphorus and albumin, consistent with vitellogenesis, whereas males had higher packed cell volume and sodium than females. Blood cell morphology was consistent across species. The two main principal components of the multivariate statistical model were unable to explain >44.9% of the variance across tortoise populations. We suggest additional research to explore the correlation between anthropogenic factors (i.e. climate change, pesticides, plastics) and blood values, for a deeper understanding of tortoise physiology and ultimately improved diagnostics and management actions. In the anthropogenic era, understanding the health status of bioindicator species like Galapagos tortoises is mandatory to inform current and future conservation priorities and actions.

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.