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- OPEN ACCESSRanaviruses are large nucleocytoplasmic DNA viruses that infect ectothermic vertebrates. Here we report the results of a scientometric analysis of the field of ranavirology for the last 10 years. Using bibliometric tools we analyse trends, identify top publications and journals, and visualise the ranavirus collaboration landscape. The Web of Science core collection contains 545 ranavirus-related publications from 2010 to 2019, with more publications produced every year and a total of 6830 citations. Research output is primarily driven by the United States and People’s Republic of China, who together account for more than 60% of ranavirus publications. We also observed a positive correlation between the average number of co-authors on ranavirus publications and the year of publication, indicating that overall collaboration is increasing. A keyword analysis of ranavirus publications from 2010 to 2019 reveals several areas of research interest including; ecology, immunology, virology/molecular biology, genetics, ichthyology, and herpetology. While ranavirus research is conducted globally, relatively few publications have co-authors from both European and Asian countries, possibly because closer countries (geographical distance) are more likely to share co-authors. To this end, efforts should be made to foster collaborations across geopolitical and cultural boundaries, especially between countries with shared research interests as ultimately, understanding global pathogens, like ranaviruses, will require global collaboration.
- OPEN ACCESSMercury mass balance models (MMBMs) for fish are powerful tools for understanding factors affecting growth and food consumption by free-ranging fish in rivers, lakes, and oceans. Moreover, MMBMs can be used to predict the consequences of global mercury reductions, overfishing, and climate change on mercury (Hg) concentration in commercially and recreationally valuable species of fish. Such predictions are useful in decision-making by resource managers and public health policy makers, because mercury is a neurotoxin and the primary route of exposure of mercury to humans is via consumption of fish. Recent evidence has emerged to indicate that the current-day version of MMBMs overestimates the rate at which fish eliminate mercury from their bodies. Consequently, MMBMs overestimate food consumption by fish and underestimate Hg concentration in fish. In this perspective, we explore underlying reasons for this overestimation of Hg-elimination rate, as well as consequences and implications of this overestimation. We highlight emerging studies that distinguish species and sex as contributing factors, in addition to body weight and water temperature, that can play an important role in how quickly Hg is eliminated from fish. Future research directions for refining MMBMs are discussed.
- OPEN ACCESSOpen access (OA) allows for peer-reviewed research to be freely accessed and there has been a collective shift from both researchers and publishers towards more OA publishing. OA typically occurs either through article-processing charges (the gold road) or via self-archiving (the green road); the former can be expensive, while the latter has seen minimal uptake. The gold road of OA has led to predatory publishers and, to some, questionable publications. Here, I used publicly available grant information in Canada and combined this with individual publishing statistics to test a variety of factors and their influence on OA publishing. I showed that an individual’s award amount, H-index, and gender did not influence the proportion of OA articles they published, but an individual’s H-index scaled with the number of OA publications. Institute size influenced OA publishing patterns, with researchers at large universities (i.e., >20 000 full-time students) publishing proportionately more OA articles than medium and small institutes. I discuss the potential for this pattern to build on pre-existing systemic biases when it comes to funding and publishing.
- OPEN ACCESS
- Preeyanan Sriwanayos,
- Kuttichantran Subramaniam,
- Natalie K. Stilwell,
- Kamonchai Imnoi,
- Vsevolod L. Popov,
- Somkiat Kanchanakhan,
- Jaree Polchana, and
- Thomas B. Waltzek
Ranaviruses are emerging pathogens associated with worldwide epizootics in farmed and wild ectothermic vertebrates. In this study, we determined the full genomes of eight ranaviruses isolated from marbled sleeper goby (Oxyeleotris marmorata), goldfish (Carassius auratus), guppy (Poecilia reticulata), tiger frog (Hoplobatrachus tigerinus), Asian grass frog (Fejervarya limnocharis), and East Asian bullfrog (H. rugulosus) cultured or imported into Thailand. These ranaviral isolates induced the same cytopathic effects (i.e., progression of coalescing round plaques) in epithelioma papulosum cyprini (EPC) cell cultures. Transmission electron microscopy of infected EPC cells revealed cytoplasmic viral particles with ultrastructural features typical for ranaviruses. Pairwise genetic comparisons of the complete major capsid protein coding sequences from the Thai ranaviruses displayed the highest identity (99.8%–100%) to a ranavirus (tiger frog virus; TFV) isolated from diseased tiger frogs cultured in China, a slightly lower identity (99.3%–99.4%) to a ranavirus (Wamena virus; WV) isolated from diseased green tree pythons (Morelia viridis) illegally exported from Papua New Guinea, and a lower identity to 35 other ranaviruses (93.7%–98.6%). Phylogenomic analyses supported the eight Thai ranaviruses, Chinese TFV, and WV as a subclade within a larger frog virus 3 clade. Our findings confirm the spread of TFV among cultured fish and amphibians in Asia and likely in reptiles in Oceania. Biosecurity measures are needed to ensure TFV does not continue to spread throughout Southeast Asia and to other parts of the world via international trade. - OPEN ACCESS
- OPEN ACCESS
- OPEN ACCESS
- Jannie F. Linnebjerg,
- Julia E. Baak,
- Tom Barry,
- Maria V. Gavrilo,
- Mark L. Mallory,
- Flemming R. Merkel,
- Courtney Price,
- Jakob Strand,
- Tony R. Walker, and
- Jennifer F. Provencher
Marine plastic is a ubiquitous environmental problem that can have an impact on a variety of marine biota, such as seabirds, making it an important concern for scientists and policy makers. Although research on plastic ingestion by seabirds is increasing, few studies have examined policies and long-term monitoring programs to reduce marine plastic in the Arctic. This paper provides a review of international, national, and regional policies and long-term monitoring programs that address marine plastic in relation to seabirds in the Arctic countries: Canada, the Kingdom of Denmark (Greenland and the Faroe Islands), Finland, Iceland, Norway, the Russian Federation, Sweden, and the United States of America. Results show that a broad range of international, national, regional and local policies address marine debris, specifically through waste management and the prevention of pollution from ships. However, few policies directly address seabirds and other marine biota. Further, policies are implemented inconsistently across regions, making it difficult to enforce and monitor the efficacy of these policies given the long-range transport of plastic pollution globally. To reduce marine plastic pollution in the Arctic environment, pan-Arctic and international collaboration is needed to implement standardized policies and long-term monitoring programs for marine plastic in the Arctic and worldwide. - OPEN ACCESS
- OPEN ACCESS
- Martin Krkošek,
- Madeline Jarvis-Cross,
- Kiran Wadhawan,
- Isha Berry,
- Jean-Paul R. Soucy,
- Korryn Bodner,
- Ariel Greiner,
- Leila Krichel,
- Stephanie Penk,
- Dylan Shea,
- Juan S. Vargas Soto,
- Ed W. Tekwa,
- Nicole Mideo, and
- Péter K. Molnár
This study empirically quantifies dynamics of SARS-CoV-2 establishment and early spread in Canada. We developed a transmission model that was simulation tested and fitted in a Bayesian framework to timeseries of new cases per day prior to physical distancing interventions. A hierarchical version was fitted to all provinces simultaneously to obtain average estimates for Canada. Across scenarios of a latent period of 2–4 d and an infectious period of 5–9 d, the R0 estimate for Canada ranges from a minimum of 3.0 (95% CI: 2.3–3.9) to a maximum of 5.3 (95% CI: 3.9–7.1). Among provinces, the estimated commencement of community transmission ranged from 3 d before to 50 d after the first reported case and from 2 to 25 d before the first reports of community transmission. Among parameter scenarios and provinces, the median reduction in transmission needed to obtain R0 < 1 ranged from 46% (95% CI: 43%–48%) to 89% (95% CI: 88%–90%). Our results indicate that local epidemics of SARS-CoV-2 in Canada entail high levels of stochasticity, contagiousness, and observation delay, which facilitates rapid undetected spread and requires comprehensive testing and contact tracing for its containment. - OPEN ACCESSThis research explores the potential hydroponic systems have for contributing to climate mitigation in fodder agriculture. Using British Columbia (BC) and Alberta as case studies, the study compares greenhouse gas (GHG) emissions and carbon sequestration potential of hydroponically grown sprouted barley fodder to conventional barley grain fodder. GHG emissions were examined through scenarios that assumed Alberta to be the main barley producer, while exploring different situations of BC and Alberta as consumers, distributed/centralized hydroponic systems, and renewable/nonrenewable energy. Carbon sequestration opportunities were examined through scenarios that explored the land sparing potential of transitioning from conventional to hydroponic barley and shifts from tillage to no-tillage practices. Sensitivity analyses were done to examine how changes in hydroponic seed-to-fodder output and energy consumption affect the systems’ climate mitigation potential. The results indicated that incorporating hydroponic systems into barley production has the potential to reduce GHG emissions, given seed-to-fodder output and energy consumption are maintained at certain levels and the systems are powered by renewable energy. Results also showed that hydroponic farming can provide greater carbon sequestration opportunities than simply shifting to no-tillage farming. The research indicates that hydroponic fodder farming could contribute to climate mitigation objectives if complemented with effective energy and land use policies.
- OPEN ACCESSRoad salt runoff is a leading cause of secondary freshwater salinization in north temperate climates. Increased chloride concentrations in freshwater can be toxic and lead to changes in organismal behavior, lethality, biotic homogenization, and altered food webs. High chloride concentrations have been reported for winter months in urban centers, as road density is highest in cities. However, summer chloride conditions are not typically studied as road salt is not actively applied outside of winter months, yet summer is when many taxa reproduce and are most sensitive to chloride. In our study, we test the spatial variability of summer chloride conditions across four watersheds in Toronto, Canada. We find 89% of 214 sampled sites exceeded the federal chronic exposure guidelines for chloride, and 13% exceeded the federal acute guidelines. Through a model linking concentration to cumulative proportion of impacted species, we estimate 34% of sites show in excess of one-quarter of all species may be impacted by their site-specific chloride concentrations, with up to two-thirds of species impacted at some sites. Our results suggest that even presumed low seasons for chloride show concentrations sufficient to cause significant negative impacts to aquatic communities.
- OPEN ACCESSBalancing human well-being with the maintenance of ecosystem services (ES) for future generations has become one of the central sustainability challenges of the 21st century. In working landscapes, past and ongoing production-centered objectives have resulted in the conversion of ecosystems into simple land-use types, which has also altered the provision of most ES. These inevitable trade-offs between the efficient production of individual provisioning ES and the maintenance of regulating and cultural ES call for the development of a land-use strategy based on the multifunctional use of the landscape. Due to the heterogeneous nature of working landscapes, both protection and restoration actions are needed to improve their multifunctionality. Systematic conservation planning (SCP) offers a decision support framework that can support landscape multifunctionality by indicating where ES management efforts should be implemented. We describe an approach that we developed to include ES provision protection and restoration objectives in SCP with the goal of providing ongoing benefits to society. We explain the general framework of this approach and discuss concepts, challenges, innovations, and prospects for the further development of a comprehensive decision support tool. We illustrate our approach with two case studies implemented in the pan-Canadian project ResNet.
- OPEN ACCESS
- Ashley L. Cooper,
- Cassandra Carter,
- Hana McLeod,
- Marie Wright,
- Prithika Sritharan,
- Sandeep Tamber,
- Alex Wong,
- Catherine D. Carrillo, and
- Burton W. Blais
Bacterial carbapenem resistance is a major public health concern since these antimicrobials are often the last resort to treat serious human infections. To evaluate methodologies for detection of carbapenem resistance, carbapenem-tolerant bacteria were isolated from wastewater treatment plants in Toronto, Ottawa, and Arnprior, Ontario. A total of 135 carbapenem-tolerant bacteria were recovered. Polymerase chain reaction (PCR) indicated the presence of carbapenem hydrolysing enzymes KPC (n = 10), GES (n = 5), VIM (n = 7), and IMP (n = 1), and β-lactamases TEM (n = 7), PER (n = 1), and OXA-variants (n = 16). A subset of 46 isolates were sequenced and analysed using ResFinder and CARD-RGI. Both programs detected carbapenem resistance genes in 35 sequenced isolates and antimicrobial resistance genes (ARGs) conferring resistance to multiple class of other antibiotics. Where β-lactamase resistance genes were not initially identified, lowering the thresholds for ARG detection enabled identification of closely related β-lactamases. However, no known carbapenem resistance genes were found in seven sequenced Pseudomonas spp. isolates. Also of note was a multi-drug-resistant Klebsiella pneumoniae isolate from Ottawa, which harboured resistance to seven antimicrobial classes including β-lactams. These results highlight the diversity of genes encoding carbapenem resistance in Ontario and the utility of whole genome sequencing over PCR for ARG detection where resistance may result from an assortment of genes. - OPEN ACCESS
- OPEN ACCESSSalt marshes are ecosystems of significant ecological importance for coastal stability and fundamental roles in marine ecosystems. Salt marshes are declining due to anthropogenic and natural causes including sea level rise. Coastal restoration efforts have increased worldwide, but many fail in long-term coastal stability. We used a naturally occurring arbuscular mycorrhizal fungus (AMF) to test whether survival and early growth of the salt marsh grass Sporobolus pumilus (formerly Spartina patens) improved under simulated salt marsh conditions. Using a tidal mesocosm bench, we grew inoculated plants with varying AMF treatments under simulated tidal regimes to determine if AMF could aid in establishment of healthy Sporobolus communities. Rhizome-derived S. pumilus had greater survival and grew faster than seed-derived plants. Plants inoculated with propagated AMF consistently outperformed both sterile and native sediment controls in terms of plant survival and growth. Use of rhizome-derived Sporobolus inoculated with propagated Funneliformis geosporum showed the most promise in producing successful plant populations for salt marsh restoration. This may be due to plant life stage and improved plant nutrient status, allowing rhizome-derived plants to grow more quickly than seed-derived plants. Using these plants in future large-scale restoration may increase re-establishment of salt marsh ecosystems.
- OPEN ACCESS
- Leonardo B. Custode,
- Matthew M. Guzzo,
- Natasha Bush,
- Claire Ewing,
- Michael Procko,
- Samantha M. Knight,
- Marie-Michele Rousseau-Clair, and
- D. Ryan Norris
Nongovernmental organizations contribute to the securement and management of protected areas, but it is not well known how their lands compare to government protected areas or the effectiveness of different land acquisition strategies. Using data from the International Union for Conservation of Nature and BirdLife International, we estimated total and at-risk terrestrial native vertebrate species richness in southern Canada among (i) private protected areas secured by the Nature Conservancy of Canada (NCC), government protected areas, and randomly sampled land; (ii) conservation agreements and fee simple (directly acquired) NCC properties; and (iii) purchased or donated fee simple properties. Controlling for property size and ecoregion, NCC protected areas were predicted to be in areas with 6% and 13% more total and at-risk species than randomly sampled land and 4% and 6% more total and at-risk species than government protected areas. Within NCC protected areas, conservation agreements were predicted to be in areas with 2% and 4% more total and at-risk species than fee simple properties, but purchased properties had similar numbers of total and at-risk species as donated properties. Although we caution that diversity estimates were based on course-grained range maps, our findings suggest that private protected areas are important in conserving biodiversity. - OPEN ACCESS
- Steven J. Cooke,
- Robert J. Lennox,
- Jacob W. Brownscombe,
- Sara J. Iverson,
- Frederick G. Whoriskey,
- Joshua J. Millspaugh,
- Nigel E. Hussey,
- Glenn T. Crossin,
- Brendan J. Godley, and
- Robert Harcourt
Monitoring animals with electronic tags is an increasingly important tool for fundamental and applied ecological research. Based on the size of the system under study, the ability to recapture the animal, and research medium (e.g., aerial, freshwater, saltwater, terrestrial), tags selected may either log data in memory (bio-logging), transmit it to a receiver or satellite (biotelemetry), or have a hybrid design. Over time, we perceive that user groups are diverging based on increasing use of technology specific terms, favouring either bio-logging or biotelemetry. It is crucial to ensure that a divide does not become entrenched in the community because it will likely hinder efforts to advance field and analytical methods and reduce accessibility of animal tracking with electronic tags to early-career and new researchers. We discuss the context for this emerging problem and the evidence that this is manifesting within the scientific community. Finally, we suggest how the animal tracking community may work to address this issue to maximize the benefits of information transfer and integration between users of the two technologies. - OPEN ACCESSLarge-scale monitoring is used to track population trends for many ecologically and economically important wildlife species. Often, population monitoring involves professional staff travelling to collect data (i.e., conventional monitoring) or in efforts to reduce monitoring costs, by engaging volunteers (i.e., community science). Although many studies have discussed the advantages and disadvantages of conventional vs. community science monitoring, few have made direct, quantitative comparisons between these two approaches. We compared data quality and financial costs between contemporaneous and overlapping conventional and community science programs for monitoring a major forest pest, the spruce budworm (Choristoneura fumiferanae Clem.). Although community science trapping sites were clumped around urban areas, abundance estimates from the programs were strongly spatially correlated. However, annual program expenditures were nearly four times lower in the community science versus the conventional program. We modelled a hypothetical hybrid model of the two programs, which provided full spatial coverage and potentially the same data, but at half the cost of the conventional program and with the added opportunity for public engagement. Our study provides a unique quantitative analysis of merits and costs of conventional versus community science monitoring. Our study offers insights on how to assess wildlife monitoring programs where multiple approaches exist.
- OPEN ACCESS
- Yannan Huang,
- Lindsay Johnston,
- Ana Parra,
- Crystal Sweeney,
- Emalie Hayes,
- Lisbeth Truelstrup Hansen,
- Graham Gagnon,
- Amina Stoddart, and
- Rob Jamieson
Wastewater-based surveillance methods have been implemented in several countries as a tool for monitoring SARS-CoV-2 at a community scale. A variety of methods have been used for concentrating, extracting, and detecting the virus, with no clear consensus on the most effective approach. In this note, we report preliminary findings from a study that is tracking SARS-CoV-2 in wastewater in Halifax, Nova Scotia, with a specific focus on the use of four reverse transcriptase quantitative PCR (RT-qPCR) assays for detecting the virus in wastewater. We were able to detect the virus in wastewater samples during the initial rise of cases in the Halifax region in early November 2020. Levels of the targeted SARS-CoV-2 gene fragments increased and fell in response to reported cases of COVID-19. The CDC N1 and E RT-qPCR assays demonstrated greater relative sensitivity than the CDC N2 and N3 assays for detection of SARS-CoV-2 in raw sewage samples. - OPEN ACCESS
- Christoph M. Deeg,
- Albina N. Kanzeparova,
- Alexei A. Somov,
- Svetlana Esenkulova,
- Emiliano Di Cicco,
- Karia H. Kaukinen,
- Amy Tabata,
- Tobi J. Ming,
- Shaorong Li,
- Gideon Mordecai,
- Angela Schulze, and
- Kristina M. Miller
Salmon are keystone species across the North Pacific, supporting ecosystems, commercial opportunities, and cultural identity. Nevertheless, many wild salmon stocks have experienced significant declines. Salmon restoration efforts focus on fresh and coastal waters, but little is known about the open ocean environment. Here we use high throughput RT-qPCR tools to provide the first report on the health, condition, and infection profile of coho, chum, pink, and sockeye salmon in the Gulf of Alaska during the 2019 winter. We found lower infectious agent number, diversity, and burden compared with coastal British Columbia in all species except coho, which exhibited elevated stock-specific infection profiles. We identified Loma sp. and Ichthyophonus hoferi as key pathogens, suggesting transmission in the open ocean. Reduced prey availability, potentially linked to change in ocean conditions due to an El Niño event, correlated with energetic deficits and immunosuppression in salmon. Immunosuppressed individuals showed higher relative infection burden and higher prevalence of opportunistic pathogens. We highlight the cumulative effects of infection and environmental stressors on overwintering salmon, establishing a baseline to document the impacts of a changing ocean on salmon. - OPEN ACCESS
- Greniqueca Mitchell,
- Paul J. Wilson,
- Micheline Manseau,
- Bridget Redquest,
- Brent R. Patterson, and
- Linda Y. Rutledge
Woodland caribou (Rangifer tarandus caribou) are threatened in Canada because of the drastic decline in population size caused primarily by human-induced landscape changes that decrease habitat and increase predation risk. Conservation efforts have largely focused on reducing predators and protecting critical habitat, whereas research on dietary niches and the role of potential food constraints in lichen-poor environments is limited. To improve our understanding of dietary niche variability, we used a next-generation sequencing approach with metabarcoding of DNA extracted from faecal pellets of woodland caribou located on Lake Superior in lichen-rich (mainland) and lichen-poor (island) environments. Amplicon sequencing of fungal ITS2 region revealed lichen-associated fungi as predominant in samples from both populations, but amplification at the chloroplast trnL region, which was only successful on island samples, revealed primary consumption of yew (Taxus spp.) based on relative read abundance (83.68%) with dogwood (Cornus spp.; 9.67%) and maple (Acer spp.; 4.10%) also prevalent. These results suggest that conservation efforts for caribou need to consider the availability of food resources beyond lichen to ensure successful outcomes. More broadly, we provide a reliable methodology for assessing ungulate diet from archived faecal pellets that could reveal important dietary shifts over time in response to climate change. - OPEN ACCESSThe performance of graduate students in research varies greatly across countries due to various factors, mainly socioeconomic and linguistic. The current situation is critical because the wealthiest countries are also the most linguistically equipped to navigate the English-dominant landscape of academia. Here, we assess the language of citations and the publishing performance of graduate students from three French-speaking countries: Algeria, Canada, and France, where Algeria is the least English proficient and the most economically disadvantaged. We found that the bibliography of PhD theses were English dominated in all regions (72.5% in Algeria compared with >93.1% in Western countries), whereas those of Masters theses were French dominated in Algeria (63.3%), relatively bilingual in France (47.6% French), but English dominated in Canada-Québec (94.7%) and Canada-BC (98.7%). Algerian PhD students produced fewer papers, were less likely to publish in journals with calculated impact factors, and received fewer citations than students who graduated from universities in France or in two Canadian provinces, British Columbia and Québec. Our results suggest that the economic and linguistic disadvantages faced by graduate students from non-Western backgrounds affect their academic performance, highlighting important issues in facing future global challenges.
- OPEN ACCESSFor cities to grow their urban forest canopy the formula appears rather straightforward: the right trees, plus the right conditions, plus the right care equals success. These simplified “tree chain of custody” steps, however, represent activities within a complex value-chain in Canada. Given that there is heightened demand for urban tree planting as natural climate solutions become the norm, how can we prepare the value-chain to meet these demands? To answer this question, we outline the pathways by which trees presently go from nurseries into urban and peri-urban areas. Delineating the actors, roles, and present barriers to success exposes the complexity of the process and relationships in the value-chain, as there are distinct phases with multiple actor groups involved who influence, and are influenced, by one another. We explore the issues that pose prominent challenges to, as well as opportunities for, the value-chain. Emergent themes include communication, forecasting demand and timing, underpricing and undervaluing tree establishment, lack of awareness on the importance of soils, juvenile tree health, species selection, and gaps in evidence-based decision support tools. The touchstones of science and innovation, collaboration, and knowledge mobilization are pertinent for the value-chain in Canada to draw upon to navigate the future.
- OPEN ACCESSPost-transcriptional regulators such as microRNAs are emerging as conserved regulators of innate antiviral immunity in vertebrates, yet their roles in amphibian antiviral responses remain uncharacterized. We profiled changes in microRNA expressions in the Xenopus laevis skin epithelial-like cell line Xela DS2 in response to poly(I:C)—an analogue of viral double-stranded RNA and inducer of type I interferons—or frog virus 3 (FV3), an immunoevasive virus associated with amphibian mortality events. Small RNA libraries generated from untreated, poly(I:C)-treated, and FV3-infected cells were sequenced. We detected 136 known X. laevis microRNAs and discovered 133 novel X. laevis microRNAs. Sixty-five microRNAs were differentially expressed in response to poly(I:C), many of which were predicted to target regulators of antiviral pathways such as cGAS-STING, RIG-I/MDA-5, TLR signaling, and type I interferon signaling, as well as products of these pathways (NF-ĸB-induced and interferon-stimulated genes). In contrast, only 49 microRNAs were altered by FV3 infection, fewer of which were predicted to interact with antiviral pathways. Interestingly, poly(I:C) treatment or FV3 infection downregulated transcripts encoding factors of the host microRNA biogenesis pathway. Our study is the first to suggest that host microRNAs regulate innate antiviral immunity in frogs and sheds light on microRNA-mediated mechanisms of immunoevasion by FV3.
- OPEN ACCESSForested vernal pools serve an integral role in the recruitment of amphibians in glaciated northeastern North America. In south-central Ontario, vernal pools exist in relatively unimpacted forest networks, but the amphibian communities face uncertain challenges from anthropogenic-induced climate change. We surveyed amphibian larvae and collected measurements of habitat characteristics from vernal pools to collect baseline information on amphibian community structure and species–habitat relationships. Amphibian communities were influenced by hydroperiod length and canopy openness, and the relative abundances of early breeding amphibians were affected by changes in the structure of vegetation communities within pools. Our study suggests that, even across moderate ranges of breeding habitat characteristics, the structure of amphibian communities is dynamic. With anthropogenic-induced climate change leading to more drought-prone summers, the conservation of intact forests that support diverse wetland assemblages will be a necessary component of future legislation.
- OPEN ACCESSScientists, like all humans, are subject to self-deceptive valuations of their importance and profile. Vainglorious practice is annoying but mostly harmless when restricted to an individual’s perception of self-worth. Language that can be associated with self-promotion and aggrandizement is destructive when incorporated into scientific writing. So too is any practice that oversells the novelty of research or fails to provide sufficient scholarship on the uniqueness of results. We evaluated whether such tendencies have been increasing over time by assessing the frequencies of articles claiming to be “the first”, and those that placed the requirement for scholarship on readers by using phrases such as “to the best of our knowledge”. Our survey of titles and abstracts of 176 journals in ecology and environmental biology revealed that the frequencies of both practices increased linearly over the past half century. We thus warn readers, journal editors, and granting agencies to use caution when assessing the claimed novelty of research contributions. A system-wide reform toward more cooperative science that values humility, and abhors hubris, might help to rectify the problem.
- OPEN ACCESS
- Arthur L. Bass,
- Andrew W. Bateman,
- Brendan M. Connors,
- Benjamin A. Staton,
- Eric B. Rondeau,
- Gideon J. Mordecai,
- Amy K. Teffer,
- Karia H. Kaukinen,
- Shaorong Li,
- Amy M. Tabata,
- David A. Patterson,
- Scott G. Hinch, and
- Kristina M. Miller
Recent decades have seen an increased appreciation for the role infectious diseases can play in mass mortality events across a diversity of marine taxa. At the same time many Pacific salmon populations have declined in abundance as a result of reduced marine survival. However, few studies have explicitly considered the potential role pathogens could play in these declines. Using a multi-year dataset spanning 59 pathogen taxa in Chinook and Coho salmon sampled along the British Columbia coast, we carried out an exploratory analysis to quantify evidence for associations between pathogen prevalence and cohort survival and between pathogen load and body condition. While a variety of pathogens had moderate to strong negative correlations with body condition or survival for one host species in one season, we found that Tenacibaculum maritimum and Piscine orthoreovirus had consistently negative associations with body condition in both host species and seasons and were negatively associated with survival for Chinook salmon collected in the fall and winter. Our analyses, which offer the most comprehensive examination of associations between pathogen prevalence and Pacific salmon survival to date, suggest that pathogens in Pacific salmon warrant further attention, especially those whose distribution and abundance may be influenced by anthropogenic stressors. - OPEN ACCESS
- Shawn R. Craik,
- Rodger D. Titman,
- Anna M. Calvert,
- Gregory J. Robertson,
- Mark L. Mallory, and
- Sarah E. Gutowsky
The addition of eggs to a nest by a conspecific is known for approximately 250 bird species. Understanding the evolution of conspecific brood parasitism (CBP) requires assessment of fitness consequences to the egg recipient (host). We addressed host traits and the effects of CBP on future reproduction (i.e., annual survival) and hatching success of hosts by following the nesting of 206 red-breasted mergansers (Mergus serrator) for a colony in which an average of 41% of nests was parasitized annually. Each host was tracked for ≥2 seasons and up to seven seasons. The proportion of a host’s nesting attempts that was parasitized averaged 43% and varied considerably across individuals (range 0%–100%). Probability of parasitism, however, was not repeatable across a host’s nests. Rather, rates of CBP throughout a host’s lifetime increased with earlier dates of nest initiation. CBP had no effect on annual survival of a host. Hatching success throughout a host’s lifetime declined with a greater number of foreign eggs added to the individual’s nests. This study revealed that there may be measurable costs of CBP to lifetime reproductive success in red-breasted mergansers, although our observations suggest that costs to hosts are limited to the most heavily parasitized clutches. - OPEN ACCESSCyanobacterial blooms and their toxigenic potential threaten freshwater resources worldwide. In Atlantic Canada, despite an increase of cyanobacterial blooms in the last decade, little is known about the toxigenic potential and the taxonomic affiliation of bloom-forming cyanobacteria. In this study, we employed polymerase chain reaction (PCR) and metagenomic approaches to assess the potential for cyanotoxin and other bioactive metabolite production in Harvey Lake (oligotrophic) and Washademoak Lake (mesotrophic) in New Brunswick, Canada, during summer and early fall months. The PCR survey detected the potential for microcystin (hepatotoxin) and anatoxin-a (neurotoxin) production in both lakes, despite a cyanobacterial bloom only being visible in Washademoak. Genus-specific PCR associated microcystin production potential with the presence of Microcystis in both lakes. The metagenomic strategy provided insight into temporal variations in the microbial communities of both lakes. It also permitted the recovery of a near-complete Microcystis aeruginosa genome with the genetic complement to produce microcystin and other bioactive metabolites such as piricyclamide, micropeptin/cyanopeptolin, and aeruginosin. Our approaches demonstrate the potential for production of a diverse complement of bioactive compounds and establish important baseline data for future studies of understudied lakes, which are frequently affected by cyanobacterial blooms.
- OPEN ACCESSOvergrazing of habitat-forming kelps by sea urchins is reshaping reef seascapes in many temperate regions. Loss of kelp, in particular as a food source, may alter individual consumer physiology, which in turn may impair their ability to respond to climate warming. Here, we measured the temperature dependence of absolute and mass-independent oxygen consumption (M˙O2) using two different exposure protocols (acute exposure and temperature “ramping”), as proxies of realized physiology, between green sea urchin (Strongylocentrotus droebachiensis) populations from neighbouring barren and kelp habitats. Sea urchins from kelp habitats consumed 8%–78% more oxygen than sea urchins from barrens (across the range of temperatures tested (4–32 °C)) and had higher maximum M˙O2 values (by 26%). This was in part because kelp urchins typically had greater body masses. However, higher mass-independent M˙O2 values of kelp urchins suggest metabolic plasticity in response to habitat per se. In addition, the M˙O2 of sea urchins from kelp habitats was less sensitive to increases in temperature. We conclude that sea urchins from barren and kelp habitats of comparable body mass represent different energetic units. This highlights that habitat type can drive population-level variation that may shape urchins activities and environmental impact. Such variation should be integrated into energy-based models.
- OPEN ACCESSCumulative human impact analysis is a promising management tool to estimate the impacts of stressors on ecosystems caused by multiple human activities. However, connecting cumulative impact scores to actual ecosystem change at appropriate spatial scales remains challenging. Here, we calculated cumulative effects (CE) scores for 187 seagrass beds in Atlantic Canada that accounts for both bay-scale and local-scale anthropogenic activities. We then developed a CE threshold to evaluate where degradation of seagrass beds from multiple human activities is more likely. Overall, the CE score was the best predictor of human impacts for seagrass beds. Locations with high watershed land alteration and nitrogen loading had the highest CE scores; however, we also identified seagrass beds with high CE scores in regions characterized by generally low levels of human activities. Forty-nine seagrass beds exceeded the CE threshold and, of these, 86% had CE scores that were influenced by three or more stressors that cumulatively amounted to a large score. This CE threshold approach can provide a simplified metric to identify areas where management of cumulative effects should be prioritized and further highlights the need to consider multiple human activities when assessing anthropogenic impacts to coastal habitats.
- OPEN ACCESSThe CLOCK gene is a core component of the circadian clock and regulates various aspects of metabolism. Therefore, any variation that affects the function/expression of the CLOCK gene may contribute to the manifestation of metabolic disorders such as obesity. This study investigated whether the CLOCK variants rs4864548 and rs6843722 are associated with obesity and related traits in Pakistanis. A total of 306 overweight/obese cases and 306 age- and gender-matched control subjects were recruited (males 336 and females 276, age range 12–63 years). Anthropometric and metabolic parameters were taken by standard procedures and biochemical analyses, respectively. Behavior-related information was collected with a questionnaire. The genotypes of the variants were determined by allelic discrimination Taqman assays. Both variants were found to have a significant association with overweight/obesity according to the over-dominant model. The rs4864548 and rs6843722 were observed to escalate the risk of overweight/obesity by 1.611 (p = 0.004) and 1.657 (p = 0.002) times, respectively. These variants were also seen to be significantly associated with various other adiposity-related anthropometric parameters (p < 0.05). However, no association of both variants with metabolic and behavioral parameters was observed (p > 0.05). Thus, these variants may contribute to increasing the risk of overweight/obesity and related anthropometric traits in Pakistanis.
- OPEN ACCESS
SARS-CoV-2 detection from the built environment and wastewater and its use for hospital surveillance
- Aaron Hinz,
- Lydia Xing,
- Evgueni Doukhanine,
- Laura A. Hug,
- Rees Kassen,
- Banu Ormeci,
- Richard J. Kibbee,
- Alex Wong,
- Derek MacFadden, and
- Caroline Nott
Patients hospitalized with SARS-CoV-2 infections are major contributors to morbidity and mortality in health care settings. Our understanding of the distribution of this virus in the built health care environment and wastewater, and relationship to disease burden, is limited. We performed a prospective multi-center study of environmental sampling of SARS-CoV-2 from hospital surfaces and wastewater and evaluated their relationships with regional and hospital COVID-19 burden. We validated a qPCR-based approach to surface sampling and collected swab samples weekly from different locations and surfaces across two tertiary care hospital campuses for a 10-week period during the pandemic, along with wastewater samples. Over the 10-week period, 963 swab samples were collected and analyzed. We found 61 (6%) swabs positive for SARS-CoV-2, with the majority of these (n = 51) originating from floor samples. Wards that actively managed patients with COVID-19 had the highest frequency of positive samples. Detection frequency in built environment swabs was significantly associated with active cases in the hospital throughout the study. Wastewater viral signal changes appeared to predate change in case burden. Our results indicate that environment sampling for SARS-CoV-2, in particular from floors, may offer a unique and resolved approach to surveillance of COVID-19. - OPEN ACCESSCryptococcus neoformans is a globally important fungal pathogen, primarily inflicting disease on immunocompromised individuals. The widespread use of antifungal agents in medicine and agriculture supports the development of antifungal resistance through evolution, and the emergence of new strains with intrinsic resistance drives the need for new therapeutics. For C. neoformans, the production of virulence factors, including extracellular peptidases (e.g., CnMpr-1 and May1) with mechanistic roles in tissue invasion and fungal survival, constitute approximately 2% of the fungal proteome and cover five classes of enzymes. Given their role in fungal virulence, peptidases represent promising targets for anti-virulence discovery in the development of new approaches against C. neoformans. Additionally, intracellular peptidases, which are involved in resistance mechanisms against current treatment options (e.g., azole drugs), as well as capsule biosynthesis and elaboration of virulence factors, present additional opportunities to combat the pathogen. In this review, we highlight key cryptococcal peptidases with defined or predicted roles in fungal virulence and assess sequence alignments against their human homologs. With this information, we define the feasibility of the select peptidases as “druggable” targets for inhibition, representing prospective therapeutic options against the deadly fungus.
- OPEN ACCESSCoastal salt marshes provide many ecosystem services; however, little is known of the biology of decomposer taxa in these systems. This study employed aboveground and belowground litterbags to characterize the fungal and mite communities associated with the dominant salt marsh grass, Sporobolus pumilus, in the Minas Basin, Nova Scotia. Decomposition rates of aboveground and belowground tissues and environmental variables were quantified to contextualize temporal patterns in community composition. Aboveground litterbag mass loss peaked in July and decreased consistently over succeeding months, which positively correlated with fungal richness. Fungal and mite richness displayed inverse relationships over time, with mites gradually increasing in diversity before peaking in November, suggesting the presence of a complex detrital network where mites and fungi respond to different and possibly unrelated environmental cues. This study offers a first look at temporal community dynamics of two neglected groups of decomposers associated with S. pumilus in Canada.
- OPEN ACCESS
- Anna Bazzicalupo,
- Susana C. Gonçalves,
- Rémi Hébert,
- Sigrid Jakob,
- Alfredo Justo,
- Gavin Kernaghan,
- Renée Lebeuf,
- Bruce Malloch,
- R. Greg Thorn, and
- Allison K. Walker
Despite the ecological importance of fungi, we still know little about their diversity in Canada. One of the largest hurdles to implementing fungal conservation initiatives is the lack of fungal distribution data. As anthropogenic impacts accelerate the speed of environmental change, it is imperative that we fill this major information gap, critical for fungal protection. To gain insight on the conservation status of Canadian macrofungi, we took advantage of the large and growing body of fungal biodiversity data from government research (Wild Species 2020), citizen science, trained independent mycologists, university, and museum biodiversity research. The majority of macrofungi are data deficient; we do not know their geographic distribution or habitat requirements, occurrence, or abundance in Canada. For mushrooms that fruit only a few days of the year and are often difficult to positively identify, there is a lot of work to overcome the uncertainty of distinguishing under-sampling from rarity. Our work stresses the importance of building a strong network of professional and amateur mycologists to develop resources, disseminate information to make educated decisions, and advance conservation actions. We found that several fungi can be prioritized; we present a short list for consideration for formal conservation assessment. - OPEN ACCESSThe lake whitefish (Coregonus clupeaformis) is a commercially valuable freshwater species with a broad distribution in North America. Some phylogeographic work has been done on this species, but little is known about genetic population subdivision among populations of the widely dispersed Mississippian lineage. We used 3,173 single nucleotide polymorphisms in 508 lake whitefish from 22 different lakes to examine population structure across central Canada and the United States. Bayesian clustering, ordination, and fixation indices identified population subdivision that largely reflected geographic distance and hydrological connectivity, with greater differentiation between lakes that are farther apart. Population subdivision was hierarchical, with greater differentiation between Canadian provinces and less differentiation based on river basins within provincial boundaries. Interestingly, isolation by distance alone was not sufficient to account for all of the observed genetic differentiation among populations. We conclude that important components of lake whitefish genetic diversity are present at different spatial scales, and that populations within the Mississippian lineage have differentiated widely across their range.
- OPEN ACCESS
- Isadora Louise Alves da Costa Ribeiro Quintans,
- Juliana Alves da Costa Ribeiro Souza, and
- Michael K Deyholos
Fusarium oxysporum f. sp. lini and Septoria linicola are causes of fusarium wilt and pasmo in flax (Linum usitatissimum). Members of a third fungal genus, Alternaria spp., have also been found in fiber and linseed varieties of flax, and are a source of post-harvest spoilage and mycotoxins in a wide range of crops. We performed a microdilution assay and calculated the median effective concentration (EC50) to compare the potency of cyclolinopeptides (CLPs), two polyamines (spermidine and spermine), and the fungicide carbendazimin in the control of three fungi that have potential pathogenic activity (F. oxysporum, S. linicola, and Alternaria spp), of which the first two are particulary significant causes of disease in flax. For carbendazim, all EC50 values were <0.6 μg/mL. The observed EC50 ranged from 111 to 340 μg/mL for a mixture of six unique CLPs, 109 to 778 μg/mL for spermine, and 21 to 272 μg/mL for spermidine. Spermidine was most effective against Alternaria sp., with an EC50 of 21 μg/mL. The results presented here showed that polyamines and CLPs possess limited antifungal activities against several fungi, with spermidines the most effective naturally occurring compound tested. Our findings do not support the hypothesis that CLPs act as potent antifungals against the three species of pathogens tested. - OPEN ACCESSMismatches between institutions and social–ecological systems (SESs) are one of the foremost challenges in natural resource management. However, while mismatches are often cited in the literature as a major challenge, empirical evidence of mismatches and their consequences is limited. This is particularly true for complex SESs, such as on the Pacific Coast of North America, where salmon drive interactions across multiple environments, jurisdictions, and scales. Here, I use the theoretical concept of fit to examine institutional alignment in a large-scale Pacific salmon SES, the Skeena River watershed in British Columbia, Canada. Utilizing Canadian federal environmental assessments as a proxy for colonial environmental governance institutions, I describe the common causes and consequences of mismatches between institutions and salmon SESs. This case study suggests that mismatches are threatening salmon sustainability and negatively affecting Indigenous People’s rights, livelihoods, and approaches to resource management and stewardship. I argue that improving social–ecological fit in salmon SESs will require new or revitalized forms of environmental governance that consciously fit the underlying social–ecological dynamics. While these findings are based on the Skeena River watershed, they may be generalizable to other salmon SESs in which mismatches between social and ecological processes and institutions exist.
- OPEN ACCESS
- Jessica Currie,
- Joseph B. Burant,
- Valentina Marconi,
- Stephanie A. Blain,
- Sandra Emry,
- Katherine Hébert,
- Garland Xie,
- Nikki A. Moore,
- Xueqi Wang,
- Andrea Brown,
- Lara Grevstad,
- Louise McRae,
- Stefano Mezzini,
- Patrick Pata, and
- Robin Freeman
To effectively combat the biodiversity crisis, we need ambitious targets and reliable indicators to accurately track trends and measure conservation impact. In Canada, the Living Planet Index (LPI) has been adapted to produce a national indicator by both World Wildlife Fund-Canada (Canadian Living Planet Index; C-LPI) and Environment and Climate Change Canada (Canadian Species Index) to provide insight into the status of Canadian wildlife, by evaluating temporal trends in vertebrate population abundance. The indicator includes data for just over 50% of Canadian vertebrate species. To assess whether the current dataset is representative of the distribution of life history characteristics of Canadian wildlife, we analyzed the representation of species-specific biotic variables (i.e., body size, trophic level, lifespan) for vertebrates within the C-LPI compared to native vertebrates lacking LPI data. Generally, there was considerable overlap in the distribution of biotic variables for species in the C-LPI compared to native Canadian vertebrate species lacking LPI data. Nevertheless, some differences among distributions were found, driven in large part by discrepancy in the representation of fishes—where the C-LPI included larger-bodied and longer-lived species. We provide recommendations for targeted data collection and additional analyses to further strengthen the applicability, accuracy, and representativity of biodiversity indicators. - OPEN ACCESS
- Jessica Garzke,
- Ian Forster,
- Sean C. Godwin,
- Brett T. Johnson,
- Martin Krkošek,
- Natalie Mahara,
- Evgeny A. Pakhomov,
- Luke A. Rogers, and
- Brian P.V. Hunt
Migrating marine taxa encounter diverse habitats that differ environmentally and in foraging conditions over a range of spatial scales. We examined body (RNA/DNA, length-weight residuals) and nutritional (fatty acid composition) condition of juvenile sockeye salmon (Oncorhynchus nerka) in British Columbia, while migrating through oceanographically variable waters. Fish were sampled in the stratified northern Strait of Georgia (NSoG); the highly mixed Johnstone Strait (JS); and the transitional zone of Queen Charlotte Strait (QCS). In 2015, body and nutritional condition were high in the NSoG but rapidly declined to reach lowest levels in JS where prey availability was low, before showing signs of compensatory growth in QCS. In 2016, juvenile salmon had significantly lower condition in the NSoG than in 2015, although zooplankton biomass was similar, condition remained low in JS, and no compensatory growth was observed in QCS. We provide evidence that differences in juvenile salmon condition between the two years were due to changes in the food quality available to juvenile fish. We propose that existing hypotheses about fish survival need to be extended to incorporate food quality in addition to quantity to understand changes in fish condition and survival between years. - OPEN ACCESSTitles of scientific papers play a key role in their discovery, and “good” titles engage and recruit readers. Humour is a particularly interesting aspect of title construction, but little is known about whether funny titles boost or limit paper impact. We used a panel of scorers to assess title humour for 2439 papers in ecology and evolution, and measured associations between humour and subsequent citation (self-citation and citation by others). Papers with funnier titles were cited less, but this appears to reflect confounding with paper importance: self-citation data suggest that authors give funnier titles to papers they consider less important. After correction for this, papers with funny titles have significantly higher citation rates (P < 2.2 × 10−16; roughly doubling from lowest to highest humour score)—suggesting that humour recruits readers. We also examined associations between citation rates and other features of titles. Inclusion of acronyms and taxonomic names was associated with lower citation rates, while assertive-statement phrasing and presence of colons, question marks, and political regions were associated with somewhat higher citation rates. Title length had no effect on citation. Our results suggest that scientists can use creativity with titles without having their work condemned to obscurity.
- OPEN ACCESS
- Alexandra M. Anderson,
- Catherine B. Jardine,
- J.R. Zimmerling,
- Erin F. Baerwald, and
- Christina M. Davy
Understanding the relationship between the height of wind turbines and wildlife fatalities is important for informing and mitigating wildlife collisions as ever taller and denser arrays of wind turbines are erected across the landscape. We examined relationships between turbine height and fatalities of bats and swallows at 811 turbines in Ontario, Canada, ranging from 119 to 186 m tall. We accounted for cut-in speeds, operational mitigation, and taller turbines projecting carcasses farther from the turbine base than shorter turbines. Fatalities of hoary bats (Lasiurus cinereus Palisot de Beauvois, 1796), silver-haired bats (Lasionycteris noctivagans Le Conte, 1831), and big brown bats (Eptesicus fuscus Palisot de Beauvois, 1796) increased with increased maximum blade height of turbines. In contrast, fatalities of little brown bat (Myotis lucifugus Le Conte, 1831) and eastern red bat (Lasiurus borealis Müller, 1776) decreased with increased turbine height. Fatalities of purple martins (Progne subis Linnaeus, 1758) and tree swallows (Tachycineta bicolor Vieillot, 1808) were higher at taller turbines than shorter turbines. However, fatalities of cliff swallow (Petrochelidon pyrrhonota Vieillot, 1817) and barn swallow (Hirundo rustica Linnaeus, 1758) were not associated with turbine height. Our results suggest that varying flight height among species may be one factor affecting collision risk. - OPEN ACCESSAcademic scientists face an unpredictable path from plant biology research to real-life application. Fundamental studies of γ-aminobutyrate and carotenoid metabolism, control of Botrytis infection, and the uptake and distribution of mineral nutrients illustrate that most academic research in plant biology could lead to innovative solutions for food, agriculture, and the environment. The time to application depends on various factors such as the fundamental nature of the scientific questions, the development of enabling technologies, the research priorities of funding agencies, the existence of competitive research, the willingness of researchers to become engaged in commercial activities, and ultimately the insight and creativity of the researchers. Applied research is likely to be adopted more rapidly by industry than basic research, so academic scientists engaged in basic research are less likely to participate in science commercialization. It is argued that the merit of Discovery Grant applications to the Natural Sciences and Engineering Research Council (NSERC) of Canada should not be evaluated for their potential impact on policy and (or) technology. Matching industry funds in Canada rarely support the search for knowledge. Therefore, NSERC Discovery Grants should fund basic research in its entirety.
- OPEN ACCESS
- OPEN ACCESSHuman access to surface water resources in the Northern Great Plains (NGP) is challenged by availability and quality, and ecosystem health objectives for these characteristics have not been well developed. Here, we present a predictive multivariate model using the reference condition approach to inform goals for ecosystem health assessment. Benthic communities and abiotic variables were collected at 280 potential reference sites and 8 test sites, and of these, reference sites with least amount of human activity (n = 83) were classified into three community groups and summary metrics. Discriminant function analysis and cross-validation determined that stream order and ecoregion predicted 68.7% of the sites correctly, thus enabling comparison of sites with unknown condition to reference site groups. We then evaluated metrics through Test Site Analysis and stressor gradient analysis in each biological group. Beetle and amphipod fauna were found to be important for condition assessment in addition to traditional metrics of species richness, abundance, detritivory, Ephemeroptera/Plecoptera/Trichoptera dominance, and assemblage composition. These results provide least disturbed reference condition and ecological insights into land use impacts in the NGP. Ultimately, this model is an effective tool for evaluating biotic condition, enables prioritizing river management strategies, and can quantify the efficacy of mitigation measures.
- OPEN ACCESSProtected areas (PAs) are a key component of most conservation strategies because they are thought to enhance biodiversity value relative to similar habitats in working landscapes. To examine whether PAs in Nova Scotia are functioning to enhance the biodiversity value of the landscapes in which they are embedded, we surveyed breeding bird communities in forested wetlands inside and outside of a large PA during 2018 and 2019. We found significantly higher species richness and diversity at sites in the working landscape relative to those inside the PA. Bird communities from different wetland types inside the PA were distinct from each other and those outside the PA, whereas bird communities at outside sites were homogenized and comprised of more early-successional species. There were numerous species of conservation concern at both inside and outside sites, indicating that both types of sites are playing important conservation roles. Abundances of these key species were driven by a combination of local (e.g., water table depth, herb, and shrub cover) and landscape scale factors (e.g., edge density and human disturbance). The higher abundance of long-distance migrants and insectivores at inside sites suggests PAs are providing critical additional support to key guilds that are in steep decline.
- OPEN ACCESS
- Britt D. Hall,
- Sichen Liu,
- Cameron G.J. Hoggarth,
- Lara M. Bates,
- Stacy A. Boczulak,
- Jamie D. Schmidt, and
- Andrew M. Ireson
Methylmercury concentrations [MeHg] in whole water were measured in 28 prairie wetland ponds in central Saskatchewan between 2006 and 2012. Ponds fell into four land use categories (established grass, recent grass, traditional cultivated, and certified organic cultivated) and two water level patterns (“Mainly Wet” ponds stayed wet at least until October and “Mainly Dry” ponds dried up each summer). Despite similar atmospheric Hg deposition, average [MeHg] and proportion of total Hg that was MeHg (%MeHg) were higher in water from ponds surrounded with established grass or organic farming; this trend may be driven by high [MeHg] at one Organic site. A stronger relationship was observed with water level patterns. Average [MeHg] and %MeHg were significantly higher in Mainly Wet ponds compared to Mainly Dry ponds. Higher [MeHg] in Mainly Wet ponds were correlated with much higher dissolved organic carbon (DOC) and sulfate (SO4−2) concentrations and higher specific UV absorbance of DOC. We suggest that prairie wetland ponds may not fit the accepted paradigm that wetlands with high [SO4−2] show inhibition of Hg methylation. Our work suggests controls such as the chemical nature of DOC or redox fluctuations in hydrologically dynamic systems may be important in determining net [MeHg] in these sites. - OPEN ACCESS
- Jessie S. Reynolds,
- Chris K. Elvidge,
- Ian J. Vander Meulen,
- Caleb T. Hasler,
- Richard A. Frank,
- John V. Headley,
- L. Mark Hewitt, and
- Diane M. Orihel
We evaluated whether naphthenic acid fraction compounds (NAFCs) extracted from oil sand tailings adversely affect fish survival and behaviour. Following a before–after-control-impact design, we housed wild-caught juvenile yellow perch (Perca flavescens) in outdoor mesocosms to assess survival and behaviour under baseline conditions, then exposed fish to one of three treatments: negative control, 2 mg/L NAFC, or 15 mg/L NAFC. We performed behavioural assays (no-stimulus activity, food stimulus, and predator stimulus using a model bird) and assessed a comprehensive suite of endpoints (equilibrium losses, activity, shoaling, burst swimming, freezing, and space use). We found that exposure to 15 mg/L NAFCs substantially reduced fish survival and impaired fish equilibrium in all three behavioural tests. Furthermore, exposure to NAFCs impaired anti-predator behaviour: while the activity of control fish increased by two-fold in response to a predator stimulus, fish exposed to 2 or 15 mg/L NAFC did not change their activity levels after stimulation. No significant changes were observed in other behavioural endpoints. Overall, our findings suggest that a week-long exposure to NAFCs at concentrations commonly found in tailings ponds, constructed wetlands, and other mining-impacted waters may affect multiple facets of fish behaviour that could ultimately lead to reduced fitness in fish populations. - OPEN ACCESSLake Winnipeg, Manitoba, is Canada’s second largest commercial inland freshwater fishery, and concern over collapse of the walleye fishery is growing. Molecular techniques have been increasingly used to study responses of wild organisms to environmental and anthropogenic stressors. The present study used transcriptomics to examine the physiology of wild-caught walleye (Sander vitreus (Mitchell, 1818)) across Lake Winnipeg using non-lethal techniques. Gill transcriptomes of walleye sampled from the north and south basins of Lake Winnipeg, and the channel connecting them, exhibited distinct profiles implicating regionally specific biological responses. North basin walleye exhibited transcriptomic responses indicative of exposure to environmental stressors. Transcriptomic patterns suggested a shift to increased reliance on anaerobic metabolism and up-regulation of hypoxia-sensitive genes in north basin fish, possibly representing exposure to low-oxygen conditions. Exposure to environmental stressors may also have driven increases in gene transcripts associated with proteasomal catabolism, DNA repair, molecular chaperones, and ion regulation. North basin fish also exhibited transcriptomic patterns indicative of gill remodeling via regulation of the mTOR pathway, cytoskeleton reorganization, and fatty acid synthesis. Our results highlight the complexity of examining wild fish across environmental gradients but also the potential use of molecular techniques in elucidating organismal sensitivity to local environmental factors.