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- OPEN ACCESSHabitat sensitivity is a consideration for decision-making under environmental laws in many jurisdictions. However, habitat sensitivity has been variously defined and there is no consistent approach to its quantification, which limits our understanding of how habitat sensitivity varies among systems and in response to different pressures. We review various definitions offered in the scientific literature and policy documents before suggesting a universal framework for habitat sensitivity as (i) a habitat trait that defines the ecological impacts from a given pressure, (ii) which is composed of three components (habitat resistance, resilience, and recoverability), and (iii) which is quantified by measuring the change and recovery in the state of key habitat attributes in response to pressures. In addition, we provide guidance toward a consistent approach to assessing habitat sensitivity, which includes the use of pressure benchmarks and standardized metrics of change in key habitat attributes to create a common scale for comparison among habitat attributes and pressures. Our framework and recommendations should help to standardize the way in which habitat sensitivity is defined and assessed, and could be integrated into decision-making processes to improve ecosystem management in different jurisdictions.
- OPEN ACCESSCanada lynx (Lynx canadensis) are keystone predators. However, contact with congenerics, like the bobcat (Lynx rufus), could alter lynx trophic ecology and destabilize boreal food webs. We set out to describe the trophic niches of these species in allopatry and sympatry to assess how resources are partitioned among them and project whether the northward expansion of the bobcats’ range will lead to the displacement of lynx. To quantify the trophic niche, we measured stable isotopes of carbon and nitrogen in muscle and liver samples of bobcat and lynx. Our results indicate that both bobcat and lynx consumed snowshoe hare as their primary prey. However, lynx specialized on hare throughout our study, whereas bobcats foraged as generalists in sympatry with lynx and hare-specialists in allopatry. Our results highlight the contrasting ecological strategies of two congeneric felids and underscore the potential relevance of foraging efficiency in shaping the trophic niche of consumers in competitive environments.
- OPEN ACCESSAssessing cat local abundance provides information on where wandering cat numbers are highest and what habitats or factors are associated with wandering cats. A variety of stakeholders can lead this research and then use the findings to make scientifically informed decisions to guide the physical locations of cat management actions. Here, we document a framework that engages community members, uses minimal equipment (six trail cameras), and provides scientifically derived information for interested parties to inform, direct, or test the effectiveness of cat management practices. Using these methods in Gatineau, Quebec, Canada, we demonstrate how we estimated cat population size and cat local abundances across a variety of co-variates while accounting for non-perfect detection by using 55 trail camera sites and N-mixture models. Urban areas had three-fold higher local wandering cat abundances than parkland areas, and neighbourhoods below the median income had the highest local abundances of wandering cats. We estimated there are between 8905 and 48,419 (mean 21,298) wandering cats in Gatineau, with 18%–73% of those cats being unowned. These findings can be used to identify locations for future cat management. If estimates of cat abundance are repeated, they can assess the effectiveness of management actions.
- OPEN ACCESSLong-term ecological research (LTER) projects are considered valuable training grounds for graduate student researchers, yet student voices are largely absent from discussions of LTER merits in the literature. We aimed to identify benefits and challenges encountered by current and former graduate students in conducting graduate research within LTER projects. To explore graduate student experiences and perspectives, we conducted a survey comprising both closed-ended questions (i.e., multiple choice and Likert scale) and open-ended questions. From the responses, we identified emergent categories related to positive and negative experiences using sentiment analysis. We found agreement with purported benefits in areas including networking and access to established field sites and protocols. However, participants also identified data accessibility, authorship decisions, communication, and interpersonal conflicts as significant sources of challenges. We synthesized survey results with existing literature to provide actionable recommendations for principal investigators in four main areas (data, authorship, communication, and management) through an LTER lens. In addition to providing longitudinal data, LTER projects offer graduate students both physical and methodological infrastructure that can serve as the scaffold for new research questions to be developed. However, the likelihood of success of student research, as well as the success of the students themselves, can be improved when the needs of graduate students are prioritized.
- OPEN ACCESSThe parallel evolution of lateral plates and body shape in the threespine stickleback (Gasterosteus aculeatus) is an iconic example of adaptation. We test a case of contemporary evolutionary transition in a recently isolated population of marine G. aculeatus in British Columbia, Canada. We investigate Ectodysplasin (Eda) genotypes, plate counts, neutral genetic divergence, and whole-body phenotypes to determine the genetic and phenotypic distance between this population and nearby comparative populations. Our focal population is in the process of adapting both genetically and phenotypically to a freshwater environment, and we provide an example of the genetic basis for parallel evolution on a contemporary timescale. The frequency of Eda genotypes and lateral plate phenotypes in our focal population is not consistent with those of marine or fully freshwater populations. Although our focal population is genetically distinct from nearby marine populations, these fish still more closely resemble marine populations in overall body shape while demonstrating an intriguing intermediate phenotype. Eda frequency and lateral plate phenotype change faster than body shape in response to freshwater conditions, suggesting that the pace of adaptation differs across traits in response to the same environmental conditions. Our results further bolster the case for G. aculeatus as a key model of contemporary evolution.
- OPEN ACCESS
- Samantha M. Knight,
- Barbara I. Bleho,
- Melissa A. Grantham,
- Richard Westwood,
- Nicola Koper, and
- Cary D. Hamel
Poweshiek skipperling (Oarisma poweshiek Parker, 1870) populations have declined precipitously in the past few decades, and their global range is now restricted to two isolated regions, one of which is the managed Manitoba tall grass prairie in Canada. In this paper, we used a decade of survey data from 2010 to 2019 to understand how habitat features, management practices, and extreme weather impact Poweshiek skipperling abundance in Manitoba. The strongest predictor of abundance was the density of black-eyed Susans (Rudbeckia hirta L.), a primary nectar plant for adults. Poweshiek skipperling abundance also had a negative relationship with both the number of years since a burn occurred and the number of years since grazing occurred. Cumulative precipitation during their active period (May–June) had a negative relationship with skipperling abundance, whereas warm early springs and cool temperatures during the active period had positive relationships. These results suggest that management actions that maintain tall grass prairie habitat in an early successional stage (burning and grazing) and maintain important nectar sources benefit this population. In contrast, extreme weather events had varying effects on Poweshiek skipperling abundance. Results from this study inform ongoing management practices in the Manitoba tall grass prairie to support this endangered population. - OPEN ACCESSExpanding local rice production to meet consumer demand is a priority action under the Government of Ghana’s Planting for Food and Jobs initiative. While studies on yield-enhancing interventions abound, fewer studies focus on food safety issues (e.g., the potential toxic element status of the production ecosystems). This study was, therefore, conducted to bridge the knowledge gap. Chemical analyses were conducted on water, soil, and rice grain samples from different production ecosystems in the Northern and Upper East regions of Ghana. Statistical analysis of the data showed that soil and rice grain arsenic concentrations were significantly higher (P < 0.001) in the Upper East region. In the Northern region, mean cadmium concentration in rice grains from the irrigated lowland fields (0.023±0.003 mg/kg) was significantly higher than in grains from the rainfed fields. All recorded concentrations of rice grain arsenic, cadmium, and lead were, however, within permissible limits, indicating a low risk of dietary exposure. The observed differences in concentrations within and between regions suggest that soil texture and other geogenic factors could influence the potential toxic element status of the rice production ecosystems. Regular monitoring is, therefore, recommended to maintain the safety of Ghana’s locally produced rice for human consumption.
- OPEN ACCESS
- Catherine Sun,
- Alys Granados,
- Christopher Beirne,
- Gillian Chow-Fraser,
- Abraham Francis,
- Lian Kwong,
- Peter Soroye,
- Helen Yip,
- Anita Miettunen,
- Jeff Bowman, and
- A. Cole Burton
Funding is critical in ecology and related fields, as it enables research and sustains livelihoods. However, early-career researchers (ECRs) from diverse backgrounds are disproportionately underrepresented as funding recipients. To help funding programs self-evaluate progress towards increasing equity, diversity, and inclusion (EDI) in their funding opportunities, we introduce the Stage-based Assessments of Grants for EDI (SAGE) Toolkit. Developed using existing literature, semi-structured interviews, and coauthors’ experiences, the toolkit considers how each funding stage (Advertisement, Application, Review, Awarding) interacts with applicants from racialized and other underrepresented backgrounds. The toolkit offers specific criteria and recommendations, with explanations and examples from funding agencies, to support applicants who have been historically marginalized in ecology and are often left out of equitable funding consideration. Changes in funding mechanisms alone will not reverse the marginalization of communities and peoples in the field of ecology, but advancing EDI must include action throughout the grant process. Efforts to increase EDI must be sustained, and the toolkit allows for additional considerations and evolving best practices. With the SAGE Toolkit, efforts to increase EDI can help to transition away from a transactional dynamic between funder and applicant to instead supportive community and collaboration. The SAGE Toolkit is available online at bit.ly/ediSAGEtoolkit. - OPEN ACCESSDespite the challenges posed by climate change and the biodiversity crisis, most academic research continues to stay within academia and the gaps between conservation science, policy, and practice remain intact. We need to improve the exchange of evidence between researchers and conservation practitioners and focus on solutions-oriented, interdisciplinary science and co-developed research. As we continue to break climate records and lose record numbers of species every year, now is the time for academics to think and act beyond their institutions.
- OPEN ACCESSPlant structures that enclose trapped air are morphologically and taxonomically diverse. They range from pubescence (trichomes) on various parts of plants to flowers, inflorescences, stems, culms (above-ground jointed stems of grasses), petioles, peduncles, scapes, fruits, bracts, leaves, galls, algal pneumatocysts, moss sporophytes, lichen podetia, and fungal fruiting bodies. Despite being familiar, such structures have not been studied systematically until recently when their complex thermodynamic functionality as microgreenhouses has been recognized. We propose the term “heliocaminiform” (Greco-Latin origin for “sun-room”) provides an umbrella term that describes form and function. Almost all the hollow structures we have examined have elevated internal temperatures of several degrees C above the surrounding air in sunshine, but those are abolished under cloud or at night. The potential importance for the additional heat is presumed to be in growth, maturation, reproduction, sexual function, and overall fitness of the plants. There seem to be no experimental studies on those effects even though they may help explain aspects of plants’ responses to climate change and to phenological mismatches with symbionts (mutualists and herbivores) as ecologically co-dependent partners. Our review and observations opens a remarkably new and hitherto surprisingly neglected avenue in botany which we hope others will explore.
- OPEN ACCESS
- Emily M. Rubidge,
- Carrie K. Robb,
- Patrick L. Thompson,
- Chris McDougall,
- Karin M. Bodtker,
- Katie S.P. Gale,
- Stephen Ban,
- Kil Hltaanuwaay Tayler Brown,
- Vicki Sahanatien,
- Sachiko Ouchi,
- Sarah K. Friesen,
- Natalie C. Ban,
- Karen L. Hunter,
- Angelica Pena,
- Amber Holdsworth, and
- Rebecca Martone
Marine protected area (MPAs) networks can buffer marine ecosystems from the impacts of climate change by allowing species to redistribute as conditions change and by reducing other stressors. There are, however, few examples where climate change has been considered in MPA network design. In this paper, we assess how climate change considerations were integrated into the design of a newly released MPA network in the Northern Shelf Bioregion in British Columbia, Canada, and then evaluate the resulting network against projected physical and biogeochemical changes and biological responses. We found that representation, replication, and size and spacing recommendations integrated into the design phase were met in most cases. Furthermore, despite varying degrees of projected changes in temperature, dissolved oxygen, and aragonite saturation across the MPA network, suitable habitat for demersal fish species is projected to remain in the network despite some redistribution among sites. We also found that mid-depth MPAs are particularly important for persistence, as fish are projected to move deeper to avoid warming in shallower areas. Our results highlight that a representative MPA network with adequate replication, that incorporates areas of varying climate change trajectory, should buffer against the impacts of climate change. - OPEN ACCESS
- 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 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 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
- Travis G. Gerwing,
- Lily Campbell,
- Diana J. Hamilton,
- Myriam A. Barbeau,
- Gregory S. Norris,
- Sarah E. Dudas, and
- Francis Juanes
While trophic and habitat-related abiotic variables (predation, competition, tolerance, etc.) are known to influence community structure in many ecosystems, some systems appear to be only minimally influenced by these variables. Sampling multiple tidal flat communities in northern BC, Canada, we investigated the relative importance of top-down and middle-out (mesopredators) variables, competition for resources (bottom up), and abiotic variables in structuring an infaunal community (invertebrates living in sediment). Similar to previous studies on mudflats in the Bay of Fundy (also at a north temperate latitude), we determined that these variables accounted for a minor (0%–9%) proportion of the observed variation in this infaunal community, suggesting that these variables play a small role in structuring this community. Based on the results of our study and in combination with previous experiments on infaunal recovery patterns post disturbance, we posit that the main factors influencing these infaunal communities likely operate at a scale of sites (kilometres) and(or) plot (metres or less) but not transects (10–100 m within site). Candidate forces structuring these intertidal communities that need future examination include regional species pools and the variables that affect these pools, sediment biogeochemistry, and disturbance/recovery history of a site. The similarity of our Pacific coast findings to those from the north temperate Atlantic coast suggests some similarity in the processes structuring these distinct infaunal communities. - OPEN ACCESSIn some cases, managing an established invasive species may do more harm to an ecosystem than allowing the invader to persist. Given limited resources available to land managers and the realities of conservation triage, we recognized the need for systematic guidance for management decisions made at the “late end” of the invasion curve. We gathered an interdisciplinary group of experts and practitioners to address the question of “under what circumstances is the active management of an established aquatic invasive species warranted?” Our working group identified three key dimensions to this question: (1) the efficacy of available management options; (2) the net benefits of management actions weighed against the null scenario of no control; and (3) the socio-ecological context that defines management goals, a manager’s ability to achieve said goals, and perceptions of management outcomes. These considerations were used to structure a consensus decision tree that supports a multi-criteria approach to decision-making. Our approach promotes interdisciplinarity and systems thinking and emphasizes the need to consider costs and benefits comprehensively, for example by considering the persistence or reversibility of impacts from both the invasive species and from efforts to suppress or eradicate it.
- OPEN ACCESSBenthic macroinvertebrate communities, which include unionid freshwater mussels, enhance the health of river ecosystems. Human impacts have driven declines within freshwater mussel communities and due to their complex life cycles, mussel recovery efforts are complex. In Canada, conservation of imperiled species has focused on biodiversity hotspots such as the Sydenham River in the Laurentian Great Lakes Basin. In practice, species conservation and habitat monitoring are siloed between federal agencies and local conservation authorities, limiting the potential for alignment of conservation policy and practice. Here we bring together federal, local, and our own survey data to explore patterns of co-occurrences between mussel species and other macroinvertebrate taxa to explore the extent to which knowledge of one benthic community informs the other. Mussel communities (species richness, community composition) differed between sites where imperiled mussel species were present and/or absent. Benthic macroinvertebrate metrics (e.g., family richness, percent Ephemeroptera, Plecoptera, and Trichoptera taxa) and specific indicator taxa were correlated with mussel species richness and the presence of imperiled mussel species. We show that benthic macroinvertebrate diversity indicators provided insight into imperiled species occurrences that warrant further investigation. These findings underscore support for coordinated watershed monitoring efforts and could be crucial for more successful freshwater mussel conservation.
- OPEN ACCESS
- Alexandra Langwieder,
- Angela Coxon,
- Natasha Louttit,
- Stephanie Varty,
- Felix Boulanger,
- Sanford Diamond,
- John Lameboy,
- Anderson Jolly,
- George Natawapineskum,
- Derek Okimaw, and
- Murray M. Humphries
Wildlife conservation is informed by detailed understanding of species demographics, habitat use, and interactions with environmental drivers. Challenges to collecting this information, particularly in remote places and on widely ranging species, can contribute to data deficiencies that detract from conservation status assessment and the effectiveness of management actions. Polar bears in James Bay face rapidly changing environmental conditions at the southern edge of their global range, but studying their ecology has been limited by community concerns about the methods typically used in polar bear research. Using a community-led and non-invasive approach, we deployed hair snare and camera trap sampling stations across 400 km of the Eeyou Marine Region in eastern James Bay. Stations collected >100 hair samples and thousands of photographs in one eight-week period that allowed for a novel investigation of this population’s distribution and body condition during the ice-free season. Polar bears were in average to above average body condition, and model selection of detections at stations revealed distance to mainland as a significant predictor of polar bear presence. Given its high potential, we suggest community-based monitoring using this method become a standard protocol to expand the scope and local leadership of polar bear research across the North. - OPEN ACCESSAnimal populations take advantage of environmental heterogeneity to partition themselves into microhabitat niches. Such partitioning plays an important role in regulating interspecific competition and community structure by allowing multiple species to coexist. Atlantic Canada has many small coastal staging sites that host southbound migrant shorebirds. However, most shorebird studies in the region have been focused on larger sites in the Bay of Fundy, resulting in limited knowledge about staging ecology at these small sites, which often host more diverse shorebird assemblages. We examined niche partitioning by shorebirds on the Northumberland Strait, New Brunswick, Canada, to better understand how small coastal staging sites support diverse shorebird populations. We found evidence of partitioning on three niche dimensions: space, foraging behaviour, and diet. Most species specialized in at least one dimension, with foraging constraints based on bill morphology and habitat access based on species size likely driving segregation. Environmental heterogeneity at sites on the Northumberland Strait created multiple dimensions for segregation and fulfilled the niche requirements of diverse shorebird species during migratory staging. These findings broaden our understanding of staging ecology of multispecies flocks and suggest that conservation of small coastal sites is important for success of migratory shorebirds in Atlantic Canada.
- OPEN ACCESSThe American common eider (Somateria mollissima dresseri) is a colonially nesting sea duck breeding on islands in the coastal regions of Atlantic Canada. Declines in colony size have been pronounced in some parts of its range, notably in Nova Scotia, and may be attributable to a variety of interconnected factors including changes in habitat conditions. Using surveys collected two decades apart, we compared nesting habitat types, availability, and use by breeding eiders on 16 islands that supported >1600 eider nests in 1992–1993, but 830 nests in 2013. While general patterns of eider nesting habitat use remained consistent (e.g., nesting preferences exhibited for Low Shrubland and Grassland habitats, and avoidance of forest or beach habitats), overall vegetation cover declined, but relative habitat changes were inconsistent across islands. Three of the islands with the greatest change in vegetation had cormorant (Phalacrocorax spp.) colonies in 2013 that were not there in the earlier years. We suggest that changes in vegetation, in some cases facilitated by cormorant colony formation, influenced susceptibility of nesting females to predators, and these interconnected factors may be contributing to local population declines.
- OPEN ACCESSInvasive species are a leading cause of biodiversity loss and species extinctions across ecosystems on a global scale. The historical and ongoing focus on single-species management of invasive species and species at risk contributes to inefficiencies in management strategies that present an obstacle to achieving desired outcomes. A holistic approach that consolidates and maps linkages between the broader collective of invasive species and species at risk in an area provides a more appropriate entry point for issue-based, rather than species-based, management planning. We present a case study of this approach from British Columbia, Canada, which synthesized the identity, mechanisms of impact, mechanisms of spread, and magnitude of impacts across 782 unique pairs of invasive species and federally listed species at risk, based on a literature review of species at risk documentation. The resulting dataset was used to summarize the nature of interactions across species pairs and taxonomic groups to help guide the development of invasive species response strategies that make the best use of limited management resources. As species invasions and extinctions become increasingly interconnected, holistic approaches rooted in cumulative effects assessment and ecosystem-based management can provide a stronger foundation for reducing or mitigating this growing threat.
- OPEN ACCESSExpanding and creating protected area networks has become a central pillar of global conservation planning. In the management and design of protected area networks, we must consider not only the positive aspects of landscape connectivity but also how that connectivity may facilitate the spread of invasive species, a challenge that has become known as the connectivity conundrum. Here, we review key considerations for landscape connectivity planning for protected area networks, focusing on interactions between network connectivity and the management of invasive species. We propose an integrative adaptive management framework for protected area network planning with five main elements, including monitoring, budgeting considerations, risk assessment, inter-organizational coordination, and local engagement. Protected area planners can address the dynamic aspects of the connectivity conundrum through collaborative and integrative adaptive management planning.
- OPEN ACCESS
- Jeremy R. Brammer,
- Allyson K. Menzies,
- Laurence S. Carter,
- Xavier Giroux-Bougard,
- Manuelle Landry-Cuerrier,
- Melanie-Louise Leblanc,
- Mikhaela N. Neelin,
- Emily K. Studd, and
- Murray M. Humphries
Traditional food systems based on harvest from the local environment are fundamental to the well-being of many communities, but their security is challenged by rapid socio-ecological change. We synthesized literature and data describing how a fundamental form of biodiversity, animal body size, contributes to the security of traditional food systems through relationships with species availability, accessibility, adequacy, and use. We found larger vertebrate species were more available, accessible, and used on a per kilogram basis, particularly for mammals. Conversely, larger species were no more or less adequate from a combined nutritional, health, and cultural perspective. Larger species represented more biomass, and this biomass required less time to harvest, with greater but more variable mean caloric returns over time. Smaller species provided more consistent caloric returns and were harvested during documented shortages of prey. This reliance on species with a range of body sizes is consistent with optimal foraging theory and the evolutionary value of flexibility, and highlights the importance of a biodiverse pool of species for traditional food security in times of change. Our synthesis of published literature and data highlights the many socio-ecological correlates of species size and how these relate to the security of traditional food systems. - 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 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 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 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
- 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 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 ACCESS
- 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
- 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
- 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 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
- 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 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
- 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 ACCESS
An analysis of threats and factors that predict trends in Canadian vertebrates designated as at-risk
The identification of factors that predict trends in population abundance is critical to formulate successful conservation strategies. Here, we explore population trends of Canadian vertebrates assessed as “at-risk” by the Committee on the Status of Endangered Wildlife in Canada and the threats affecting these trends using data from the Canadian Living Planet Index. We investigate how threat profiles—the combination of threats for a given species—vary among species and taxonomic groups. We then investigate threat profile as a predictor of temporal trends—both exclusively and in combination with additional biotic and abiotic factors. Species had 5.06 (±2.77) threats listed on average, and biological resource use (BRU) was the most frequently cited. Our analysis also revealed an association between taxonomic group and population trends, as measured by the proportion of annual increases (years with a positive interannual change). By contrast, the predictive power of threat profile was poor. This analysis yielded some useful insight for conservation action, particularly the prioritization of abating BRU. However, the predictive models were not as meaningful as originally anticipated. We provide recommendations on methodological improvements to advance the understanding of factors that predict trends in population abundance for prioritizing conservation action. - OPEN ACCESSHarvest records suggest that the abundance of bobcats (Lynx rufus) has increased and the leading edge of their distribution has spread northward, while the trailing edge of the Canada lynx (Lynx canadensis) range has contracted in Ontario, Canada. There has been a debate about whether these closely related felids might compete in areas of sympatry, but there is little research on sympatric populations of bobcat and lynx. Both species are found on the north shore of Lake Huron in Ontario, Canada, which provided an opportunity to investigate their spatial patterns and habitat use. We surveyed snowmobile routes for snow tracks over three winters and estimated probability of occupancy for the two felid species while accounting for detectability. Bobcat and lynx tracks were never found on the same survey route. Bobcat occupancy increased with habitat heterogeneity, whereas lynx occupancy increased with homogeneity. Our results fit with the common assumption of the generalist and specialist natures of bobcat and lynx, respectively. Our findings suggest that bobcats invaded former lynx territory after these areas became vacant. The story of the bobcat and the lynx is one of the loss of a unique, boreal specialist due to anthropogenic change, and eventual replacement by an adaptable generalist.
- OPEN ACCESSShale-gas production could impact freshwater quality through contamination of the physical and chemical habitat (e.g., fracturing fluids, untreated or treated effluent) or development-related impacts. Despite environmental concerns, information is lacking to support biomonitoring as a diagnostic tool to assess impacts of shale-gas production. We characterized water quality and biota in areas of high shale gas potential (Early Carboniferous bedrock in New Brunswick, Canada) and surrounding geologic areas, and we assessed patterns in benthic macroinvertebrate (BMI) and fish assemblages. Early Carboniferous stations differed primarily based on water chemistry, and BMI were associated with a gradient in conductivity and temperature across geologic classes. Concordance analysis indicated similar classification of stations by both organism groups, though fish were more related to turbidity and nutrients. Concordance among fish and BMI was strongest at high conductivity, Early Carboniferous stations. These results suggest that geology plays a strong role in driving abiotic habitats and biotic communities of streams, even at small spatial scales. Furthermore, they suggest BMI and fish can provide complementary information for biomonitoring in shale-gas development areas, with BMI responding to increased ion concentrations from surface water contamination, and fish responding to changes in nutrients and turbidity resulting from development.
- OPEN ACCESS
- R. Drew Carleton,
- Emily Owens,
- Holly Blaquière,
- Stéphane Bourassa,
- Joseph J. Bowden,
- Jean-Noël Candau,
- Ian DeMerchant,
- Sara Edwards,
- Allyson Heustis,
- Patrick M.A. James,
- Alison M. Kanoti,
- Chris J.K. MacQuarrie,
- Véronique Martel,
- Eric R.D. Moise,
- Deepa S. Pureswaran,
- Evan Shanks, and
- Rob C. Johns
Insect outbreaks can cover vast geographic areas making it onerous to cost-effectively monitor populations to address management or ecological questions. Community science (or citizen science), which entails engaging the public to assist with data collection, provides a possible solution to this challenge for the spruce budworm (Choristoneura fumiferana Clemens), a major defoliating pest in North America. Here, we lay out the Budworm Tracker Program, a contributory community science program developed to help monitor spruce budworm moths throughout eastern Canada. The program outsources free pheromone trap kits to volunteers who periodically check and collect moths from their traps throughout the budworm flight period, then return them in a prepaid envelope to the organizers. Over three years, the program engaged an average of 216–375 volunteers and yielded a data return rate of 68%–89%, for a total of 16 311–54 525 moths per year. Volunteer retention among years was 71%–89%. Data from this program offer compelling evidence for the range of long-distance moth dispersal. Although our program was designed for spruce budworm, this template could easily be adapted for forestry, urban forestry, and agricultural systems to monitor any of the numerous organisms for which there is an established trapping method. - OPEN ACCESS
- Kyle A. Schang,
- Andrew J. Trant,
- Sara A. Bohnert,
- Alana M. Closs,
- Megan Humchitt,
- Kelsea P. McIntosh,
- Robert G. Way, and
- Sara B. Wickham
The relationship between Indigenous peoples and the functioning of terrestrial ecosystems has received increased attention in recent years. As a result, it is becoming more critical for researchers focusing on terrestrial ecosystems to work with Indigenous groups to gain a better understanding of how past and current stewardship of these lands may influence results. As a case study to explore these ideas, we systematically reviewed articles from 2008 to 2018 where research was conducted in North America, South America, and Oceania. Of the 159 articles included, 11 included acknowledgement of Indigenous stewardship, acknowledged the Indigenous Territories or lands, or named the Indigenous group on whose Territory the research was conducted. Within the scope of this case study, our results demonstrate an overall lack of Indigenous acknowledgement or consideration within the scope of our review. Given the recent advancements in our understanding of how Indigenous groups have shaped their lands, we implore researchers to consider collaboration among local Indigenous groups as to better cultivate relationships and foster a greater understanding of their ecosystems. - OPEN ACCESS
- Amy K. Teffer,
- Jonathan Carr,
- Amy Tabata,
- Angela Schulze,
- Ian Bradbury,
- Denise Deschamps,
- Carole-Anne Gillis,
- Eric B. Brunsdon,
- Gideon Mordecai, and
- Kristina M. Miller
Infectious agents are key components of animal ecology and drivers of host population dynamics. Knowledge of their diversity and transmission in the wild is necessary for the management and conservation of host species like Atlantic salmon (Salmo salar). Although pathogen exchange can occur throughout the salmon life cycle, evidence is lacking to support transmission during population mixing at sea or between farmed and wild salmon due to aquaculture exposure. We tested these hypotheses using a molecular approach that identified infectious agents and transmission potential among sub-adult Atlantic salmon at marine feeding areas and adults in three eastern Canadian rivers with varying aquaculture influence. We used high-throughput qPCR to quantify infection profiles and next generation sequencing to measure genomic variation among viral isolates. We identified 14 agents, including five not yet described as occurring in Eastern Canada. Phylogenetic analysis of piscine orthoreovirus showed homology between isolates from European and North American origin fish at sea, supporting the hypothesis of intercontinental transmission. We found no evidence to support aquaculture influence on wild adult infections, which varied relative to environmental conditions, life stage, and host origin. Our findings identify research opportunities regarding pathogen transmission and biological significance for wild Atlantic salmon populations. - OPEN ACCESS
- OPEN ACCESSCowichan Lake lamprey (Entosphenus macrostomus) is a threatened species resident to Mesachie Lake, Cowichan Lake, and adjoining Bear Lake and their major tributaries in British Columbia. Decreases in trapping success have created concerns that the population is declining. Some potential threats include water use, climate change, and management actions. Owing to the absence of long-term data on population trends, little information is available to estimate habitat quality and factors that influence it. We sought to fill this gap by examining associations between habitat area and variables representing suspected key drivers of habitat availability. Critical habitat areas were imaged using an unmanned aerial vehicle over a period of three years at three sites at Cowichan Lake and a subsequent habitat area was classified. Meteorological and anthropogenic controls on habitat area were investigated through automatic relevance detection regression models. The major driver of habitat area during the critical spawning period was water level during the storage season, which also depends on the meteorological variables and anthropogenic control. It is recommended that regulation of the weir should aim to ensure that the water level remains above the 1 m mark, which roughly equates to the 67% coverage of water on the habitat area used for spawning.
- OPEN ACCESSSustainable forest management implies successful regeneration after disturbances. Low N availability and competition can, however, limit tree establishment in boreal ecosystems. To develop silviculture strategies that maintain productivity in such context, we established a field trial in northern Québec, Canada. We evaluated if a companion N2-fixing species (Alnus alnobetula) promotes or hinders Picea mariana and Pinus banksiana establishment over six growing seasons. We tested if Alnus has a facilitation effect through nutritional processes and a competition effect through light interception. Foliar stable nitrogen isotope ratio (δ15N = 15N/14N, ‰) results confirmed that Alnus obtains a substantial part of its N through biological fixation and represents an N source in this system. Although we did not observe increased foliar N concentrations in either conifer species in the presence of Alnus, Pinus growth was nonetheless higher in presence of Alnus, whereas no difference was observed for Picea. In the plots where Alnus cohabited with the conifers, the former had a negative impact on seedling growth, suggesting a significant competition for light. Overall, the net effect of Alnus was positive for Pinus and neutral for Picea. Our results have significant implications for silviculture in N-limited systems, especially in the context of climate change that imposes increased levels of stress on regeneration.
- OPEN ACCESS
- Joe-Felix Bienentreu,
- Leon Grayfer,
- Danna M. Schock,
- Matthew Guerreiro,
- Melanie Mehes-Smith,
- Stephanie J. DeWitte-Orr,
- Jacques Robert,
- Craig R. Brunetti, and
- David Lesbarrères
Ranaviruses have been associated with rising numbers of mass die-offs in amphibian populations around the globe. However, most studies on ranaviruses to date focused on larval amphibians. To assess the role of postmetamorphic amphibians in the epidemiology of ranaviruses and to determine the role of viral immune-suppression genes, we performed a bath-exposure study on post-metamorphic wood frogs (Rana sylvatica) using environmentally relevant concentrations of wild-type Frog virus 3 (WT FV3), and a gene-knockout mutant (KO FV3), deficient for the putative immune-suppression gene vIF-2α. We observed a 42% infection rate and 5% mortality across the virus challenges, with infection rates and viral loads following a dose-dependent pattern. Individuals exposed to the knockout variant exhibited significantly decreased growth and increased lethargy compared with wild-type treatments. Although 85% of exposed individuals exhibited common signs of ranavirosis throughout the experiment, most of these individuals did not exhibit signs of infection by 40 d post-exposure. Overall, we showed that even a single short time exposure to environmentally relevant concentrations of ranavirus may cause sublethal infections in postmetamorphic amphibians, highlighting the importance of this life stage in the epidemiology of ranaviruses. Our study also supports the importance of the vIF-2α gene in immune-suppression in infected individuals. - OPEN ACCESS
- Alison Mikulyuk,
- Ellen Kujawa,
- Michelle E. Nault,
- Scott Van Egeren,
- Kelly I. Wagner,
- Martha Barton,
- Jennifer Hauxwell, and
- M. Jake Vander Zanden
Invasive species are known to have negative ecological effects. However, few studies have evaluated the impacts of invasive species relative to the effects of invasive species control, thereby limiting our ability to make informed decisions considering the benefits and drawbacks of a given management approach. To address this gap, we compared the ecological effects of the invasive aquatic plant Eurasian watermilfoil (Myriophyllum spicatum L.) with the effects of lake-wide herbicide treatments used for M. spicatum control using aquatic plant data collected from 173 lakes in Wisconsin, USA. First, a pre–post analysis of aquatic plant communities found significant declines in native plant species in response to lake-wide herbicide treatment. Second, multi-level modeling using a large data set revealed a negative association between lake-wide herbicide treatments and native aquatic plants, but no significant negative effect of invasive M. spicatum. Taken together, our results indicate that lake-wide herbicide treatments aimed at controlling M. spicatum had larger effects on native aquatic plants than did the target of control—invasive M. spicatum. Our comparison reveals an important management tradeoff and encourages careful consideration of how we balance the real and perceived impacts of invasive species and the methods used for their control. - OPEN ACCESSA 2012 Expert Panel Report on marine biodiversity by the Royal Society of Canada (RSC) concluded that Canada faced significant challenges in achieving sustainable fisheries, regulating aquaculture, and accounting for climate change. Relative to many countries, progress by Canada in fulfilling international obligations to sustain biodiversity was deemed poor. To track progress by Canada since 2012, the RSC struck a committee to track policy and statutory developments on matters pertaining to marine biodiversity and to identify policy challenges, and leading options for implementation that lie ahead. The report by the Policy Briefing Committee is presented here. It concluded that Canada has made moderate to good progress in some areas, such as prioritization of oceans stewardship and strengthening of the evidentiary use of science in decision-making. Key statutes were strengthened through amendments, including requirements to rebuild depleted fisheries (Fisheries Act) and new means of creating marine protected areas (Oceans Act) that allowed Canada to exceed its international obligation to protect 10% of coastal and marine areas by 2020. Public release of mandate letters has strengthened ministerial accountability. However, little or no progress has been made in reducing regulatory conflict with Fisheries and Oceans Canada (DFO), decreasing ministerial discretion under the Fisheries Act, clarifying the role of science in sustainable fisheries policy, and accounting for climate change. Five future policy challenges are identified: (1) Ensure climate change impacts and projections are incorporated into ocean-related decision making and planning processes; (2) Resolve DFO’s regulatory conflict to conserve and exploit biodiversity; (3) Limit ministerial discretionary power in fisheries management decisions; (4) Clarify ambiguities in how the Precautionary Approach is applied in sustainable fisheries policy; and (5) Advance and implement marine spatial planning. Since 2012, there has been progress in recovering and sustaining the health of Canada’s oceans. Failure to further strengthen biodiversity conservation threatens the capacity of Canada’s oceans to provide ecosystem services that contribute to the resilience of marine life and the well-being of humankind. Unprecedented and enduring changes in the ocean caused by climate change have made the achievement of meaningful progress all the more urgent.
- OPEN ACCESSRanaviruses are an emerging group of pathogens capable of infecting all cold-blooded vertebrates. In Europe, ranaviruses pose a particularly potent threat to wild amphibian populations. Since the 1980s research on amphibian-infecting ranaviruses in Europe has been growing. The wide distribution of amphibian populations in Europe, the ease with which many are monitored, and the tractable nature of counterpart ex situ experimental systems have provided researchers with a unique opportunity to study many aspects of host–ranavirus interactions in the wild. These characteristics of European amphibian populations will also enable researchers to lead the way as the field of host–ranavirus interactions progresses. In this review, we provide a summary of the current key knowledge regarding amphibian infecting ranaviruses throughout Europe. We then outline important areas of further research and suggest practical ways each could be pursued. We address the study of potential interactions between the amphibian microbiome and ranaviruses, how pollution may exacerbate ranaviral disease either as direct stressors of amphibians or indirect modification of the amphibian microbiome. Finally, we discuss the need for continued surveillance of ranaviral emergence in the face of climate change.
- OPEN ACCESS
- Kelsey Hauser,
- Milan Popovic,
- Amulya Yaparla,
- Daphne V. Koubourli,
- Phillip Reeves,
- Aashish Batheja,
- Rose Webb,
- María J. Forzán, and
- Leon Grayfer
The ranavirus Frog Virus 3 (FV3) and the chytrid fungus Batrachochytrium dendrobatidis (Bd) are significant contributors to the global amphibian declines and both pathogens target the amphibian skin. We previously showed that tadpoles and adults of the anuran amphibian Xenopus laevis express notable levels of granulocyte chemokine genes (cxcl8a and cxcl8b) within their skin and likely possess skin-resident granulocytes. Presently, we show that tadpole and adult X. laevis indeed possess granulocyte-lineage cells within their epidermises that are distinct from their skin mast cells, which are found predominantly in lower dermal layers. These esterase-positive cells responded to (r)CXCL8a and rCXCL8b in a concentration- and CXCR1/CXCR2-dependent manner, possessed polymorphonuclear granulocyte morphology, granulocyte marker surface staining, and exhibited distinct immune gene expression from conventional granulocytes. Our past work indicates that CXCL8b recruits immunosuppressive granulocytes, and here we demonstrated that enriching esterase-positive skin granulocytes with rCXCL8b (but not rCXCL8a) may increase tadpole susceptibility to FV3 and adult frog susceptibility to Bd. Furthermore, pharmacological depletion of skin-resident granulocytes increased tadpole susceptibility to FV3. This manuscript provides new insights into the composition and roles of immune cells within the amphibian skin, which is a critical barrier against pathogenic contributors to the amphibian declines. - OPEN ACCESSHigh-latitude countries often contain the polar range edge of species that are common farther south, potentially focusing national conservation efforts toward range-edge populations. The global conservation value of edge populations is controversial, but if they occur where biodiversity is high, there need not be trade-offs in protecting them. Using 152 of 158 terrestrial mammal species in Canada, we tested how species’ distributions relate to their national conservation status and total mammal richness. We found that half of “Canadian” mammals had <20% of their global range in Canada. National threat status was strongly associated with range area; mammals considered “at risk” had 42% smaller Canadian ranges than mammals considered secure. However, after accounting for range area, taxa with smaller proportions of their global range in Canada were not more likely to be considered at risk, suggesting edge populations are not inherently more vulnerable. When we calculated mammal diversity across Canada (100 × 100 km grid cells), we found that hotspots of at-risk or range-edge mammals were twice as species rich as nonhotspot cells, containing up to 44% of Canadian mammal diversity per grid cell. Our results suggest that protecting areas with the most at-risk or range-edge mammals would simultaneously protect habitat for many species currently deemed secure.
- OPEN ACCESSThere is a gap between fundamental science and managers. There are many general solutions including the need to better leverage the primary scientific literature for decision-making. Herein, we provide a list of 10 simple rules to support environmental management through better scientific writing and suggest practices for more transparent publications. These rules can also be used as a checklist for reusing the primary literature when searching for relevant evidence in the environmental sciences. We need to better structure knowledge in papers for connections within sustainable societies.
- OPEN ACCESS
- Megan L. Larsen,
- Helen M. Baulch,
- Sherry L. Schiff,
- Dana F. Simon,
- Sébastien Sauvé, and
- Jason J. Venkiteswaran
The increasing prevalence of cyanobacteria-dominated harmful algal blooms is strongly associated with nutrient loading and changing climatic patterns. Changes to precipitation frequency and intensity, as predicted by current climate models, are likely to affect bloom development and composition through changes in nutrient fluxes and water column mixing. However, few studies have directly documented the effects of extreme precipitation events on cyanobacterial composition, biomass, and toxin production. We tracked changes in a eutrophic reservoir following an extreme precipitation event, describing an atypically early toxin-producing cyanobacterial bloom and successional progression of the phytoplankton community, toxins, and geochemistry. An increase in bioavailable phosphorus by more than 27-fold in surface waters preceded notable increases in Aphanizomenon flos-aquae throughout the reservoir approximately 2 weeks postevent and ∼5 weeks before blooms typically occur. Anabaenopeptin-A and three microcystin congeners (microcystin-LR, -YR, and -RR) were detected at varying levels across sites during the bloom period, which lasted between 3 and 5 weeks. These findings suggest extreme rainfall can trigger early cyanobacterial bloom initiation, effectively elongating the bloom season period of potential toxicity. However, effects will vary depending on factors including the timing of rainfall and reservoir physical structure. - OPEN ACCESS
- Nicole A. Lopez Vargas,
- Laura Adamovicz,
- Brittany Willeford,
- Brian F. Allan, and
- Matthew C. Allender
Ranaviruses are worldwide pathogens of ectothermic vertebrates that can threaten herptile conservation efforts. Identifying transmission routes is critical for understanding disease ecology and promoting species conservation. Frog virus 3 (FV3) DNA was detected in mosquitoes during a ranavirus outbreak in semicaptive box turtles, but the role that insect vectors play under natural conditions is unknown. To address this knowledge gap, we collected mosquito species known to take blood meals from reptiles and amphibians (Aedes canadensis, Culex erraticus, Culex territans, and Uranotaenia sapphirina) from mid-May to early August, 2014, at four study sites in Vermilion County, Illinois, two of which had historic or ongoing FV3 outbreaks in box turtles and amphibians. Mosquitoes were batched by date and species, DNA was extracted, and quantitative polymerase chain reaction was performed for detection of FV3. FV3 was not detected despite one of the sites having an active FV3 outbreak during the study period. Our findings indicate that FV3 detection is uncommon in mosquitoes during outbreak and nonoutbreak conditions at these sites in Illinois. Thus, we cannot establish that mosquitoes contribute to transmission during natural mortality events without performing further studies. - OPEN ACCESS
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- OPEN ACCESSMonarch butterflies (Danaus plexippus, Linnaeus, 1758) are comprised of two migratory populations separated by the Rocky Mountains and are renowned for their long-distance movements among the United States, Canada, and Mexico. Both populations have declined over several decades across North America prompting all three countries to evaluate conservation efforts. Monitoring monarch distribution and abundance is a necessary aspect of ongoing management in Canada where they are a species at risk. We used presence-only data from two citizen science data sets to estimate the annual breeding distribution of monarch butterflies in Canada between 2000 and 2015. Monarch breeding distribution in Canada varied widely among years owing to natural variation, and when considering the upper 95% of the probability of occurrence, the annual mean breeding distribution in Canada was 484 943 km2 (min: 173 449 km2; max: 1 425 835 km2). The area of occurrence was approximately an order of magnitude larger in eastern Canada than in western Canada. Habitat restoration for monarch butterflies in Canada should prioritize productive habitats in southern Ontario where monarchs occur annually and, therefore, likely contribute most to the long-term viability of monarchs in eastern North America. Overall, our assessment sets the geographic context to develop successful management strategies for monarchs in Canada.
- OPEN ACCESSThe salmon louse Lepeophtheirus salmonis (Krøyer 1837) displays numerous sexually dimorphic characteristics. Insights into their underlying molecular components have only recently been explored, which serve to better understand both the basic biology of the louse, associated impacts on drug sensitivity, and evolution of resistance. Expression of 16 L. salmonis genes putatively involved in sexual dimorphism and reproduction were used to determine differences between sexes and better understand responses to mating using RT-qPCR of pre-adult and adult lice. Analysis of these genes revealed the dynamic nature of sex-biased expression across stages. However, female reception of a spermatophore did not appear to impact the expression of these particular genes. Furthermore six of these transcripts and 84 others identified previously in a large-scale louse transcriptomics experiment were used to estimate differences in evolutionary rates and codon-usage bias of sex-related genes using phylogenetic analysis by maximum likelihood (PAML) and codonW. Results suggest male-biased genes are evolving at significantly greater rates than female-biased and unbiased genes as evidenced by higher rates of non-synonymous substitutions and lower codon-usage bias in these genes. These analyses expand our understanding of interactions of sex-biased expression across the pre-adult and adult life stages and provide foundations for better understanding evolutionary differences in sex-biased genes of L. salmonis.
- OPEN ACCESSAddition of nutrients, such as nitrogen, can degrade water quality in lakes, rivers, and estuaries. To predict the fate of nutrient inputs, an understanding of the biogeochemical cycling of nutrients is needed. We develop and employ a novel, parsimonious, process-based model of nitrogen concentrations and stable isotopes that quantifies the competing processes of volatilization, biological assimilation, nitrification, and denitrification in nutrient-impacted rivers. Calibration of the model to nitrogen discharges from two wastewater treatment plants in the Grand River, Ontario, Canada, show that ammonia volatilization was negligible relative to biological assimilation, nitrification, and denitrification within 5 km of the discharge points.
- OPEN ACCESS
- James M.C. Jones,
- Elizabeth A. Webb,
- Michael D.J. Lynch,
- Trevor C. Charles,
- Pedro M. Antunes, and
- Frédérique C. Guinel
Carbonatites are unusual alkaline rocks with diverse compositions. Although previous work has characterized the effects these rocks have on soils and plants, little is known about their impacts on local ecosystems. Using a deposit within the Great Lakes–St. Lawrence forest in northern Ontario, Canada, we investigated the effect of a carbonatite on soil chemistry and on the structure of plant and soil microbial communities. This was done using a vegetation survey conducted above and around the deposit, with corresponding soil samples collected for determining soil nutrient composition and for assessing microbial community structure using 16S/ITS Illumina Mi-Seq sequencing. In some soils above the deposit a soil chemical signature of the carbonatite was found, with the most important effect being an increase in soil pH compared with the non-deposit soils. Both plants and microorganisms responded to the altered soil chemistry: the plant communities present in carbonatite-impacted soils were dominated by ruderal species, and although differences in microbial communities across the surveyed areas were not obvious, the abundances of specific bacteria and fungi were reduced in response to the carbonatite. Overall, the deposit seems to have created microenvironments of relatively basic soil in an otherwise acidic forest soil. This study demonstrates for the first time how carbonatites can alter ecosystems in situ. - OPEN ACCESSCoastal biogenic habitats are vulnerable to human impacts from both terrestrial and marine realms. Yet the broad spatial scale used in current approaches of quantifying anthropogenic stressors is not relevant to the finer scales affecting most coastal habitats. We developed a standardized human impact metric that includes five bay-scale and four local-scale (0–1 km) terrestrial and marine-based impacts to quantify the magnitude of anthropogenic impacts to coastal bays and nearshore biogenic habitats. We applied this metric to 180 seagrass beds (Zostera marina), an important biogenic habitat prioritized for marine protection, in 52 bays across Atlantic Canada. The results show that seagrass beds and coastal bays exist across a wide human impact gradient and provide insight into which are the most and least affected by human threats. Generally, land alteration, nutrient loading, and shellfish aquaculture were higher in the Gulf of St. Lawrence, whereas invasive species and fishing activities were higher along the Atlantic coast. Sixty-four percent of bays were at risk of seagrass decline from nitrogen loading. We also found high within-bay variation in impact intensity, emphasizing the necessity of quantifying impacts at multiple spatial scales. We discuss implications for management and conservation planning, and application to other coastal habitats in Canada and beyond.
- OPEN ACCESS
- Beth C. Norman,
- Paul C. Frost,
- Graham C. Blakelock,
- Scott N. Higgins,
- Md Ehsanul Hoque,
- Jennifer L. Vincent,
- Katarina Cetinic, and
- Marguerite A. Xenopoulos
Silver nanoparticles (AgNPs) are an emerging class of contaminants with the potential to impact ecosystem structure and function. AgNPs are antimicrobial, suggesting that microbe-driven ecosystem functions may be particularly vulnerable to AgNP exposure. Predicting the environmental impacts of AgNPs requires in situ investigation of environmentally relevant dosing regimens over time scales that allow for ecosystem-level responses. We used 3000 L enclosures installed in a boreal lake to expose plankton communities to chronic and pulse AgNP dosing regimens with concentrations mimicking those recorded in natural waters. We compared temporal patterns of plankton responses, Ag accumulation, and ecosystem metabolism (i.e., daily ecosystem respiration, gross primary production, and net ecosystem production) for 6 weeks of chronic dosing and 3 weeks following a pulsed dose. Ag accumulated in microplankton and zooplankton, but carbon-specific Ag was nonlinear over time and generally did not predict plankton response. Ecosystem metabolism did not respond to either AgNP exposure type. This lack of response corresponded with weak microplankton responses in the chronic treatments but did not reflect the stronger microplankton response in the pulse treatment. Our results suggest that lake ecosystem metabolism is somewhat resistant to environmentally relevant concentrations of AgNPs and that organismal responses do not necessarily predict ecosystem-level responses. - OPEN ACCESSPrey individuals employ several adaptive behaviours to reduce predation risk. We need to learn how those behaviours interact in an overall strategy of risk management, how strategies vary with changing conditions, and whether some behaviours might compensate for others. I addressed these issues with manipulative experiments evaluating how snowshoe hares’ (Lepus americanus) vigilance varies with their giving-up densities (GUDs) in artificial food patches. I tested whether the results, collected when there was no evidence of predation, were congruent with an earlier study under higher predation. When predator sign was common, vigilance depended directly on habitat. But when risk was low, habitat’s influence on vigilance was indirect. Hares were least vigilant during the new moon where the distance to escape habitat was far, but only in open risky habitat. Hares were more vigilant during the full moon, but only at stations far from escape habitat. Moon phase and additional cover had no effect on GUDs that were highest at open risky stations far from escape habitat. The results suggest that reduced risk allowed hares to allocate less time to vigilance, but they needed to forage for similar amounts of food during each moon phase to maintain their energetic state.
- OPEN ACCESSThe use of fossil moth wing scales has recently been introduced as a new method to reconstruct population histories of lepidopterans and provide a proxy for insect disturbance. We investigated the potential for using wing-scale ultrastructure to distinguish between the five most common outbreak species of moth pests in eastern North America: spruce budworm (Choristoneura fumiferana Clemens), hemlock looper (Lambdina fiscellaria Guenée), forest tent caterpillar (Malacosoma disstria Hübner), blackheaded budworm (Acleris variana Fernie), and jack pine budworm (Choristoneura pinus Freeman). Using scanning electron images of scales, we made qualitative and quantitative comparisons of morphological traits at the ultrastructural level. We found that hemlock looper and eastern blackheaded budworm scales could be categorically separated from each other and from the three other species. We developed a quadratic discriminant function using measurements of ultrastructure traits that distinguishes scales of the three remaining species with an overall accuracy of 66%. We found that forest tent caterpillar could be well separated based on these traits, but we were less confident in distinguishing the closely related jack pine and spruce budworm. Our method offers potential advantages in scale identification for future studies in paleoecology, while providing the additional advantage of not requiring intact, unfolded, and undamaged scales.
- OPEN ACCESSWe report on the results of the first mark–recapture survey of freshwater turtles in an isolated urban wetland complex in one of Canada’s fastest growing municipalities. Although we found turtles in every surveyed wetland, the density and assemblage of turtles in smaller wetlands were significantly different than in larger wetland bodies. We also documented two species of turtles that were thought to be absent from this wetland complex, the Northern Map turtle and Eastern Musk turtle. We noted that a wetland that was bisected by a high-traffic road showed a male-skewed sex ratio in the population of Midland Painted turtles but not in the population of Eastern Snapping turtles. As a whole, the sex ratios inside the wetland complex were not skewed. These results reinforce the conclusions of a previous study of a single wetland within this same complex that had found a correlation between road mortality and a male-skewed sex ratio in Midland painted turtles. We discuss population sources and sinks within the complex and the importance of protecting the overland corridors that support the safe turtle movements within this provincially significant wetland complex.
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- OPEN ACCESSCimicid insects, bed bugs and their allies, include about 100 species of blood-feeding ectoparasites. Among them, a few have become widespread and abundant pests of humans. Cimicids vary in their degree of specialization to hosts. Whereas most species specialize on insectivorous birds or bats, the common bed bug can feed on a range of distantly related host species, such as bats, humans, and chickens. We suggest that association with humans and generalism in bed bugs led to fundamentally different living conditions that fostered rapid growth and expansion of their populations. We propose that the evolutionary and ecological success of common bed bugs reflected exploitation of large homeothermic hosts (humans) that sheltered in buildings. This was a departure from congeners whose hosts are much smaller and often heterothermic. We argue that interesting insights into the biology of pest species may be obtained using an integrated view of their ecology and evolution.
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Age matters: Submersion period shapes community composition of lake biofilms under glyphosate stress
The phosphonate herbicide glyphosate, which is the active ingredient in the commercial formulation Roundup®, is currently the most globally used herbicide. In aquatic ecosystems, periphytic biofilms, or periphyton, are at the base of food webs and are often the first communities to be in direct contact with runoff. Microcosm experiments were conducted to assess the effects of a pulse exposure of glyphosate on community composition and chlorophyll a concentrations of lake biofilms at different colonization stages (2 months, 1 year, and 20 years). This is the first study that uses such contrasting submersion periods. Biofilms were exposed to either environmental levels of pure analytical grade glyphosate (6 μg/L, 65 μg/L, and 600 μg/L) or to corresponding phosphorus concentrations. Community composition was determined by deep sequencing of the 18S and 16S rRNA genes to target eukaryotes and cyanobacteria, respectively. The results showed that submersion period was the only significant contributor to community structure. However, at the taxon level, the potentially toxic genus Anabaena was found to increase in relative abundance. We also observed that glyphosate releases phosphorus into the surrounding water, but not in a bioavailable form. The results of this study indicate that environmental concentrations of glyphosate do not seem to impact the community composition or metabolism of lake biofilms under pulse event conditions. - OPEN ACCESS
- OPEN ACCESSWe examined how Arctic spider (Araneae) biodiversity is distributed at multiple spatial scales in northern Canada using a standardized hierarchical sampling design. We investigated which drivers, environmental or spatial, influence the patterns observed. Spatial patterns of Arctic spider species richness and composition were assessed in 12 sites located in arctic, subarctic, and north boreal ecoclimatic regions, spanning 30 degrees of latitude and 80 degrees of longitude. Variation in diversity was partitioned in relation to multiple environmental and spatial drivers of diversity patterns. Over 23 000 adult spiders, representing 306 species in 14 families, were collected in northern Canada, with 107 species (35% of the total species collected) representing new territorial or provincial records. Spider diversity was structured at the regional scale across ecoclimatic regions but was not structured with latitude. Longitudinal patterns of spider diversity across Canada may be explained by post-glacial dispersal. At local scales, diversity was non-randomly distributed and possibly limited by biotic interactions. We recommend the use of ecoclimatic regions as a framework for conservation of biodiversity in northern Canada and spiders as useful bioindicators that can help us understand the effects of climate change across ecoclimatic regions of northern Canada.
- OPEN ACCESSMercury (Hg) and polycyclic aromatic hydrocarbons (PAHs) are global pollutants known for their toxicity to wildlife. Because of their trophic position, common loons (Gavia immer (Brünnich 1764)) are excellent indicators of environmental quality. In 2014 and 2015, tissue samples of ten adult common loons (plus one recapture) were obtained in Meadow Lake Provincial Park, Saskatchewan, and assessed for Hg and PAH exposure. Blood and feather levels of these contaminants are indicative of exposure during breeding and in wintering areas, respectively. Compared with an international Hg database, blood Hg levels were low (<1 μg/g). In most loons (90.5%, 10 out of 11), blood PAH concentrations were also low (<10 ng/g), but high (120 ng/g) for one individual (9.5% 1 out of 11). Feather PAH concentrations were high (95.9 ng/g and 250.6 ng/g) in two of the four loons (50%) caught in 2015. These data indicate that loons breeding in Meadow Lake Provincial Park were exposed to low levels of Hg; however, some individuals are being exposed to PAHs in both their breeding and wintering locations. The effect of these environmental pollutants on individual loon fitness is unclear, but because of their extreme toxicity in biological systems we suggest that future monitoring in the surrounding region is warranted.
- OPEN ACCESSHoney bees (Apis mellifera Linnaeus, 1758) potentially rely on a variety of visual cues when searching for flowers in the environment. Both chromatic and achromatic (brightness) components of flower signals have typically been considered simultaneously to understand how flower colours have evolved. However, it is unclear whether honey bees actually use brightness information in their colour perception. We investigated whether free-flying honey bees can process brightness cues in achromatic stimuli when presented at a large visual angle of 28° to ensure colour processing. We found that green contrast (modulation of the green receptor against the background) and brightness contrast (modulation of all three receptors against the background) did not have a significant effect on the proportion of correct choices made by bees, indicating that they did not appear to use brightness cues in a colour processing context. Our findings also reveal that, even at a small visual angle, honeybees do not reliably process single targets solely based on achromatic information, at least considering values up to 60% modulation of brightness. We discuss these findings in relation to proposed models of bee colour processing. Therefore, caution should be taken when interpreting elemental components of complex flower colours as perceived by different animals.
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- Julio Mercader,
- Tolutope Akeju,
- Melisa Brown,
- Mariam Bundala,
- Matthew J. Collins,
- Les Copeland,
- Alison Crowther,
- Peter Dunfield,
- Amanda Henry,
- Jamie Inwood,
- Makarius Itambu,
- Joong-Jae Kim,
- Steve Larter,
- Laura Longo,
- Thomas Oldenburg,
- Robert Patalano,
- Ramaswami Sammynaiken,
- María Soto,
- Robert Tyler, and
- Hermine Xhauflair
Ancient starch research illuminates aspects of human ecology and economic botany that drove human evolution and cultural complexity over time, with a special emphasis on past technology, diet, health, and adaptation to changing environments and socio-economic systems. However, lapses in prevailing starch research demonstrate the exaggerated expectations for the field that have been generated over the last few decades. This includes an absence of explanation for the millennial-scale survivability of a biochemically degradable polymer, and difficulties in establishing authenticity and taxonomic identification. This paper outlines new taphonomic and authenticity criteria to guide future work toward designing research programs that fully exploit the potential of ancient starch while considering growing demands from readers, editors, and reviewers that look for objective compositional identification of putatively ancient starch granules. - OPEN ACCESS
- Emily M. Merlo,
- Kathryn A. Milligan,
- Nola B. Sheets,
- Christopher J. Neufeld,
- Tao M. Eastham,
- A.L. Ka’ala Estores-Pacheco,
- Dirk Steinke,
- Paul D.N. Hebert,
- Ángel Valdés, and
- Russell C. Wyeth
The mollusc nudibranch genus Hermissenda Bergh, 1879 was recently discovered to include three pseudocryptic species, dividing a single species H. crassicornis (sensu lato) into H. crassicornis Escholtz, 1831, H. opalescens J.G. Cooper, 1863, and H. emurai Baba, 1937. The species were distinguished by both genetic and morphological evidence, and the distribution of sampled animals suggested the three species had mostly distinct geographical ranges. Here, we report the presence of both H. crassicornis and H. opalescens in Barkley and Clayoquot Sounds, British Columbia, Canada, based on diagnostic characters and molecular data congruent with the differences described for these two species. This result extends the region of sympatry for the two species from northern California, USA, to, at least, Vancouver Island, British Columbia in 2016. Depending on how long this overlap has occurred, the possible northward expansion of H. opalescens would have implications for understanding the effects of short- or long-term environmental changes in ocean temperatures as well as complicating the interpretation of past neurobiological studies of H. crassicornis (sensu lato). - OPEN ACCESSThreespine stickleback (Gasterosteus aculeatus Linnaeus, 1758) exhibit a well-documented reduction in plate number associated with adaptation to freshwater environments. We tested the hypothesis that changes in plate number are accompanied by changes in plate bone mineral density and plate shape, reflecting the presence of a complex plate “armour” phenotype and a complex adaptive response to different selective pressures in changing habitats. We used traditional and novel morphometric techniques to characterize armour traits from stickleback occupying three marine habitats and one tidally influenced freshwater stream in southwestern British Columbia. Stickleback inhabiting marine environments share a conserved plate phenotype that includes a full complement of highly mineralized plates that exhibit a characteristic density profile along the plate. Stickleback inhabiting tidally influenced fresh water display an average reduction in plate number along with increased variation in number and reduced total mineralization despite maintenance of a marine-like density profile. Further, we found that although mineralization and armour shape are correlated with size, after accounting for size variation in both traits remains attributable to habitat. Our results hint at an important role for development in structuring phenotypic variation during the process of adaptive change in stickleback.
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- OPEN ACCESSPrey individuals possess four basic strategies to manage predation risk while foraging: time allocation, space use, apprehension, and foraging tenacity. But there are no direct tests of theory detailing how spatial strategies change and covary from fine to coarse scales of environmental variability. We address this shortcoming with experiments that estimated space use and vigilance of snowshoe hares while we measured foraging tenacity in artificial resource patches placed in risky open versus safe alder habitat. Hares employed only two of eight a priori options to manage risk. Hares increased vigilance and reduced foraging in open areas as the distance from cover increased. Hares did not differentiate between open and alder habitats, increase vigilance at the coarse-grained scale, or reduce vigilance and foraging tenacity under supplemental cover. Hares were more vigilant in the putatively safe alder than in the purportedly risky open habitat. These apparently paradoxical results appear to reflect a trade-off between the benefit of alder as escape habitat and the cost of obscured sight lines that reduce predator detection. The trade-off also appears to equalize safety between habitats at small scales and suggests that common-sense predictions detailing how prey reduce risk may make no sense at all.
- OPEN ACCESSThe Prairie Pothole Region (PPR) in the northern Great Plains is an area of ecological significance, serving as an important breeding site for avian wildlife. However, organisms feeding within the PPR may be at risk of mercury (Hg) exposure due to deposition of anthropogenic emissions and the high Hg methylation potential of PPR wetlands. We quantified Hg concentrations in red-winged blackbirds’ (Agelaius phoeniceus (Linnaeus, 1766); RWBLs) blood, feathers, and eggs in the spring and summer breeding season and compared our values with those from RWBLs sampled from ecoregions across North America. Hg concentrations in whole water, aeshnid dragonfly nymphs, and RWBL tissues varied by wetland and were below those considered to elicit acute effects in wildlife, and egg total Hg (THg) concentrations were significantly related to spring whole water methylmercury concentrations. Only RWBL blood THg concentrations showed a clear increase in summer compared with spring, resulting in decoupling of summer blood and feather THg concentrations. Moreover, blood THg concentrations varied by ecoregion, with those impacted by an industrial point source exhibiting high Hg levels. Our study emphasizes that tissue renewal time as well as ecological factors such as competition and diet shifts are important considerations when using RWBLs to assess biological Hg exposure.
- OPEN ACCESSMercury (Hg) in wildlife remains of great concern, especially for apex piscivores. Despite this, exposure information from many species in many areas is lacking, so that management decisions are hampered. Here we examine Hg concentrations in fur, liver, and kidney tissues from river otters (Lontra canadensis (Schreber, 1777)) (n = 203) to quantify existing Hg concentrations over a broad geographic area in Saskatchewan. Mean fur total Hg (THg) (9.68 ± 7.52 mg/kg fresh weight (f.w.)) was significantly correlated with THg and organic Hg (OHg) in liver and kidney tissue, showcasing the potential for using fur as a noninvasive method of monitoring Hg in top-level mammals. Livers of males had higher mean OHg concentrations than livers of females (males: 2.71 mg/kg d.w., females: 1.87 mg/kg d.w.), but not significantly so. No sex-related differences were observed in kidney OHg concentrations. THg concentrations in otter fur collected in the Boreal Shield ecozone (Churchill River Upland) were significantly higher (mean = 16.1 mg/kg f.w.) than in otter fur collected from the Boreal Plain ecozone (mean = 8.59 mg/kg f.w.). Fur from otters (n = 20; trapping block N66) trapped near a decommissioned smelter contained the highest concentrations of THg in the study (mean = 18.4 mg/kg f.w.).
- OPEN ACCESSRecently, the use of small-bodied fish in environmental monitoring has increased, particularly within the Canadian environmental effects monitoring (EEM) and other adaptive programs. Although it is possible to measure changes with many small-bodied species, interpretation is often complicated by the absence of information on the biology and ecology of fish not of commercial, recreational, or traditional interest. Knowing and understanding the basic biology of these fishes aids in the sensitivity of study designs (i.e., ability to detect change) and the interpretation of all biological levels of responses (e.g., cellular to community). The increased use of slimy sculpin (Cottus cognatus Richardson, 1836) in impact assessment studies in North America provides a considerable amount of information on life history aspects. The slimy sculpin has the most ubiquitous North American distribution among cottids but yet has a very small home range, thus integrating environmental conditions of localized areas. This paper describes aspects of slimy sculpin life cycle that affect collection efficiency and timing, and describes and provides data collected over more than 10 years of studies at more than 20 reference study sites. This overview provides a functional and informative compilation to support adaptive environmental monitoring and provide a baseline for comparative ecological study.
- OPEN ACCESSDistinguishing between intra- and inter-specific variation in genetic studies is critical to understanding evolution because the mechanisms driving change among populations are expected to be different than those that shape reproductive isolation among lineages. Genetic studies of north Atlantic green sea urchins Strongylocentrotus droebachiensis (Müller, 1776) have detected significant population substructure and asymmetric gene flow from Europe to Atlantic Canada and interspecific hybridization between S. droebachiensis and Strongylocentrotus pallidus (Sars, 1871). However, combined with patterns of divergence at mtDNA sequences, morphological divergence at gamete traits suggests that the European and North American lineages of S. droebachiensis may be cryptic species. Here, we use a combination of cytochrome c oxidase subunit I (COI) sequences and single nucleotide polymorphisms (SNPs) to test for cryptic species within Strongylocentrotus sea urchins and hybrids between S. droebachiensis and S. pallidus populations. We detect striking patterns of habitat and reproductive isolation between two S. droebachiensis lineages, with offshore deep-water collections consisting of S. pallidus in addition to a cryptic lineage sharing genetic similarity with previously published sequences from eastern Atlantic S. droebachiensis. We detected only limited hybridization among all three lineages of sea urchins, suggesting that shared genetic differences previously reported may be a result of historical introgression or incomplete lineage sorting.
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- Michael R.S. Coffin,
- Simon C. Courtenay,
- Kyle M. Knysh,
- Christina C. Pater, and
- Michael R. van den Heuvel
In this study, we examined the effects of dissolved oxygen, via metrics based on hourly measurements, and other environmental variables on invertebrate assemblages in estuaries spanning a gradient of nutrient loading and geography in the southern Gulf of St. Lawrence, Canada. Upper areas (15–25 practical salinity units (PSU)) of 13 estuaries that were dominated by either seagrass (Zostera marina Linnaeus, 1753) or macroalgae (Ulva spp. Linnaeus, 1753) were sampled from June to September 2013. Macroinvertebrate assemblages from Z. marina were found to be distinct from Ulva assemblages for both epifauna and infauna. Small snails dominated each vegetation type, specifically cerithids in Z. marina and hydrobids in Ulva. Although Z. marina had higher species richness, approximately 70% of species were common to both habitats. Faunal communities differed among estuaries with large, within-estuary, temporal variance only observed at Ulva sites impacted by hypoxia and particularly at sites with long water residence time. Indeed, abundances varied by several orders of magnitude in Ulva ranging from zero to thousands of macroinvertebrates. There was a strong negative correlation between hypoxic or anoxic water, 48 h prior to sampling, with relative abundances of amphipods, and a positive correlation with the relative abundances of snails. As one of the first studies to use high-frequency oxygen monitoring, this study revealed probable impacts and the transient nature of hypoxia in eutrophication. - OPEN ACCESSIn some species where males make no direct contribution to a female’s lifetime reproductive success, females choose mates based on the indirect benefits manifested in their offspring. One trait that may be subject to this sexual selection is immunocompetence (the ability to mount an immune response following exposure to pathogens); however, the results of previous work on its link to male attractiveness have been ambiguous. Herein we examine the life history consequences of mating with males with a history of failure or success in reproductive competitions in Drosophila melanogaster. By examining egg-to-adult survival, body weights, and bacterial loads of offspring reared in either the absence or presence of a bacterial pathogen, we were able to examine whether sire reproductive success was associated with their offsprings’ ability to respond to an immunological challenge and other life history traits. Our results are partially consistent with the predictions of the “immunocompetence handicap hypothesis”: competitively successful males (“studs”) sire male offspring that are better able to handle an immunological challenge than those sired by competitively unsuccessful males (“duds”). However, our assay also revealed the opposite pattern in female offspring, suggestive of the complicating presence of alleles with sexually antagonistic effects on the expression of this important life history trait.
- OPEN ACCESSWith increasing input of neurotoxic mercury to environments as a result of anthropogenic activity, it has become imperative to examine how mercury may enter biotic systems through its methylation to bioavailable forms in aquatic environments. Recent development of stable isotope-based methods in methylation studies has enabled a better understanding of the factors controlling methylation in aquatic systems. In addition, the identification and tracking of the hgcAB gene cluster, which is necessary for methylation, has broadened the range of known methylators and methylation-conducive environments. Study of abiotic factors in methylation with new molecular methods (the use of stable isotopes and genomic methods) has helped elucidate the confounding influences of many environmental factors, as these methods enable the examination of their direct effects instead of merely correlative observations. Such developments will be helpful in the finer characterization of mercury biogeochemical cycles, which will enable better predictions of the potential effects of climate change on mercury methylation in aquatic systems and, by extension, the threat this may pose to biota.
- OPEN ACCESSAcanthodians may represent a paraphyletic assemblage of stem chondrichthyans, stem osteichthyans, stem gnathostomes, or some combination of the three. One of the difficulties in determining the phylogenetic affinities of this group of mostly small, spiny fishes is that several subgroups of acanthodians are represented by relatively little information in the fossil record. It is becoming increasingly apparent that to understand the evolution of gnathostomes, we must understand more about acanthodians. This study uses micro-computed tomography to test hypotheses about acanthodian jaw function, and in doing so provides insight into the form, function, and ecological role of ischnacanthiform acanthodian jaws and teeth from an extraordinary Early Devonian fossil locality in the Northwest Territories of Canada. The results of this study suggest that ischnacanthiform acanthodians may have coexisted by trophic niche differentiation, employing specialized feeding strategies during the Silurian and Early Devonian.