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- OPEN ACCESS
- Claire N. Freeman,
- Lena Scriver,
- Kara D. Neudorf,
- Lisbeth Truelstrup Hansen,
- Rob C. Jamieson, and
- Christopher K. Yost
Wastewater treatment plants (WWTPs) have been identified as hotspots for antimicrobial resistance genes (ARGs) and thus represent a critical point where patterns in ARG abundances can be monitored prior to their release into the environment. The aim of the current study was to measure the impact of the release of the final treated effluent (FE) on the abundance of ARGs in the receiving water of a recently upgraded WWTP in the Canadian prairies. Sample nutrient content (phosphorous and nitrogen species) was measured as a proxy for WWTP functional performance, and quantitative PCR (qPCR) was used to measure the abundance of eight ARGs, the intI1 gene associated with class I integrons, and the 16S rRNA gene. The genes ermB, sul1, intI1, blaCTX-M, qnrS, and tetO all had higher abundances downstream of the WWTP, consistent with the genes with highest abundance in the FE. These findings are consistent with the increasing evidence suggesting that human activity affects the abundances of ARGs in the environment. Although the degree of risk associated with releasing ARGs into the environment is still unclear, understanding the environmental dimension of this threat will help develop informed management policies to reduce the spread of antibiotic resistance and protect public health. - 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 ACCESSAn increase in greenhouse gas emissions has led to a rise in average global air and ocean temperatures. Increased sea surface temperatures can cause changes in species’ distributions, particularly those species close to their thermal tolerance limits. We use a bioclimate envelope approach to assess potential shifts in the range of marine macroalgae harvested in North American waters: rockweed (Fucus vesiculosus Linnaeus, 1753), serrated wrack (Fucus serratus Linnaeus, 1753), knotted wrack (Ascophyllum nodosum (Linnaeus) Le Jolis, 1863), carrageen moss (Chondrus crispus Stackhouse, 1797), and three kelp species (Laminaria digitata (Hudson) J.V. Lamouroux, 1813; Saccharina latissima (Linnaeus) C.E. Lane, C. Mayes, Druehl et G.W. Saunders, 2006; and Saccharina longicruris (Bachelot de la Pylaie) Kuntze, 1891). We determined species’ thermal limits from the current sea surface temperatures associated with their geographical distributions. Future distributions were based on sea surface temperatures projected for the year ∼2100 by four atmosphere-ocean general circulation models and earth system models for regional concentration pathways (RCPs) 4.5 and 8.5. Future distributions based on RCP 8.5 indicate that the presence of all but rockweed (F. vesiculosus) is likely to be threatened by warming waters in the Gulf of St. Lawrence and along the Atlantic coast of Nova Scotia. Range retractions of macroalgae will have significant ecological and economic effects including impacts on commercial fisheries and harvest rates and losses of floral and faunal biodiversity and production, and should be considered in the designation of marine protected areas.
- OPEN ACCESSA distributed optical strain-sensing technique is presented as a solution for measuring the strain distribution along ground support members used in tunnelling and mining works. The technique employs a Rayleigh optical frequency domain reflectometry technology, which measures strain at a spatial resolution of 0.65 mm along the length of a standard optical fiber. A rationale for selecting this technology as a potential monitoring technique for ground support elements over alternative commercially available technologies is discussed. The development of a technique to couple optical fiber sensors with rock bolt, umbrella arch, and cable bolt support members is also demonstrated. A robust laboratory investigation of such optically instrumented support members demonstrated the capability of the technique to capture the expected in situ support behaviour in the form of coaxial, lateral, and shear loading arrangements as would be anticipated in the field. Moreover, the micro-scale data obtained by this optical sensing technique are shown to provide unprecedented insight into the local/micro-scale geomechanistic complexities associated with the bearing capacity of ground support members, especially when compared with data obtained by discrete strain-sensing technologies.
- OPEN ACCESSInnovative, highly processed foods are often designed to “substitute” for traditional, less-processed items in the diet. Yet, concerns about the unhealthfulness of diets high in highly processed foods are growing. Their dominance in the diet has been hypothesized to relate, in part, to the strategic use of on-package nutrition promotion. Our goal was to compare front-of-package (FOP) labelling on highly processed products that appear to have been explicitly designed as substitutes for traditional foods with the FOP labelling on their traditional counterparts. FOP references were recorded from packaged foods in three major Toronto grocery stores (N = 20520). Foods were categorized as substitute or traditional counterparts if these had (1) immediate interchangeability within the diet, (2) inherently different formulation, and (3) the substitute was more heavily processed than its traditional counterpart. Eight substitute–traditional pairs were identified, comprising 18% of products in the data set. Substitute foods were more likely than traditional products to bear FOP nutrition, “organic”, and “natural” references. Substitute foods bore 1.21 times more FOP references, the majority of which highlighted nutrients inherent to the traditional counterpart. Our findings support the contention that highly processed foods may be displacing less-processed foods at least in part through the use of strategic on-package marketing.
- OPEN ACCESSIn 1956, Shell Oil Company geologist M. King Hubbert published a model for the growth and decline over time of the production rates of oil extracted from the land mass of the continental US. Employing an estimate for the amount of ultimately recoverable oil and a logistic curve for the oil production rate, he accurately predicted a peak in US oil production for 1970. His arguments and the success of his prediction have been much celebrated, and the original paper has 1400 publication citations to date. The theory of “peak oil” (and subsequently, of natural resource scarcity in general) has consequently become associated with Hubbert and “Hubbert” curves and models. However, his prediction for the timing of a world peak oil production rate and the subsequent predictions of many others have proven inaccurate. We revisit the Hubbert model for oil extraction and provide an analysis of it and several variants in the language of (time) autonomous differential equations.
- OPEN ACCESSNovel, non-invasive, painless oral therapeutic agents are needed to replace the painful conventional treatment of arsenic-associated health hazards with metal chelators. Our aim was to examine the effect of spirulina (Spirulina platensis (Geitler, 1925)) on arsenic-mediated uterine toxicity. Female Wistar rats were divided equally into four experimental treatment groups: control group, sodium arsenite group (1.0 mg/100 g body mass), spirulina placebo group (20 mg/100 g body mass), and sodium arsenite + spirulina group. In contrast with the control group, spectrophotometric and electrozymographic evaluation revealed that rats that ingested arsenic for 8 d showed significant diminution of the activities of superoxide dismutase, catalase, and peroxidase (p < 0.001). Mutagenic uterine DNA breakage and tissue damage were prominent following arsenic consumption by the rats. Oral delivery of spirulina resulted in a significant amelioration of arsenic-induced adverse oxidative stress and genotoxic state of rats. A significant low-signaling (p < 0.001) of gonadotropins and estradiol was also noted in the arsenic-treated rats, which was terminated by spirulina; this arsenic-primed adverse effect was significant (p < 0.05, p < 0.01). The spirulina treatment mechanism could be associated with augmentation of the antioxidant defense system that protects the arsenic-mediated pathological state of the uterus.
- OPEN ACCESS
- Angela L. Shamchuk,
- Brian J. Blunt,
- Danielle D. Lyons,
- Mo Qi Wang,
- Anastasia Gasheva,
- Carlie R. Lewis,
- Kirsten Tomlin,
- E. Starr Hazard,
- Gary Hardiman, and
- Keith B. Tierney
The sensory system of animals detects a massive and unknown array of chemical cues that evoke a diversity of physiological and behavioural responses. One group of nitrogen-containing carbon ring chemicals—nucleobases—are thought to be involved in numerous behaviours yet have received little attention. We took a top-down approach to examine responses evoked by nucleobases at behavioural, tissue, and gene expression levels. Fish generally avoided nucleobases, and this behaviour, when observed, was driven by purines but not pyrimidines. At the tissue level, olfactory neuron generator potential responses tended to be concentration specific and robust at concentrations lower than amino acid detection ranges. In terms of gene expression, more than 2000 genes were significantly upregulated following nucleobase exposure, some of which were expected (e.g., genes involved in purine binding) and some of which were not (e.g., tubulin-related genes). Humanized RNA pathway analysis showed that we had exposed the animal to a nucleobase. Our data indicate that responses to nucleobase-containing compounds may be highly structure based and are evident from changes in behaviour to mRNA expression. Many of these responses were surprising, and all provide numerous routes for further research endeavour. - OPEN ACCESSAichi Biodiversity Target 19 calls on Parties to the United Nations Convention on Biological Diversity (CBD) to improve, share, transfer, and apply knowledge. In this study, we provide an initial assessment of the state of evidence-based decision-making in Canada’s protected areas organizations by examining (1) the value and use of various forms of evidence by managers and (2) the extent to which institutional conditions enable or inhibit the use of evidence in decision-making. Results revealed that although managers value and use many forms of evidence in their decision-making, information produced by staff and their organizations are given priority. Other forms of evidence, such as Indigenous knowledge and peer-reviewed information, are valued and used less. The most significant barriers to evidence-based decision-making were limited financial resources, lack of staff, inadequate timeframes for decision-making, a lack of monitoring programs, and a disconnect between researchers and decision-makers. Overall, our results suggest that the potential benefits of evidence-based approaches are not being maximized in Canada’s protected areas organizations. We propose several recommendations to introduce or improve the use of diverse forms of evidence to enhance management effectiveness of Canada’s protected areas and by extension conservation outcomes.
- OPEN ACCESSThe Canadian Environmental Protection Act (CEPA) enables the Minister of Environment and Climate Change to develop policy to curtail international air pollution. However, regional air pollution generated during the manufacturing of products outside of Canada is not addressed in CEPA. Using cement manufacturing in China as a case study, three policy options were devised to manage export-based regional air pollution. The options investigated included Policy 1—an open border with direct support for domestic cement manufacturers, Policy 2—a restricted border with no support for domestic cement manufacturers, and Policy 3—a selective border with partial support for domestic cement manufacturers. An analytic hierarchy process, in conjunction with the three actionable solidarities of cultural theory, was applied to the policy options and their supporting mechanisms. Results indicated that Policy 3 was strongly favoured (52.5%), followed by Policy 2 (33.4%), with Policy 1 being the least favoured (14.2%). Regarding policy mechanisms, a verification process was preferred by all three solidarities. From the standpoint of a universal approach to trade it is recommended that an air quality agreement between China and Canada under CEPA be established with a framework to eventually incorporate environmental production declarations. With respect to cement exports, it is recommended that manufacturers in China provide emissions intensities and winter smog assessments.
- OPEN ACCESS
- Leonora King,
- Lucy MacKenzie,
- Marc Tadaki,
- Sara Cannon,
- Kiely McFarlane,
- David Reid, and
- Michele Koppes
Effective policies promoting diversity in geoscience require understanding of how the values and practices of the community support the inclusion of different social groups. As sites of knowledge exchange and professional development, academic conferences are important culturing institutions that can alleviate or reproduce barriers to diversity in geoscience. This study examines diversity at a 2017 geoscience conference, the joint Canadian Geophysical Union and Canadian Society of Agricultural and Forest Meteorology annual meeting, through observation of participation, presentation content, and behaviour in conference sessions. Across 256 observed presentations, women constituted 28% of speakers, whereas women of colour made up only 5%. Participation rates differed between disciplinary sections, with the most populous sessions (Hydrology and Earth Surface) having the lowest percentage of women. Examination of presentation content reveals that the methods and scholarly contributions of both women and people of colour differed from the majority, suggesting an intellectual division of labour in geoscience. Examination of audience behaviours between presenters reveals how a “chilly climate” can be experienced by women and other marginalized demographics in conferences. We argue that there is more to be done than simply increasing numbers of women or other minorities in geoscientific spaces, and we suggest pathways to making geoscience a more inclusive and democratic pursuit. - OPEN ACCESS
- Krishna K. Thakur,
- Raphaël Vanderstichel,
- Shaorong Li,
- Emilie Laurin,
- Strahan Tucker,
- Chrys Neville,
- Amy Tabata, and
- Kristina M. Miller
Infectious diseases are likely contributing to large-scale declines in chinook salmon stocks in the Pacific Northwest, but the specific agents and diseases involved, and the prevalences in migratory salmon, are mostly unknown. We applied a high-throughput microfluidics platform to screen for 45 infectious agents in 556 out-migrating juvenile chinook salmon, collected from freshwater (FW) and saltwater (SW) locations in the Cowichan River system on Vancouver Island, Canada, during 2014. Nineteen agents (5 bacterial, 2 viral, and 12 parasitic) were detected, with prevalences ranging from 0.2% to 57.6%. Co-infections between Candidatus Branchiomonas cysticola Toenshoff, Kvellestad, Mitchell, Steinum, Falk, Colquhoun & Horn, 2012, Paranucleospora theridion Nylund, Nylund, Watanabe, Arnesen & Kalrsbakk, 2010, and gill chlamydia, all associated with gill disease, were observed in SW samples. We detected agents known to cause large-scale mortalities in Pacific salmon (Ceratonova shasta (Noble, 1950), Parvicapsula minibicornis Kent, Whitaker & Dawe, 1977), and agents only recently reported in Pacific salmon in BC (Ca. B. cysticola, P. theridion, Facilispora margolisi Jones, Prosperi-Porta & Kim, 2012 and Parvicapsula pseudobranchicola Karlsbakk, Saether, Hostlund, Fjellsoy & Nylund, 2002). Wild and hatchery fish were most divergent in agent profiles in FW, with higher agent diversity in wild fish. Differences in prevalence largely dissipated once they converged in the marine environment, although hatchery fish may be infected by a greater diversity of agents sooner after ocean entry by virtue of their more rapid migration from nearshore to offshore environments. - OPEN ACCESSNickel (Ni) leaching from oil sands petroleum coke can have toxicological effects on aquatic organisms. However, geochemical controls on Ni release, transport, and attenuation within coke deposits remains limited. We examined the geochemistry of fluid coke and associated pore waters from two deposits at an oil sands mine near Fort McMurray, Alberta, Canada. Synchrotron-based micro-X-ray fluorescence (μXRF) and micro-X-ray absorption near edge structure (μXANES) spectroscopy show that Ni(II)-porphyrin complexes dominate, but inorganic phases including Ni(II)-sulfide and Ni(II)-oxide comprise a minor component of fluid coke. Sequential chemical extractions suggested that sorption–desorption reactions may influence Ni mobility within fluid coke deposits. Although only a small proportion of total Ni (<4%) is susceptible to leaching under environmentally relevant concentrations, dissolved Ni concentrations (n = 65) range from 2 to 120 μg·L−1 (median 7.8 μg·L−1) within the two deposits and generally decrease with depth below the water table. Pore water Ni concentrations are negatively correlated with pH, but not with dissolved sulfate, bicarbonate, or chloride. Overall, our findings suggest that pore water pH and sorption–desorption reactions are principal controls on dissolved Ni concentrations within oil sands fluid petroleum coke deposits.
- 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.
- OPEN ACCESSThe constitutive regenerative ability of the goldfish central nervous system makes them an excellent model organism to study neurogenesis. Intraperitoneal injection of neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was used to deplete tyrosine hydroxylase-positive neurons in the adult goldfish telencephalon. We report novel information on the ability of the goldfish to regenerate (∼3–4 d post-MPTP insult) damaged neurons in telencephalic tissue by observing the rapid incorporation of bromodeoxyuridine into newly generated cells, which precedes the recovery of motor function in MPTP-treated animals. Specifically, the telencephalon area telencephali pars dorsalis in female goldfish, which is associated with fish motor activity, regenerates following MPTP toxicity. The remarkable ability of goldfish to rapidly regenerate damaged neurons provides insight into their use as model organisms to study neuroregenerative abilities within a few days following injury. We provide evidence that goldfish are able to regenerate neurons in ∼3–4 d to both replenish and recover baseline catecholaminergic levels, thus enabling the fish to reestablish basic activities such as swimming. The study of neuron regeneration in the damaged goldfish brain will increase our understanding of vertebrate neurogenesis and regeneration processes following central nervous system injury.
- 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.
- OPEN ACCESSThe measurement of statistical evidence is of considerable current interest in fields where statistical criteria are used to determine knowledge. The most commonly used approach to measuring such evidence is through the use of p-values, even though these are known to possess a number of properties that lead to doubts concerning their validity as measures of evidence. It is less well known that there are alternatives with the desired properties of a measure of statistical evidence. The measure of evidence given by the relative belief ratio is employed in this paper. A relative belief multiple testing algorithm was developed to control for false positives and false negatives through bounds on the evidence determined by measures of bias. The relative belief multiple testing algorithm was shown to be consistent and to possess an optimal property when considering the testing of a hypothesis randomly chosen from the collection of considered hypotheses. The relative belief multiple testing algorithm was applied to the problem of inducing sparsity. Priors were chosen via elicitation, and sparsity was induced only when justified by the evidence and there was no dependence on any particular form of a prior for this purpose.
- OPEN ACCESSThere have been strong calls for scientists to share their discoveries with society. Some scientists have heeded these calls through social media platforms such as Twitter. Here, we ask whether Twitter allows scientists to promote their findings primarily to other scientists (“inreach”), or whether it can help them reach broader, non-scientific audiences (“outreach”). We analyzed the Twitter followers of more than 100 faculty members in ecology and evolutionary biology and found that their followers are, on average, predominantly (∼55%) other scientists. However, beyond a threshold of ∼1000 followers, the range of follower types became more diverse and included research and educational organizations, media, members of the public with no stated association with science, and a small number of decision-makers. This varied audience was, in turn, followed by more people, resulting in an exponential increase in the social media reach of tweeting academic scientists. Tweeting, therefore, has the potential to disseminate scientific information widely after initial efforts to gain followers. These results should encourage scientists to invest in building a social media presence for scientific outreach.
- OPEN ACCESSOrganic waste, which contains essential plant nutrients such as phosphorus, constitutes 30%–50% of municipal solid waste in developed countries. Unfortunately, much of this resource is buried in landfills or incinerated. Many jurisdictions have, therefore, adopted the diversion of organic waste and the recycling of nutrients as policy goals. We used data sets from Europe and Ontario, Canada, to explore the impact of socio-economic and management factors on the rates of organic waste diversion and examined the effect of this diversion on phosphorus recycling. Organic diversion rates were highly correlated with income in Europe and with infrastructure, such as source-separated organic waste collection, in Ontario. Significant correlations were also observed between diversion rates and the use of policy instruments such as economic incentives, legislative organic waste bans, and curbside bag limits. We estimated that 39%–63% of the phosphorus in diverted organics is returned to arable land. Ultimately, we found that although socio-economic factors influence the success of organic waste diversion, policies, accessible infrastructure, economic incentives, and legislative requirements can be leveraged to improve the recycling rate of organic waste and the nutrients they contain.
- 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.