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Rock glaciers have been the subject of extensive research in recent years due to their potential to serve as indicators of past and present climate conditions and their potential impacts on water resources. Location and descriptive rock glacier data within the Mackenzie Mountains were used to build a rock glacier inventory that will serve as a valuable resource for future research and monitoring efforts. Additionally, this study maps the likelihood of rock glacier presence using extracted variables in a generalized additive model (GAM). The model incorporates attribute data, including potential incoming solar radiation (PISR), topographic position index (TPI), slope, elevation, and lithology as controls for rock glacier development. Topographic data were compiled for three study regions of the Mackenzie Mountains from a 30 m digital elevation model (DEM). The analysis of the GAM showed that the most significant explanatory variables were PISR, elevation, slope, and TPI. The GAM model had an accuracy of 0.87 with a sensitivity of 0.92. This study provides important insights into the controls, distribution, and dynamics of rock glaciers in the Mackenzie Mountains, as well as both the limitations and the potential of statistical models in predicting their occurrence.

Most small land-terminating glaciers in Svalbard have experienced large recession since the Little Ice Age (LIA) and today are thin, cold, and largely inactive. This likely contrasts to their LIA conditions, but the observational record from that time is sparse. We investigate the evolution of five small glaciers in central Nordenskiöld Land, Svalbard, from the LIA to 2019. Photogrammetric reconstructions and ground penetrating radar are used to reconstruct their geometric changes since 1936, and historical observation, photographs, and geomorphological mapping extend this history to before the 1900s. Our results show that from 1936 to 2019, the study glaciers on average lost 49.6% of their area and 77.4% ± 7.7% of their volume, with the greatest volume loss at Scott Turnerbreen of 91% ± 5%. Four out of these five glaciers strongly indicate a history of surge-like advances near the end of the LIA within one or two decades, and the rate of subsequent mass loss seems connected to their previous dynamics. This apparent switch to high activity during a period of rapid climatic change, could have implications for our understanding of past and future glacier evolution; climate change and highly dynamic glacier responses may be more connected than previously thought.

Arctic terrestrial invertebrate biodiversity is generally poorly known, but the archipelago of Svalbard has one of the most up-to-date inventories of its terrestrial and freshwater faunas of any Arctic region, offering a baseline for long term monitoring of invertebrate communities in space and time. Since the most recent review of the Svalbard invertebrate fauna was produced in 2014, knowledge of this fauna has developed and this inventory is here critically revised and updated. Our aims are (1) to critically review the inventory based on current taxonomic knowledge, (2) publish the complete species inventory, including cross-referencing to the relevant publications, in an open access data archive (GBIF), and (3) highlight the particular advantages that working in Svalbard may bring for scientists working on terrestrial, freshwater, and cryospheric environments. The inventory contains a total 1091 valid species names or interim names. A gap analysis in the Barcode of Life Data Systems reveals that 50% of the species currently documented from Svalbard lack COI (Cytochrome c oxidase subunit 1) barcode reference sequences in this database. Gaps in our knowledge of the Svalbard fauna and how these may be resolved are discussed.

True abundance of lesser snow (Anser caerulescens caerulescens, Linnaeus 1758) and Ross's geese (Anser rossii, Cassin 1861, collectively referred to as “light geese”, in North America had been unknown in the 1980s. However, different indices of abundance suggested steady increases at the time. The Karrak Lake Research Station (KLRS) was established partly because it was not known if the breeding biology from more southern latitudes (the only information available at the time) was representative of more northern colonies where 90% of the midcontinent population of lesser snow geese nested. Visits in 1990 confirmed the continued importance of Karrak Lake and surrounding areas in Canada’s central Arctic to a large nesting concentration of both snow and Ross's geese documented previously. Key activities at KLRS were (1) colony-wide annual monitoring of nesting goose abundance and nesting performance and (2) large-scale marking efforts to monitor survival, range-wide abundance, distribution, and exploitation rate from hunter harvest and natural mortality rate. The scope of research expanded to include their interaction with local vegetation and other sympatric wildlife, including Arctic foxes (Vulpes lagopus, Linnaeus 1758), king eiders (Somateria spectabilis, Linnaeus 1758), long-tailed ducks (Clangula hyemalis, Linnaeus 1758), and cackling geese (Branta hutchinsii). Following exponential growth in the 1990s and 2000s, nesting populations of light geese at Karrak lake collapsed since 2012, presenting a unique opportunity to examine how local ecosystems recover and revert from heavy grazing by hyperabundant geese.

The expanding area of glacier forelands provides new terrain for ecosystem development. Plant succession facilitates this development, but this process remains poorly documented in marginal environments such as the High Arctic. This paper presents the results of the first repeat study of glacier foreland chronosequences conducted in the Canadian High Arctic. The forelands of Twin Glacier, Beitstad Glacier, and Teardrop Glacier near Alexandra Fiord, Ellesmere Island, Nunavut were first surveyed in 1995, and these surveys were repeated 21 years later using the same methods. The objectives of this study were to document the patterns of vascular plant species composition and abundance across these three forelands to (1) determine the accuracy of the hypothesis from the original study that succession on these forelands was directional, and (2) investigate the use of the chronosequence method in High Arctic succession studies. Forelands were surveyed using % cover estimates or presence/absence counts. Indicator species analysis and rates of change were used to quantify shifts in vascular plant species over time. Total plant cover increased by 2.4% in the first 100 m of the Twin Glacier foreland study area, and species richness also increased on younger terrain. Rates of peak cover and first appearance advance varied greatly between species and forelands, but were generally faster for graminoid and forb species than shrub species, and slower on species-poor Beitstad Glacier foreland. At all three forelands there was a general pattern of directional succession as all species advanced towards the retreating glacier margin. This supports the original hypothesis that directional succession is a common pattern for glacier forelands in the High Arctic. However, we also found that species-specific patterns and rates of change acted to create assemblages that differed between 1995 and 2016. Different abundances of species and successional trajectories were observed between the three forelands, pointing to the importance of local species pools and dispersal limitation. Finally, we observed that the first occurrence of most species was further from the glacier margin in 2016 compared to 1995, perhaps due to accelerating rates of glacier retreat. These species-specific patterns, differences between forelands, and the delayed response of vegetation to glacier retreat demonstrate the importance of using repeat studies over time and replication over space to confirm the results observed in High Arctic glacier foreland chronosequence studies.

Systematic surveys of marine birds from ships were first conducted by the Canadian Wildlife Service in Atlantic Canada in 1965, and then expanded to the Canadian Arctic in 1969 under PIROP (Programme intégré de recherches sur les oiseaux pélagiques). PIROP surveys ended in 1992, then resumed in 2006 under the Eastern Canada Seabirds at Sea program with an updated survey protocol. Surveys under both monitoring programs were conducted from a variety of ship types engaged in scientific, transport, and supply activities, totalling over 120 000 km within sub-Arctic and Arctic Canada waters and over a million marine birds observed, primarily northern fulmar (Fulmarus glacialis), black-legged kittiwake (Rissa tridactyla), thick-billed murre (Uria lomvia), and dovekie (Alle alle). The data collected inform offshore ecological inquiries, environmental impact reviews, mortality estimates from accidental oil releases, and define areas in need of protection. Although surveys were designed to quantify seabird distribution within the waters of eastern Canada, the data also include sightings of non-avian taxa that are made publicly available. Long-term and large-scale monitoring programs will remain essential for assessing the status and health of Canada's marine birds, including surveys that take place at sea where these species spend most of their time.

Vertical profiles of salinity, and isotopic abundance ratios of hydrogen (δ2H) and oxygen (δ18O) of 18 landfast ice cores, collected along the northeast coast of James Bay in March 2019, and one ice core collected in Belcher Islands, were used to obtain the winter timeseries of the spatiotemporal evolution of the under-ice plume of La Grande River (LGR), the dominant river in the area. Variability in the isotopic composition and salinity of the ice cores indicated changes to the water source composition at the ice–water interface when the ice layers formed. The increased presence of river water beneath the ice during January–March was marked by more negative isotopic ratios in the lower portion of the ice as river discharge was increased for hydroelectric production. River water was the source of ∼43% of the ice in our ice core samples (n = 320) with the interquartile range from 16% to 71%. The river water fractions incorporated into the ice indicate that LGR under-ice plume extended more than 75 km north and at least 30 km south of the river mouth for ∼3 months. These findings correspond well with more challenging to obtain hydrographic observations. End-of-winter ice core sampling and analysis for isotopic abundance has potential as a tool to monitor dispersal of LGR discharge into the ice-covered coastal environment.

Indigenous-driven and community-partnered research projects seeking to develop salient, legitimate, and credible knowledge bases for environmental decision-making require a multiple knowledge systems approach. When involving partners in addition to communities, diverging perspectives and priorities may arise, making the pathways to engaging in principled research while generating actionable knowledge unclear to disciplinarily-trained natural science researchers. Here, we share insights from the Eeyou Coastal Habitat Comprehensive Research Project (CHCRP), an interdisciplinary, Cree-driven community-academic partnership. This project brought together Cree community members, regional organizations, industry (Hydro-Québec), and academics from seven universities across Canada to address the unprecedented loss of seagrass Zostera marina (eelgrass), the concurrent decline in migratory Canada geese and its impact on fall goose harvest activities in Eeyou Istchee. After describing the history and context of the project, we discuss the challenges, complexities, and benefits of the collaborative approach balancing saliency, legitimacy, and credibility of the knowledge produced. We suggest the paper may be of use to researchers and partners seeking to engage in principled and actionable research related to environmental change including impacts of past development.

Yamal Nenets herders have historically developed a rich knowledge of lichens and vascular plants, which feature in the diet of their migratory reindeer herds in the tundra zone of northwest Siberia. In the Nenets language there are native names for certain species of lichens and other reindeer forage plants, including graminoids, herbs, shrubs, berries, and mushrooms. During participant fieldwork together with nomadic tundra Nenets herders, we documented names and definitions of reindeer food on herding territories during their long migration routes from the northern forest-tundra transition zone to the northern coastal tundra. Like many other Indigenous peoples of Siberia, Nenets have noticed that the Arctic is changing and some of its recent dynamics are seriously affecting their livelihood. The degradation of some lichen composition and cover on tundra pastures has also contributed to a decrease of herders’ linguistic palette for describing these losses in a concrete manner. Since the Nenets language is on the list of endangered languages of the world, this has an especially negative impact on the language skills and traditional knowledge of the younger generations of Nenets people, who may not know what these lichens look like and why they are important for the Nenets reindeer herding culture.

A scenario-based approach was used to test air and ground response to warming with and without changes to inverted surface lapse rates in four Yukon valleys. Generally, climate warming coupled with weakening of temperature inversions resulted in the greatest increase in air temperature at low elevations. However, ground temperatures at high elevations showed the greatest response to warming and variability between scenarios due to increased connectivity between air and ground. Low elevations showed less of a response to warming and permafrost was largely preserved in these locations. Local models also predicted higher permafrost occurrence compared to a regional permafrost probability model, due to the inclusion of differential surface and thermal offsets. Results show that the spatial warming patterns in these mountains may not follow those predicted in other mountain environments following elevation-dependent warming (EDW). As a result, the concept of EDW should be expanded to become more inclusive of a wider range of possible spatial warming distributions. The purpose of this paper is not to provide exact estimations of warming, but rather to provide hypothetical spatial warming patterns, based on logical predictions of changes to temperature inversion strength, which may not directly follow the distribution projected through EDW.

Permafrost landscapes are becoming increasingly susceptible to widespread thaw due to climate change. Collating historical and ongoing data are critical for assessing permafrost conditions and spatiotemporal changes. Electrical resistivity tomography (ERT) is a geophysical technique that has become standard practice for characterizing permafrost. However, resistivity data—particularly raw measurements—often go unpublished and unshared, resulting in missed opportunities for knowledge exchange and collaboration. To fill this gap, we created the Canadian Permafrost Electrical Resistivity Survey database and established clear guidelines for data archival and reuse. Here, we present the first release of the database, which currently houses 280 ERT datasets, including standardized metadata, collected between 2008 and 2022 in British Columbia, Labrador, Northwest Territories, Québec, Yukon, and Alaska. These data present unique opportunities to better understand spatial and temporal variability of permafrost conditions across North America.

Seasonal migrations allow access to temporally varying resources and individuals may show fidelity to specific locations, particularly for important life processes such as reproduction. Polar bears (Ursus maritimus) are a sea ice-dependent species that migrate between marine and terrestrial habitats, the latter being important for parturition and early cub rearing. However, fidelity to maternity dens is poorly understood. Using capture and telemetry data collected between 1979 and 2018, we assessed site fidelity of female polar bears in the Western Hudson Bay subpopulation in Manitoba, Canada. We compared within-individual inter-year distances between dens to between-individual distances via non-parametric bootstrapping, and used generalized additive models to assess how maternal age, years between denning events, and sea ice conditions affected fidelity. Within-individual distances were smaller than between-individual distances by approximately 18.7 km, indicating some evidence of fidelity. Inter-den distances increased with time between denning events, but no other variables significantly affected fidelity. Our findings suggest that western Hudson Bay polar bears may exhibit fidelity to areas within the larger denning region, but not to specific dens. Understanding the site fidelity of maternal polar bears has important implications for population dynamics, on-land spatial distributions, and conservation efforts aimed at preserving important habitat for reproduction.

Thinning sea ice cover and earlier melt in the Arctic impact primary producer (PP) phenology, causing earlier ice algal bloom termination and phytoplankton bloom commencement. However, logistic constraints limit capturing the complete seasonal evolution of PPs and their physical drivers. Here, we combine spectral irradiance data from subsurface oceanographic moorings with synthetic aperture radar backscatter and meteorological variables to study light in Dease Strait, investigating its relation to timing and magnitude of surface PPs for 2017 and 2019. Ice algal blooms in 2017 and 2019 lasted 66 and 84 days, respectively, peaking within 2 days of snow melt onset. In 2019, lower temperatures and a deeper snowpack before snow melt extended the ice algal bloom. Melt pond formation increased light transmission, enabling a short, 6–7-day under-ice phytoplankton bloom in both years that was likely nutrient-limited. The 2019 phytoplankton bloom was less productive, possibly due to the longer ice algal bloom depleting surface nutrients. After ice break-up in 2019, a 31-day late-summer bloom occurred via wind-driven mixing. Our findings suggest that the combined remote sensing technique has novel applicability in other settings, providing insights into the changing state of PP phenology, and the need for long-term Arctic observations to discern regional climate change effects.

During aerial surveys, we opportunistically located clusters of polar bear (Ursus maritimus Phipps, 1774) earth dens on and near the Seal and Caribou Rivers in Northern Manitoba in 2011, 2022, and 2023. Polar bear denning has not been documented in the published literature there before, but there is local knowledge of denning in this area. These dens are of two different types (shallow dens and pits), with similar characteristics to those in the Western Hudson Bay polar bear subpopulation’s main denning area, 120 km farther south. It is not possible to determine whether these findings represent a northward extension of denning by this subpopulation but changes in den distribution, particularly in such previously overlooked areas, need to be monitored and understood to effectively conserve polar bears in a warming climate.

Coastal areas in the Western Canadian Arctic are predicted to experience increases in the frequency and intensity of storm surges as rapid climate change continues. Although storm surges have the potential to cause widespread and persistent vegetation loss, little information is available about the influence of decreasing disturbance intervals (between storms), expected timelines of recovery for vegetation, and how vegetation change alters habitat availability and (or) quality for local wildlife populations. We investigated how Arctic bird diversity is affected by heterogeneous vegetation recovery post-storm. Specifically, we employed field survey protocols from the Program for Regional and International Shorebird Monitoring to investigate how avian community assemblages were affected by heterogeneous re-vegetation 20 years following a record 1999 storm surge. Comparisons of these bird survey data with vegetation and habitat factors showed that the drier, post-storm vegetation barrens were preferred by ground-nesters and species that use open habitats such as Lapland longspur (Calcarius lapponicus) and semipalmated plover (Charadrius semipalmatus), whereas the wetter (usually with surface water) revegetated habitats were frequented by species of ducks (Anas spp.), red-necked phalarope (Phalaropus lobatus), and savannah sparrow (Passerculus sandwichensis). Overall, this research shows that areas that have revegetated after the 1999 storm can be considered as functionally recovered in comparison to our Reference (i.e., unaffected) sites in terms of vegetation and bird communities, but that areas still exist ∼20 years post-storm that do not show evidence of recovery.

The Arctic is as a key place to perform environmental measurements given its combination of reduced human activity and increased sensitivity to climate change. The Svalbard archipelago constitutes an invaluable measurement location, due to its ease of access and the presence of the Ny-Ålesund research center. Sensors are usually not designed to sustain prolonged periods of time in demanding environments like the Arctic; therefore, chances of failures, drift, and errors are higher than elsewhere. Maintenance and calibration of these sensors must be rigorous and frequent, to avoid poor-quality data, or even their loss. Within the frame of EURAMET EMRP project “MeteoMet 2”, calibration of the temperature sensors hosted by the Climate Change Tower (CCT), a unique research facility designed to monitor lower-atmosphere profiles of several meteorological quantities, has been performed. The calibration campaign pointed out sensor errors up to 1 °C and corrected the measurements, straightening the skewed temperature profiles. Absolute calibration uncertainties have been evaluated at ∼0.2 °C, less than half of those stated by the manufacturer, while an evaluation of relative uncertainties yielded values of just few 0.01 °C. This experience stimulated the creation of an in-situ calibration facility, to the benefit of the whole scientific community based in Ny-Ålesund.

Spatial maps of the air and ground thermal regime were generated for four Yukon valleys. The aim was to model air, ground surface, and ground temperature (at fine spatial resolution) using locally measured inverted surface lapse rates (SLR) to better predict temperature along an elevation gradient. These local models were then compared to a regional permafrost probability model, which utilized differing inversion assumptions, as well as circumpolar and national models generated without considering inversions. Overall, permafrost probability in the regional model matched well with the local models where assumptions of treeline and inverted SLRs held true. When normal SLRs were assumed, permafrost presence was overestimated in each valley. This discrepancy was greatest at high elevations where permafrost was predicted to be the coldest and most widespread. However, the difference between valleys was dependent on surface and subsurface characteristics such as higher snow cover, mature forest, or thick organic layers which show a greater disassociation from the air temperature overall. Appropriate characterization of the SLR is essential for accurate predictions of the ground thermal regime’s spatial distribution and permafrost presence. These models also provide a starting point for better predictions of warming in these valleys and other areas subject to inversions of similar magnitudes.

Sediment cores were collected from Wrong (WL) and Lenore (LL) lakes in boreal central Yukon Territory, Canada, spanning circa 6000 years. Analyses of pollen, charcoal, magnetic susceptibility, levoglucosan, and down-scaled paleoclimatic data reveal the vegetation history and character/drivers of Holocene fire disturbance. Boreal forest has persisted in the region for millennia, with a regional mid-Holocene expansion of Picea mariana (Mill.) Britton, Sterns & Poggenb. followed by expansion of Pinus contorta var. latifolia Douglas ex Loudon Engelm. ex S. Watson in the latest Holocene. The shortest reconstructed fire return intervals (FRIs; ca. 110–125 years) occurred in the mid-Holocene, coincident with the development of highly flammable Picea-dominated forest and warm, dry summers that were characterized by elevated June-August 500 hPa geopotential height anomalies (JJA Z500) and associated with an eastward/intense Aleutian Low. In the late-Holocene, FRI increased to ca. 240 years at WL and 280 years LL. Drivers of this change include regional cooling and increased precipitation, with a westward/weaker Aleutian Low position delivering more moisture to interior Yukon. Longer FRIs allowed for greater fuel accumulation between fires, enhancing fire size/severity. While higher fire frequency is noted in the mid-Holocene and increased fire size/severity in the late-Holocene, recent changes in Yukon fire disturbance suggest that the fire regime may soon lie outside the natural range of mid- and late-Holocene variability.

Environmental variability and seasonality of resources influence species distribution and demographic parameters such as survival. We quantified the spatiotemporal dynamics of sea ice that remains in Hudson Bay during break-up (remnant ice) and assessed relationships with apparent survival for three age classes of male polar bears (Ursus maritimus Phipps, 1774): subadult (1–4 years), prime age (5–19 years), and senescent (≥20 years) captured in Western Hudson Bay in 1980–2019. Remnant ice distribution varied annually, and we identified ice-related covariates that were correlated with detection probabilities and male apparent survival. Apparent survival declined by 10% for prime age males during the earliest retreat dates within Hudson Bay. Apparent survival for senescent bears declined during earlier sea ice retreat within western Hudson Bay. Subadult apparent survival was time constant and not significantly influenced by sea ice; however, detection probability was higher when remnant ice occurred in the west compared to the eastern half of Hudson Bay. Our results suggest that spatiotemporal sea dynamics at varying spatial scales affected males based on age class, had important impacts on estimating apparent survival, and has implications for assessing population status.

The occurrence of the invasive pink salmon (Oncorhynchus gorbuscha, Walbaum 1792) in Greenland was initially described in 2019 using social media to collect data on their presence. In this study we continue data collection through social media and initiate a monitoring program of the Kapisillit River in Southwest Greenland using snorkeling and environmental DNA (eDNA) metabarcoding in 2020 and 2021. The Kapisillit River is the only freshwater system in Greenland, where the red-listed Atlantic salmon (Salmo salar, Linnaeus 1758) is known to spawn. This genetically unique population of Atlantic salmon has been found to decline, wherefore there is general conservation concern that the occurrence of pink salmon at some point can become an additional stressor to the “Kapisillit salmon”. In 2021, pink salmon were present near all larger populated areas in Greenland and likely more abundant than in 2019. From visual observations and using eDNA, the presence of pink salmon was documented in the Kapisillit River in 2021. From the number of individuals observed combined with the spatial distribution of eDNA detections in the river, we suggest that the pink salmon invasion in the Kapisillit River is at an early stage.

Current permafrost models in Canadian boreal forests are generally of low spatial resolution as they cover regional or continental scales. This study aims to understand the viability of creating a temperature at the top of permafrost (TTOP) model on a local scale in the boreal wetland environment of Whatì, Northwest Territories from short-term field-collected temperature data. The model utilizes independent variables of vegetation, topographic position index, and elevation, with the dependent variables being ground surface temperature collected from 60 ground temperature nodes and 1.5 m air temperature collected from 10 temperature stations. In doing this, the study investigates the relationship vegetation and disturbance have on ground temperature and permafrost distribution. The model predicts that 31% of the ground is underlain by permafrost, based on a mean annual temperature at TTOP of

Plastic pollution, including microplastics (

Plant phenological and growth responses to experimental warming are widely documented, but less is known about warming effects on plant–pollinator interactions. We investigated the effects of short- and long-term passive warming on flowering phenology, insect visitation, fruit production, and floral rewards in the Low Arctic in northern Alaska. To better understand the role of insect visitors in plant reproductive success, we quantified pollen loads on floral visitors and tested for pollen limitation in four species. Long-term warming advanced flowering onset in evergreen shrubs and forbs. Warming, in general, increased the duration of flowering for forbs, evergreen shrubs, and deciduous shrubs. Considering all growth forms together, long-term warming increased floral density. This pattern was primarily driven by deciduous and evergreen shrubs. Dipterans accounted for more visits than Hymenopterans, although Hymenopterans had higher pollen loads. Insect exclusion and warming decreased fruit set in the forb, Bistorta officinalis Delarbre. Nectar volume in the deciduous shrub, Vaccinium uliginosum, was higher in the warmed plots than the control, but nectar quality did not differ. Advanced flowering onset, longer flowering duration, and increased flower density and nectar volume may have important implications for the pollinator community, warranting further research on long-term warming effects on tundra ecosystems.

Anthropogenic climate change has driven an increase in the frequency, size, and severity of fires at high latitudes. Recent research shows that increasing fire severity in the subarctic is altering the trajectories of forest succession, but to date, research on the effect of fire severity on tundra succession has been limited. In this study, we investigated short-term recovery of shrub tundra communities following fire in the Tuktoyaktuk Coastal Plain and Anderson River Plain ecoregions of the Northwest Territories. To understand the effects of fire severity, we documented vegetation and permafrost recovery within moderately burned, severely burned, and unburned portions of six tundra fires that burned in 2012. We found that vegetation structure at moderately and severely burnt sites recovered rapidly toward pre-fire levels, but that differences in community composition, characterized by a decrease in shrub and lichen cover as well as an increase in abundance of ruderals and graminoids, persisted at severely burned sites. The persistence of thermal changes and increased thaw depth indicate that while biotic recovery can occur promptly, severe fire may have long-term impacts on belowground conditions.

This paper explores cultural narratives and oral histories related to two examples of traditional northern transport—long seal hunting journeys in the Baltic region and nomadic reindeer travel in northeastern Siberia. Ample material has been collected and reviewed regarding means of nonmotorised transport in the polar regions. However, scientific literature concerning the experiences and perspectives of the Indigenous and traditional community members who took part in these journeys remains scarce. This article explores the recorded narratives of two people involved in the journeys described. It assesses how these long-distance travels form significance, meaning, observations, and belonging to landscapes for these people. This analysis reveals that, rather than inhabiting northern ice and tundra scapes that are often described as barren and devoid of life, seal hunters and reindeer herders live in story-scapes rich in meaning. The sacred places, surrender to ice flow dynamics, and ways of living “inside” northern habitats that emerge from these testimonies offer a skeleton key for re-reading the misunderstood homelands of Arctic and tundra communities.

The North Water Polynya is one of the most productive Arctic regions on Earth, sustaining the world's northernmost Inuit communities for millennia. The polynya is a large and persistent region of open water surrounded by sea ice and exhibits high primary productivity, is a biodiversity hotspot, and is a key habitat and migration corridor for Arctic species. Many aspects of the ecosystem structure and the role of resident species in the North Water Polynya remain uncertain. To shed light on these, we developed the first representation of the North Water Polynya food web using the Ecopath modelling framework. Modelled trophic flows indicated that pelagic and benthic communities were primarily connected by Age 1+ Arctic cod (Boreogadus saida), walrus (Odobenus rosmarus), and ringed seal (Pusa hispida). Large copepods, Age 1+ Arctic cod, and bivalves were key prey species. Overall productivity in the North Water Polynya was higher compared to Western Baffin Bay and Western Greenland, corroborating expectations of relatively high productivity within the polynya. This model provides a baseline description of the North Water Polynya ecosystem structure and function prior to future climate-driven food web changes and the emergence of large-scale commercial fisheries.

Marine protected areas contribute to mitigating the effects of human activities on marine ecosystems. The waters of Southampton Island, Nunavut, Canada are under consideration to become a marine protected area, but baseline information of marine mammal presence and habitat use is lacking. This study represents the first passive acoustic monitoring of marine mammals in this area, with data collected in 2018 and 2019. Bioacoustics analyses and generalized linear models were used to investigate species seasonal and temporal vocalization trends; infer behavior and habitat use from vocal cues; and explore vocal activity correlation with sea ice. Over a diel period, bearded seals (Erignathus barbatus (Erxleben, 1777)) and walruses (Odobenus rosmarus (Linnaeus, 1758)) were found to increase their vocal activity at night, whereas belugas (Delphinapterus leucas (Pallas, 1776)) mainly vocalized during daytime. Seasonally, bearded seals were recorded only during their breeding season at sea ice break-up, while walruses vocalized consistently throughout the open-water period outside their breeding season. Beluga vocal trends suggest their use of the area as a migratory corridor during sea ice break-up and freeze-up. Finally, bowhead whales (Balaena mysticetus Linnaeus, 1758) were recorded later than expected, concurrently with the onset of their mating vocal displays during the fall migration at sea ice freeze-up.

The ivory gull (Pagophila eburnea Phipps 1774) is a rare seabird found in the Canadian High Arctic. The Seymour Island Migratory Bird Sanctuary has supported the core colony for ivory gull research since the 1970s, but by the 2000s, survey work was extended across the species’ range in Nunavut, prompted by growing Indigenous concerns of population declines, which led to regular monitoring of colonies. We found marked declines in numbers of ivory gulls since the 1980s, especially in the southern part of the range, leading the Canadian Committee on the Status of Endangered Wildlife in Canada to recommend uplisting ivory gulls to Endangered under Canada’s Species At Risk Act, which the federal government did in 2009. This resulted in the development of a national Recovery Strategy that outlined research and monitoring needs. Canadian results prompted international concern and led to coordinated, international research and monitoring on this iconic Arctic species, which collectively suggested worldwide declines in the species’ numbers. Despite our efforts, the future of monitoring, and indeed of ivory gulls in Canada, remains unclear.

Dań Zhùr (Donjek) Glacier is a surge-type glacier that undergoes cyclical periods of rapid advance over ∼1–2 years, followed by retreat for ∼10 years. Since the 1990s, the advances have caused the formation of ice-dammed Dań Zhùr Lake, which has filled and drained in summers following a surge event. Here, we report how these drainages initially occur through a subglacial channel under the glacier terminus, which then typically closes the following winter, enabling another lake to form and drain the next summer. However, our remote sensing and field observations indicate that after several drainage events, a subaerial ice canyon is formed through the glacier terminus, which prevents another lake from forming until after the glacier surges again. We predict that the next surge of Dań Zhùr Glacier will occur around the mid-2020s, causing the formation of a larger Dań Zhùr Lake during the following quiescent phase because, despite periodic advances, a long-term trend of glacier recession is exposing a larger basin for the lake to form in. However, each subsequent surge is causing less terminus advance than the previous one, until ultimately the surges will be insufficient to dam Dań Zhùr Chù’ (Donjek River), and lakes will cease to form.

The Arctic is warming twice as fast as anywhere else on the planet, in the European Arctic mainly driven by exalted Atlantic Water inflow. Microbial eukaryotes are diverse and essential to the functioning of marine ecosystems, thus environmental perturbations altering their communities influence the entire ecosystem. To study seasonal and interannual variation and the potential effects of Atlantification, a long-term marine time series has been established in Isfjorden-Adventfjorden (IsA), West Spitsbergen. We here present three years of high-resolution data including hydrography, nutrients, photosynthetic biomass, flow cytometry and community composition of microbial eukaryotes (0.45–10μm, based on Illumina metabarcoding of 18S rDNA and rRNA). The timing, magnitude and species composition of the spring bloom varied interannually, with the more Atlantic spring 2014 being distinctly different from the two other years. A strong recurring seasonal pattern was evident in biodiversity, cell abundances and community composition. Winter communities were characterized by high alpha diversity and very low cell numbers with a dominance of heterotrophic and parasitic taxa. Despite large intra- and interannual differences in communities during the productive time of the year, winter communities were always highly similar, suggesting that the polar night represents a strong environmental forcing that resets the microbial communities.

Tuttuk [caribou (Rangifer tarandus)] populations are in decline across Canada, making them a major conservation concern for Inuit of Nunatsiavut (Northern Labrador) and Nunavik (Northern Quebec). This study investigates changes to caribou forage over 14-years at two tundra sites in northern Nunatsiavut, Labrador. We ask: 1) How much of the total vegetation is suitable caribou forage and how has this changed with time and experimental warming; and 2) Which forage species are most affected by recent climate change? At control and warming plots, we identified selected, edible, and avoided caribou forage based on published literature, and modeled observed changes in forage availability. We found that the relative frequency of selected winter forage was lower than summer forage at both sites. Caribou appear to be more forage limited in the winter than summer, and birch (Betula spp.), and ericaceous shrub species (Vaccinium spp.), increased over time. Our research provides valuable insight into recent changes in caribou forage availability and develops a novel methodology that can be applied across other caribou ranges. This knowledge will inform conservation and management measures by helping identify possible forage limitations and can contribute to recovery targets across Nunatsiavut and ultimately the social-ecological resilience of northern communities.

In 1966, Environment and Climate Change Canada (ECCC) (then Canadian Wildlife Service) initiated a research program on polar bears belonging to the Western Hudson Bay subpopulation (WH). This paper provides an overview of that program, highlighting the long-term research on WH polar bears with a focus on ECCC-led work. The WH research program, which has now extended across five decades with data on over 4600 individual bears, has evolved from a study of the basic ecology of polar bears into foundational work on the life history, demography, genetics, movement, behaviour, and ecology of an apex predator in a rapidly changing Arctic. Research on polar bears in Canada supports commitments under the Agreement on the Conservation of Polar Bears (1973), the Convention on Biological Diversity (1992), and Canada’s Species at Risk Act (2002). Among Canada’s 13 polar bear subpopulations, only WH has sufficient long-term monitoring of individuals to assess demographic, behavioural, and life history consequences of climate change and other anthropogenic stressors. Future research should continue to ask key questions on how long-term environmental changes impact the ecology of polar bears. Integrating community priorities into the research program is necessary for it to continue to be successful in the future.

Across the world, local communities are actively engaging in management and monitoring of natural resources. The underlying driver of most community-driven efforts goes beyond the utilizations of natural resources to entail a deeper relation to the place or ecosystem they are managing. The aim of this study is to understand what motivates a local volunteer group to spend considerable amount of time and resources to manage and restore a subarctic lake. We used a case study approach combining analysis of documents, participant observation and semi-structured interviews to explore their narrative. The findings show that values, such as care, responsibility, and stewardship, were the primary motivation of this effort and its ultimate goal. The project also promoted relational values like social cohesion, cultural identity, and knowledge-sharing. Despite no longer being essential for subsistence, the lake retains cultural and social significance, highlighting the need to document informal community-based monitoring and management practices for understanding ecological dynamics. The implications include the importance of recognizing relational values in shaping behaviour towards nature for achieving sustainability.

We report anthropogenic particles (AP) > 100μm, including microplastics and microfibers, from 70 surface snow samples collected from the urban Greater Toronto Area (GTA), remote and sparsely inhabited regions in the Yukon and Northwest Territories, and the unpopulated high Arctic. Concentrations and proportions of particles of anthropogenic origin were conservatively estimated after blank and ‘anthropogenic origin’ corrections were performed based on visual analysis and micro-Fourier transform infrared spectroscopy (µFTIR). AP were dominated by microfibers (95-100%), with variable concentrations across and within regions. Microfibers were distinguished as synthetic, regenerated semi-synthetic, anthropogenically modified cellulosic, and natural cellulosic or proteinaceous. Among microfibers with confirmed anthropogenic origin, most were polyester/PET (8-22%) and semi-synthetic rayon (1-18%), with anthropogenic cellulose comprising a small proportion (3-7%) across all regional areas. Greater diversity of coloured non-fibrous particles (fragments, films and foams) in settled regions (i.e., GTA and Carcross, Yukon) suggests direct input from local sources. Back trajectory analyses performed for days leading up to sample collection showed high frequency transport (>10%) from population centres exceeding 200km distance. Our findings of APs in snow from uninhabited areas support the hypothesis that APs, especially microfibers, undergo long-range atmospheric transport whereby snow can scavenge and deposit APs in remote northern regions.

Vertebrate carrion is an integral part of foodwebs in ecosystems and can impact biodiversity at the local as well as the landscape scale. However, very little knowledge currently exists about the ecological role of carrion in the Arctic ecosystems. We conducted a ground survey on the cover of five plant functional groups at paired reindeer carcass and control sites and analysed the relationship between cover and carcass presence in the Arctic tundra of Svalbard. Vegetation indices from Red-Green-Blue (RGB) imagery captured by drones complemented this, assessing plant productivity in terms of ‘spectral greening’ and modelling the relationship between vegetation index values and carcass distance. We show that graminoids capitalised most from carcass presence, whereas bryophytes and lichen showed decreases in cover. Woody plant and forb covers were not significantly impacted by carcass presence. The Red Green Blue Vegetation Index decreased locally at fresh carcasses (i.e. 1 year). We show that carcasses have differential impacts on the plant functional groups of Svalbard’s tundra and induce a local ‘green-up’ through secondary succession within 2 metres of the carcass. Given their non-random distribution, carcasses may contribute to vegetation heterogeneity at landscape scales. This is relevant for understanding how climate change-induced reindeer mortalities will impact tundra plant community composition in the future.

Nanorriutit are specialized dogs integral to traditional nanoq (polar bear) hunting in Avanersuaq (Thule district, North Greenland). This practice, involving a deep relationship between the piniartoq (hunter), the nanoq, and the qimmeq (dog), is a crucial aspect of Inughuit cultural heritage in the region. However, the hunting culture associated with nanorriutit faces significant challenges due to the contemporary lifestyle, urbanization and impacts of climate change, which are deteriorating the traditional hunting grounds. This study aims to examine the evolving role of nanorriutit in polar bear hunting practices and the broader cultural context of Avanersuaq. Utilizing a qualitative approach, data were collected through fourteen semi-structured interviews with thirteen knowledge holders from the settlement of Savissivik and the town of Qaanaaq, conducted in Inuktun and kalaallisut. The findings illustrate both the enduring significance of nanorriutit, and the adaptations required in response to changing environmental conditions. This research contributes to the understanding of how the contemporary lifestyles and climate change is influencing Inughuit hunting practices and emphasizes the need to preserve this valuable cultural tradition amidst a rapidly transforming Arctic urbanization and environment.

Climate-driven landscape change, legacy waste and ongoing infrastructural investment are leading to concerns about contaminant release in Arctic Indigenous and Local communities. Sustainable development that considers threats posed by accelerating environmental change requires accessible, appropriate, and sustained environmental data to inform strategic decision-making. Collaborative partnerships and capacity sharing are necessary to promote resilient and sustainable environmental monitoring approaches, however effective collaboration has been hindered by mismatches in priorities and timelines between communities and research programs. We outline the development and later evolution of a community-based environmental research program focused on monitoring contamination threats posed by legacy infrastructure sourced from industry, transportation and domestic waste sites. Capacities and insights from diverse knowledge systems guided each stage of our research approach. Reflections provided by an Indigenous and non-Indigenous Early Career Researcher (ECR) share insights into different aspects of the research process. We highlight how cross-cultural partnerships and capacity sharing have enabled evolving and reflexive community-based contaminant monitoring. Our approach facilitates a structural shift from collaborative monitoring with external analysis to autonomous monitoring that supports equity in research outcomes. Appropriately considered and resourced co-development at regular points of the research process has been critical to developing a complete and effective Indigenous-led research project.

Polar bears (Ursus maritimus) rely on seals as their primary prey, yet predator-prey spatial relationships are poorly understood. We examined the spatial relationship between Davis Strait polar bears and harp seals (Pagophilus groenlandicus), using satellite-telemetry for both species. We analyzed sea ice trends using remote sensing (1979-2021) to examine how their environment may be changing using four sea ice seasons (freeze-up, winter, break-up, and summer). Sea ice cover decreased and summer season lengthened over time. Polar bears (n=23) tracked in 1991-2001 for 7-12 months had a mean 95% minimum convex polygon home range size (MCP) of 102,864 km2 (SE=15,236 km2) and a mean 95% kernel density home range size (KDE) of 66,215 km2 (SE=59,688 km2). Harp seals (n=29) tracked for 5-8 months in 1993-2005 had a mean 95% MCP of 464,330 km2 (SE=47,009 km2) and a mean 95% KDE of 256,016 km2 (SE=31,566 km2). During freeze-up, the core-use areas of both species did not overlap, but the broad-use areas did. During break-up, the broad-use areas overlapped more than the core-use areas. The space use of both species was influenced by the sea ice seasons and these seasons have changed over time.

In East Greenland, the recommendations for the closure of the narwhal (Monodon monoceros) hunt coincide with a pressing demand to continue hunting for meat to supply local communities. By analysing catch statistics and estimating average meat yields, the available meat from marine mammals, polar bears (Ursus maritimus), and muskox (Ovibos moschatus) in East Greenland can be assessed. On average, there was approximately 426 tonnes of meat available per year during this period. However, this quantity declined due to reduced catches of hooded seals (Cystophora cristata) and ringed seals (Phoca hispida) after 2007. This decline was somewhat offset by the inclusion of new species in the hunt, such as dolphins (Delphinidae), killer whales (Orcinus orca), and pilot whales (Globicephala melas). The average annual meat availability per inhabitant decreased from 150 kg before 2008 to 94 kg afterward. Narwhals consistently contributed approximately 5–6% of the total annual meat supply in Greenland over the observed period, which suggests that narwhal meat is not critical for the overall food supply. The inclusion of the need for meat in discussions surrounding sustainable harvest levels has been a point of controversy, particularly in cases where an urgent halt to hunting is needed.

Glacier fronts are hotspots of pelagic productivity due to upwelling of nutrient-rich water. As tidewater glaciers retreat into land, this subglacial circulation will disappear and sedimentation from terrestrial runoff will increase, leading to a decrease in pelagic productivity with a decline in the abundance of fish and zooplankton. We used Billefjorden, a high Arctic fjord with a glacier recently transitioned from sea- to land-terminating as a case study to identify spatial differences and small-scale environmental drivers of density and vertical distribution of fish and zooplankton along a gradient of glacier retreat (directly in front of the land-terminating glacier front, a river bay with terrestrial input from land-terminating glaciers further inland and a location with minimal glacial input). We developed a sustainable and efficient protocol to safely sample the glacier front and shallow coastal areas using hydroacoustics and a remote autonomous vehicle combined with oceanographic measurements and baited remote cameras. Over two years, pelagic density was lowest at the now land-terminating glacier front and highest at the site with lowest terrestrial input. Temperature, depth and turbidity explained less than 8% of the variation each.

Arctic warming is causing widespread “greening” of tundra ecosystems. What this means for plant-herbivore relations, including the grazing pressure herbivores exert on increasingly productive tundra ecosystems, is poorly understood. Svalbard is one of the fastest warming places on Earth, with concomitant increases in both forage biomass and reindeer numbers. In 11 years between 1998 and 2023, we measured grass biomass and the proportion of shoots grazed in mesic grass-dominated tundra to evaluate whether increased forage biomass of grass absorbed the grazing pressure of more reindeer. Also, we used GPS data from adult female reindeer (2009-2023) to identify if grazing pressure was relieved by spillover into other habitats. During the study period, reindeer abundance, estimated by annual capture-mark-recapture, tripled, while grass biomass only doubled. Grazing pressure increased from 4% to 8%, which was lower than expected from the increased reindeer density. This discrepancy was not caused by spillover into other habitats, but rather by increased grazing in higher-biomass patches that have emerged with summer warming. Our findings support the notion that increased summer forage has contributed to Svalbard reindeer population growth, notably by making available higher biomass grass swards that allow for greater food offtake.

Redistribution and shifting habitat envelopes are impacting organisms across many taxa, which in turn are impacting Indigenous ways of life. In Arctic Alaska, Pacific salmon are known to have occurred for at least a century, but in recent years appear to be increasingly common. With the goal of holistically understanding and describing these changes in a way that equitably considers Indigenous, local, and western knowledge, we share our experience and methodologies in facilitating the Arctic Alaska Salmon Workshop. We share our perspective, approach, and methods as fisheries natural scientists convening this workshop, which included community-based knowledge holders from the Iñupiat communities of Kotzebue, Point Hope, Utqiaġvik, and Kaktovik, and western scientists and researchers from universities, fishery management agencies, and local community government. After briefly discussing some of the workshop highlights, we conclude with four key takeaways: 1) that the process of co-production of knowledge is an ideal towards which we must strive, but acknowledge we may rarely, if ever, fully achieve, 2) pursuit of the ‘good science’ should guide our work, 3) examination and assessment of assumptions should occur early and often, and 4) Anglanikina! Make sure you have a good time, (Yup’ik).

The Kjell Henriksen Observatory (KHO) is the world's largest optical observatory for auroral and airglow measurements, operated by the University Centre in Svalbard (UNIS). KHO is a unique site that lies underneath the dayside cusp, a funnel-shaped region where particles from the Sun can directly enter the Earth's upper atmosphere, including the ionosphere. Building on the pioneering observations of its predecessor --- the Auroral Station in Adventdalen, Svalbard --- KHO has played a pivotal role in advancing our understanding of phenomena in the polar atmosphere. The Auroral Station and KHO have amassed climatological measurements over Svalbard for an impressive 40-year period. KHO's diverse instrumentation, combined with other co-located optical and radar infrastructure and in-situ measurements from satellites and sounding rockets, has paved the way for impactful multi-instrument studies. Serving as an accessible testbed for instrument development, new types of instruments have recently been installed, both at KHO and on satellites. Beyond its scientific contributions, KHO has become an integral part of the Longyearbyen community, with students, visitors, and locals participating in tours and educational initiatives. This connection underscores KHO's multi-functional role, not only as a centre for excellent research but also as a vital hub for public outreach and engagement.

Arctic seabirds are key bio-indicators of marine plastic pollution due to their transient movement and large populations. Although many studies have quantified the ingestion of microplastic particles (100 µm in size), 19 of which were analyzed for material composition using Fourier Transform Infrared Spectroscopy and Raman micro-spectroscopy. Of these, 13 particles were successfully matched to materials, with five as plastic. This produced an average concentration of 0.08 ± 0.28 microplastic particles per fecal sample, with no difference of occurrence between chicks and adults. Particle lengths ranged from 113 - 751 µm. The presence of microplastics larger than our lower limit of detectability of 100-µm suggests a need for analysis of smaller particles and microfibers in this species. We contribute to understanding how microplastics pass through little auks and characterize how this species interacts with the plastic pathways.

The ecological and evolutionary consequences of ploidy-driven trait variation, particularly for autopolyploids, remain poorly understood. Saxifraga oppositifolia L. (purple saxifrage), is a highly successful arctic-alpine plant species with significant genetic and phenotypic variation potentially related to autopolyploidy. Over the past decade, we have accumulated knowledge of S. oppositifolia through student projects at the University Centre in Svalbard. Building on this knowledge, we initiated the long-term “SO-field study” in 2018 including 768 permanently tagged plants screened for ploidy level, trait variation and environmental associations. Here we summarize main findings from unpublished student projects, consolidating and extending these findings with the available data from the ongoing SO-field study, containing 63% diploids, 16% triploids, and 21% tetraploids. Our results support that Svalbard is a mixed-ploidy contact zone, where ploidy is strongly associated with certain traits, including growth form, leaf mass area, flower investment, seed production and habitat. Autopolyploidy has significantly influenced both ecology and evolution of S. oppositifolia and needs to be accounted for when autopolyploids are used as a study species or evaluated for management purposes. Our findings suggest considerable re-interpretation of former research and pave the way for new inquiries and hypotheses to be tested within this framework.

Indigenous Peoples across the world have a history of colonization that continues today. Additionally, Indigenous Peoples have experienced harm from research. This paper explores conducting research with Indigenous Peoples in a “good way.“ Relationships built prior to and throughout the research process are foundational to conducting research in a good way, meaning it respects and recognized inherent sovereignty; is culturally centered; relational; participatory; asset based; anti-racist; decolonizing; trauma-informed; survivor-centered; and engages free, prior, and informed, consent and Indigenous methodologies. This approach draws on the strength of Indigenous cultures, centering Indigenous Knowledges, and working toward Indigenous goals. A case study details the use of an Indigenous relational theoretical framework in practice, building life-long relationships through a research project that adapted a historically non-Indigenous methodology (ethnographic futures research) through a self-determining, participatory, and co-production project with the Ninilchik Village Tribe in Alaska. Our discussion broadens the application of this approach to research in any context with Indigenous children, youth, families, and Elders, reminding the reader that decolonization is not a metaphor but an actual change in researchers, institutions, and funders.

This study investigates the impact of large herbivores on soil organic matter (OM) stability in Arctic permafrost and seasonally frozen ground ecosystems, focusing on the potential preservation effect of grazing. Soil samples were collected from Siberian and Finnish permafrost and non-permafrost areas and organic carbon content, carbon-to-nitrogen ratio, stable carbon isotopes as well as the content of n-alkanes and n-alcohols were analysed to assess OM stability. The results suggest that grazing activity, particularly in permafrost environments, preserves soil OM by reducing decomposition. Permafrost soils exhibit higher functionalized to non-functionalized biomarker ratios, indicating in general better preservation under frozen conditions. While differences in grazing intensities had minor effects, the data also showed variability due to soil heterogeneity, especially in seasonally frozen ground ecosystems. Nevertheless, there are slight trends towards enhanced OM preservation with increasing grazing intensity, especially in permafrost, emphasising the potential role of grazing in locally preserving Arctic soil OM. This pilot study offers initial insights into the impact of large herbivores on OM stability in cold-region ecosystems, suggesting that significant effects may require prolonged, intensive grazing pressure.

The composition of vegetation cover in Arctic environments is evolving due to climate change. This study focused on estimating carbon and nitrogen stocks in vegetation and soil for different Arctic habitats (i.e., sub-ecosystem environments) with contrasted plant communities and soil profiles, to better understand the spatial variation of these stocks and the relationships between aboveground vegetation and soil characteristics in these environments. Vegetation composition and soil characteristics were measured in different habitats in a mire and a heathland ecosystem in northern Sweden. Multivariate analyses were used to define dominant vegetation and soil profile types, and carbon and nitrogen stocks were computed and compared across these types. Shrub-dominated and graminoid-dominated vegetation types presented similar carbon stocks but different nitrogen stocks, and shrub-dominated environments presented significantly higher proportions of their stocks distributed in the long-lived (i.e., woody) compartment. Soil stocks varied considerably between ecosystems. However, no clear relationships could be established between current vegetation community composition and soil carbon and nitrogen stocks across environments. The increase in shrub or graminoid abundance may affect carbon and nitrogen cycles most through biomass distribution between plant compartments rather than through the absolute stocks they represent. Ultimately, in arctic and subarctic ecosystems experiencing climate change, the interactions between plant biomass composition and soil characteristics could have contrasted consequences for ecological functioning and C and N cycles.

Arctic biodiversity is under threat from both climate induced environmental change and anthropogenic activity. However, the rapid rate of change and the challenging conditions for studying Arctic environments mean that many research questions must be answered before we can strategically allocate resources for management. Addressing threats to biodiversity in the Arctic is further complicated by the region's complex geopolitics, as eight countries claim jurisdiction over the area, with multiple local considerations such as Indigenous sovereignty and resource rights. Here, we identify research priorities to serve as a starting point for addressing the most pressing threats to Arctic biodiversity. We began by collecting pressing research questions about Arctic biodiversity, thematizing them as either threats or actions, and then categorizing them further into 18 groups. Then, drawing on cross-disciplinary and global expertise of professionals in Arctic science, management, and policy, we considered the barriers to answering these questions and proposed potential solutions that could be implemented if barriers were overcome. Overall, our horizon scan provides an expert assessment of threats (e.g., species’ responses to climate change) and actions (e.g., a lack of fundamental information regarding Arctic biodiversity) needing attention and is intended to guide future conservation action within the Arctic.

Environmental DNA (eDNA) assays represent a non-invasive approach for biomonitoring. To assess Arctic grayling (Thymallus arcticus) populations in the Little Nahanni watershed of Northwest Territories (NWT), Canada, an eDNA assay that has been previously validated for use in fish of the Beringia lineage was used in conjunction with traditional survey methods (i.e., electrofishing). Forty-six 100-metre reaches of streams were assessed in August 2015. The assay successfully detected Arctic grayling of the Nahanni lineage, with an eDNA signal recorded at each of the 17 sites in which Arctic grayling were observed by traditional fish surveys, but also at 3 of the 29 sites where Arctic grayling were not observed. The presence of eDNA was related to habitat metrics via Random Forest and correlation analyses. Riffles and water temperature were identified as being predictive of Arctic grayling eDNA abundance; however, no significant relationship between eDNA abundance and biomass proxies (fish abundance and fork length metrics) could be established. The high congruence between traditional approaches and eDNA surveys suggests adoption of the latter method will enhance the temporal and spatial acuity of biomonitoring, thereby improving field assessment of Arctic grayling populations and contributing towards more effective conservation management of this species.