A decreasing trend in narwhal (Monodon monoceros Linnaeus, 1758) abundance has been identified in a small population in Scoresby Sound, Southeast Greenland. We hypothesize that excessive hunting has affected life history and population dynamics of this population. Biological information and samples collected from the Inuit hunt, from satellite-tagged narwhals and from official hunters’ reports, were used to estimate age, growth, and reproduction. During 2007 through 2019, a decreasing proportion of young and increasing proportion of older whales were harvested. Male and female body length and male tusk length increased significantly, while body mass of both sexes showed a nonsignificant increase. The probability of catching a female decreased significantly, while a nonsignificant decline of catching a pregnant female was observed in both biological samples and hunters’ reports. Narwhal swimming speeds correlated with fluke widths indicated that larger whales attain greater speeds. The decline in juveniles and females is probably due to an opportunistic hunting practice targeting the easiest-to-catch whales, where bigger whales are faster and more difficult to catch. The cumulative effect of overharvest with a declining proportion of females, an overrepresentation of large males, and a lack of calves and juveniles has detrimental implications for this small narwhal population.

Natural regeneration after anthropogenic disturbance is slow in the tundra biome, but assisted regeneration can help speed up this process. A tracked off-road vehicle damaged a High Arctic dwarf shrub heath in Svalbard in May 2009, drastically reducing the vegetation cover, soil seed banks, and incoming seed rain. We assisted regeneration the following year using six different revegetation treatments and monitored their effects one month, and one and eight years after their application. By 2018, all treatments still had lower vegetation cover and limited species composition than the undamaged reference vegetation. The fertiliser treatment was the most effective in restoring vegetation cover (71% vegetation cover, of which 62% were bryophytes and 38% were vascular plant species). Compared to the reference plots (98% vegetation cover, of which 32% were bryophytes and 66% were vascular plant species), the composition of the disturbed vegetation was still far from regenerated to its original state nine years after the tracks were made. The slow regrowth demonstrated in this study underlines the importance of avoiding the disturbance of fragile tundra and implementing and upholding regulations that restrict or ban such disturbances.

Plant climate responses may depend on site-specific environmental context. Using fences and open-top chambers, we enhanced snow depth (creating Ambient, Medium, and Deep regimes) over an 11-year period and increased temperatures for two summers in dry heath and mesic meadow habitats on Svalbard, Norway. Comparison of plant growth form abundance and diversity responses in these two habitats showed that the response was more limited in the dry heath than in the mesic meadow. Common to both habitats was a decrease in shrub abundance and vascular plant species richness in the Deep snow regimes. Bryophyte abundance increased with enhanced snow cover in both habitats, but only up to a certain extent of snow depth in the meadow. However, for many growth forms, the effects of snow enhancement were habitat specific. In the mesic meadow, the abundance of forbs and bryophytes increased with snow enhancement, but the effect was stronger when combined with summer warming. The “bryofication” — that is, an increased abundance of bryophytes in response to snow enhancement and summer warming — also influenced overall plant diversity in the mesic meadow. Bryophytes are species-rich taxa and may respond differently than vascular plants to environmental change. We show that the inclusion of even the most common bryophytes in measures of diversity may determine overall plant diversity responses to environmental change in the Arctic.

As temperatures in the circumpolar north continue to warm, shifts in species distribution and the breakdown of environmental barriers for arthropods may impact the diversity and distribution of ectoparasites in Arctic ecosystems. In May 2019, fur loss over the neck and shoulders was observed on Arctic foxes in a terrestrial Arctic ecosystem (Karrak Lake) in central Nunavut, Canada. This was inconsistent with normal patterns of shedding winter fur and had not been observed on Arctic foxes in this population over the previous 19 years of live-trapping. Operculated eggs attached to hair shafts were collected from one affected fox. Conventional PCR using universal louse primers targeting conserved regions of mitochondrial 12S and 16S rDNA confirmed that the eggs belonged to the order Phthiraptera. Sequencing results were inconclusive at the species level. Further investigation revealed a single unpublished report of an Arctic fox with similar fur loss trapped on mainland Nunavut, in 1997. Adult lice collected from this fox were identified as sucking lice (potentially from the genus Linognathus). Our findings emphasize the need for further monitoring and have significant implications for trappers and wildlife management, as infestations negatively impact the pelt quality of these important furbearers.

Leaf toughness is an important functional trait that confers resistance to herbivory and mechanical damage. We sought to determine how species composition, climate, seasonality, and nutrient availability influence leaf toughness in two types of tundra in northern Alaska. We measured leaf toughness as force to punch for 11 species of Arctic plants in tussock tundra and dry heath tundra at 17 sites distributed along a latitudinal gradient. Rubus chamaemorus L. and the graminoids occupied opposite ends of the leaf toughness spectrum, with Rubus chamaemorus requiring the least force to punch, whereas one of the graminoids, Eriophorum vaginatum L., required the most. Leaf toughness increased with mean summer temperature for Eriophorum vaginatum and Betula nana L., whereas it declined with warmer temperatures for the other species. Toughness of mature leaves of Eriophorum vaginatum did not vary through the growing season but declined significantly after senescence. Application of N and P fertilizer in an experimental site decreased leaf toughness in three species but had no effect on four others. Leaf toughness of four out of five species in dry heath was greater than for the same species in tussock tundra, but there was no difference in community-weighted mean toughness between tussock tundra and dry heath.

Although intestinal microbial communities from anadromous Arctic char (Salvelinus alpinus (Linnaeus, 1758)) in Kitikmeot, Nunavut, Canada, differ depending on the timing and location of capture, determinants of gut microbiota in other wild Arctic salmonids are largely unknown. Using high-throughput 16S rRNA gene sequence data, we compared intestinal microbiota from Arctic char to those from a related and sympatric salmonid, lake whitefish (Coregonus clupeaformis (Mitchill, 1818)). Shifts in lake whitefish gut microbial community composition were observed between brackish water and freshwater, similar to impacts of salinity reported previously for Arctic char. Despite these similarities, gut community profiles for the two salmonids differed, with whitefish having higher diversities and increased proportions of taxa affiliated with potential pathogens. Geography seemed to have a greater impact on freshwater whitefish gut microbiota than on corresponding Arctic char. Additionally, microbiota diversity was significantly more affected by feeding behavior in whitefish compared with sympatric Arctic char. As sampled whitefish were at their northern range limits and grew slowly, we speculate that they, and their microbial consortia, could be more vulnerable to certain abiotic and biotic factors than Arctic char, which are well adapted to conditions found in these high latitude environments and have the most northern distribution of any freshwater fish.

A detailed account of a variety of species foraging on Greenland halibut (Reinhardtius hippoglossoides (Walbaum, 1792)) fisheries discards associated with a commercial fishing vessel in central Baffin Bay, Nunavut, Canada is presented. Species observed included three marine mammals: northern bottlenose whales (Hyperoodon ampullatus (Forster, 1770)), sperm whales (Physeter macrocephalus Linnaeus, 1758), and a hooded seal (Cystophora cristata (Erxleben, 1777)), and two marine bird species: northern fulmars (Fulmarus glacialis (Linnaeus, 1761)) and glaucous gulls (Larus hyperboreus Gunnerus, 1767). Interspecies and intraspecies interactions were observed while species were in close proximity to the stern and starboard of a commercial fishing vessel confirming anecdotal reports from boat captains. Improved understanding of marine mammal and bird interactions with fisheries in the Arctic is required to accurately assess financial and ecological (i.e., bycatch) losses, potential for entanglement and to predict the likely impact on energy flow and transport of these resource subsidies throughout the Arctic marine ecosystem.

Current scientific evidence indicates that the threatened Cumberland Sound beluga whale (Delphinapterus leucas (Pallas, 1776)) population is genetically differentiated and spatially segregated from other beluga whale populations. This population has been hunted for subsistence for centuries by Inuit who now live in the community of Pangnirtung, Nunavut, Canada, and was harvested commercially from 1860 until 1966. The commercial harvest removed at least 10 000 individuals from the population. Visual and photographic aerial surveys were flown during August 2014 and 2017 and produced beluga whale abundance estimates of 1151 (CV = 0.214; 95% confidence interval (CI) = 760–1744) and 1381 (CV = 0.043; CI = 1270–1502), respectively. Long-term trends in abundance were examined by fitting a Bayesian surplus-production population model to a time series of abundance estimates (n = 5), flown between 1990 and 2017, taking into account reported subsistence harvests (1960–2017). The model suggests the population is declining. Engaged co-management of the Cumberland Sound beluga population and information on demographic parameters, such as reproductive rates, and age and sex composition of the harvest, are needed to restore the ecological integrity of the Cumberland Sound marine ecosystem.

The multiple islands and narrow channels that form the Canadian Arctic Archipelago (CAA) complicate snow/ice monitoring, as coarse resolution satellite observations are unable to resolve smaller-scale changes in snow/ice cover. We present the first study showing the utility of the Interactive Multisensor Snow and Ice Mapping System (IMS) 24 km (1997–2018) and 4 km (2004–2018) products to investigate changes in sea ice and snow phenology together in the CAA. Although ice break-up and snow retreat are shifting earlier (p > 0.05), on par with other Arctic regions, the final summer clearing of ice is shifting later. This, combined with trends towards earlier ice freeze and snow fall (p < 0.05), result in shorter open water and snow free seasons in the CAA. Spatial links between sea ice and snow are evident as significant clusters of trends were identified for all phenology parameters. The western regions were dominated by shifts towards shorter snow/ice seasons, whereas eastern regions tended to exhibit longer cover. Our research highlights the considerable regional and interannual variability in the timing of sea ice and snow advance/retreat within the CAA and emphasizes how the ice and snow dynamics in this complex region are responding to ongoing changing climate conditions.

Inuit are at the forefront of ecosystem change in the Arctic, yet their observations and interpretations are rarely reported in the literature. Climate change impacts are rapidly unfolding in the Arctic and there is a need for monitoring and reporting unique observations. In this short communication, we draw upon observations and experiential knowledge from western Canadian Inuit (Inuvialuit) harvesters combined with a scientific assessment to describe and interpret an unusual account of gelatinous organisms at high densities during summer 2019 in eastern Amundsen Gulf, near Ulukhaktok, Northwest Territories. The gelatinous organisms were identified as primarily appendicularian larvaceans (Oikopleura spp., pelagic tunicates) and their gelatinous “houses”. The organisms were observed within 3–5 km of the marine coast, from ∼1–2 m below the surface and to depths of ∼30 m with an underwater camera. Pelagic tunicates have rarely been documented in the eastern Amundsen Gulf and, to our knowledge, this was the first time these organisms had been noted by the people of Ulukhaktok. The pelagic tunicates clogged subsistence fishing nets and Inuvialuit harvesters were concerned about negative impacts to marine mammals and fishes, which they depend on for food security. These interpretations highlight major knowledge gaps for appendicularians in the Arctic. Video Inuit Ukiuktaktumi nunamingni tautukpaktut nunaktik aalangnujuhianik, taimaa tautukpaktait ilihimaliktait titiraqtauyuitut titiqani. Nunam aallangujuhia tautuktauyuq kayumikhipluni Ukiuktaktun nunanni, taimatun munariyauyukhak titiraqhimayukhat aallangujuhiit. Uvani tittiqaniInuit tautukpaktait ilihimaliktait titiraqhimayut Inuvialuit anguniaqtiinnit attauttimut iliblugit qablunaat tittiratainnutilituritiarumaplugitumayuutigut tamainnut auyanani 2019mi, tahamani Admundson Gulfmi Ulukhaktuum haniani North west Territoriesmi. Tahapkuat uumayut hauniittut imangmi attauttimiitpaktut. Uumayut tahapkuat tautuktauvaktut pingahunikluunniin tallimanitulluunniin kilometresmik ungahiktilanganik tariukmitalvattauk atauhikmikluunniin, malguknikluunniin metresnik ititigiyumi. Ilaani ititqiyami 30 metresmi takunnaqpaktun ajiliurunmun. Tahapkuninga tautuyuittugaluat taja kihimi tautukpaliktait. Ulukhaktuunmiutat taja tautukpaliktait. Tahapkuat uumayut nuvaktut inmate kuvyanut himiutkpiaqpaktut, kuvyallu iqaluguikhutik. Inuit iqalukhiuktullu anguniaqtullu ihumaalugiliktait anguyamingnik niqiqaramik. Tahapkuat ilituriliktavut ilihimatttaingitnaptigit nunaptingni ukiuktaktumi ilitturrinahuaqqaqhaluavut.