Polynyas, tidal straits, and variable water column structure support diverse and productive habitats around Southampton Island, northern Hudson Bay, Nunavut, Canada. This study provides the first description of zooplankton at depths between 18 and 313 m around the island, including pelagic larval stages of benthic invertebrates (i.e., meroplankton). From the stations sampled in August 2018 and 2019, 83 taxa were identified with an average station species richness of 27. Bivalve larvae were present at all stations and were the most abundant meroplankton taxa. A distinct Northern and Southern zooplankton assemblage was identified. Average total zooplankton abundance was 5.4 times higher at Northern stations in Frozen Strait, and at stations adjacent to Foxe Basin and Foxe Channel, relative to Southern stations. The Northern assemblage was numerically dominated by calanoid copepods whereas the Southern assemblage had higher abundances of cyclopoid copepods including Oithona similis. Metridia longa and Oikopleura spp. were strong indicator taxa of the Northern assemblage, in contrast to hydrozoans (i.e., Aglantha digitale and Aeginopsis laurentii) and the nauplii of euphausiids for the Southern assemblage. This study also documented a transient coastal assemblage caused by a wind event that decreased zooplankton abundance and biomass by an order of magnitude in Fisher Strait. The zooplankton around Southampton Island reflect small-scale variability at the intersection of sub-Arctic and Arctic regions with limited estuarine influence, resulting in summer assemblages distinct from southern or western coastal Hudson Bay and nearby waters of Hudson Strait or central Hudson Bay.
The wild reindeer (Rangifer tarandus L.) is a threatened species and all populations in the European part of Russia are listed in the Red Data Book of the Russian Federation. The population in the Republic of Karelia declined more than twofold in the mid-to-late 1990s and the species range became fragmented. In this study, the genetic diversity and population structure of wild forest reindeer (Rangifer tarandus fennicus) in the Republic of Karelia were assessed by analyzing polymorphism in the mitochondrial DNA control region and at 14 microsatellite loci. The average number of alleles per locus was 9.07. The observed heterozygosity across all loci was 0.68, and a low inbreeding coefficient (Fis = 0.06) was detected. Twenty-one mitochondrial DNA control region haplotypes were identified, showing high haplotype diversity (Hd = 0.91). Fourteen of these haplotypes are widespread among wild and domestic reindeer in Norway, Finland, and Russia, while seven were found only within the studied region. Genetic analysis of the wild forest reindeer population in Karelia showed that it is weakly structured and has a relative high level of genetic diversity. Only the eastern Ilekso-Kozhozerskaya group showed genetic differentiation from the rest of the population, which may be due to anthropogenic habitat transformation. The results indicate possible evidence of hybridization between wild forest reindeer in Karelia and domestic reindeer from neighboring regions, which raises concerns that reindeer husbandry may pose a threat to the genetic purity of the wild population. Ongoing anthropogenic habitat transformation could lead to the further isolation of groups inhabiting the periphery of the species’ range.
Accurate land cover modelling is crucial for ecosystem management. Understanding the relationships between topographic and climatic gradients and the spatial distribution of different ecosystems is needed to develop accurate conservation and sustainable land-use strategies. This is especially important where different ecosystems are intermixed in the landscape, e.g., in Tierra del Fuego (southern Patagonia), where Nothofagus forests, peatlands, shrublands, and grasslands generate complex landscapes that are sensitive to environmental changes. Therefore, using a newly generated high-resolution (10 m) Sentinel-2 derived land cover map for Isla Grande de Tierra del Fuego (Argentina) and Isla de los Estados, this study aimed to quantify the relationship among topo-climatic drivers, intrinsic forest structural descriptors, and spatial patterns of major land cover types. Sentinel-2 imagery (2021–2024) obtained during summer periods was classified into 13 classes using a hierarchical supervised method in QGIS. The resulting map was validated using over 5,991 independent observations, and environmental associations were analysed using Generalised Linear Model and Principal Component Analysis. The map achieved an overall accuracy of 86.3
The energetic costs associated with foraging activity were quantified for breeding Magellanic penguins from Martillo Island, located in the Beagle Channel, Tierra del Fuego, Argentina (54°54′ S, 67°23′ W). Individuals were equipped in 2023–2024 with multi-sensor biologging devices that recorded body acceleration, pressure and location during the early chick-rearing period. These data were used to characterize the structure of foraging trips and rates of energy expenditure and later upscaled to estimate prey-intake of the whole colony. Foraging trips were found to last slightly less than one day and to cover up to more than a hundred kilometers within the Beagle Channel. Estimates of metabolic power, derived from Overall Dynamic Body Acceleration (ODBA), indicated relatively consistent energetic expenditure rates among individuals ( 63 W), although total energy expenditure increased with trip duration up to 7000 kJ per trip. Diving patterns showed that foraging activity occurred throughout most of the transit and central phase of trips, suggesting that no clear separation between those occur, whereas higher travel speeds defined the return to the colony. Energetic estimates were subsequently converted into prey consumption requirements to evaluate the trophic demand generated by breeding adults. When extrapolated to the colony scale, these requirements indicate a substantial energy flow (6–15 tons of prey) from local marine resources to the penguin population. These results highlight the ecological importance of the Beagle Channel as a productive feeding environment supporting this colony and other seabird populations.
Cold adapted plant species often dependent on seed dormancy breakage for successful germination, yet the effects of climate-driven changes in soil temperature on this process remain unclear. To improve our understanding of temperature impacts on seed dormancy breakage of Arctic plant species and populations, we investigated how different durations of cold-moist stratification at 0 °C or -5 °C affected seed germination of three Greenlandic plant species: Luzula spicata, Juncus trifidus, and Luzula multiflora. Seeds were collected from natural populations at low (0 m a.s.l) and high (500 m a.s.l.) elevations. Germination patterns differed between species, however, in general germination percentages were significantly higher for low elevational seeds compared to high elevational seeds for all three species. Elevation affected day of first germination only in J. trifidus. Stratification temperature, however, affected both day of first germination for J. trifidus and L. multiflora and the germination rate of L. spicata. Several species-specific interactions among stratification duration, elevation, and stratification temperature were identified. These findings show that Arctic plant species, and even their individual populations, exhibit different dormancy patterns. Climate change may thus affect populations and species differently, with important consequences for future Arctic plant community dynamics.
In colonial animals, territory selection and defence are shaped by both environmental physical constraints and interactions among conspecifics. Understanding the spatial arrangement of individuals within colonies thus provides a valuable framework for assessing the forces that shape colony structure and may influence its demography. Here, we aim to determine how environmental and colonial factors jointly influence the size and shape of individual nesting territories in a colonial bird species, the Adélie penguin. We derived spatial and topographic features from drone-based digital elevation models obtained in Adélie Land (AL), the Western Antarctic Peninsula (WAP), and the Eastern Antarctic Peninsula (EAP). We show that individual territories are shaped by local slope and distance to the colony edge. On average, territory size decreases towards the centre and then stabilises, whereas shape optimisation level increases monotonically, revealing a decoupling between size and shape optimisation level. In contrast, we find no consistent effect of elevation, nor any effect of colony shape or number of nests on individual territories. Colony-specific patterns were evident at Heroína (EAP) and Petrel Island (AL), where these centre-periphery gradients in both size and shape were significant, whereas no such gradients were detected at Torgersen and Yalour Islands (WAP). These colony-level differences may reflect local variation in predation pressure, territorial behaviour, or ground conditions, although the relative contribution of each factor remains unclear. Our findings highlight the importance of considering within-colony heterogeneity and the environmental context to refine our understanding of spatial organisation.
The western Arctic is experiencing rapid environmental change, and the Chukchi Borderland is characterised by a strongly stratified water-mass structure during the summer sea-ice retreat period. However, how this contemporary stratification is reflected in pelagic metazoan communities remains poorly understood. Here, we used metazoan-targeted, COI-based environmental DNA (eDNA) metabarcoding to investigate community patterns across three major water masses in the Chukchi Borderland: the Polar Mixed Layer (PML, 0–50 m), Arctic Halocline Water (AHW, 50–200 m), and Atlantic Water (AW, 200–2000 m). During the summer sea-ice retreat period in July-August 2023, we collected 24 seawater samples from eight stations, spanning depth layers corresponding to these water masses. Metazoan α-diversity differed significantly among water masses (p < 0.05) and generally peaked in AHW, while the freshened PML showed the lowest diversity. Community composition also showed vertical structuring, with Weighted UniFrac analyses revealing significant differentiation among water masses and closer similarity between AHW and AW than between either deeper layer and PML. Co-occurrence network analyses suggested that AHW supported a relatively sparse but more modular metazoan network, whereas PML and AW exhibited more densely connected networks. Environmental variables showed strong vertical gradients, and salinity and temperature emerged as the main environmental correlates of community structure, with salinity showing the strongest independent explanatory contribution. These results demonstrate that COI-based eDNA metabarcoding can resolve water-mass-associated community patterns in stratified Arctic waters. Rather than inferring temporal sea-ice-driven change, this study provides a baseline snapshot of how contemporary water-mass structure is associated with metazoan community organisation in the Chukchi Borderland during the summer sea-ice retreat period.
This study evaluated the concentrations of cadmium (Cd), cobalt (Co), and lead (Pb) in the hair of water voles (Arvicola amphibius L., 1758) from the three islands of the White Sea (Bolshoy Zhuzhmuy, Kondostrov, and the unnamed island near Perkh-Luda) using atomic absorption spectrometry. Due to the limited and uneven sample size (n = 16), simultaneous modeling of the potential effects of spatial, sexual, and ontogenetic factors was not statistically feasible. However, we detected substantially higher median Cd levels in the hair of the animals from the unnamed island and higher median Pb levels in the Bolshoy Zhuzhmuy’s samples compared to samples from other islands. The maximal values of Co concentrations were detected in the voles from Kondostrov. A comparison of metal concentrations in the hair of the water vole with relevant data for other mammal species revealed that the median levels of Cd, Co, and Pb detected were generally consistent with values recorded in regions not subjected to considerable anthropogenic pressure. However, we cannot state that the observed metal levels in the hair of the water voles reflect natural geochemical background levels or anthropogenic pollution, as there are no reference data from the ecosystem itself. The study contributes to our understanding of the accumulation of potentially toxic elements in an understudied species. The data provide an initial ecological baseline for assessing the elemental status of the fauna in northern island ecosystems. The identified element concentrations can be used in long-term ecological planning and serve as a starting point for larger-scale monitoring programs.
Glaciers are significant components of Earth’s biomes, functioning as ecosystems and shaping adjacent systems. The retreating glaciers form ice-free areas on their forefields, which become colonized by pioneering organisms. Although these dynamic ecosystems are investigated worldwide, the diversity, distribution, and role of mites (Acari) in newly deglaciated areas remain virtually unknown, with few studies published to date. In this study, the diversity of acariform mites (Prostigmata and Endeostigmata) in glacier forefields and moraines of European and Arctic glaciers was investigated for the first time. Soil and vegetation samples were collected from Spitsbergen (Svalbard), the Alps, and the Pyrenees. Prostigmatic and endeostigmatic mites were present in all sampling sites. Collectively, 34 species were found, including 29 species of Prostigmata and five species of Endeostigmata. This dominance of Prostigmata over Endeostigmata reflects a much higher global diversity of the former. The two prostigmatic superfamilies, Eupodoidea and Tydeoidea, were the most species-rich in the examined material. Representatives of both groups are known from harsh, cold environments and have the potential to be pioneer fauna and the first faunal component of trophic webs in forefields and moraines. This study demonstrates that Prostigmata and Endeostigmata are surprisingly diverse in the forefields and moraines. Due to their diverse diet, they can play important roles in food webs during post-glacial forefield succession and thus should not be overlooked in ecological studies.
The hooded seal (Cystophora cristata) is an Arctic phocid seal occasionally observed far outside its native range, including the European Atlantic shelf seas. This study presents the movements and diving behaviour of two female hooded seal pups after rehabilitation and release in the German North Sea. We tracked the animals using satellite telemetry to evaluate post-release survival and movement behaviour. Within one month, one seal travelled through the North Sea to the coast of United Kingdom, and then further northward to the Norwegian west coast, suggesting a successful return to Arctic waters. In contrast, the second seal remained in the North Sea and exhibited shallower and shorter dives over time, with extensive surface resting. She was ultimately found in poor condition in the United Kingdom and placed in permanent captivity. These cases highlight the species’ high dispersal capacity, yet also underline the challenges vagrant individuals face in suboptimal non-native habitats. The contrasting outcomes suggest that rehabilitation and release of such Arctic vagrants should be assessed case-by-case, considering the animal’s age, health, and timing of the release in relation to the expected prey availability. This study emphasizes the importance of satellite telemetry in evaluating post-release success and contributes to the broader discussion on the viability and ethics of rehabilitating extralimital marine mammals.
Assessing benthic carbon stocks provides key insights into ecosystem functioning. We compiled macrozoobenthic data, including abundance, biomass, body mass, and environmental variables (e.g., chlorophyll-a (Chl-a), temperature, and total organic matter (TOM)), from 101 stations across the sub-Antarctic Chilean Patagonian Fjords and Channels between 1994 and 2010. Artificial neural networks were applied to estimate secondary production and productivity. The highest abundance and biomass were found in Beagle Channel and Bernardo O’Higgins National Park (BONP)/Kawésqar National Reserve (KNR), where mollusks accounted for the largest proportion of benthic carbon. Community production was highest values in BONP ( 96.96 g C m−² y−¹), while the highest P/B ratios occurred in glacially influenced locations such as Gallegos Sound ( 6.68 y−¹), indicating rapid biomass turnover primarily contributed by arthropods and annelids. Depth and TOM were the strongest predictors of spatial patterns: production declined with depth, whereas elevated P/B ratios were associated with TOM-rich sediments, indicating efficient carbon recycling. These patterns reveal two contrasting benthic functional contexts: shallow, organic-rich fjords with high production, and deeper, glacially influenced systems with lower production but higher turnover. Mollusks contribute disproportionately to secondary production, arthropods drive biomass renewal, and annelids underpin sedimentary organic-matter processing. Together, these functional roles highlight the significance of different taxa within benthic communities in regional carbon cycling and offer essential context for aquaculture planning, conservation, and ecosystem-based management in sub-Antarctic marine environments.
The decline of major known Magellanic penguin (Spheniscus magellanicus) colonies has highlighted the need to obtain information from other, less-studied colonies. Although smaller in size, and with only one previous assessment in the Tuckers Islets, located in Whiteside Channel in the Chilean sector of Tierra del Fuego, Chile, we updated abundance estimates and examined interannual variations in size and spatial distribution. Using a Bayesian spatial model, we analyzed three consecutive breeding seasons (2022/2023–2024/2025) on the main islet (Tucker 1), incorporating the smaller Tucker 2 during the final season. Posterior abundance estimates for Tucker 1 ranged between 1,532 (95
Phthalate acid esters (PAEs) are widely used plastic additives that have become ubiquitous contaminants in marine environments. Filter-feeding baleen whales may be exposed to these pollutants through water, prey or ingested plastic debris. While macroplastics have been reported in the gut of a southern right whale (SRW, Eubalaena australis), exposure to PAEs has not been assessed. Here, we quantified three lipophilic PAEs, dimethyl phthalate (DMP), dibutyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP), in the blubber of 13 SRWs (three calves, three juveniles and seven adults) stranded in 2021 at Península Valdés, Argentina. More than 90
At the southern end of the Americas, the Cape Horn Biosphere Reserve (CHBR) hosts a unique and diverse array of forest birds. The survival of these birds is increasingly challenged by a combination of anthropogenic and environmental factors such as the spread of zoonotic diseases, including infection by avian malaria (Plasmodium) and related parasites (Haemoproteus and Leucocytozoon) from the Order Haemosporidia. These haemosporidian parasites have likely long been present in the CHBR due to the presence of long-distance migrants that winter in malaria hotspots. Until recently, however, there has not been a competent malaria vector in the region to mediate transmission between migrants and resident birds. In 2015, probably linked to global climate change and higher connectivity, the presence of novel potential malaria vectors (Culicidae spp.) was first detected in the region. We examined the prevalence and identified strains of avian malaria infection in the forest bird communities of the CHBR using two complementary techniques – microscopy and PCR-based genetic analyses. We detected haemosporidian infection in 65 birds (29.15
Human activities are a primary driver of biodiversity loss, significantly impacting mammal populations, with nearly one in four species currently facing the threat of extinction. Conventional detection methods, such as surveys, camera traps, and live traps, require intensive fieldwork and post-processing, which may limit their application in certain contexts. Consequently, environmental DNA (eDNA) has emerged as a non-invasive and efficient alternative for species detection, including rare or low-detectability species. Advances in next-generation sequencing and metabarcoding have enabled rapid biodiversity assessments from water, sediment, and air samples. Given the challenges associated with sampling in inaccessible and adverse environments, such as Tierra del Fuego, exploring innovative approaches to species sampling is imperative. This study assessed the feasibility of environmental DNA (eDNA) metabarcoding targeting the mitochondrial 12S rRNA gene to characterize mammalian diversity from water samples. Results from a single day of sampling demonstrated the detection of 76
Glacier-influenced Arctic fjords are highly dynamic systems where environmental gradients strongly shape benthic communities. We analyzed live meiobenthic foraminiferan assemblages along an inner–outer gradient in Kongsfjorden (Svalbard) using trait-based approaches, RLQ ordination analysis/fourth-corner analysis, and co-occurrence networks to resolve community assembly and functional resilience. Sixty species were classified into 16 traits and 37 functional entities across nine stations. Community structure was governed by a dominant gradient linking coarser, lower organic inner-fjord sediments to finer, organic-enriched outer-fjord habitats. Infaunal, calcareous, and suboxic-tolerant taxa dominated overall, while epifaunal and oxic-associated species were restricted to well-oxygenated substrates, indicating strong habitat filtering. RLQ analysis confirmed significant trait–environment coupling driven by sediment texture, and organic enrichment. Network analysis revealed three distinct species modules, suggesting non-random assembly and habitat-linked functional guilds. Functional diversity indices remained stable across zones despite shifts in species composition, indicating conservation of functional space. However, 73
The Falkland skua (Stercorarius antarcticus antarcticus) is a long-lived seabird breeding primarily in the Falkland Islands. Despite its current Least Concern status by the IUCN, its population is declining, and trends remain poorly understood. We surveyed breeding populations across 18 islands and compared the changes in population size on New Island and Steeple Jason Island, the two largest known nesting sites. Between 2009 and 2023, the New Island population declined by 26
Positive interactions among plants are a key in structuring alpine plant communities, particularly under severe environmental conditions. Cushion plants are widely recognized as important facilitators in alpine ecosystems, but their effects on non-vascular plants remain poorly understood. Here, we evaluated spatial associations of vascular plants and mosses with the cushion plant Bolax gummifera in the alpine zone of Navarino Island (55°S), the southernmost alpine environment of the Southern Hemisphere. We compared species richness, community composition, and species-level associations within and outside cushions on equatorial- and polar-facing slopes characterized by contrasting microclimatic conditions. A total of 52 species were recorded, including 34 mosses and 18 vascular plants, confirming the high importance of bryophytes in subantarctic alpine habitats. Vascular plants showed significantly higher richness within cushions than outside them on both slopes, whereas moss richness did not differ between microhabitats. Relative Interaction Index (RII) values were positive for vascular plants on both slopes, particularly on the equatorial slope, indicating stronger positive associations with cushions under more severe environmental conditions. In contrast, mosses exhibited weak or neutral RII values, suggesting lower dependence on cushion-mediated habitat amelioration at the community level. Nevertheless, several moss species showed significant positive associations with cushions, especially on the polar slope. Ordination analyses revealed that both slope aspect and cushion presence generated distinct species assemblages, highlighting the combined effects of microhabitat filtering and topographic heterogeneity on alpine community structure. Microclimatic analyses showed that the equatorial slope experienced higher thermal amplitude, lower snow persistence, lower vegetation cover, and greater substrate instability than the polar slope, despite being warmer on average. Our results demonstrate that vascular plants and mosses differ in their responses to cushion plants and emphasize the importance of aspect-driven microclimatic heterogeneity in shaping species interactions and community assembly in subantarctic alpine ecosystems.
Ecosystem engineering is an important factor influencing species establishment in novel environments. Here we tested how shell middens created by kelp gulls (Larus dominicanus) affect the growth of candidate non-native plants under simulated Antarctic conditions. Calcium compounds derived from the shells raised the organic Antarctic substrate pH from 6.0 to 7.3 and resulted in increased plant biomass (21–100
Southern long-finned pilot whale is one of the most abundant cetaceans in Falkland Islands waters but no information is available on its food and feeding ecology. Here, stomach contents were collected from 86 whales mass-stranded in East Falkland to detail their diet and trophic relationships. A total of 6032 cephalopod beaks were collected from 56 whale stomachs. Twenty-six taxa were identified, including 23 oegopsids, one myopsid, one sepiolid and one octopod. The cephalopod diet was dominated by the onychoteuthid Moroteuthopsis ingens, which accounted for 81
