This paper reports on interviews conducted during June and July 2015 to document ecological knowledge of beluga whales (Delphinapterus leucas) in Ulukhaktok, Northwest Territories. Beluga whales are not a traditionally available or important species for Ulukhaktomiut, but they have appeared in increasing numbers in the waters around the community, and hunters have actively pursued and taken them. We conducted interviews in English with 31 Inuit about their beluga knowledge. A Key Words in Context (KWIC) analysis of the word “know” in the narratives reveals different conceptions of what it means to know something about whales. “Know” variously references practical skill, concern and empathy for others, or the developing awareness of one’s place in the world. Each of these meanings is coded uniquely in Inuinnaqtun, providing insights about the important differences between researchers and Inuit in how “ecological knowledge” is understood and activated.

The interaction between bottom-up and top-down forces in regulating plant communities is a long-standing topic of interest in ecology. Factorial field experiments examining these factors have been relatively few, but recent meta-analyses provide predictions that can be tested in a range of ecosystems. We tested the prediction that added nutrients would reduce species richness and evenness, while herbivore activity would offset those changes in two tundra plant communities after 11 years. In moist acidic tundra (MAT), herbivores reduced richness more in fertilized plots when mammals were present compared with fertilized plots without herbivores. In dry heath (DH), evenness was significantly reduced in fertilized plots only when herbivores were present, also providing evidence that herbivores enhanced community changes caused by greater nutrient availability. The difference in response between MAT and the meta-analysis predictions appears to be driven by Betula nana, the species that dramatically increased with added nutrients in MAT. Unlike in similar studies and in DH, B. nana is not as palatable as most of the species in the community and is generally avoided by herbivores. These results highlight how the effects of herbivory and nutrients differ across communities and can be affected by the traits of the species present.

Arctic Museum collections: Documenting and understanding changes in biological and cultural diversity through time and spaceThe role of museums and herbaria in biodiversity and cultural synthesis efforts in the Arctic is to preserve the physical and cultural specimens and to advance scientific knowledge by improving access to digitized information.The information associated with these collections, such as geographic, cultural, environmental, phenology, and other information about associated organisms, collector field notes, and tissues and molecular data extracted from the specimens is an invaluable resource providing the baseline from which to further biodiversity research and provide critical information about existing gaps in our knowledge of life in the Arctic.Effective management and conservation of high-latitude biological and cultural diversity in the face of unprecedented rates of climate change requires information on past and current patterns of diversity and their evolution.This special issue of Arctic Science presents results from a workshop entitled "Arctic Museum Collections: Documenting and understanding changes in biological and cultural diversity through time and space" held during Arctic Science Summit Week in March 2016 at the University of Alaska Fairbanks.The workshop brought together scientists from many Arctic nations and focused on current informatics infrastructure, developing large networks of Arctic collections collaborators, and engaging new members and their students in many issues relevant to the Arctic and Subarctic.Lewis et al. review the status of knowledge of genetic diversity and evolutionary history for bryophyte taxa as it relates to shifting species ranges and colonization of new habitats.The University of Alaska Museum is a leader in Arctic and Subarctic collections and their digitization (with our multicollection database Arctos, arctosdb.org).Sikes et al. review rapid digitization efforts in entomological collections in the Arctic and highlight the open-access, online presence of the University of Alaska Museum's rapidly growing entomological collection.To answer relevant questions on the impact of change on high-latitude biological and cultural diversity, we need to synthesize and continue to generate baseline information on Arctic and Subarctic systems.Winker and Withrow show the inadequacy of most specimen collections to the task at hand of facilitating biodiversity assessment and conservation using the bird collections at the University of Alaska Museum as an example.They argue that we need to work collectively to fill temporal, spatial, and taxonomic gaps so we can develop and wield the science that will make us better stewards of Arctic environments.Several contributions in this special volume underscore the international, collaborative scope of Arctic research, including a detailed account of the historical exploration and specimen contributions from Finnish botanists and mycologists by Väre, or the description of baseline data acquisition on plant communities on Greenland accomplished through the Greenland Botanical Survey and subsequent field campaigns, the specimens from which are

Polygonal peatlands are carbon-rich permafrost ecosystems that will likely be significantly affected by climate change. However, studies are often constrained to one measurement per day, which impedes assessments of the temporal variability in carbon fluxes. For this reason, we measured ecosystem respiration (ER) of CO2 in a polygonal peatland underlain by continuous permafrost over an entire growing season to determine the effects of temperature and water table depth on the temporal variability of ER. We used four automated closed chambers to measure ER under varying temperature and soil moisture regimes. Temporal variability was approximately the same for the four plots, on both a diurnal and a seasonal scale. Both diurnal and seasonal variations in ER were strongly controlled by changes in soil surface temperature. Fluctuations of the water table depth associated with important rainfall events was also an important factor affecting ER on the seasonal scale. We found that water table level fluctuations below 20–25 cm did not significantly affect ER and that most soil respiration took place in the top 10 cm, likely in the surface 2 cm. Our results highlight the importance of monitoring future changes in tundra hydrology, which will determine the depth of organic matter available for aerobic decomposition.

Industrial land use such as petroleum exploration and infrastructure development has important and lasting impacts on Arctic landscapes. Detailed, site-level investigations have noted impacts that include vehicle tracks, surface and vegetation alteration, soil compaction, and degradation of ice wedge features. We investigated the long-term impact of an extended period of hydrocarbon exploration on Melville Island in the Canadian High Arctic using available remotely sensed data supplemented with field observations over a ∼370 km2 area. Aerial photographs from 1959, 1972, and 1977 and recent satellite imagery (2011 and 2013) were used to determine the effects of industrial activity over periods corresponding to pre-activity, mid-activity, and post-activity. We show that vehicle tracks, site disturbance, and vegetative impacts are still evident after 40 years in this area. Permafrost has degraded at sites with concentrated activity (drill sites, airstrips) and changes to vegetation are clearly discernable. The results demonstrate the utility of this approach for assessment of land use impacts on High Arctic landscapes and provide a means to determine locations for more detailed site-specific field studies. These results may contribute to strategies for environmental monitoring in remote areas where access is impractical or resource intensive.

This study investigates the impacts of active layer detachments (ALDs) on nitrogen in seasonal runoff from High Arctic hillslope catchments. We examined dissolved nitrogen in runoff from an undisturbed catchment (Goose (GS)) and one that was disturbed (Ptarmigan (PT)) by ALDs, prior to disturbance (2007) and 5 years after disturbance (2012). The seasonal dynamics of nitrogen species concentrations and fluxes were similar in both catchments in 2007, but the mean seasonal nitrate concentration and mass flux from the disturbed catchment were on the order of 30 times higher relative to the undisturbed catchment in 2012. Stormflow yielded 45% and 60% of the 2012 total dissolved nitrogen flux in GS and PT, respectively, although rainfall runoff provided less than 25% of seasonal discharge. Results support that through the combined effects of increased disturbance and rainfall, climate change stands to significantly enhance the export of nitrate from High Arctic watersheds. This study highlights that the increase in the delivery of nitrate from disturbance is especially pronounced late in the season when downstream productivity and the biological demand for this often limiting nutrient are high. Our results also demonstrate that the impact of ALDs on nitrate export can persist more than 5 years following disturbance.

Repeated freeze–thaw cycles on slopes trigger sorting and solifluction mass movements, while subsequent displacement of material modifies the geomorphology of slopes as well as permafrost dynamics. This study focuses on the geomorphology and the cryostratigraphy of a polar desert stone-banked solifluction lobe with the objective to clarify the impact of slow mass movements on ground ice aggradation. The morphology of the solifluction lobe was characterized by peripheral ridges of coarse gravel, partially surrounding a depression filled with finer sediments saturated with water and covered by organics. Cryostratigraphic analysis demonstrated that the solifluction lobe’s formation led to the development of a syngenetic layer of permafrost with an ice content that varied according to the location in the lobe. The ice-rich cryofacies formed in the central depression of the lobe should act as a buffer to potential active layer deepening, slowing down its thawing, whereas the ice-poor cryofacies formed under the ridges is expected to thaw faster than the central depression under climate warming scenarios. Thawing of the ice-rich zone in the future will result in differential thaw subsidence between the ridges and the central depression of solifluction lobes, along with increased drainage through the ridges and subsequent changes in hydrology.

Finnish botanists and mycologists have studied Arctic areas and timberline regions since the beginning of the 18th century. Most expeditions to the Kola Peninsula were made between 1800 and 1917 and until 1945 to Lapponia petsamoënsis on the western rim of the Kola Peninsula. Since those years, these areas have been part of the Soviet Union or Russia. Svalbard and Newfoundland and Labrador have been studied repeatedly as well, Svalbard since the 1860s and Newfoundland and Labrador since the 1930s. This article focuses on Finnish collections. These are deposited in the herbaria of Helsinki, Turku, and Oulu universities, except materials from the Nordenskiöld expeditions, which were mainly deposited in Stockholm. Concerning the Kola Peninsula, collections at Helsinki are the most extensive. The exact number of specimens is not known, but by rough estimation, the number is about 60 000, with an additional 110 000 observations included in the database. These expeditions have provided material to describe 305 new taxa to science, viz. 47 algae, 78 bryophytes, 25 fungi, 136 lichens, and 19 vascular plants. This number is an underestimate, as many new species have been described in several separate taxonomic articles. At least 63 persons have contributed to making these collections to Finnish herbaria. Of those, 52 are of Finnish nationality.

Permafrost disturbances (such as active layer detachment (ALD) slides) and thermal perturbation (deep ground thaw from high soil temperatures) alter Arctic surface water chemistry. However, the potential multi-year impacts on water chemistry and the ultimate recovery time are not well understood. This study evaluates the impacts on surface waters and recovery following disturbance of a High Arctic catchment in 2007 from ALDs. We measured ion concentrations and stable isotopes in surface waters collected between 2006 and 2014 from paired catchments — one disturbed and the other not. The years 2007 and 2012 were exceptionally warm and represent unusual thermal perturbation for both catchments. Results indicate that the exposure and mobilization of soluble ions in near surface soil is a key control over dissolved ion concentrations and composition following ALDs. Runoff in the disturbed catchment shows increased total dissolved solute (TDS) concentrations and seasonal TDS fluxes and changes to the relative composition of individual ions in surface water. These impacts persisted for the 7 year study duration after disturbance and are consistent with the thawing of the solute-rich transient layer and upper permafrost. Thermal perturbation increased TDS concentrations and seasonal fluxes in runoff for up to 2 years, as ions released from ground thaw appear to be available for flushing in subsequent summers.

Evidence from remote sensing studies suggests that the frequency of thermokarst lake drainage events is increasing in response to climate change, but the consequences of these changes on the limnology of remaining waterbodies remain unknown. Here, we utilize a multiparameter paleolimnological record and post-drainage water isotope and chemistry monitoring to characterize the limnological evolution of Zelma Lake in Old Crow Flats, Yukon. During the early part of the record (~1678 to 1900 CE), analysis of geochemical variables and algal pigments indicate relatively stable limnological conditions. Abruptly beginning at ~1900, Zelma Lake experienced a 40 year phase of reduced production, likely resulting from thermokarst shoreline expansion and associated increases in turbidity and low light availability. This was followed by ~70 years of increasing production, likely from the stabilization of shorelines combined with a warming climate. Zelma Lake catastrophically drained in June 2007. Post-drainage conditions were characterized by intense eutrophication marked by increases in nutrient and major ion concentrations and the unprecedented occurrence of okenone and diatoxanthin pigments. Comparison to the post-drainage paleolimnological record from another thermokarst lake in Old Crow Flats indicates that a sharp increase of production is likely a common outcome of thermokarst lake drainage, yet intensity differs owing to site-specific catchment characteristics.