The Peel Plateau, NT, Canada, is underlain by warm continuous permafrost where changes in soil moisture, snow conditions, and shrub density have increased ground temperatures next to the Dempster Highway. In this study, ground temperatures, snow, and thaw depth were monitored before and after tall shrub removal (2014). A snow survey after tall shrub removal indicated that snow depth decreased by a third and lowered winter ground temperatures when compared with control tall shrub sites. The response of ground temperatures to shrub removal depended on soil type. The site with organic soils had cooler winter temperatures and no apparent change in summer temperatures following shrub removal. At sites with mineral soil, moderate winter ground cooling insufficiently counteracted increases in summer ground heat flux caused by canopy removal. Given the predominance of mineral soil along the Dempster, these observations suggest tall shrub removal is not a viable short-term permafrost management strategy. Additionally, the perpendicular orientation of the Highway to predominant winter winds stimulates snow drift formation and predisposes the site to warmer permafrost temperatures, altered hydrology, and tall shrub proliferation. Subsequent research should explore effectiveness of tall shrub removal at sites with colder winter conditions or different snow accumulation patterns.
{"title":"Impacts of shrub removal on snow and near-surface thermal conditions in permafrost terrain adjacent to the Dempster Highway, NT, Canada","authors":"Emily A Cameron, Trevor C Lantz, Steven V. Kokelj","doi":"10.1139/as-2022-0032","DOIUrl":"https://doi.org/10.1139/as-2022-0032","url":null,"abstract":"The Peel Plateau, NT, Canada, is underlain by warm continuous permafrost where changes in soil moisture, snow conditions, and shrub density have increased ground temperatures next to the Dempster Highway. In this study, ground temperatures, snow, and thaw depth were monitored before and after tall shrub removal (2014). A snow survey after tall shrub removal indicated that snow depth decreased by a third and lowered winter ground temperatures when compared with control tall shrub sites. The response of ground temperatures to shrub removal depended on soil type. The site with organic soils had cooler winter temperatures and no apparent change in summer temperatures following shrub removal. At sites with mineral soil, moderate winter ground cooling insufficiently counteracted increases in summer ground heat flux caused by canopy removal. Given the predominance of mineral soil along the Dempster, these observations suggest tall shrub removal is not a viable short-term permafrost management strategy. Additionally, the perpendicular orientation of the Highway to predominant winter winds stimulates snow drift formation and predisposes the site to warmer permafrost temperatures, altered hydrology, and tall shrub proliferation. Subsequent research should explore effectiveness of tall shrub removal at sites with colder winter conditions or different snow accumulation patterns.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136306647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present the history of research activities at the Bylot Island Field Station of the Centre d’études nordiques, a hotspot of biodiversity in the Canadian Arctic. Intensive wildlife studies started at the station in the late 1980s, initially focussing on greater snow goose ecology and its impacts on the tundra vegetation. Since then, studies have expanded to encompass the whole vertebrate food web and have become one of the most comprehensive ecological monitoring programs in the Canadian Arctic. The main vertebrate species monitored include snow geese, lemmings, shorebirds, avian predators, buntings, and Arctic foxes. Over time, we recorded 66 bird and 10 mammal species, including 51 confirmed breeders. Contributions of the program to the field of ecology are numerous, but our demonstration of the dominant role played by predator–prey interactions in the Arctic food web is especially significant for the understanding of direct and indirect trophic interactions. Our studies provided essential information for management decisions taken to control the overabundant greater snow goose population and supported international efforts to assess the state of Arctic biodiversity. Future directions will reflect the need to deepen our understanding of trophic interactions and the effects of climate change using innovative advanced technologies.
{"title":"Long-term study of the tundra food web at a hotspot of Arctic biodiversity, the Bylot Island Field Station","authors":"Gilles Gauthier, Marie-Christine Cadieux, Dominique Berteaux, Joël Bêty, Dominique Fauteux, Pierre Legagneux, Esther Lévesque, Caterine-Alexandra Gagnon","doi":"10.1139/as-2023-0029","DOIUrl":"https://doi.org/10.1139/as-2023-0029","url":null,"abstract":"We present the history of research activities at the Bylot Island Field Station of the Centre d’études nordiques, a hotspot of biodiversity in the Canadian Arctic. Intensive wildlife studies started at the station in the late 1980s, initially focussing on greater snow goose ecology and its impacts on the tundra vegetation. Since then, studies have expanded to encompass the whole vertebrate food web and have become one of the most comprehensive ecological monitoring programs in the Canadian Arctic. The main vertebrate species monitored include snow geese, lemmings, shorebirds, avian predators, buntings, and Arctic foxes. Over time, we recorded 66 bird and 10 mammal species, including 51 confirmed breeders. Contributions of the program to the field of ecology are numerous, but our demonstration of the dominant role played by predator–prey interactions in the Arctic food web is especially significant for the understanding of direct and indirect trophic interactions. Our studies provided essential information for management decisions taken to control the overabundant greater snow goose population and supported international efforts to assess the state of Arctic biodiversity. Future directions will reflect the need to deepen our understanding of trophic interactions and the effects of climate change using innovative advanced technologies.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136307068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Benoît Lauzon, L. Copland, W. Van Wychen, W. Kochtitzky, R. McNabb
Various remotely sensed data, including historical aerial photographs, declassified intelligence satellite photographs, optical satellite imagery, and synthetic aperture radar data were used to undertake the first comprehensive reconstruction of the dynamics of Airdrop Glacier on Axel Heiberg Island, Nunavut. Observations show a continuous terminus advance totalling ~6 km since 1950 and notably less variability in its surface velocities in comparison to adjacent Iceberg Glacier. This advance is concurrent with relatively high flow rates over its entire surface, resulting in significant thickening near the terminus, and thinning at higher elevations. Velocities have more than halved from the mid-2000s to 2021, but without any definitive evidence of previous flow instabilities, we cannot confirm whether Airdrop’s behaviour is cyclic in nature and therefore characteristic of a surge. Instead, Airdrop Glacier could be experiencing a delayed response to positive mass balance conditions of the Little Ice Age, which could also explain the advance of other nearby glaciers. Its recent slowdown could then be indicative of a gradual adjustment to recent climatic conditions. This study highlights the need for comprehensive studies of glacier dynamics in the Canadian Arctic to improve our understanding of the factors triggering dynamic instabilities and causing the observed variety of behaviours.
利用各种遥感数据，包括历史航空照片、解密情报卫星照片、光学卫星图像和合成孔径雷达数据，对Nunavut Axel Heiberg岛空投冰川的动态进行了首次综合重建。观测显示，自1950年以来，终末冰川连续前进了约6公里，与邻近的冰山冰川相比，其表面速度的变异性明显较小。这种进步与整个表面的相对高流速同时发生，导致在末端附近显着增厚，在较高海拔处变薄。从2000年代中期到2021年，速度下降了一半以上，但由于没有任何明确的证据表明之前的流动不稳定，我们无法确认Airdrop的行为是否具有周期性，因此是否是激增的特征。相反，空投冰川可能正在经历对小冰期正质量平衡条件的延迟反应，这也可以解释附近其他冰川的前进。因此，最近的放缓可能预示着对近期气候条件的逐渐调整。这项研究强调了对加拿大北极地区冰川动力学进行全面研究的必要性，以提高我们对触发动态不稳定性和导致观察到的各种行为的因素的理解。
{"title":"Evolution of the dynamics of Airdrop Glacier, western Axel Heiberg Island, over a seven decade long advance","authors":"Benoît Lauzon, L. Copland, W. Van Wychen, W. Kochtitzky, R. McNabb","doi":"10.1139/as-2022-0045","DOIUrl":"https://doi.org/10.1139/as-2022-0045","url":null,"abstract":"Various remotely sensed data, including historical aerial photographs, declassified intelligence satellite photographs, optical satellite imagery, and synthetic aperture radar data were used to undertake the first comprehensive reconstruction of the dynamics of Airdrop Glacier on Axel Heiberg Island, Nunavut. Observations show a continuous terminus advance totalling ~6 km since 1950 and notably less variability in its surface velocities in comparison to adjacent Iceberg Glacier. This advance is concurrent with relatively high flow rates over its entire surface, resulting in significant thickening near the terminus, and thinning at higher elevations. Velocities have more than halved from the mid-2000s to 2021, but without any definitive evidence of previous flow instabilities, we cannot confirm whether Airdrop’s behaviour is cyclic in nature and therefore characteristic of a surge. Instead, Airdrop Glacier could be experiencing a delayed response to positive mass balance conditions of the Little Ice Age, which could also explain the advance of other nearby glaciers. Its recent slowdown could then be indicative of a gradual adjustment to recent climatic conditions. This study highlights the need for comprehensive studies of glacier dynamics in the Canadian Arctic to improve our understanding of the factors triggering dynamic instabilities and causing the observed variety of behaviours.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45265807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Research on ecologically and economically important sea cucumbers has been focused on temperate and tropical species, leaving those from higher latitudes, such as the Canadian Arctic, understudied. This study compared the phenotypic characters of the sea cucumber Cucumaria frondosa sampled from populations of the Arctic (Hudson Bay, Nunavut) and Northwest Atlantic (Newfoundland). Organ indices and external and internal tissue pigmentation, and various biochemical metrics (proximate composition, lipids, fatty acids, amino acids, lipid-soluble vitamins, carotenoids) were assessed. All sea cucumbers had similar total body weights, but those from Newfoundland had heavier gonads and body walls, while the tissue pigmentation of Nunavut individuals was distinctive (more red and yellow trivium, darker brown pigmentation). Moisture and ash contents of sea cucumbers were similar between locations; however, protein and lipid contents in Nunavut samples were 12 and 50% lower, respectively. Inversely, Nunavut samples contained more ω-3 fatty acids, a greater degree of lipid desaturation, double the concentration of proline and vitamin A, and more carbohydrates and astaxanthin than Northwest Atlantic samples. Examining phenotypic variability across latitudes and longitudes, including into the Arctic highlights unique physical and biochemical features attributed to this specific environment and may support the sustainable development of sea cucumber fisheries.
{"title":"Comparative analysis of phenotypes in the sea cucumber Cucumaria frondosa from the Arctic and the NW Atlantic","authors":"R. Morrison, J. Hamel, Jiamin Sun, A. Mercier","doi":"10.1139/as-2023-0025","DOIUrl":"https://doi.org/10.1139/as-2023-0025","url":null,"abstract":"Research on ecologically and economically important sea cucumbers has been focused on temperate and tropical species, leaving those from higher latitudes, such as the Canadian Arctic, understudied. This study compared the phenotypic characters of the sea cucumber Cucumaria frondosa sampled from populations of the Arctic (Hudson Bay, Nunavut) and Northwest Atlantic (Newfoundland). Organ indices and external and internal tissue pigmentation, and various biochemical metrics (proximate composition, lipids, fatty acids, amino acids, lipid-soluble vitamins, carotenoids) were assessed. All sea cucumbers had similar total body weights, but those from Newfoundland had heavier gonads and body walls, while the tissue pigmentation of Nunavut individuals was distinctive (more red and yellow trivium, darker brown pigmentation). Moisture and ash contents of sea cucumbers were similar between locations; however, protein and lipid contents in Nunavut samples were 12 and 50% lower, respectively. Inversely, Nunavut samples contained more ω-3 fatty acids, a greater degree of lipid desaturation, double the concentration of proline and vitamin A, and more carbohydrates and astaxanthin than Northwest Atlantic samples. Examining phenotypic variability across latitudes and longitudes, including into the Arctic highlights unique physical and biochemical features attributed to this specific environment and may support the sustainable development of sea cucumber fisheries.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46106399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Lapalme, C. Spence, D. Costa, B. Bonsal, Jordan L. Musetta-Lambert, Yalda Fazli
This study is a meta-analysis of recent global research articles on hydrogeochemical modelling of permafrost regions to determine trends and consensus on research gaps and future research directions. The hydrogeochemical response of permafrost to climate change remains challenging to estimate and forecast despite evidence of large-scale impacts on freshwater and ecological cycles. We investigate the feasibility, need, and potential for hydrogeochemical modelling of permafrost landscapes by reviewing recommendations from previous modelling, review, and primer papers, including discussing ways to advance this type of modelling science. Key permafrost hydrogeochemical processes are discussed, including heat transfer and associated freeze–thaw regimes, biogeochemical processes and rates, and surface and subsurface flow. Modelling considerations (i.e., model dimension, scale, heterogeneity, and permafrost zonation) and model parameters are subsequently examined. Finally, limitations and additional considerations for advancing permafrost hydrogeochemical modelling efforts are reviewed. The findings of this review are summarized in recommendations, tables, and two schematics incorporating key considerations for future hydrogeochemical modelling initiatives in permafrost environments.
{"title":"Towards the incorporation of hydrogeochemistry into the modelling of permafrost environments: a review of recent recommendations, considerations, and literature","authors":"C. Lapalme, C. Spence, D. Costa, B. Bonsal, Jordan L. Musetta-Lambert, Yalda Fazli","doi":"10.1139/as-2022-0038","DOIUrl":"https://doi.org/10.1139/as-2022-0038","url":null,"abstract":"This study is a meta-analysis of recent global research articles on hydrogeochemical modelling of permafrost regions to determine trends and consensus on research gaps and future research directions. The hydrogeochemical response of permafrost to climate change remains challenging to estimate and forecast despite evidence of large-scale impacts on freshwater and ecological cycles. We investigate the feasibility, need, and potential for hydrogeochemical modelling of permafrost landscapes by reviewing recommendations from previous modelling, review, and primer papers, including discussing ways to advance this type of modelling science. Key permafrost hydrogeochemical processes are discussed, including heat transfer and associated freeze–thaw regimes, biogeochemical processes and rates, and surface and subsurface flow. Modelling considerations (i.e., model dimension, scale, heterogeneity, and permafrost zonation) and model parameters are subsequently examined. Finally, limitations and additional considerations for advancing permafrost hydrogeochemical modelling efforts are reviewed. The findings of this review are summarized in recommendations, tables, and two schematics incorporating key considerations for future hydrogeochemical modelling initiatives in permafrost environments.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41978305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Fuirst, K. Elliot, S. Ferguson, A. Fisk, L. Harris, K. Hedges, Kevin B. Jacobs, K. Johnson, T. Loewen, C. Matthews, C. Mundy, A. Niemi, Wesley R. Ogloff, C. Watt, D. Yurkowski
Temporal variation in food web structure is widespread among highly seasonal environments, such as the Arctic and is driven by changes in resource availability. Variation in resource availability can lead to species differences in diet composition, isotopic niche width, and trophic position (TP) across seasons. Here, we used tissue samples that represent two distinct turnover rates for diet (liver = shorter-term, muscle = longer-term) from 18 fish and three marine mammal species to investigate seasonal (i) variation in TPs within the Southampton Island marine ecosystem of Hudson Bay, (ii) variation in consumer isotopic niche width within this part of the food web, and (iii) variation in community niche dynamics among a fish and marine mammal community using stable carbon (δ13C) and nitrogen (δ15N) isotope analyses. Many zooplanktivores and piscivores increased in TP in summer (i.e. shorter-term turnover period), whereas benthic-feeders dependent on ice-obligate prey decreased in TP. Most isotopic niche widths and community metrics (δ15N range, total ellipse area, mean centroid distance) were higher in liver than muscle. Our findings demonstrate seasonal changes in TPs, which suggests that Arctic communities may be differentially affected by longer ice-free periods and earlier onset of primary production due to accelerated climate change.
{"title":"Seasonal variation in trophic structure and community niche dynamics of an Arctic coastal community of marine vertebrates","authors":"M. Fuirst, K. Elliot, S. Ferguson, A. Fisk, L. Harris, K. Hedges, Kevin B. Jacobs, K. Johnson, T. Loewen, C. Matthews, C. Mundy, A. Niemi, Wesley R. Ogloff, C. Watt, D. Yurkowski","doi":"10.1139/as-2023-0027","DOIUrl":"https://doi.org/10.1139/as-2023-0027","url":null,"abstract":"Temporal variation in food web structure is widespread among highly seasonal environments, such as the Arctic and is driven by changes in resource availability. Variation in resource availability can lead to species differences in diet composition, isotopic niche width, and trophic position (TP) across seasons. Here, we used tissue samples that represent two distinct turnover rates for diet (liver = shorter-term, muscle = longer-term) from 18 fish and three marine mammal species to investigate seasonal (i) variation in TPs within the Southampton Island marine ecosystem of Hudson Bay, (ii) variation in consumer isotopic niche width within this part of the food web, and (iii) variation in community niche dynamics among a fish and marine mammal community using stable carbon (δ13C) and nitrogen (δ15N) isotope analyses. Many zooplanktivores and piscivores increased in TP in summer (i.e. shorter-term turnover period), whereas benthic-feeders dependent on ice-obligate prey decreased in TP. Most isotopic niche widths and community metrics (δ15N range, total ellipse area, mean centroid distance) were higher in liver than muscle. Our findings demonstrate seasonal changes in TPs, which suggests that Arctic communities may be differentially affected by longer ice-free periods and earlier onset of primary production due to accelerated climate change.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44989618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Increased soil nutrient availability, and associated increases in vegetation productivity, could create a negative feedback between Arctic ecosystems and the climate system, thereby reducing the contribution of Arctic ecosystems to future climate change. To predict whether this feedback will develop, it is important to understand the environmental controls over nutrient cycling in High Arctic ecosystems and their impact on carbon cycling processes. Here, we examined the environmental controls over soil nitrogen availability in a High Arctic wet sedge meadow and how abiotic factors and soil nitrogen influenced carbon dioxide exchange processes. The importance of environmental variables was consistent over the three years, but the magnitudes of their effect varied depending on climate conditions. Ammonium availability was higher in warmer years and wetter conditions, while drier areas within the wetland had higher nitrate availability. Carbon uptake was driven by soil moisture, active layer depth, and variability between sampling sites and years (R2 = 0.753), while ecosystem respiration was influenced by nitrogen availability, soil temperature, active layer depth, and sampling year (R2 = 0.848). Considered together, the future carbon dioxide source or sink potential of high latitude wetlands will largely depend on climate-induced changes in moisture and subsequent impacts on nutrient availability.
{"title":"Drivers of soil nitrogen availability and carbon exchange processes in a High Arctic wetland","authors":"J. Hung, N. Scott, P. Treitz","doi":"10.1139/as-2022-0048","DOIUrl":"https://doi.org/10.1139/as-2022-0048","url":null,"abstract":"Increased soil nutrient availability, and associated increases in vegetation productivity, could create a negative feedback between Arctic ecosystems and the climate system, thereby reducing the contribution of Arctic ecosystems to future climate change. To predict whether this feedback will develop, it is important to understand the environmental controls over nutrient cycling in High Arctic ecosystems and their impact on carbon cycling processes. Here, we examined the environmental controls over soil nitrogen availability in a High Arctic wet sedge meadow and how abiotic factors and soil nitrogen influenced carbon dioxide exchange processes. The importance of environmental variables was consistent over the three years, but the magnitudes of their effect varied depending on climate conditions. Ammonium availability was higher in warmer years and wetter conditions, while drier areas within the wetland had higher nitrate availability. Carbon uptake was driven by soil moisture, active layer depth, and variability between sampling sites and years (R2 = 0.753), while ecosystem respiration was influenced by nitrogen availability, soil temperature, active layer depth, and sampling year (R2 = 0.848). Considered together, the future carbon dioxide source or sink potential of high latitude wetlands will largely depend on climate-induced changes in moisture and subsequent impacts on nutrient availability.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43561907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Kokelj, T. Gingras-Hill, Seamus V. Daly, P. Morse, Stephen A. Wolfe, A. Rudy, Jurjen van der Sluijs, N. Weiss, B. O’Neill, J. Baltzer, T. Lantz, C. Gibson, Dieter Cazon, R. Fraser, D. Froese, G. Giff, Charles Klengenberg, S. Lamoureux, W. Quinton, M. Turetsky, Alexandre Chiasson, Celtie Ferguson, Mike Newton, Mike Pope, Jason A Paul, Alice Wilson, J. Young
This paper documents the first comprehensive inventory of thermokarst and thaw-sensitive terrain indicators for a 2 million km2 region of northwestern Canada. This is accomplished through the Thermokarst Mapping Collective (TMC), a research collaborative to systematically inventory indicators of permafrost thaw sensitivity by mapping and aerial assessments across the Northwest Territories (NT), Canada. The increase in NT-based permafrost capacity has fostered science leadership and collaboration with government, academic, and community researchers to enable project implementation. Ongoing communications and outreach have informed study design and strengthened Indigenous and stakeholder relationships. Documentation of theme-based methods supported mapper training, and flexible data infrastructure facilitated progress by Canada-wide researchers throughout the COVID-19 pandemic. The TMC inventory of thermokarst and thaw-sensitive landforms agree well with fine-scale empirical mapping (69% to 84% accuracy) and aerial inventory (74% to 96% accuracy) datasets. National- and circumpolar-scale modelling of sensitive permafrost terrain contrasts significantly with TMC outputs, highlighting their limitations and the value of empirically-based mapping approaches. We demonstrate that the multi-parameter TMC outputs support a holistic understanding and refined depictions of permafrost terrain sensitivity, provide novel opportunities for syntheses, and inform future modelling approaches, which are urgently required to comprehend better what permafrost thaw means for Canada’s North.
{"title":"The Northwest Territories Thermokarst Mapping Collective: A northern-driven mapping collaborative toward understanding the effects of permafrost thaw","authors":"S. Kokelj, T. Gingras-Hill, Seamus V. Daly, P. Morse, Stephen A. Wolfe, A. Rudy, Jurjen van der Sluijs, N. Weiss, B. O’Neill, J. Baltzer, T. Lantz, C. Gibson, Dieter Cazon, R. Fraser, D. Froese, G. Giff, Charles Klengenberg, S. Lamoureux, W. Quinton, M. Turetsky, Alexandre Chiasson, Celtie Ferguson, Mike Newton, Mike Pope, Jason A Paul, Alice Wilson, J. Young","doi":"10.1139/as-2023-0009","DOIUrl":"https://doi.org/10.1139/as-2023-0009","url":null,"abstract":"This paper documents the first comprehensive inventory of thermokarst and thaw-sensitive terrain indicators for a 2 million km2 region of northwestern Canada. This is accomplished through the Thermokarst Mapping Collective (TMC), a research collaborative to systematically inventory indicators of permafrost thaw sensitivity by mapping and aerial assessments across the Northwest Territories (NT), Canada. The increase in NT-based permafrost capacity has fostered science leadership and collaboration with government, academic, and community researchers to enable project implementation. Ongoing communications and outreach have informed study design and strengthened Indigenous and stakeholder relationships. Documentation of theme-based methods supported mapper training, and flexible data infrastructure facilitated progress by Canada-wide researchers throughout the COVID-19 pandemic. The TMC inventory of thermokarst and thaw-sensitive landforms agree well with fine-scale empirical mapping (69% to 84% accuracy) and aerial inventory (74% to 96% accuracy) datasets. National- and circumpolar-scale modelling of sensitive permafrost terrain contrasts significantly with TMC outputs, highlighting their limitations and the value of empirically-based mapping approaches. We demonstrate that the multi-parameter TMC outputs support a holistic understanding and refined depictions of permafrost terrain sensitivity, provide novel opportunities for syntheses, and inform future modelling approaches, which are urgently required to comprehend better what permafrost thaw means for Canada’s North.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47383003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subsistence harvest in Arctic marine ecosystems is influenced by sea ice conditions affecting species distributions, abundance, and accessibility. We tracked 78 polar bears (Ursus maritimus) of different age, sex, and reproductive classes via satellite telemetry in the Canadian Beaufort Sea (2007-2014, n=71 258). We assessed vulnerability to harvest (no/low/medium/high) based on telemetry data overlap with density of historical harvest locations (1985-1987, n=121). All classes of polar bears were detected in historical harvest areas of low- to high-risk in greater proportion than expected from available area during the harvest period (January to ice break-up), and all but solitary adult females had >50% of locations in the risk areas. Subadult males were proportionally more often inside risk areas, yet were not observed in the high-risk areas. Other classes were observed <1% of the time in high-risk areas, yet still proportionally greater than expected from available area. Landfast ice has declined in the pre-melt (January-March) and end-of-harvest (June-July) seasons (1980-2021), with the rate of decline being greater in lower-risk areas (p≤0.05). With sea ice predicted to decline into the future, we suggest that polar bears in the Beaufort Sea may become more concentrated into areas of higher harvest risk.
{"title":"Spatial and temporal harvest risk to polar bears in the Canadian Beaufort Sea","authors":"S. Hamilton, E. Henderson, A. Derocher","doi":"10.1139/as-2023-0003","DOIUrl":"https://doi.org/10.1139/as-2023-0003","url":null,"abstract":"Subsistence harvest in Arctic marine ecosystems is influenced by sea ice conditions affecting species distributions, abundance, and accessibility. We tracked 78 polar bears (Ursus maritimus) of different age, sex, and reproductive classes via satellite telemetry in the Canadian Beaufort Sea (2007-2014, n=71 258). We assessed vulnerability to harvest (no/low/medium/high) based on telemetry data overlap with density of historical harvest locations (1985-1987, n=121). All classes of polar bears were detected in historical harvest areas of low- to high-risk in greater proportion than expected from available area during the harvest period (January to ice break-up), and all but solitary adult females had >50% of locations in the risk areas. Subadult males were proportionally more often inside risk areas, yet were not observed in the high-risk areas. Other classes were observed <1% of the time in high-risk areas, yet still proportionally greater than expected from available area. Landfast ice has declined in the pre-melt (January-March) and end-of-harvest (June-July) seasons (1980-2021), with the rate of decline being greater in lower-risk areas (p≤0.05). With sea ice predicted to decline into the future, we suggest that polar bears in the Beaufort Sea may become more concentrated into areas of higher harvest risk.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45685021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emma L. Ausen, D. Barber, Atreya Basu, J. Ehn, D. Walker, L. Dalman, M. Marcoux
River estuaries along western Hudson Bay, Canada, are important summer habitats for beluga whales (Delphinapterus leucus), and subject to increasing industrial development activities including vessel traffic. The feasibility of establishing a National Marine Conservation Area (NMCA) in western Hudson Bay is under consideration, requiring baseline studies and habitat monitoring. In this study, beluga whale locations were identified using aerial photographs collected during summer 2018 of the Seal, Knife, Churchill, and Nelson River estuaries. Sentinel 2 wavelength bands were used to outline river plume boundaries for the Seal, Knife and Churchill Rivers. Multiple discriminant analysis was used to differentiate between beluga habitat areas according to their environmental characteristics including concentration of total suspended sediments (TSS), and colored dissolved organic matter (CDOM). The Seal River estuary, Knife River estuary, Churchill River outer estuary, Churchill River estuary and Nelson River estuary were identified as distinct habitat areas. Resource selection functions and model selection were used to determine that habitat variables related to prey availability were important for beluga habitat selection, including TSS, CDOM, and the distance to river mouth or river plume. Identification of preferred habitat and habitat areas in this study are imperative for future management decisions including establishment of a NMCA.
{"title":"River influenced beluga (Delphinapterus leucas) summer habitat use in western Hudson Bay, Canada","authors":"Emma L. Ausen, D. Barber, Atreya Basu, J. Ehn, D. Walker, L. Dalman, M. Marcoux","doi":"10.1139/as-2022-0040","DOIUrl":"https://doi.org/10.1139/as-2022-0040","url":null,"abstract":"River estuaries along western Hudson Bay, Canada, are important summer habitats for beluga whales (Delphinapterus leucus), and subject to increasing industrial development activities including vessel traffic. The feasibility of establishing a National Marine Conservation Area (NMCA) in western Hudson Bay is under consideration, requiring baseline studies and habitat monitoring. In this study, beluga whale locations were identified using aerial photographs collected during summer 2018 of the Seal, Knife, Churchill, and Nelson River estuaries. Sentinel 2 wavelength bands were used to outline river plume boundaries for the Seal, Knife and Churchill Rivers. Multiple discriminant analysis was used to differentiate between beluga habitat areas according to their environmental characteristics including concentration of total suspended sediments (TSS), and colored dissolved organic matter (CDOM). The Seal River estuary, Knife River estuary, Churchill River outer estuary, Churchill River estuary and Nelson River estuary were identified as distinct habitat areas. Resource selection functions and model selection were used to determine that habitat variables related to prey availability were important for beluga habitat selection, including TSS, CDOM, and the distance to river mouth or river plume. Identification of preferred habitat and habitat areas in this study are imperative for future management decisions including establishment of a NMCA.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44084079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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