M. Painter, L. Copland, C. Dow, W. Kochtitzky, D. Medrzycka
Dań Zhùr (Donjek) Glacier is a surge-type glacier that undergoes cyclical periods of rapid advance over ~1-2 years, followed by retreat for ~10 years. Since the 1990s the advances have caused the formation of ice-dammed Dań Zhùr Lake, which has filled and drained in summers following a surge event. Here we report how these drainages initially occur through a subglacial channel under the glacier terminus, which then typically closes the following winter, enabling another lake to form and drain the next summer. However, our remote sensing and field observations indicate that after several drainage events a subaerial ice canyon is formed through the glacier terminus, which prevents another lake from forming until after the glacier surges again. We predict that the next surge of Dań Zhùr Glacier will occur around the mid-2020s, causing the formation of a larger Dań Zhùr Lake during the following quiescent phase because, despite periodic advances, a long-term trend of glacier recession is exposing a larger basin for the lake to form in. However, each subsequent surge is causing less terminus advance than the previous one, until ultimately the surges will be insufficient to dam Dań Zhùr Chù’ (Donjek River) and lakes will cease to form.
{"title":"Patterns and mechanisms of repeat drainages of glacier-dammed Dań Zhùr (Donjek) Lake, Yukon","authors":"M. Painter, L. Copland, C. Dow, W. Kochtitzky, D. Medrzycka","doi":"10.1139/as-2023-0001","DOIUrl":"https://doi.org/10.1139/as-2023-0001","url":null,"abstract":"Dań Zhùr (Donjek) Glacier is a surge-type glacier that undergoes cyclical periods of rapid advance over ~1-2 years, followed by retreat for ~10 years. Since the 1990s the advances have caused the formation of ice-dammed Dań Zhùr Lake, which has filled and drained in summers following a surge event. Here we report how these drainages initially occur through a subglacial channel under the glacier terminus, which then typically closes the following winter, enabling another lake to form and drain the next summer. However, our remote sensing and field observations indicate that after several drainage events a subaerial ice canyon is formed through the glacier terminus, which prevents another lake from forming until after the glacier surges again. We predict that the next surge of Dań Zhùr Glacier will occur around the mid-2020s, causing the formation of a larger Dań Zhùr Lake during the following quiescent phase because, despite periodic advances, a long-term trend of glacier recession is exposing a larger basin for the lake to form in. However, each subsequent surge is causing less terminus advance than the previous one, until ultimately the surges will be insufficient to dam Dań Zhùr Chù’ (Donjek River) and lakes will cease to form.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41389514","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}
Extreme environmental conditions and limited understanding of ecosystem processes and community dynamics pose significant challenges for arctic ecosystem restoration activities. As pioneer species, bryophytes are critical to the function and structure of northern ecosystems and play an important role in facilitating soil and microhabitat development. A total of 11 bryophytes species were collected from a mixed community near Lac de Gras in the Northwest Territories, Canada and a 12 week laboratory study was conducted. Three propagule types (large (2.1-40 mm), medium (1.0-2 mm), small (<1 mm) phyllids) and three slurries (distilled water, beer, buttermilk) were used to determine effective bryophyte propagation techniques and slurries for species introduction in arctic restoration sites. Medium size fragments were more effective than large or small for propagating bryophytes as they led to greater bryophyte plant count and cover. Water and beer were more effective than buttermilk, although their effects were lessening after 12 weeks. Bryum pseudotriquetrum was the most abundant species propagated, followed by Aulacomium turgidum and Ceratodon purpureus. This study suggests propagation with medium size fragments and distilled water would be most efficient for field application in arctic ecosystem restoration if bryophyte revegetation is a focus.
极端的环境条件和对生态系统过程和群落动态的有限了解对北极生态系统恢复活动构成了重大挑战。苔藓植物作为先锋物种，对北方生态系统的功能和结构至关重要，在促进土壤和微生境发展方面发挥着重要作用。共从加拿大西北地区Lac de Gras附近的一个混合群落中采集了11种苔藓植物，并进行了为期12周的实验室研究。使用三种繁殖体类型（大（2.1-40mm）、中（1.0-2mm）、小（<1mm）千枚）和三种浆料（蒸馏水、啤酒、酪乳）来确定有效的苔藓植物繁殖技术和用于北极恢复区物种引进的浆料。中型碎片比大型或小型碎片更有效地繁殖苔藓植物，因为它们能增加苔藓植物的数量和覆盖率。水和啤酒比酪乳更有效，尽管12周后效果有所减轻。假三叶草是繁殖数量最多的物种，其次是浮夸草和紫色Ceratodon。这项研究表明，如果苔藓植物重新植被是一个重点，那么用中等大小的碎片和蒸馏水繁殖将是北极生态系统恢复中最有效的野外应用。
{"title":"A Propagation Technique For Native Tundra Bryophytes For Arctic Ecosystem Restoration","authors":"Jasmine JM Lamarre, A. Dhar, M. Naeth","doi":"10.1139/as-2022-0046","DOIUrl":"https://doi.org/10.1139/as-2022-0046","url":null,"abstract":"Extreme environmental conditions and limited understanding of ecosystem processes and community dynamics pose significant challenges for arctic ecosystem restoration activities. As pioneer species, bryophytes are critical to the function and structure of northern ecosystems and play an important role in facilitating soil and microhabitat development. A total of 11 bryophytes species were collected from a mixed community near Lac de Gras in the Northwest Territories, Canada and a 12 week laboratory study was conducted. Three propagule types (large (2.1-40 mm), medium (1.0-2 mm), small (<1 mm) phyllids) and three slurries (distilled water, beer, buttermilk) were used to determine effective bryophyte propagation techniques and slurries for species introduction in arctic restoration sites. Medium size fragments were more effective than large or small for propagating bryophytes as they led to greater bryophyte plant count and cover. Water and beer were more effective than buttermilk, although their effects were lessening after 12 weeks. Bryum pseudotriquetrum was the most abundant species propagated, followed by Aulacomium turgidum and Ceratodon purpureus. This study suggests propagation with medium size fragments and distilled water would be most efficient for field application in arctic ecosystem restoration if bryophyte revegetation is a focus.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44426143","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}
Kate McMillian, Carie Hoover, J. Iacozza, J. Peyton, L. Loseto
The development of indicators as tools for ecosystem monitoring is a key step in the management of Marine Protected Areas (MPAs). This study uses previously developed sex-specific body condition indices, blubber thickness and girth, to assess temporal changes in body condition from 2000 to 2015 in harvested Eastern Beaufort Sea (EBS) beluga whales (Delphinapterus leucas). Specifically, the goals were to (1) examine seasonal and inter-annual trends of beluga body condition indicators over the harvest season; (2) evaluate associations of body condition indicators across sexes; and (3) test annual means of each body condition index for correlations to regional scale environmental drivers, (i.e. the Pacific Decadal Oscillation (PDO) and sea-ice minimum (SIM) in the Beaufort Sea). Significant seasonal changes in male blubber thickness and female girth indices demonstrated the importance of short term seasonal drivers. Whilst inter-annual changes in girth and blubber thickness indices revealed longer-term changes, that were correlated between males and females. Only the male girth index had significant relationships with environmental drivers: a negative relationship with the PDO at a zero-year lag ,and a negative relationship with the SIM at a two-year lag. [more in manuscript]
{"title":"Beluga Whale Body Condition: Evaluating environmental variables on beluga body condition indicators in the Tarium Niryutait MPA, Beaufort Sea.","authors":"Kate McMillian, Carie Hoover, J. Iacozza, J. Peyton, L. Loseto","doi":"10.1139/as-2021-0026","DOIUrl":"https://doi.org/10.1139/as-2021-0026","url":null,"abstract":"The development of indicators as tools for ecosystem monitoring is a key step in the management of Marine Protected Areas (MPAs). This study uses previously developed sex-specific body condition indices, blubber thickness and girth, to assess temporal changes in body condition from 2000 to 2015 in harvested Eastern Beaufort Sea (EBS) beluga whales (Delphinapterus leucas). Specifically, the goals were to (1) examine seasonal and inter-annual trends of beluga body condition indicators over the harvest season; (2) evaluate associations of body condition indicators across sexes; and (3) test annual means of each body condition index for correlations to regional scale environmental drivers, (i.e. the Pacific Decadal Oscillation (PDO) and sea-ice minimum (SIM) in the Beaufort Sea). Significant seasonal changes in male blubber thickness and female girth indices demonstrated the importance of short term seasonal drivers. Whilst inter-annual changes in girth and blubber thickness indices revealed longer-term changes, that were correlated between males and females. Only the male girth index had significant relationships with environmental drivers: a negative relationship with the PDO at a zero-year lag ,and a negative relationship with the SIM at a two-year lag. [more in manuscript]","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48884495","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}
A temporal upscaling study was conducted to estimate net ecosystem exchange (NEE) of carbon dioxide and net methane exchange (NME) for a Low-Center Polygon (LCP) ecosystem in the Mackenzie River Delta, for each of eleven growing seasons (2009 to 2019). We used regression models to create a time series of flux drivers from in-situ weather observations (2009-2019) combined with ERA5 reanalysis and satellite data. We then used neural network that were trained and validated on a single growing season (2017) of eddy covariance data to model NEE and NME over each growing season. The study indicates growing season NEE was negative (net uptake) and NME was positive (net emission) in this LCP ecosystem. Cumulative carbon (C) uptake was estimated to be -46.7 g C m-2 [CI95% ± 45.3] per growing season, with methane emissions offsetting an average 5.6% of carbon dioxide uptake (in g C m-2) per growing season. High air temperatures (> 15 °C) reduced daily CO2 uptake and cumulative NEE was positively correlated with mean air growing season temperatures. Cumulative NME was positively correlated with the length of the growing season. Our analysis suggests warmer climate conditions may reduce carbon uptake in this LCP ecosystem.
对麦肯齐河三角洲低中心多边形(LCP)生态系统的二氧化碳净生态系统交换(NEE)和甲烷净生态系统交换(NME)进行了时间升级研究，估算了11个生长季节(2009 - 2019)中每个季节的净生态系统交换(NEE)。结合ERA5再分析和卫星数据，利用回归模型建立了2009-2019年现场天气观测的通量驱动因素时间序列。然后，我们使用在单个生长季节(2017年)的涡动相关方差数据上进行训练和验证的神经网络来模拟每个生长季节的NEE和NME。研究表明，该生态系统生长季NEE为负(净吸收)，NME为正(净排放)。估计每个生长季累积碳(C)吸收量为-46.7 g C m-2 [CI95%±45.3]，其中甲烷排放抵消了每个生长季平均5.6%的二氧化碳吸收量(g C m-2)。高温(50 ~ 15°C)降低了日CO2吸收量，累积NEE与平均空气生长季节温度呈正相关。累积NME与生长季长度呈正相关。我们的分析表明，温暖的气候条件可能会减少LCP生态系统的碳吸收。
{"title":"Modelling Growing Season Carbon Fluxes at a Low-Center Polygon Ecosystem in the Mackenzie River Delta","authors":"June Skeeter, A. Christen, G. Henry","doi":"10.1139/as-2022-0033","DOIUrl":"https://doi.org/10.1139/as-2022-0033","url":null,"abstract":"A temporal upscaling study was conducted to estimate net ecosystem exchange (NEE) of carbon dioxide and net methane exchange (NME) for a Low-Center Polygon (LCP) ecosystem in the Mackenzie River Delta, for each of eleven growing seasons (2009 to 2019). We used regression models to create a time series of flux drivers from in-situ weather observations (2009-2019) combined with ERA5 reanalysis and satellite data. We then used neural network that were trained and validated on a single growing season (2017) of eddy covariance data to model NEE and NME over each growing season. The study indicates growing season NEE was negative (net uptake) and NME was positive (net emission) in this LCP ecosystem. Cumulative carbon (C) uptake was estimated to be -46.7 g C m-2 [CI95% ± 45.3] per growing season, with methane emissions offsetting an average 5.6% of carbon dioxide uptake (in g C m-2) per growing season. High air temperatures (> 15 °C) reduced daily CO2 uptake and cumulative NEE was positively correlated with mean air growing season temperatures. Cumulative NME was positively correlated with the length of the growing season. Our analysis suggests warmer climate conditions may reduce carbon uptake in this LCP ecosystem.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44798469","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. Allard, E. L’Hérault, Sarah Aubé-Michaud, A. Carbonneau, V. Mathon-Dufour, Arianne B-St_Amour, Sarah Gauthier
In order to support climate change adaptation in the communities of Nunavik, an innovative multi-technique approach to map permafrost conditions and assess risks of geohazards at the community-scale level was applied. Four maps were produced for each community: 1- a surficial geology map, 2- a map of permafrost conditions based on ground-ice content and depth to bedrock, 3- a map of potential for construction and 4- a geohazard risk assessment map. Local ground temperature data from thermistor cables were used to calibrate one-dimensional numerical models to estimate future permafrost temperature changes and probable rates of degradation in different environmental settings within the communities and under different climate change scenarios for the 2019-2100 period. Throughout this project, abundant consultations were held in communities and with stakeholders to better understand their concerns and to provide pragmatic recommendations for improving construction methods and land-use planning to face the challenges of permafrost thaw. Specific recommendations were made to the higher levels of government for improving construction practices. Inuit aspirations, culture and leadership remain keys in how to integrate permafrost geotechnical knowledge in planning a safe future for the communities.
{"title":"Facing the challenge of permafrost thaw in Nunavik communities: innovative integrated methodology, lessons learnt and recommendations to stakeholders.","authors":"M. Allard, E. L’Hérault, Sarah Aubé-Michaud, A. Carbonneau, V. Mathon-Dufour, Arianne B-St_Amour, Sarah Gauthier","doi":"10.1139/as-2022-0024","DOIUrl":"https://doi.org/10.1139/as-2022-0024","url":null,"abstract":"In order to support climate change adaptation in the communities of Nunavik, an innovative multi-technique approach to map permafrost conditions and assess risks of geohazards at the community-scale level was applied. Four maps were produced for each community: 1- a surficial geology map, 2- a map of permafrost conditions based on ground-ice content and depth to bedrock, 3- a map of potential for construction and 4- a geohazard risk assessment map. Local ground temperature data from thermistor cables were used to calibrate one-dimensional numerical models to estimate future permafrost temperature changes and probable rates of degradation in different environmental settings within the communities and under different climate change scenarios for the 2019-2100 period. Throughout this project, abundant consultations were held in communities and with stakeholders to better understand their concerns and to provide pragmatic recommendations for improving construction methods and land-use planning to face the challenges of permafrost thaw. Specific recommendations were made to the higher levels of government for improving construction practices. Inuit aspirations, culture and leadership remain keys in how to integrate permafrost geotechnical knowledge in planning a safe future for the communities.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49280190","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}
Morgan J. Martin, W. Halliday, J. Citta, L. Quakenbush, L. Harwood, E. V. Lea, F. Juanes, J. Dawson, Adrian Nicoll, S. Insley
Arctic marine mammals face many challenges linked to climate change, including increasing anthropogenic noise from vessel traffic. The bowhead whale (Balaena mysticetus), an Arctic endemic cetacean, relies on acoustic communication, with documented overlapping frequencies between communication and vessel noise. Bering-Chukchi-Beaufort (BCB) bowhead whales migrate through areas with the highest levels of vessel traffic in the Pacific Arctic. Here, we document the spatial and temporal overlap between 25 satellite-tagged BCB bowhead whales and vessels during July to December, 2012−2018. We report 1,332 occasions when a vessel was within 125 km of a tagged whale, and where possible, quantified changes in swim speed to investigate individual behavioural responses to vessel approaches within a 50 km radius (n = 18 encounters). In the quantitative analysis, bowhead whales were not observed to alter swim speed within 8–50 km of vessels (we could not assess distances <8 km). Our results suggest bowhead whales did not exhibit detectable long-range (i.e., up to 50 km) behavioural responses to vessels, consistent with observations of closely related North Atlantic right whales (Eubalaena glacialis), for which vessel strikes are a leading cause of mortality. More work is required to assess how bowhead whales react to vessels at closer distances.
{"title":"Exposure and behavioural responses of tagged bowhead whales (Balaena mysticetus) to vessels in the Pacific Arctic","authors":"Morgan J. Martin, W. Halliday, J. Citta, L. Quakenbush, L. Harwood, E. V. Lea, F. Juanes, J. Dawson, Adrian Nicoll, S. Insley","doi":"10.1139/as-2022-0052","DOIUrl":"https://doi.org/10.1139/as-2022-0052","url":null,"abstract":"Arctic marine mammals face many challenges linked to climate change, including increasing anthropogenic noise from vessel traffic. The bowhead whale (Balaena mysticetus), an Arctic endemic cetacean, relies on acoustic communication, with documented overlapping frequencies between communication and vessel noise. Bering-Chukchi-Beaufort (BCB) bowhead whales migrate through areas with the highest levels of vessel traffic in the Pacific Arctic. Here, we document the spatial and temporal overlap between 25 satellite-tagged BCB bowhead whales and vessels during July to December, 2012−2018. We report 1,332 occasions when a vessel was within 125 km of a tagged whale, and where possible, quantified changes in swim speed to investigate individual behavioural responses to vessel approaches within a 50 km radius (n = 18 encounters). In the quantitative analysis, bowhead whales were not observed to alter swim speed within 8–50 km of vessels (we could not assess distances <8 km). Our results suggest bowhead whales did not exhibit detectable long-range (i.e., up to 50 km) behavioural responses to vessels, consistent with observations of closely related North Atlantic right whales (Eubalaena glacialis), for which vessel strikes are a leading cause of mortality. More work is required to assess how bowhead whales react to vessels at closer distances.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47770807","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. Little, Nicole Winters, Adel Achouba, Adriano Magesky, P. Ayotte, Tommy Palliser, A. Naylor, Willie Jararuse, M. Lemire
The harvest and consumption of country food is a cornerstone of Inuit culture, sovereignty, food security, and nutrition. Qilalugaq (beluga whales) ( Delphinapterus leucas (Pallas, 1776)) are hunted across the Canadian Arctic and are an especially important food source for Inuit communities in Nunavik, northern Québec, Canada. The presence of environmental contaminants and nutrients in beluga has been the subject of recent research interest, including the role of selenoneine and its interactions with methylmercury. Using interviews conducted in Quaqtaq and analyses of beluga tissue samples harvested by hunters, this study aimed to bridge Inuit knowledge and scientific knowledge to understand how beluga hunting, preparation, and consumption practices may explain the different levels of selenoneine found in Nunavimmiut (Inuit from Nunavik). It also sought to characterize the health, social, and cultural importance of beluga and factors influencing its consumption. Research findings confirmed the important role of beluga in Nunavimmiut culture, food security, and nutrition. Findings documented gender-based consumption practices, including consumption of the selenoneine-rich beluga tail exclusively by women, which may explain previously documented gender differences in blood selenoneine levels. This study demonstrates the utility of weaving Inuit knowledge and scientific knowledge to inform future environmental health research, public health communications, and wildlife comanagement.
{"title":"Weaving together Inuit knowledge and western science: a mixed-methods case study of qilalugaq (beluga whale) in Quaqtaq, Nunavik","authors":"M. Little, Nicole Winters, Adel Achouba, Adriano Magesky, P. Ayotte, Tommy Palliser, A. Naylor, Willie Jararuse, M. Lemire","doi":"10.1139/as-2022-0039","DOIUrl":"https://doi.org/10.1139/as-2022-0039","url":null,"abstract":"The harvest and consumption of country food is a cornerstone of Inuit culture, sovereignty, food security, and nutrition. Qilalugaq (beluga whales) ( Delphinapterus leucas (Pallas, 1776)) are hunted across the Canadian Arctic and are an especially important food source for Inuit communities in Nunavik, northern Québec, Canada. The presence of environmental contaminants and nutrients in beluga has been the subject of recent research interest, including the role of selenoneine and its interactions with methylmercury. Using interviews conducted in Quaqtaq and analyses of beluga tissue samples harvested by hunters, this study aimed to bridge Inuit knowledge and scientific knowledge to understand how beluga hunting, preparation, and consumption practices may explain the different levels of selenoneine found in Nunavimmiut (Inuit from Nunavik). It also sought to characterize the health, social, and cultural importance of beluga and factors influencing its consumption. Research findings confirmed the important role of beluga in Nunavimmiut culture, food security, and nutrition. Findings documented gender-based consumption practices, including consumption of the selenoneine-rich beluga tail exclusively by women, which may explain previously documented gender differences in blood selenoneine levels. This study demonstrates the utility of weaving Inuit knowledge and scientific knowledge to inform future environmental health research, public health communications, and wildlife comanagement.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41873400","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}
Remote sensing has detected recent trends of increased vegetation productivity on the Bathurst caribou herd’s range. The cause of this spectral greening is unknown but is hypothesized to be the result of a change in the composition, establishment, structure, and/or growth of erect deciduous shrubs. We combined field investigation and dendroecology to compare shrubs between areas where productivity has increased (Greening sites) and areas where productivity has remained stable (No Change sites) based on a Moderate Resolution Imaging Spectroradiometer (MODIS) time series for the period from 2000 to 2017. Contrary to expectations, species composition, timing of stem establishment, stem density, stem length, and vertical and diameter growth rates did not differ between the two site types. However, shrub cover was 13% greater at Greening sites and shrubs at No Change sites had 9% more dead stems regardless of the size of the shrub. This suggests that the differences observed remotely are due to a combination of increased foliage production or survival at Greening sites and a dimming of the vegetation index at No Change sites. Our findings offer a population-level validation of specific shrub characteristics contributing to trends in spectral greening in an understudied region of the southern Arctic tundra.
{"title":"GREENING ON THE BATHURST CARIBOU RANGE IN NORTHERN CANADA: ARE ERECT SHRUBS RESPONSIBLE FOR REMOTELY-SENSED TRENDS?","authors":"Carolyn Bonta, Gregory King, R. Danby","doi":"10.1139/as-2022-0036","DOIUrl":"https://doi.org/10.1139/as-2022-0036","url":null,"abstract":"Remote sensing has detected recent trends of increased vegetation productivity on the Bathurst caribou herd’s range. The cause of this spectral greening is unknown but is hypothesized to be the result of a change in the composition, establishment, structure, and/or growth of erect deciduous shrubs. We combined field investigation and dendroecology to compare shrubs between areas where productivity has increased (Greening sites) and areas where productivity has remained stable (No Change sites) based on a Moderate Resolution Imaging Spectroradiometer (MODIS) time series for the period from 2000 to 2017. Contrary to expectations, species composition, timing of stem establishment, stem density, stem length, and vertical and diameter growth rates did not differ between the two site types. However, shrub cover was 13% greater at Greening sites and shrubs at No Change sites had 9% more dead stems regardless of the size of the shrub. This suggests that the differences observed remotely are due to a combination of increased foliage production or survival at Greening sites and a dimming of the vegetation index at No Change sites. Our findings offer a population-level validation of specific shrub characteristics contributing to trends in spectral greening in an understudied region of the southern Arctic tundra.","PeriodicalId":48575,"journal":{"name":"Arctic Science","volume":" ","pages":""},"PeriodicalIF":3.3,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43572582","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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