1
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Weijers S. Declining temperature and increasing moisture sensitivity of shrub growth in the Low‐Arctic erect dwarf‐shrub tundra of western Greenland. Ecol Evol 2022; 12:e9419. [PMCID: PMC9637549 DOI: 10.1002/ece3.9419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Stef Weijers
- Department of Geography University of Bonn Bonn Germany
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2
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Yu L, Leng G, Python A. Varying response of vegetation to sea ice dynamics over the Arctic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 799:149378. [PMID: 34352465 DOI: 10.1016/j.scitotenv.2021.149378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
Recent reduction of sea ice may have contributed to vegetation growth over the Arctic through albedo feedback effects to atmospheric warming. Understanding the varying response of vegetation to sea ice dynamics is critical for predicting future climate change over the Arctic and middle-high latitudes. Instead of looking at the direct response characteristics, we perform a systematic analysis of the time-lag and time-cumulation responses of vegetation to sea ice dynamics, using a long-term Arctic Normalized Difference Vegetation Index (NDVI) dataset and three sea ice indices (sea ice concentration (SIC), sea ice area (SIA) and sea ice extent (SIE)) from 1982 to 2015. The results show that annual NDVI in the Arctic has exhibited a significant (p < 0.05) increase during 1982 to 2015, while a significant (p < 0.05) decrease is detected for annual SIC, SIA and SIE. The results of a regression analysis on NDVI identify a lag time of 7-months, 8-months and 9-months for vegetation response to SIC, SIA and SIE in February, March and April, respectively, while no evident lag response is observed in summer except for August. For the cumulation response, NDVI in February, March and April shows the largest response to the previous 5, 7 and 9 months of sea ice variations, respectively, while a short cumulation response of 1 to 3 months is found in summer. The differences in the spatial patterns of lagged time are usually not statistically significant in autumn and winter. A shorter lag response (1-3 month) is found in the Yamalia region in June. Further analysis suggests that vegetation response to sea ice dynamics depends on bio - climatic characteristics and soil pH, with vegetation responding faster to sea ice changes in acidic soil. This study provides observational evidences on the varying response of vegetation to sea ice dynamics over the Arctic, which has great implications for predicting vegetation-climate feedback and climate change.
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Affiliation(s)
- Linfei Yu
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guoyong Leng
- Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Andre Python
- Center for Data Science, Zhejiang University, Hangzhou 310058, China; Big Data Institute, University of Oxford, Oxford OX3 7LF, UK
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3
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Parker VT. Small-Scale Winter Damage on Plants: Wind and Ice can Remove Plant Pubescence. WEST N AM NATURALIST 2021. [DOI: 10.3398/064.081.0307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- V. Thomas Parker
- Department of Biology, San Francisco State University, San Francisco, CA 94132
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4
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Dobbert S, Pape R, Löffler J. Contrasting growth response of evergreen and deciduous arctic‐alpine shrub species to climate variability. Ecosphere 2021. [DOI: 10.1002/ecs2.3688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Svenja Dobbert
- Department of Geography University of Bonn Meckenheimer Allee 166 Bonn D‐53115 Germany
| | - Roland Pape
- Department of Natural Sciences and Environmental Health University of South‐Eastern Norway Gullbringvegen 36 Bø N‐3800 Norway
| | - Jörg Löffler
- Department of Geography University of Bonn Meckenheimer Allee 166 Bonn D‐53115 Germany
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5
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Le Moullec M, Sandal L, Grøtan V, Buchwal A, Hansen BB. Climate synchronises shrub growth across a high‐arctic archipelago: contrasting implications of summer and winter warming. OIKOS 2020. [DOI: 10.1111/oik.07059] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Mathilde Le Moullec
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Högskoleringen 5 NO‐7491 Trondheim Norway
| | - Lisa Sandal
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Högskoleringen 5 NO‐7491 Trondheim Norway
| | - Vidar Grøtan
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Högskoleringen 5 NO‐7491 Trondheim Norway
| | - Agata Buchwal
- Dept of Biological Sciences, Univ. of Alaska Anchorage AK USA
- Inst. of Geoecology and Geoinformation, Adam Mickiewicz Univ. Poznan Wielkopolskie Poland
| | - Brage Bremset Hansen
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Högskoleringen 5 NO‐7491 Trondheim Norway
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6
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Ravolainen V, Soininen EM, Jónsdóttir IS, Eischeid I, Forchhammer M, van der Wal R, Pedersen ÅØ. High Arctic ecosystem states: Conceptual models of vegetation change to guide long-term monitoring and research. AMBIO 2020; 49:666-677. [PMID: 31955396 PMCID: PMC6989444 DOI: 10.1007/s13280-019-01310-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 12/03/2019] [Accepted: 12/13/2019] [Indexed: 05/26/2023]
Abstract
Vegetation change has consequences for terrestrial ecosystem structure and functioning and may involve climate feedbacks. Hence, when monitoring ecosystem states and changes thereof, the vegetation is often a primary monitoring target. Here, we summarize current understanding of vegetation change in the High Arctic-the World's most rapidly warming region-in the context of ecosystem monitoring. To foster development of deployable monitoring strategies, we categorize different kinds of drivers (disturbances or stresses) of vegetation change either as pulse (i.e. drivers that occur as sudden and short events, though their effects may be long lasting) or press (i.e. drivers where change in conditions remains in place for a prolonged period, or slowly increases in pressure). To account for the great heterogeneity in vegetation responses to climate change and other drivers, we stress the need for increased use of ecosystem-specific conceptual models to guide monitoring and ecological studies in the Arctic. We discuss a conceptual model with three hypothesized alternative vegetation states characterized by mosses, herbaceous plants, and bare ground patches, respectively. We use moss-graminoid tundra of Svalbard as a case study to discuss the documented and potential impacts of different drivers on the possible transitions between those states. Our current understanding points to likely additive effects of herbivores and a warming climate, driving this ecosystem from a moss-dominated state with cool soils, shallow active layer and slow nutrient cycling to an ecosystem with warmer soil, deeper permafrost thaw, and faster nutrient cycling. Herbaceous-dominated vegetation and (patchy) bare ground would present two states in response to those drivers. Conceptual models are an operational tool to focus monitoring efforts towards management needs and identify the most pressing scientific questions. We promote greater use of conceptual models in conjunction with a state-and-transition framework in monitoring to ensure fit for purpose approaches. Defined expectations of the focal systems' responses to different drivers also facilitate linking local and regional monitoring efforts to international initiatives, such as the Circumpolar Biodiversity Monitoring Program.
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Affiliation(s)
- Virve Ravolainen
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway.
- Norwegian Polar Institute, Fram Centre, 9062, Tromsø, Norway.
| | | | - Ingibjörg Svala Jónsdóttir
- University of Iceland, 101, Reykjavik, Iceland
- The University Centre in Svalbard, 9171, Longyearbyen, Norway
| | - Isabell Eischeid
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
- UiT, The Arctic University of Norway, 9037, Tromsø, Norway
| | - Mads Forchhammer
- The University Centre in Svalbard, 9171, Longyearbyen, Norway
- The Centre for Macroecology, Evolution and Climate (CMEC) and Greenland Perspective (GP), Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - René van der Wal
- Department of Ecology, Swedish University of Agricultural Sciences (SLU), Ulls väg 16, 75651, Uppsala, Sweden
- University of Aberdeen, AB24 3UU, Aberdeen, Scotland
| | - Åshild Ø Pedersen
- Norwegian Polar Institute, Fram Centre, 9296, Tromsø, Norway
- Norwegian Polar Institute, Fram Centre, 9062, Tromsø, Norway
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7
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González VT, Moriana-Armendariz M, Hagen SB, Lindgård B, Reiersen R, Bråthen KA. High resistance to climatic variability in a dominant tundra shrub species. PeerJ 2019; 7:e6967. [PMID: 31205822 PMCID: PMC6556101 DOI: 10.7717/peerj.6967] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/17/2019] [Indexed: 11/20/2022] Open
Abstract
Climate change is modifying temperature and precipitation regimes across all seasons in northern ecosystems. Summer temperatures are higher, growing seasons extend into spring and fall and snow cover conditions are more variable during winter. The resistance of dominant tundra species to these season-specific changes, with each season potentially having contrasting effects on their growth and survival, can determine the future of tundra plant communities under climate change. In our study, we evaluated the effects of several spring/summer and winter climatic variables (i.e., summer temperature, growing season length, growing degree days, and number of winter freezing days) on the resistance of the dwarf shrub Empetrum nigrum. We measured over six years the ability of E. nigrum to keep a stable shoot growth, berry production, and vegetative cover in five E. nigrum dominated tundra heathlands, in a total of 144 plots covering a 200-km gradient from oceanic to continental climate. Overall, E. nigrum displayed high resistance to climatic variation along the gradient, with positive growth and reproductive output during all years and sites. Climatic conditions varied sharply among sites, especially during the winter months, finding that exposure to freezing temperatures during winter was correlated with reduced shoot length and berry production. These negative effects however, could be compensated if the following growing season was warm and long. Our study demonstrates that E. nigrum is a species resistant to fluctuating climatic conditions during the growing season and winter months in both oceanic and continental areas. Overall, E. nigrum appeared frost hardy and its resistance was determined by interactions among different season-specific climatic conditions with contrasting effects.
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Affiliation(s)
- Victoria T. González
- Institute of Arctic and Marine biology, University of Tromsø, Tromsø, Norway
- Department of Ecosystems in the Barents region, Norwegian institute of Bioeconomy Research-NIBIO, Svanvik, Norway
| | | | - Snorre B. Hagen
- Department of Ecosystems in the Barents region, Norwegian institute of Bioeconomy Research-NIBIO, Svanvik, Norway
| | - Bente Lindgård
- Institute of Arctic and Marine biology, University of Tromsø, Tromsø, Norway
| | - Rigmor Reiersen
- Institute of Arctic and Marine biology, University of Tromsø, Tromsø, Norway
| | - Kari Anne Bråthen
- Institute of Arctic and Marine biology, University of Tromsø, Tromsø, Norway
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8
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Hansen BB, Lorentzen JR, Welker JM, Varpe Ø, Aanes R, Beumer LT, Pedersen ÅØ. Reindeer turning maritime: Ice‐locked tundra triggers changes in dietary niche utilization. Ecosphere 2019. [DOI: 10.1002/ecs2.2672] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Brage Bremset Hansen
- Centre for Biodiversity Dynamics Department of Biology Norwegian University of Science and Technology N‐7491 Trondheim Norway
| | - Jon Runar Lorentzen
- Centre for Biodiversity Dynamics Department of Biology Norwegian University of Science and Technology N‐7491 Trondheim Norway
- Department of Arctic Biology The University Centre in Svalbard N‐9171 Longyearbyen Norway
| | - Jeffrey M. Welker
- UArctic & University of Oulo Oulo 90014 Finland
- University of Alaska Anchorage Anchorage Alaska 99516 USA
| | - Øystein Varpe
- Department of Arctic Biology The University Centre in Svalbard N‐9171 Longyearbyen Norway
- Akvaplan‐niva Fram Centre N‐9296 Tromsø Norway
| | - Ronny Aanes
- Centre for Biodiversity Dynamics Department of Biology Norwegian University of Science and Technology N‐7491 Trondheim Norway
- Norwegian Polar Institute Fram Centre N‐9296 Tromsø Norway
| | - Larissa Teresa Beumer
- Department of Arctic Biology The University Centre in Svalbard N‐9171 Longyearbyen Norway
- Department of Bioscience Aarhus University Frederiksborgvej 399 4000 Roskilde Denmark
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9
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Bjerke JW, Treharne R, Vikhamar-Schuler D, Karlsen SR, Ravolainen V, Bokhorst S, Phoenix GK, Bochenek Z, Tømmervik H. Understanding the drivers of extensive plant damage in boreal and Arctic ecosystems: Insights from field surveys in the aftermath of damage. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:1965-1976. [PMID: 28558420 DOI: 10.1016/j.scitotenv.2017.05.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 06/07/2023]
Abstract
The exact cause of population dieback in nature is often challenging to identify retrospectively. Plant research in northern regions has in recent decades been largely focussed on the opposite trend, namely increasing populations and higher productivity. However, a recent unexpected decline in remotely-sensed estimates of terrestrial Arctic primary productivity suggests that warmer northern lands do not necessarily result in higher productivity. As large-scale plant dieback may become more frequent at high northern latitudes with increasing frequency of extreme events, understanding the drivers of plant dieback is especially urgent. Here, we report on recent extensive damage to dominant, short, perennial heath and tundra plant populations in boreal and Arctic Norway, and assess the potential drivers of this damage. In the High-Arctic archipelago of Svalbard, we recorded that 8-50% of Cassiope tetragona and Dryas octopetala shoots were dead, and that the ratios of dead shoots increased from 2014 to 2015. In boreal Norway, 38-63% of Calluna vulgaris shoots were dead, while Vaccinium myrtillus had damage to 91% of shoots in forested sites, but was healthy in non-forested sites. Analyses of numerous sources of environmental information clearly point towards a winter climate-related reason for damage to three of these four species. In Svalbard, the winters of 2011/12 and 2014/15 were documented to be unusually severe, i.e. insulation from ambient temperature fluctuation by snow was largely absent, and ground-ice enforced additional stress. In boreal Norway, the 2013/14 winter had a long period with very little snow combined with extremely low precipitation rates, something which resulted in frost drought of uncovered Calluna plants. However, extensive outbreaks of a leaf-defoliating geometrid moth were identified as the driver of Vaccinium mortality. These results suggest that weather and biotic extreme events potentially have strong impacts on the vegetation state of northern lands.
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Affiliation(s)
- Jarle W Bjerke
- Norwegian Institute for Nature Research (NINA), FRAM - High North Research Centre for Climate and the Environment, PO Box 6606, Langnes, NO-9296 Tromsø, Norway.
| | - Rachael Treharne
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | | | - Stein R Karlsen
- Northern Research Institute - Tromsø, Science Park, NO-9294 Tromsø, Norway
| | - Virve Ravolainen
- Norwegian Polar Institute, FRAM - High North Research Centre for Climate and the Environment, PO Box 6606, Langnes, NO-9296 Tromsø, Norway
| | - Stef Bokhorst
- Norwegian Institute for Nature Research (NINA), FRAM - High North Research Centre for Climate and the Environment, PO Box 6606, Langnes, NO-9296 Tromsø, Norway; Department of Ecological Science, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Gareth K Phoenix
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | | | - Hans Tømmervik
- Norwegian Institute for Nature Research (NINA), FRAM - High North Research Centre for Climate and the Environment, PO Box 6606, Langnes, NO-9296 Tromsø, Norway
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10
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Weijers S, Buchwal A, Blok D, Löffler J, Elberling B. High Arctic summer warming tracked by increased Cassiope tetragona growth in the world's northernmost polar desert. GLOBAL CHANGE BIOLOGY 2017; 23:5006-5020. [PMID: 28464494 DOI: 10.1111/gcb.13747] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 04/18/2017] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Rapid climate warming has resulted in shrub expansion, mainly of erect deciduous shrubs in the Low Arctic, but the more extreme, sparsely vegetated, cold and dry High Arctic is generally considered to remain resistant to such shrub expansion in the next decades. Dwarf shrub dendrochronology may reveal climatological causes of past changes in growth, but is hindered at many High Arctic sites by short and fragmented instrumental climate records. Moreover, only few High Arctic shrub chronologies cover the recent decade of substantial warming. This study investigated the climatic causes of growth variability of the evergreen dwarf shrub Cassiope tetragona between 1927 and 2012 in the northernmost polar desert at 83°N in North Greenland. We analysed climate-growth relationships over the period with available instrumental data (1950-2012) between a 102-year-long C. tetragona shoot length chronology and instrumental climate records from the three nearest meteorological stations, gridded climate data, and North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) indices. July extreme maximum temperatures (JulTemx ), as measured at Alert, Canada, June NAO, and previous October AO, together explained 41% of the observed variance in annual C. tetragona growth and likely represent in situ summer temperatures. JulTemx explained 27% and was reconstructed back to 1927. The reconstruction showed relatively high growing season temperatures in the early to mid-twentieth century, as well as warming in recent decades. The rapid growth increase in C. tetragona shrubs in response to recent High Arctic summer warming shows that recent and future warming might promote an expansion of this evergreen dwarf shrub, mainly through densification of existing shrub patches, at High Arctic sites with sufficient winter snow cover and ample water supply during summer from melting snow and ice as well as thawing permafrost, contrasting earlier notions of limited shrub growth sensitivity to summer warming in the High Arctic.
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Affiliation(s)
- Stef Weijers
- Department of Geography, University of Bonn, Bonn, Germany
| | - Agata Buchwal
- Institute of Geoecology and Geoinformation, Adam Mickiewicz University, Poznan, Poland
- Department of Biological Sciences, Ecosystem and Biomedical Lab, University of Alaska Anchorage, Anchorage, AK, USA
| | - Daan Blok
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Jörg Löffler
- Department of Geography, University of Bonn, Bonn, Germany
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
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11
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Saccone P, Hoikka K, Virtanen R. What if plant functional types conceal species-specific responses to environment? Study on arctic shrub communities. Ecology 2017; 98:1600-1612. [DOI: 10.1002/ecy.1817] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 02/02/2017] [Accepted: 03/06/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Patrick Saccone
- Department of Ecology and Genetics; University of Oulu; P.O. Box 3000 FI-90014 Oulu Finland
| | | | - Risto Virtanen
- Department of Ecology and Genetics; University of Oulu; P.O. Box 3000 FI-90014 Oulu Finland
- Department of Physiological Diversity; Helmholtz Center for Environmental Research - UFZ; Permoserstrasse 15 04318 Leipzig Germany
- German Center for Integrative Biodiversity Research (iDiv); Deutscher Platz 5a 04103 Leipzig Germany
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12
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Albon SD, Irvine RJ, Halvorsen O, Langvatn R, Loe LE, Ropstad E, Veiberg V, van der Wal R, Bjørkvoll EM, Duff EI, Hansen BB, Lee AM, Tveraa T, Stien A. Contrasting effects of summer and winter warming on body mass explain population dynamics in a food-limited Arctic herbivore. GLOBAL CHANGE BIOLOGY 2017; 23:1374-1389. [PMID: 27426229 DOI: 10.1111/gcb.13435] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 07/05/2016] [Indexed: 05/27/2023]
Abstract
The cumulative effects of climate warming on herbivore vital rates and population dynamics are hard to predict, given that the expected effects differ between seasons. In the Arctic, warmer summers enhance plant growth which should lead to heavier and more fertile individuals in the autumn. Conversely, warm spells in winter with rainfall (rain-on-snow) can cause 'icing', restricting access to forage, resulting in starvation, lower survival and fecundity. As body condition is a 'barometer' of energy demands relative to energy intake, we explored the causes and consequences of variation in body mass of wild female Svalbard reindeer (Rangifer tarandus platyrhynchus) from 1994 to 2015, a period of marked climate warming. Late winter (April) body mass explained 88% of the between-year variation in population growth rate, because it strongly influenced reproductive loss, and hence subsequent fecundity (92%), as well as survival (94%) and recruitment (93%). Autumn (October) body mass affected ovulation rates but did not affect fecundity. April body mass showed no long-term trend (coefficient of variation, CV = 8.8%) and was higher following warm autumn (October) weather, reflecting delays in winter onset, but most strongly, and negatively, related to 'rain-on-snow' events. October body mass (CV = 2.5%) increased over the study due to higher plant productivity in the increasingly warm summers. Density-dependent mass change suggested competition for resources in both winter and summer but was less pronounced in recent years, despite an increasing population size. While continued climate warming is expected to increase the carrying capacity of the high Arctic tundra, it is also likely to cause more frequent icing events. Our analyses suggest that these contrasting effects may cause larger seasonal fluctuations in body mass and vital rates. Overall our findings provide an important 'missing' mechanistic link in the current understanding of the population biology of a keystone species in a rapidly warming Arctic.
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Affiliation(s)
| | | | - Odd Halvorsen
- Natural History Museum, University of Oslo, Box 1172 Blindern, NO-0318, Oslo, Norway
| | - Rolf Langvatn
- University Courses in Svalbard (UNIS), P.O. Box 156, NO-9171, Longyearbyen, Norway
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Sluppen, NO-7485, Trondheim, Norway
| | - Leif E Loe
- Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432, Aas, Norway
| | - Erik Ropstad
- Norwegian University of Life Sciences, P.O. Box 8146, NO-0033, Oslo, Norway
| | - Vebjørn Veiberg
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Sluppen, NO-7485, Trondheim, Norway
| | - René van der Wal
- Aberdeen Centre for Environmental Sustainability (ACES), School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
| | - Eirin M Bjørkvoll
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science & Technology (NTNU), N-7491, Trondheim, Norway
| | - Elizabeth I Duff
- Biomathematics & Statistics Scotland (BioSS), Aberdeen, AB15 8QH, UK
| | - Brage B Hansen
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science & Technology (NTNU), N-7491, Trondheim, Norway
| | - Aline M Lee
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science & Technology (NTNU), N-7491, Trondheim, Norway
| | - Torkild Tveraa
- Norwegian Institute for Nature Research (NINA), Fram Centre, NO-9296, Tromsø, Norway
| | - Audun Stien
- Norwegian Institute for Nature Research (NINA), Fram Centre, NO-9296, Tromsø, Norway
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