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Climate adaptation is not enough: warming does not facilitate success of southern tundra plant populations in the high Arctic.

https://arctichealth.org/en/permalink/ahliterature274351
Source
Glob Chang Biol. 2016 Jul 8;
Publication Type
Article
Date
Jul-8-2016
Author
Anne D Bjorkman
Mark Vellend
Esther R Frei
Gregory H R Henry
Source
Glob Chang Biol. 2016 Jul 8;
Date
Jul-8-2016
Language
English
Publication Type
Article
Abstract
Rapidly rising temperatures are expected to cause latitudinal and elevational range shifts as species track their optimal climate north and upward. However, a lack of adaptation to environmental conditions other than climate - for example photoperiod, biotic interactions, or edaphic conditions - might limit the success of immigrants in a new location despite hospitable climatic conditions. Here we present one of the first direct experimental tests of the hypothesis that warmer temperatures at northern latitudes will confer a fitness advantage to southern immigrants relative to native populations. As rates of warming in the Arctic are more than double the global average, understanding the impacts of warming in Arctic ecosystems is especially urgent. We established experimentally warmed and non-warmed common garden plots at Alexandra Fiord, Ellesmere Island in the Canadian High Arctic with seeds of two forb species (Oxyria digyna and Papaver radicatum) originating from 3-5 populations at different latitudes across the Arctic. We found that plants from the local populations generally had higher survival and obtained a greater maximum size than foreign individuals, regardless of warming treatment. Phenological traits varied with latitude of the source population, such that southern populations demonstrated substantially delayed leaf-out and senescence relative to northern populations. Our results suggest that environmental conditions other than temperature may influence the ability of foreign populations and species to establish at more northerly latitudes as the climate warms, potentially leading to lags in northward range shifts for some species. This article is protected by copyright. All rights reserved.
PubMed ID
27391174 View in PubMed
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Contrasting effects of warming and increased snowfall on Arctic tundra plant phenology over the past two decades.

https://arctichealth.org/en/permalink/ahliterature264976
Source
Glob Chang Biol. 2015 Jul 27;
Publication Type
Article
Date
Jul-27-2015
Author
Anne D Bjorkman
Sarah C Elmendorf
Alison L Beamish
Mark Vellend
Gregory H R Henry
Source
Glob Chang Biol. 2015 Jul 27;
Date
Jul-27-2015
Language
English
Publication Type
Article
Abstract
Recent changes in climate have led to significant shifts in phenology, with many studies demonstrating advanced phenology in response to warming temperatures. The rate of temperature change is especially high in the Arctic, but this is also where we have relatively little data on phenological changes and the processes driving these changes. In order to understand how Arctic plant species are likely to respond to future changes in climate, we monitored flowering phenology in response to both experimental and ambient warming for four widespread species in two habitat types over 21 years. We additionally used long-term environmental records to disentangle the effects of temperature increase and changes in snowmelt date on phenological patterns. While flowering occurred earlier in response to experimental warming, plants in unmanipulated plots showed no change or a delay in flowering over the 21-year period, despite more than 1 ?C of ambient warming during that time. This counterintuitive result was likely due to significantly delayed snowmelt over the study period (0.05-0.2 days/year) due to increased winter snowfall. The timing of snowmelt was a strong driver of flowering phenology for all species - especially for early-flowering species - while spring temperature was significantly related to flowering time only for later-flowering species. Despite significantly delayed flowering phenology, the timing of seed maturation showed no significant change over time, suggesting that warmer temperatures may promote more rapid seed development. The results of this study highlight the importance of understanding the specific environmental cues that drive species' phenological responses as well as the complex interactions between temperature and precipitation when forecasting phenology over the coming decades. As demonstrated here, the effects of altered snowmelt patterns can counter the effects of warmer temperatures, even to the point of generating phenological responses opposite to those predicted by warming alone. This article is protected by copyright. All rights reserved.
PubMed ID
26216538 View in PubMed
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Experiment, monitoring, and gradient methods used to infer climate change effects on plant communities yield consistent patterns.

https://arctichealth.org/en/permalink/ahliterature259277
Source
Proc Natl Acad Sci U S A. 2014 Dec 29;
Publication Type
Article
Date
Dec-29-2014
Author
Sarah C Elmendorf
Gregory H R Henry
Robert D Hollister
Anna Maria Fosaa
William A Gould
Luise Hermanutz
Annika Hofgaard
Ingibjörg I Jónsdóttir
Janet C Jorgenson
Esther Lévesque
Borgþór Magnusson
Ulf Molau
Isla H Myers-Smith
Steven F Oberbauer
Christian Rixen
Craig E Tweedie
Marilyn Walker
Source
Proc Natl Acad Sci U S A. 2014 Dec 29;
Date
Dec-29-2014
Language
English
Publication Type
Article
Abstract
Inference about future climate change impacts typically relies on one of three approaches: manipulative experiments, historical comparisons (broadly defined to include monitoring the response to ambient climate fluctuations using repeat sampling of plots, dendroecology, and paleoecology techniques), and space-for-time substitutions derived from sampling along environmental gradients. Potential limitations of all three approaches are recognized. Here we address the congruence among these three main approaches by comparing the degree to which tundra plant community composition changes (i) in response to in situ experimental warming, (ii) with interannual variability in summer temperature within sites, and (iii) over spatial gradients in summer temperature. We analyzed changes in plant community composition from repeat sampling (85 plant communities in 28 regions) and experimental warming studies (28 experiments in 14 regions) throughout arctic and alpine North America and Europe. Increases in the relative abundance of species with a warmer thermal niche were observed in response to warmer summer temperatures using all three methods; however, effect sizes were greater over broad-scale spatial gradients relative to either temporal variability in summer temperature within a site or summer temperature increases induced by experimental warming. The effect sizes for change over time within a site and with experimental warming were nearly identical. These results support the view that inferences based on space-for-time substitution overestimate the magnitude of responses to contemporary climate warming, because spatial gradients reflect long-term processes. In contrast, in situ experimental warming and monitoring approaches yield consistent estimates of the magnitude of response of plant communities to climate warming.
PubMed ID
25548195 View in PubMed
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Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes.

https://arctichealth.org/en/permalink/ahliterature279042
Source
Glob Chang Biol. 2017 Jan 11;
Publication Type
Article
Date
Jan-11-2017
Author
Janet Prevéy
Mark Vellend
Nadja Rüger
Robert D Hollister
Anne D Bjorkman
Isla H Myers-Smith
Sarah C Elmendorf
Karin Clark
Elisabeth J Cooper
Bo Elberling
Anna Maria Fosaa
Gregory H R Henry
Toke T Høye
Ingibjörg Svala Jónsdóttir
Kari Klanderud
Esther Lévesque
Marguerite Mauritz
Ulf Molau
Susan M Natali
Steven F Oberbauer
Zoe A Panchen
Eric Post
Sabine B Rumpf
Niels M Schmidt
Ted Schuur
Phillip R Semenchuk
Tiffany Troxler
Jeffrey M Welker
Christian Rixen
Source
Glob Chang Biol. 2017 Jan 11;
Date
Jan-11-2017
Language
English
Publication Type
Article
Abstract
Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher-latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering were more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient, and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms. This article is protected by copyright. All rights reserved.
PubMed ID
28079308 View in PubMed
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Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2 gain but reduces soil carbon and nutrient pools.

https://arctichealth.org/en/permalink/ahliterature289431
Source
Glob Chang Biol. 2018 Feb 07; :
Publication Type
Journal Article
Date
Feb-07-2018
Author
Casper T Christiansen
Melissa J Lafreniére
Gregory H R Henry
Paul Grogan
Author Affiliation
Department of Biology, Queen's University, Kingston, ON, Canada.
Source
Glob Chang Biol. 2018 Feb 07; :
Date
Feb-07-2018
Language
English
Publication Type
Journal Article
Abstract
Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7-9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0-10 cm depth) and nitrate in the mineral soil layer (15-25 cm depth) were substantially reduced within the snowfences (47-70 and 43%-73% reductions, respectively, across sampling times). Finally, the snowfences tended (p = .08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years.
PubMed ID
29411950 View in PubMed
Less detail

Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2 gain but reduces soil carbon and nutrient pools.

https://arctichealth.org/en/permalink/ahliterature289589
Source
Glob Chang Biol. 2018 Feb 07; :
Publication Type
Journal Article
Date
Feb-07-2018
Author
Casper T Christiansen
Melissa J Lafreniére
Gregory H R Henry
Paul Grogan
Author Affiliation
Department of Biology, Queen's University, Kingston, ON, Canada.
Source
Glob Chang Biol. 2018 Feb 07; :
Date
Feb-07-2018
Language
English
Publication Type
Journal Article
Abstract
Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7-9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0-10 cm depth) and nitrate in the mineral soil layer (15-25 cm depth) were substantially reduced within the snowfences (47-70 and 43%-73% reductions, respectively, across sampling times). Finally, the snowfences tended (p = .08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years.
PubMed ID
29411950 View in PubMed
Less detail

Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2 gain but reduces soil carbon and nutrient pools.

https://arctichealth.org/en/permalink/ahliterature297418
Source
Glob Chang Biol. 2018 08; 24(8):3508-3525
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
08-2018
Author
Casper T Christiansen
Melissa J Lafreniére
Gregory H R Henry
Paul Grogan
Author Affiliation
Department of Biology, Queen's University, Kingston, ON, Canada.
Source
Glob Chang Biol. 2018 08; 24(8):3508-3525
Date
08-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Carbon - analysis
Carbon Dioxide - metabolism
Northwest Territories
Nutrients - analysis
Plant Development
Seasons
Snow
Soil - chemistry
Tundra
Abstract
Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7-9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0-10 cm depth) and nitrate in the mineral soil layer (15-25 cm depth) were substantially reduced within the snowfences (47-70 and 43%-73% reductions, respectively, across sampling times). Finally, the snowfences tended (p = .08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years.
PubMed ID
29411950 View in PubMed
Less detail

7 records – page 1 of 1.