Winter climate change increases physiological stress in calcareous fen bryophytes
Winter climate change increases physiological stress in calcareous fen bryophytes
Calcareous spring fens are among the rarest and most endangered wetland types worldwide. The majority of these ecosystems can be found at high latitudes, where they are affected by above average rates of climate change. Particularly winter temperatures are increasing, which results in decreased snow cover. As snow provides an insulating layer that protects ecosystems from subzero temperatures, its decrease is likely to induce stress to plants. To investigate the sensitivity of the bryophyte community – key to the functioning of calcareous spring fens – to changing climatic conditions, we studied the annual variation in ecophysiology of two dominant bryophytes: Campylium stellatum and Scorpidium scorpioides. Further, a snow removal experiment was used to simulate the effect of changing winter conditions. In both species, we observed lowest efficiency of photosystem II (Fv/Fm) in spring, indicating physiological stress, and highest chlorophyll-a, -b and carotenoid concentrations in autumn. Snow removal exacerbated physiological stress in bryophytes. Consequently Fv/Fm, pigment concentrations and chlorophyll to carotenoids ratios declined, while chlorophyll-a to -b ratios increased. Moreover, these effects of winter climate change cascaded to the growing season. C. stellatum, a low hummock inhabitor, suffered more from snow removal (annual mean decline in Fv/Fm 7.7% and 30.0% in chlorophyll-a) than S. scorpioides, a hollow species (declines 5.4% and 14.5%, respectively). Taken together, our results indicate that spring fen bryophytes are negatively impacted by winter climate change, as a result of longer frost periods and increased numbers of freeze-thaw cycles in combination with higher light intensity and dehydration.
Chlorophyll, Mosses, Peatlands, Phenology, Snow
1-9
Küttim, Martin
7e6be476-dd0e-4d0f-9645-4b124de287ae
Laine, Anna M.
2f28b5c0-c4c9-49f2-b6ba-fcbb3b50c316
Küttim, L.
7e36a86a-e3c9-4d49-bc98-8088bf378c48
Ilomets, Mati
bd5a6b8e-8564-41d1-8cb4-0a5ecae2e696
Robroek, Bjorn J.M.
06dcb269-687c-41db-ab73-f61899617f92
10 December 2019
Küttim, Martin
7e6be476-dd0e-4d0f-9645-4b124de287ae
Laine, Anna M.
2f28b5c0-c4c9-49f2-b6ba-fcbb3b50c316
Küttim, L.
7e36a86a-e3c9-4d49-bc98-8088bf378c48
Ilomets, Mati
bd5a6b8e-8564-41d1-8cb4-0a5ecae2e696
Robroek, Bjorn J.M.
06dcb269-687c-41db-ab73-f61899617f92
Küttim, Martin, Laine, Anna M., Küttim, L., Ilomets, Mati and Robroek, Bjorn J.M.
(2019)
Winter climate change increases physiological stress in calcareous fen bryophytes.
Science of the Total Environment, 695, , [133867].
(doi:10.1016/j.scitotenv.2019.133867).
Abstract
Calcareous spring fens are among the rarest and most endangered wetland types worldwide. The majority of these ecosystems can be found at high latitudes, where they are affected by above average rates of climate change. Particularly winter temperatures are increasing, which results in decreased snow cover. As snow provides an insulating layer that protects ecosystems from subzero temperatures, its decrease is likely to induce stress to plants. To investigate the sensitivity of the bryophyte community – key to the functioning of calcareous spring fens – to changing climatic conditions, we studied the annual variation in ecophysiology of two dominant bryophytes: Campylium stellatum and Scorpidium scorpioides. Further, a snow removal experiment was used to simulate the effect of changing winter conditions. In both species, we observed lowest efficiency of photosystem II (Fv/Fm) in spring, indicating physiological stress, and highest chlorophyll-a, -b and carotenoid concentrations in autumn. Snow removal exacerbated physiological stress in bryophytes. Consequently Fv/Fm, pigment concentrations and chlorophyll to carotenoids ratios declined, while chlorophyll-a to -b ratios increased. Moreover, these effects of winter climate change cascaded to the growing season. C. stellatum, a low hummock inhabitor, suffered more from snow removal (annual mean decline in Fv/Fm 7.7% and 30.0% in chlorophyll-a) than S. scorpioides, a hollow species (declines 5.4% and 14.5%, respectively). Taken together, our results indicate that spring fen bryophytes are negatively impacted by winter climate change, as a result of longer frost periods and increased numbers of freeze-thaw cycles in combination with higher light intensity and dehydration.
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Accepted/In Press date: 9 August 2019
e-pub ahead of print date: 10 August 2019
Published date: 10 December 2019
Keywords:
Chlorophyll, Mosses, Peatlands, Phenology, Snow
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Local EPrints ID: 433897
URI: http://eprints.soton.ac.uk/id/eprint/433897
ISSN: 0048-9697
PURE UUID: 1a7e93b5-558e-408c-a38a-05bb81d59ab0
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Date deposited: 05 Sep 2019 16:30
Last modified: 16 Mar 2024 08:08
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Author:
Martin Küttim
Author:
Anna M. Laine
Author:
L. Küttim
Author:
Mati Ilomets
Author:
Bjorn J.M. Robroek
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