Threshold peat burn severity breaks evaporation‐limiting feedback
Abstract A suite of autogenic ecohydrological feedbacks and moss traits are important for protecting vast peatland carbon stocks following wildfire disturbance. Here, we examine how peat burn severity and water table depth (WTD) affect the strength of one such feedback—the hydrophobicity–evaporation...
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crwiley:10.1002/eco.2168 2024-09-15T18:06:56+00:00 Threshold peat burn severity breaks evaporation‐limiting feedback Wilkinson, Sophie L. Verkaik, Gregory J. Moore, Paul A. Waddington, James M. 2019 http://dx.doi.org/10.1002/eco.2168 https://onlinelibrary.wiley.com/doi/pdf/10.1002/eco.2168 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/eco.2168 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Ecohydrology volume 13, issue 1 ISSN 1936-0584 1936-0592 journal-article 2019 crwiley https://doi.org/10.1002/eco.2168 2024-08-20T04:16:53Z Abstract A suite of autogenic ecohydrological feedbacks and moss traits are important for protecting vast peatland carbon stocks following wildfire disturbance. Here, we examine how peat burn severity and water table depth (WTD) affect the strength of one such feedback—the hydrophobicity–evaporation feedback (HEF). The HEF is an evaporation‐limiting feedback known to minimize water loss following wildfire. The peatland surface becomes hydrophobic creating an evaporative cap and thereby reducing post‐fire evaporation; however, recent studies hypothesize that this is dependent on peat burn severity. To test this hypothesis, we studied plots along a peat burn severity gradient in a partially drained black spruce peatland that burned during the 2016 Fort McMurray Horse River wildfire. Evaporation rates were significantly lower in plots where hydrophobicity was present. Hydrophobicity was lowest in the severely burned area, and the average instantaneous evaporation rate (2.75 mm day −1 ) was significantly higher than moderately and typical‐lightly burned areas (0.82 and 1.64 mm day −1 , respectively). Based on lab results, increasing WTD affected hydrophobicity within lightly burned (singed) feather moss samples but not in heavily burned feather moss, showing the importance of post‐fire ground cover and in situ WTD. Our results provide evidence of a burn severity threshold where increased depth of burn removes the feather moss evaporative cap and causes the HEF to break down. We argue that this threshold has important implications for boreal peatlands, which are predicted to undergo climate‐mediated pre‐fire drying and increasing burn severities, potentially leading to further carbon losses due to enhanced post‐fire drying and concomitant decomposition. Article in Journal/Newspaper Fort McMurray Wiley Online Library Ecohydrology 13 1 |
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English |
description |
Abstract A suite of autogenic ecohydrological feedbacks and moss traits are important for protecting vast peatland carbon stocks following wildfire disturbance. Here, we examine how peat burn severity and water table depth (WTD) affect the strength of one such feedback—the hydrophobicity–evaporation feedback (HEF). The HEF is an evaporation‐limiting feedback known to minimize water loss following wildfire. The peatland surface becomes hydrophobic creating an evaporative cap and thereby reducing post‐fire evaporation; however, recent studies hypothesize that this is dependent on peat burn severity. To test this hypothesis, we studied plots along a peat burn severity gradient in a partially drained black spruce peatland that burned during the 2016 Fort McMurray Horse River wildfire. Evaporation rates were significantly lower in plots where hydrophobicity was present. Hydrophobicity was lowest in the severely burned area, and the average instantaneous evaporation rate (2.75 mm day −1 ) was significantly higher than moderately and typical‐lightly burned areas (0.82 and 1.64 mm day −1 , respectively). Based on lab results, increasing WTD affected hydrophobicity within lightly burned (singed) feather moss samples but not in heavily burned feather moss, showing the importance of post‐fire ground cover and in situ WTD. Our results provide evidence of a burn severity threshold where increased depth of burn removes the feather moss evaporative cap and causes the HEF to break down. We argue that this threshold has important implications for boreal peatlands, which are predicted to undergo climate‐mediated pre‐fire drying and increasing burn severities, potentially leading to further carbon losses due to enhanced post‐fire drying and concomitant decomposition. |
format |
Article in Journal/Newspaper |
author |
Wilkinson, Sophie L. Verkaik, Gregory J. Moore, Paul A. Waddington, James M. |
spellingShingle |
Wilkinson, Sophie L. Verkaik, Gregory J. Moore, Paul A. Waddington, James M. Threshold peat burn severity breaks evaporation‐limiting feedback |
author_facet |
Wilkinson, Sophie L. Verkaik, Gregory J. Moore, Paul A. Waddington, James M. |
author_sort |
Wilkinson, Sophie L. |
title |
Threshold peat burn severity breaks evaporation‐limiting feedback |
title_short |
Threshold peat burn severity breaks evaporation‐limiting feedback |
title_full |
Threshold peat burn severity breaks evaporation‐limiting feedback |
title_fullStr |
Threshold peat burn severity breaks evaporation‐limiting feedback |
title_full_unstemmed |
Threshold peat burn severity breaks evaporation‐limiting feedback |
title_sort |
threshold peat burn severity breaks evaporation‐limiting feedback |
publisher |
Wiley |
publishDate |
2019 |
url |
http://dx.doi.org/10.1002/eco.2168 https://onlinelibrary.wiley.com/doi/pdf/10.1002/eco.2168 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/eco.2168 |
genre |
Fort McMurray |
genre_facet |
Fort McMurray |
op_source |
Ecohydrology volume 13, issue 1 ISSN 1936-0584 1936-0592 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/eco.2168 |
container_title |
Ecohydrology |
container_volume |
13 |
container_issue |
1 |
_version_ |
1810444288768606208 |