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Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss

Coastal wetlands are susceptible to loss in both health and extent via stressors associated with global climate change and anthropogenic disturbance. Peat collapse may represent an additional phenomenon contributing to coastal wetland loss in organic‐rich soils through rapid vertical elevation decli...

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Autores principales: Chambers, Lisa G., Steinmuller, Havalend E., Breithaupt, Joshua L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850666/
https://www.ncbi.nlm.nih.gov/pubmed/30933312
http://dx.doi.org/10.1002/ecy.2720
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author Chambers, Lisa G.
Steinmuller, Havalend E.
Breithaupt, Joshua L.
author_facet Chambers, Lisa G.
Steinmuller, Havalend E.
Breithaupt, Joshua L.
author_sort Chambers, Lisa G.
collection PubMed
description Coastal wetlands are susceptible to loss in both health and extent via stressors associated with global climate change and anthropogenic disturbance. Peat collapse may represent an additional phenomenon contributing to coastal wetland loss in organic‐rich soils through rapid vertical elevation decline. However, the term “peat collapse” has been inconsistently used in the literature, leading to ambiguities regarding the mechanisms, timing, and spatial extent of its contribution to coastal wetland loss. For example, it is unclear whether peat collapse is distinct from general subsidence, or what biogeochemical changes or sequence of events may constitute peat collapse. A critical analysis of peer‐reviewed literature related to peat collapse was supplemented with fundamental principles of soil physics and biogeochemistry to develop a conceptual framework for coastal wetland peat collapse. We propose that coastal wetland peat collapse is a specific type of shallow subsidence unique to highly organic soils in which a loss of soil strength and structural integrity contributes to a decline in elevation, over the course of a few months to a few years, below the lower limit for emergent plant growth and natural recovery. We further posit that coastal wetland peat collapse is driven by severe stress or death of the vegetation, which compromises the supportive structure roots provide to low‐density organic soils and shifts the carbon balance of the ecosystem toward a net source, as mineralization is no longer offset by sequestration. Under these conditions, four mechanisms may contribute to peat collapse: (1) compression of gas‐filled pore spaces within the soil during dry‐down conditions; (2) deconsolidation of excessively waterlogged peat, followed by transport; (3) compaction of aerenchyma tissue in wetland plant roots, and possibly collapse of root channels; and (4) acceleration of soil mineralization due to the addition of labile carbon (dying roots), oxygen (decreased flooding), nutrients (eutrophication), or sulfate (saltwater intrusion). Scientists and land managers should focus efforts on monitoring vegetation health across the coastal landscape as an indicator for peat collapse vulnerability and move toward codifying the term “peat collapse” in the scientific literature. Once clarified, the contribution of peat collapse to coastal wetland loss can be evaluated.
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spelling pubmed-68506662019-11-18 Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss Chambers, Lisa G. Steinmuller, Havalend E. Breithaupt, Joshua L. Ecology Concepts & Synthesis Coastal wetlands are susceptible to loss in both health and extent via stressors associated with global climate change and anthropogenic disturbance. Peat collapse may represent an additional phenomenon contributing to coastal wetland loss in organic‐rich soils through rapid vertical elevation decline. However, the term “peat collapse” has been inconsistently used in the literature, leading to ambiguities regarding the mechanisms, timing, and spatial extent of its contribution to coastal wetland loss. For example, it is unclear whether peat collapse is distinct from general subsidence, or what biogeochemical changes or sequence of events may constitute peat collapse. A critical analysis of peer‐reviewed literature related to peat collapse was supplemented with fundamental principles of soil physics and biogeochemistry to develop a conceptual framework for coastal wetland peat collapse. We propose that coastal wetland peat collapse is a specific type of shallow subsidence unique to highly organic soils in which a loss of soil strength and structural integrity contributes to a decline in elevation, over the course of a few months to a few years, below the lower limit for emergent plant growth and natural recovery. We further posit that coastal wetland peat collapse is driven by severe stress or death of the vegetation, which compromises the supportive structure roots provide to low‐density organic soils and shifts the carbon balance of the ecosystem toward a net source, as mineralization is no longer offset by sequestration. Under these conditions, four mechanisms may contribute to peat collapse: (1) compression of gas‐filled pore spaces within the soil during dry‐down conditions; (2) deconsolidation of excessively waterlogged peat, followed by transport; (3) compaction of aerenchyma tissue in wetland plant roots, and possibly collapse of root channels; and (4) acceleration of soil mineralization due to the addition of labile carbon (dying roots), oxygen (decreased flooding), nutrients (eutrophication), or sulfate (saltwater intrusion). Scientists and land managers should focus efforts on monitoring vegetation health across the coastal landscape as an indicator for peat collapse vulnerability and move toward codifying the term “peat collapse” in the scientific literature. Once clarified, the contribution of peat collapse to coastal wetland loss can be evaluated. John Wiley and Sons Inc. 2019-04-26 2019-07 /pmc/articles/PMC6850666/ /pubmed/30933312 http://dx.doi.org/10.1002/ecy.2720 Text en © 2019 The Authors. Ecology published by Wiley Periodicals, Inc. on behalf of Ecological Society of America This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Concepts & Synthesis
Chambers, Lisa G.
Steinmuller, Havalend E.
Breithaupt, Joshua L.
Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
title Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
title_full Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
title_fullStr Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
title_full_unstemmed Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
title_short Toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
title_sort toward a mechanistic understanding of “peat collapse” and its potential contribution to coastal wetland loss
topic Concepts & Synthesis
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6850666/
https://www.ncbi.nlm.nih.gov/pubmed/30933312
http://dx.doi.org/10.1002/ecy.2720
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