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Moderate drop in water table increases peatland vulnerability to post-fire regime shift.

Kettridge N, Turetsky MR, Sherwood JH, Thompson DK, Miller CA, Benscoter BW, Flannigan MD, Wotton BM, Waddington JM - Sci Rep (2015)

Bottom Line: We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands.The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem.This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

View Article: PubMed Central - PubMed

Affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.

ABSTRACT
Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

No MeSH data available.


Related in: MedlinePlus

Conceptual diagram showing the degradation of the peatland carbon stock.Far left cycle (A) represents the low frequency peatland fire cycle. The compound disturbance of fire and drainage breaks this cycle, transferring the peatland to the central fire cycle (B). This represents a spiral of decline in peatland carbon stocks. After repeated high frequency fire cycles, peatland stocks are lost to the atmosphere and the landscape is transferred to a stable mineral soil fire cycle (C).
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f1: Conceptual diagram showing the degradation of the peatland carbon stock.Far left cycle (A) represents the low frequency peatland fire cycle. The compound disturbance of fire and drainage breaks this cycle, transferring the peatland to the central fire cycle (B). This represents a spiral of decline in peatland carbon stocks. After repeated high frequency fire cycles, peatland stocks are lost to the atmosphere and the landscape is transferred to a stable mineral soil fire cycle (C).

Mentions: In the absence of drainage, the peatland followed a typical pattern of post-fire recovery614 (Figure 1; cycle A). After wildfire, the specific yield remained high (0.59 within the top 0.1 m of the profile)14, maintaining a high water table position (maximum water table depth of 0.13 m during 2010 growing season). This likely promoted the observed establishment of a moss-dominated ground layer within a decade since fire (Figure 2a). This reestablishment of the peatland ecosystems results in a net accumulation of carbon 10 years post disturbance6 which will begin to offset carbon lost during the wildfire. This stable pattern of vegetation succession promotes peat accumulation and is exemplifying the resilience of peatlands to fire.


Moderate drop in water table increases peatland vulnerability to post-fire regime shift.

Kettridge N, Turetsky MR, Sherwood JH, Thompson DK, Miller CA, Benscoter BW, Flannigan MD, Wotton BM, Waddington JM - Sci Rep (2015)

Conceptual diagram showing the degradation of the peatland carbon stock.Far left cycle (A) represents the low frequency peatland fire cycle. The compound disturbance of fire and drainage breaks this cycle, transferring the peatland to the central fire cycle (B). This represents a spiral of decline in peatland carbon stocks. After repeated high frequency fire cycles, peatland stocks are lost to the atmosphere and the landscape is transferred to a stable mineral soil fire cycle (C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4306970&req=5

f1: Conceptual diagram showing the degradation of the peatland carbon stock.Far left cycle (A) represents the low frequency peatland fire cycle. The compound disturbance of fire and drainage breaks this cycle, transferring the peatland to the central fire cycle (B). This represents a spiral of decline in peatland carbon stocks. After repeated high frequency fire cycles, peatland stocks are lost to the atmosphere and the landscape is transferred to a stable mineral soil fire cycle (C).
Mentions: In the absence of drainage, the peatland followed a typical pattern of post-fire recovery614 (Figure 1; cycle A). After wildfire, the specific yield remained high (0.59 within the top 0.1 m of the profile)14, maintaining a high water table position (maximum water table depth of 0.13 m during 2010 growing season). This likely promoted the observed establishment of a moss-dominated ground layer within a decade since fire (Figure 2a). This reestablishment of the peatland ecosystems results in a net accumulation of carbon 10 years post disturbance6 which will begin to offset carbon lost during the wildfire. This stable pattern of vegetation succession promotes peat accumulation and is exemplifying the resilience of peatlands to fire.

Bottom Line: We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands.The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem.This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

View Article: PubMed Central - PubMed

Affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.

ABSTRACT
Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

No MeSH data available.


Related in: MedlinePlus