Peatland plant functional type effects on early decomposition indicators are non-pervasive, but microhabitat dependent
Peatland plant functional type effects on early decomposition indicators are non-pervasive, but microhabitat dependent
Ombrotrophic peatlands are important long-term sinks for atmospheric carbon as plant productivity exceeds litter decomposition. Changes in plant community composition may alter decomposition rates through alterations in microbial communities and activity. Such plant community driven changes in decomposition rates may however differ between microhabitats. Nevertheless, the microhabitat-context-dependency of plant community composition effects on decomposition remains poorly understood. We used a long-term (> 10 year) plant removal experiment to study how vascular plant functional types (PFTs, i.e. graminoids and ericoids) influence decomposition processes in wet lawns and hummocks. We employed the Tea Bag Index (TBI) as an indicator for early litter decomposition and carbon stabilization and assessed the potential activity of five hydrolytic extracellular enzymes (EEAs) as indicators for microbial activity. PFT removal had no effect on the TBI decomposition rate constant (k), nor on the stabilization factor (S). Yet, k increased slightly when both PFTs were absent. In the lawns, we observed higher values of k and S as compared to hummocks. PFT composition influenced four out of five hydrolytic EEAs that can drive decomposition. Yet, this influence was non-pervasive and microhabitat dependent. In wet lawns, PFT removal generally increased enzyme activities, while opposite trends were detected in the hummocks. Our results suggest an important role for vegetation change, through their influence on enzyme activity, along the lawn-hummock gradient in regulating decomposition processes in northern peatlands. This implies that potential consequences of vegetation changes on organic matter turnover, hence the peatland carbon sink function, cannot be generalized across peatland microhabitats.
Sahar, Najam E.
ac454553-8dbf-4e81-8a05-1bd1aef7eb24
Robroek, Bjorn J.M.
6beb3126-25d6-428c-b5e7-49a1e2d40a40
Mills, Robert T.E.
f73e68a8-3c0e-469d-aef3-a95aee049ffe
Dumont, Marc G.
afd9f08f-bdbb-4cee-b792-1a7f000ee511
Barel, Janna M.
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20 October 2022
Sahar, Najam E.
ac454553-8dbf-4e81-8a05-1bd1aef7eb24
Robroek, Bjorn J.M.
6beb3126-25d6-428c-b5e7-49a1e2d40a40
Mills, Robert T.E.
f73e68a8-3c0e-469d-aef3-a95aee049ffe
Dumont, Marc G.
afd9f08f-bdbb-4cee-b792-1a7f000ee511
Barel, Janna M.
5ca7c6b4-3997-497f-8919-3ab451684561
Sahar, Najam E., Robroek, Bjorn J.M., Mills, Robert T.E., Dumont, Marc G. and Barel, Janna M.
(2022)
Peatland plant functional type effects on early decomposition indicators are non-pervasive, but microhabitat dependent.
Wetlands, 42, [98].
(doi:10.1007/s13157-022-01626-7).
Abstract
Ombrotrophic peatlands are important long-term sinks for atmospheric carbon as plant productivity exceeds litter decomposition. Changes in plant community composition may alter decomposition rates through alterations in microbial communities and activity. Such plant community driven changes in decomposition rates may however differ between microhabitats. Nevertheless, the microhabitat-context-dependency of plant community composition effects on decomposition remains poorly understood. We used a long-term (> 10 year) plant removal experiment to study how vascular plant functional types (PFTs, i.e. graminoids and ericoids) influence decomposition processes in wet lawns and hummocks. We employed the Tea Bag Index (TBI) as an indicator for early litter decomposition and carbon stabilization and assessed the potential activity of five hydrolytic extracellular enzymes (EEAs) as indicators for microbial activity. PFT removal had no effect on the TBI decomposition rate constant (k), nor on the stabilization factor (S). Yet, k increased slightly when both PFTs were absent. In the lawns, we observed higher values of k and S as compared to hummocks. PFT composition influenced four out of five hydrolytic EEAs that can drive decomposition. Yet, this influence was non-pervasive and microhabitat dependent. In wet lawns, PFT removal generally increased enzyme activities, while opposite trends were detected in the hummocks. Our results suggest an important role for vegetation change, through their influence on enzyme activity, along the lawn-hummock gradient in regulating decomposition processes in northern peatlands. This implies that potential consequences of vegetation changes on organic matter turnover, hence the peatland carbon sink function, cannot be generalized across peatland microhabitats.
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s13157-022-01626-7
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Accepted/In Press date: 13 October 2022
Published date: 20 October 2022
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Local EPrints ID: 479834
URI: http://eprints.soton.ac.uk/id/eprint/479834
ISSN: 0277-5212
PURE UUID: a22f5d39-2354-45f0-8a25-64c533eb1a6b
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Date deposited: 27 Jul 2023 15:00
Last modified: 18 Mar 2024 03:33
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Author:
Bjorn J.M. Robroek
Author:
Robert T.E. Mills
Author:
Janna M. Barel
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