The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment
Warming may increase the extent and intensity of insect defoliations within Arctic ecosystems. A thorough understanding of the implications of this for litter decomposition is essential to make predictions of soil-atmosphere carbon (C) feedbacks. Soil nitrogen (N) and C cycles naturally are interlin...
Published in: | Biogeochemistry |
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Online Access: | https://lup.lub.lu.se/record/b0cd4749-263d-4b29-bfdb-38358ef2867d https://doi.org/10.1007/s10533-018-0448-8 |
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ftulundlup:oai:lup.lub.lu.se:b0cd4749-263d-4b29-bfdb-38358ef2867d 2023-05-15T15:11:46+02:00 The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment Kristensen, Jeppe A. Metcalfe, Daniel B. Rousk, Johannes 2018-05-05 https://lup.lub.lu.se/record/b0cd4749-263d-4b29-bfdb-38358ef2867d https://doi.org/10.1007/s10533-018-0448-8 eng eng Springer https://lup.lub.lu.se/record/b0cd4749-263d-4b29-bfdb-38358ef2867d http://dx.doi.org/10.1007/s10533-018-0448-8 scopus:85046488756 Biogeochemistry; 138(3), pp 323-336 (2018) ISSN: 0168-2563 Geosciences Multidisciplinary Ecology Biogeochemistry Herbivory Nitrogen mineralisation Soil microbial ecology Soil respiration Subarctic birch forest contributiontojournal/article info:eu-repo/semantics/article text 2018 ftulundlup https://doi.org/10.1007/s10533-018-0448-8 2023-02-01T23:36:46Z Warming may increase the extent and intensity of insect defoliations within Arctic ecosystems. A thorough understanding of the implications of this for litter decomposition is essential to make predictions of soil-atmosphere carbon (C) feedbacks. Soil nitrogen (N) and C cycles naturally are interlinked, but we lack a detailed understanding of how insect herbivores impact these cycles. In a laboratory microcosm study, we investigated the growth responses of heterotrophic soil fungi and bacteria as well as C and N mineralisation to simulated defoliator outbreaks (frass addition), long-term increased insect herbivory (litter addition at higher background N-level) and non-outbreak conditions (litter addition only) in soils from a Subarctic birch forest. Larger amounts of the added organic matter were mineralised in the outbreak simulations compared to a normal year; yet, the fungal and bacterial growth rates and biomass were not significantly different. In the simulation of long-term increased herbivory, less litter C was respired per unit mineralised N (C:N of mineralisation decreased to 20 ± 1 from 38 ± 3 for pure litter), which suggests a directed microbial mining for N-rich substrates. This was accompanied by higher fungal dominance relative to bacteria and lower total microbial biomass. In conclusion, while a higher fraction of foliar C will be respired by insects and microbes during outbreak years, predicted long-term increases in herbivory linked to climate change may facilitate soil C-accumulation, as less foliar C is respired per unit mineralised N. Further work elucidating animal-plant-soil interactions is needed to improve model predictions of C-sink capacity in high latitude forest ecosystems. Article in Journal/Newspaper Arctic Climate change Subarctic Lund University Publications (LUP) Arctic Biogeochemistry 138 3 323 336 |
institution |
Open Polar |
collection |
Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Geosciences Multidisciplinary Ecology Biogeochemistry Herbivory Nitrogen mineralisation Soil microbial ecology Soil respiration Subarctic birch forest |
spellingShingle |
Geosciences Multidisciplinary Ecology Biogeochemistry Herbivory Nitrogen mineralisation Soil microbial ecology Soil respiration Subarctic birch forest Kristensen, Jeppe A. Metcalfe, Daniel B. Rousk, Johannes The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment |
topic_facet |
Geosciences Multidisciplinary Ecology Biogeochemistry Herbivory Nitrogen mineralisation Soil microbial ecology Soil respiration Subarctic birch forest |
description |
Warming may increase the extent and intensity of insect defoliations within Arctic ecosystems. A thorough understanding of the implications of this for litter decomposition is essential to make predictions of soil-atmosphere carbon (C) feedbacks. Soil nitrogen (N) and C cycles naturally are interlinked, but we lack a detailed understanding of how insect herbivores impact these cycles. In a laboratory microcosm study, we investigated the growth responses of heterotrophic soil fungi and bacteria as well as C and N mineralisation to simulated defoliator outbreaks (frass addition), long-term increased insect herbivory (litter addition at higher background N-level) and non-outbreak conditions (litter addition only) in soils from a Subarctic birch forest. Larger amounts of the added organic matter were mineralised in the outbreak simulations compared to a normal year; yet, the fungal and bacterial growth rates and biomass were not significantly different. In the simulation of long-term increased herbivory, less litter C was respired per unit mineralised N (C:N of mineralisation decreased to 20 ± 1 from 38 ± 3 for pure litter), which suggests a directed microbial mining for N-rich substrates. This was accompanied by higher fungal dominance relative to bacteria and lower total microbial biomass. In conclusion, while a higher fraction of foliar C will be respired by insects and microbes during outbreak years, predicted long-term increases in herbivory linked to climate change may facilitate soil C-accumulation, as less foliar C is respired per unit mineralised N. Further work elucidating animal-plant-soil interactions is needed to improve model predictions of C-sink capacity in high latitude forest ecosystems. |
format |
Article in Journal/Newspaper |
author |
Kristensen, Jeppe A. Metcalfe, Daniel B. Rousk, Johannes |
author_facet |
Kristensen, Jeppe A. Metcalfe, Daniel B. Rousk, Johannes |
author_sort |
Kristensen, Jeppe A. |
title |
The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment |
title_short |
The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment |
title_full |
The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment |
title_fullStr |
The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment |
title_full_unstemmed |
The biogeochemical consequences of litter transformation by insect herbivory in the Subarctic : a microcosm simulation experiment |
title_sort |
biogeochemical consequences of litter transformation by insect herbivory in the subarctic : a microcosm simulation experiment |
publisher |
Springer |
publishDate |
2018 |
url |
https://lup.lub.lu.se/record/b0cd4749-263d-4b29-bfdb-38358ef2867d https://doi.org/10.1007/s10533-018-0448-8 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change Subarctic |
genre_facet |
Arctic Climate change Subarctic |
op_source |
Biogeochemistry; 138(3), pp 323-336 (2018) ISSN: 0168-2563 |
op_relation |
https://lup.lub.lu.se/record/b0cd4749-263d-4b29-bfdb-38358ef2867d http://dx.doi.org/10.1007/s10533-018-0448-8 scopus:85046488756 |
op_doi |
https://doi.org/10.1007/s10533-018-0448-8 |
container_title |
Biogeochemistry |
container_volume |
138 |
container_issue |
3 |
container_start_page |
323 |
op_container_end_page |
336 |
_version_ |
1766342568210071552 |