How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)

Abstract

Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree evapotranspiration could potentially deepen water tables, thus stimulating peat decomposition and carbon release. Bridging the gap between modelling and field studies, we conducted a three-year mesocosm experiment subjecting natural bog vegetation to three birch tree densities, and studied the changes in subsurface temperature, water balance components, leaf area index and vegetation composition. We found the deepest water table in mesocosms with low tree density. Mesocosms with high tree density remained wettest (i.e. highest water tables) whereas the control treatment without trees had intermediate water tables. These differences are attributed mostly to differences in evapotranspiration. Although our mesocosm results cannot be directly scaled up to ecosystem level, the systematic effect of tree density suggests that as bogs become colonized by trees, the effect of trees on ecosystem water loss changes with time, with tree transpiration effects of drying becoming increasingly offset by shading effects during the later phases of tree encroachment. These density-dependent effects of trees on water loss have important implications for the structure and functioning of peatbogs.
Original languageEnglish
Article numbere91748
Number of pages11
JournalPLoS ONE
Volume9
Issue number3
DOIs
Publication statusPublished - 2014

Fingerprint

peatlands
Water
Groundwater
Ecosystems
water
Experiments
water table
Ecosystem
Wetlands
Evapotranspiration
bogs
Carbon
evapotranspiration
ecosystems
Transpiration
Peat
Carbon Sequestration
high water table
Betula
vegetation

Keywords

  • sphagnum mosses
  • vascular plants
  • carbon-dioxide
  • climate-change
  • boreal mire
  • scots pine
  • vegetation
  • bogs
  • evapotranspiration
  • table

Cite this

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title = "How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment",
abstract = "Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree evapotranspiration could potentially deepen water tables, thus stimulating peat decomposition and carbon release. Bridging the gap between modelling and field studies, we conducted a three-year mesocosm experiment subjecting natural bog vegetation to three birch tree densities, and studied the changes in subsurface temperature, water balance components, leaf area index and vegetation composition. We found the deepest water table in mesocosms with low tree density. Mesocosms with high tree density remained wettest (i.e. highest water tables) whereas the control treatment without trees had intermediate water tables. These differences are attributed mostly to differences in evapotranspiration. Although our mesocosm results cannot be directly scaled up to ecosystem level, the systematic effect of tree density suggests that as bogs become colonized by trees, the effect of trees on ecosystem water loss changes with time, with tree transpiration effects of drying becoming increasingly offset by shading effects during the later phases of tree encroachment. These density-dependent effects of trees on water loss have important implications for the structure and functioning of peatbogs.",
keywords = "sphagnum mosses, vascular plants, carbon-dioxide, climate-change, boreal mire, scots pine, vegetation, bogs, evapotranspiration, table",
author = "J. Limpens and M. Holmgren and C.M.J. Jacobs and {van der Zee}, S.E.A.T.M. and E. Karofeld and F. Berendse",
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How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment. / Limpens, J.; Holmgren, M.; Jacobs, C.M.J.; van der Zee, S.E.A.T.M.; Karofeld, E.; Berendse, F.

In: PLoS ONE, Vol. 9, No. 3, e91748, 2014.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - How Does Tree Density Affect Water Loss of Peatlands? A Mesocosm Experiment

AU - Limpens, J.

AU - Holmgren, M.

AU - Jacobs, C.M.J.

AU - van der Zee, S.E.A.T.M.

AU - Karofeld, E.

AU - Berendse, F.

PY - 2014

Y1 - 2014

N2 - Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree evapotranspiration could potentially deepen water tables, thus stimulating peat decomposition and carbon release. Bridging the gap between modelling and field studies, we conducted a three-year mesocosm experiment subjecting natural bog vegetation to three birch tree densities, and studied the changes in subsurface temperature, water balance components, leaf area index and vegetation composition. We found the deepest water table in mesocosms with low tree density. Mesocosms with high tree density remained wettest (i.e. highest water tables) whereas the control treatment without trees had intermediate water tables. These differences are attributed mostly to differences in evapotranspiration. Although our mesocosm results cannot be directly scaled up to ecosystem level, the systematic effect of tree density suggests that as bogs become colonized by trees, the effect of trees on ecosystem water loss changes with time, with tree transpiration effects of drying becoming increasingly offset by shading effects during the later phases of tree encroachment. These density-dependent effects of trees on water loss have important implications for the structure and functioning of peatbogs.

AB - Raised bogs have accumulated more atmospheric carbon than any other terrestrial ecosystem on Earth. Climate-induced expansion of trees and shrubs may turn these ecosystems from net carbon sinks into sources when associated with reduced water tables. Increasing water loss through tree evapotranspiration could potentially deepen water tables, thus stimulating peat decomposition and carbon release. Bridging the gap between modelling and field studies, we conducted a three-year mesocosm experiment subjecting natural bog vegetation to three birch tree densities, and studied the changes in subsurface temperature, water balance components, leaf area index and vegetation composition. We found the deepest water table in mesocosms with low tree density. Mesocosms with high tree density remained wettest (i.e. highest water tables) whereas the control treatment without trees had intermediate water tables. These differences are attributed mostly to differences in evapotranspiration. Although our mesocosm results cannot be directly scaled up to ecosystem level, the systematic effect of tree density suggests that as bogs become colonized by trees, the effect of trees on ecosystem water loss changes with time, with tree transpiration effects of drying becoming increasingly offset by shading effects during the later phases of tree encroachment. These density-dependent effects of trees on water loss have important implications for the structure and functioning of peatbogs.

KW - sphagnum mosses

KW - vascular plants

KW - carbon-dioxide

KW - climate-change

KW - boreal mire

KW - scots pine

KW - vegetation

KW - bogs

KW - evapotranspiration

KW - table

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