Forests and Extreme Climatic Events

DRAIN – Impact of repeated Droughts and heavy RAIN on greenhouse gas emissions in a temperate beech forest

Climate projections predict that both frequency and intensity of extreme weather events such as droughts and heavy rainfalls will increase considerably in the forthcoming decades. Resent research recognizes the threat that weather extremes pose to ecosystems because they have the power to alter ecosystem processes fundamentally. In this study, in the framework of which I am writing my dissertation, we address the impact of more frequent and more severe drought-rewetting cycles on soil greenhouse gas emissions, soil nutrient cycling and soil microbiology.

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From 2013 to 2015, we have simulated two different scenarios of extreme events (short drought periods with little rainfall, and long drought periods with subsequent heavy rainfall) in a natural Austrian beech forest. In 2016, we are determining ecosystem recovery to repeated extreme events. We are measuring responses of soil greenhouse gas fluxes (CO2, CH4 and N2O), soil nutrients and soil microbial community compositions.

Our research questions are:

  • What are the effects of increased drought-rewetting frequencies on soil nutrient- cycling and the availability of forest soil organic C?
  • Will total soil emissions of greenhouse gases be reduced by extended drought periods or will potential pulses during rewetting periods compensate or even outweigh this reduction, thereby leading to increased overall fluxes?
  • How do soil microbial communities respond to increased frequency and intensity of drying-rewetting cycles in a beech forest?

Related publications:

Journal articles:

Leitner S, Minixhofer P, Inselsbacher E, Keiblinger KM, Zimmermann M, Zechmeister-Boltenstern S (2017): Short-term soil mineral and organic nitrogen fluxes during moderate and severe drying-rewetting events. Applied Soil Ecology 114: 28-33, doi:10.1016/j.apsoil.2017.02.014.

Leitner S, Sae-Tun O, Kranzinger L, Zechmeister-Boltenstern S, Zimmermann M (2016): Contribution of litter layer to soil greenhouse gas emissions in a temperate beech forest. Plant and Soil, 403: 455-469, doi:10.1007/s11104-015-2771-3.

Schwen A, Zimmermann M, Leitner S, Woche SK (2015): Soil Water Repellency and its Impact on Hydraulic Characteristics in a Beech Forest under Simulated Climate Change. Vadose Zone Journal, 14 (12), doi:10.2136/vzj2015.06.0089.

Schwen A, Zimmermann M, Bodner G (2014): Vertical variations of soil hydraulic properties within two soil profiles and its relevance for soil water simulations. Journal of Hydrology, 516: 169-181, doi:10.1016/j.jhydrol.2014.01.042.

Press releases:

BOKU Homepage Top Story (16.10.2012, in German)

BOKU Magazin (02/06 2014, in German)

LTER ForAustria (in German)

Websites:

BOKU Forest Demonstration Center “Lehrforst Rosalia”

Funding:

ACRP KR13AC6K11008 (PI Michael Zimmermann)

AXA Research Fund DOC Fellowship (awarded to Sonja Leitner)