TY - JOUR

T1 - Effects of climate and ecosystem disturbances on biogeochemical cycling in a semi-natural terrestrial ecosystem

AU - Beier, Claus

AU - Schmidt, Inger Kappel

AU - Kristensen, Hanne Lakkenborg

N1 - Funding Information: The project was funded by EU under the projects CLIMOOR (Contract ENV4-CT97-0694) and VULCAN (Contract EVK2-CT-2000-00094) and the participating research institutes. We owe a lot of grateful thanks to all other institutes and researchers involved with the Climoor and Vulcan projects for inspiration and enthusiasm and in particular to the technical staff at our institutes for their skillful field and lab work. Further information about the project can be found on www.vulcanproject.com.

PY - 2004

Y1 - 2004

N2 - The effects of increased temperature and potential ecosystem disturbances on biogeochemical cycling were investigated by manipulation of temperature in a mixed Calluna/grass heathland in Denmark. A reflective curtain covered the vegetation during the night to reduce the heat loss of IR radiation from the ecosystem to the atmosphere. This 'night time warming' was done for 3 years and warmed the air and soil by 1.1 °C. Warming was combined with ecosystem disturbances, including infestation by Calluna heather beetles (Lochmaea suturalis Thompson) causing complete defoliation of Calluna leaves during the summer 2000, and subsequent harvesting of all aboveground biomass during the autumn. Small increases in mineralisation rates were induced by warming and resulted in increased leaching of nitrogen from the organic soil layer. The increased nitrogen leaching from the organic soil layer was re-immobilised in the mineral soil layer as warming stimulated plant growth and thereby increased nitrogen immobilisation. Contradictory to the generally moderate effects of warming, the heather beetle infestation had very strong effects on mineralisation rates and the plant community. The grasses completely out-competed the Calluna plants which had not re-established two years after the infestation, probably due to combined effects of increased nutrient availability and the defoliation of Calluna. On the short term, ecosystem disturbances may have very strong effects on internal ecosystem processes and plant community structure compared to the more long-term effects of climate change.

AB - The effects of increased temperature and potential ecosystem disturbances on biogeochemical cycling were investigated by manipulation of temperature in a mixed Calluna/grass heathland in Denmark. A reflective curtain covered the vegetation during the night to reduce the heat loss of IR radiation from the ecosystem to the atmosphere. This 'night time warming' was done for 3 years and warmed the air and soil by 1.1 °C. Warming was combined with ecosystem disturbances, including infestation by Calluna heather beetles (Lochmaea suturalis Thompson) causing complete defoliation of Calluna leaves during the summer 2000, and subsequent harvesting of all aboveground biomass during the autumn. Small increases in mineralisation rates were induced by warming and resulted in increased leaching of nitrogen from the organic soil layer. The increased nitrogen leaching from the organic soil layer was re-immobilised in the mineral soil layer as warming stimulated plant growth and thereby increased nitrogen immobilisation. Contradictory to the generally moderate effects of warming, the heather beetle infestation had very strong effects on mineralisation rates and the plant community. The grasses completely out-competed the Calluna plants which had not re-established two years after the infestation, probably due to combined effects of increased nutrient availability and the defoliation of Calluna. On the short term, ecosystem disturbances may have very strong effects on internal ecosystem processes and plant community structure compared to the more long-term effects of climate change.

KW - Defoliation

KW - Ecosystem disturbance

KW - Ecosystem response

KW - Experimental manipulation

KW - Heathland

KW - Nitrogen cycling

KW - temperature increase

KW - Warming

U2 - 10.1023/B:WAFO.0000028354.34016.af

DO - 10.1023/B:WAFO.0000028354.34016.af

M3 - Journal article

AN - SCOPUS:4344585664

VL - 4

SP - 191

EP - 206

JO - Water, Air and Soil Pollution

JF - Water, Air and Soil Pollution

SN - 1567-7230

ER -