Uni-Bayreuth grafik-uni-bayreuth

Sprungmarken

 

The importance of outside ambient weather conditions for ecosystem drought manipulation experiments

Fahmida Sultana1, Juergen Kreyling2, Thomas Foken3, Anke Jentsch1
1 Disturbance Ecology, University of Bayreuth, Germany
2 Biogeography, University of Bayreuth, Germany
3 Micrometeorology, University of Bayreuth, Germany

O 3.6 in Ökosysteme: Funktion und Leistungen

11.10.2012, 15:45-16:00, H8

Field experiments to reveal the effects of drought events on ecosystems by using rainout shelters are becoming central in climate impact research. However, the question is whether this rainout shelter technique is really effective for studying drought effects as it increases temperature, reduces wind speed and alters radiation inside the shelter while being potentially dependent from outside weather conditions. Here we used a standardized phytometer approach to reveal the effectiveness of using rainout shelters for studying drought effects in an existing precipitation manipulation experiment in the Ecological Botanical Garden of the University of Bayreuth. Standardized phytometers (potted individuals of Plantago lanceolata of the same in size, age, pot size, substrate and soil moisture for each experimental run) were exposed in the field experiment for 7 days with replications during opposing outside weather conditions. Microclimatic conditions inside and outside the rainout shelters were quantified, yet, here we focus on the plant response. Phytometers inside the rain-out shelters responded significantly different under opposing outside conditions. The phytometers showed significantly higher water potential, lower fluorescence yield and also lower stomatal conductance during warm and dry compared to cool and wet outside weather. Above-ground biomass productivity was also significantly lower during warm and sunny outside weather. However, chlorophyll content was higher during warmer periods. We conclude that outside weather conditions strongly affect drought manipulations by rainout shelters. For the same length of drought manipulation, water stress builds up much faster during warm and dry than during cool and wet outside weather conditions. These findings will help in improved interpretation of the results obtained in numerous precipitation manipulation experiments.



Export as iCal: Export iCal

Letzte Änderung 21.09.2012