Effects of temperature enhancement on growth and reproduction (top), different life stages (middle) and different growth forms (bottom). Level of significance (*p<0.05; **p<0.01; ***p<0.001; from Kudernatsch 2008)
 

The ambient temperature of the vegetation and the temperature of the upper soil were passively raised using open top chambers (OTCs). The effect size is defined as the natural logarithm of the response ratio (the ratio of the experimental mean to the control mean).
An effect size of zero indicates no experimental effect. Values above zero indicate a ‘‘positive’’ effect (i.e. the manipulation caused an increase in the measured variable); values below zero indicate a ‘‘negative’’ effect (decrease in the variable).