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Carbon isotope composition (δ13C) of leaves of Quercus ilex and Arctostaphylos uva-ursi in sun and shade habitats collected at the end of the summer 2005; letters at the base of each bar indicate statistically homogenous groups (ANOVA, Fisher l.s.d. post hoc test). Each data point is the mean of a minimum of six plants. Error bars indicate the 95 % confidence intervals for the mean.
