Figure 2.

Relationships (a) between insect herbivory on silver birch leaves and mean annual temperature and (b) between insect herbivory and tree species richness for two contrasted temperature levels. The figure shows observed data (points) as well as model predictions (solid lines) and standard errors (shaded areas). In panel (a), species richness was set at a median value to compute predictions. ‘Warm’ and ‘cold’ temperature levels corresponded to 0.25 and 0.75 quartiles of the observed temperature range, respectively