Figure 4. (a) Cumulative apparent net ecosystem production (NEP_APP) for years when potential [=maximum 30-day mean NEP_APP] NEP (NEP_POT) occurred at the grasslands sites Neustift (N), Monte Bondone (MB), Torgnon (TN), Lethbridge (L), Vaira (V), Tojal (T), Dripsey (D), Wexford (W) and Carlow (CW). Red slopes visualize NEP_POT sustained over 30 days; numbers in rectangles show associated slope values; dotted vertical lines visualize the timing of NEP_POT (b) NEP_POT for grasslands in the cold-temperate (blue), Mediterranean (red), and maritime (green) regions; grey band indicates the convergence zone for NEP_POT (dotted horizontal line shows mean NEP_POT); same letters indicate no significant difference; error bars indicate ±2 standard error of site-specific NEP_POT (n = 30).