We carried out the study within the Ebre Delta Natural Park
(0◦50 E, 40◦42 N, Fig. 2), Catalonia, NE Iberia, which is one of
the biggest deltas in Europe (320 km2). Approximately 65 km2 are
wetlands, 240 km2 are crops (203 km2 of which are paddies) and
16 km2 are urban areas that host around 5000 inhabitants. Mean
annual temperatures range between 17 and 18 ◦C, mean annual
precipitation between 500 and 550 mm, and mean annual evapotranspiration
between 855 and 997 mm, in what is essentially a
semi-arid Mediterranean climate, with a pronounced summerdrought.