Rice is commonly cultivated under irrigated conditions, serving
as artificial wetlands for many plant and animal species
(FAO, 2004a; Fasola and Ruiz, 1996). As in other complex and
multifunctional wetlands, the hydrological regime plays a key
role in the ecology of these agroecosystems (Bambaradeniya
and Amarasinghe, 2003). The source and frequency of irrigation
directly affects the ecology and biodiversity of rice cultivations.
The source of water determines both the physiochemical characteristics
and the composition of aquatic biota. The duration,
regularity and predictability of rice field flooding have effects on
the temporal variation of the water depth (volume) and chemistry,