Comparative study of plant communities of rice fields and aquatic and marshy environments of Entre Ríos (Argentina).

Flooded rice fields are an appropriate habitat for aquatic and marshy weeds. In rivers and streams are used as water source for flooding of irrigation water, some plants develop and disseminate by seeds or segments, and sprout later on rice fields becoming weeds. The objective was to study the composition of plant communities of aquatic and marshy environments and the fllooding rice crops of Entre Ríos. The study was carried out between December 1993 and February 1995. One hundred and fifty four stations were sampled by censing vegetation of 11 types of aquatic and marshy environments. Species abundance and cover were estimated, and similarity of environments was obtained with euclidean distance and classified according to the most distant neighbor’s technique. One hundred and five species were registered, and the prevailing families were Poaceae, Asteraceae, Cyperaceae, Polygonaceae and Apiaceae. Small streams would be the environment with higher contribution of marshy and aquatic weeds, and so they have higher probability of being the source of weed invasions. In the rice fields prevails the covering of marshy species with regard to other biological forms.

Key words: rice fields, aquatic and marshy environments, floristic similarity, Entre Ríos, Argentina.