DYNAMICS OF HIDROPHYLOUS COMMUNITIES ASSOCIATED TO DRAINAGE CHANNELS IN THE ALTO VALLE OF RIO NEGRO (ARGENTINA)

Abstract

The objective of the present work was to know the floristic composition of the hidrophytic vegetation located in adjacent areas to irrigation and drainage
channels in the Alto Valle of Rio Negro ; its dynamic in relation to fluctuations of the water level. The vegetation was sampled following the Braun Blanquet methodology and from this information was determined that the communities present in these zones mostly belong to the classes Phragmito Magnocaricetea and Salicornietea ambiguae. In spring-summer (irrigation time), the water level reaches its highest point and it produces the typical flooding that favours the development of the rushes of Scirpus californicus. When the water level descends, and salinity increases, it develops a community of Salicornia ambigua and Distichlis spicata, that in extreme cases of dryness causes the formation of a dense pasture of Distichlis scoparia .