AGROECOLOGICAL RESULTS FATHERED BY SUPPRESSION OF GRAZING IN COLLECTIVE WET GRASSLANDS IN MARAIS-POITEVIN (FRANCE)

In 1990, the setting up of an exclosure in a collective grassland, in order to exclude the plurispecific grazing, allowed us to study the fl oristic and pedologic dynamics. The absence of disturbance presents tw o consequences regarding vegetation; first, the floristic diversity de crease in all groupements and secondly, the dominance of Agrostis stol onifera and Elymus repens which have a powerful of vegetative reproduc tion. Concurrently, an hydrologic study shows a desalinization phenome non in intermediate slopes, where halophyte species are developed. The se modifications induce irreversible changes in soil and vegetation re garding this particular agro-ecosystem These establishments confirm th e grazing management importance.