The breeding of beef cattle is the predominant activity in the Flooding Pampa wet grasslands. The stocking rate of this region is increasing because of livestock displaced by agriculture in other regions. This increased load has been achieved through the alteration of grassland with the use of herbicides and fertilizers or replacement thereof by pasture (Cahuepé and Hidalgo 2005). The large herbivores grazing cause changes in species composition and diversity (Hall et al. 1986) in both the original and the modified grassland. The aim of this study was to evaluate the effects of different stocking rates under continuous grazing and exclusion of grazing on the floristic composition and diversity of wet mesophytes prairie, modified during 10 years by the application of herbicides
