The term 'multi-specific pastures' corresponds to a great diversity of herbaceous vegetations of agricultural use, all of them acknowledged as being environmental importance. The management of this diversity by adequate agricultural practices requires performant generic diagnostic tools, such as typologies, in order to assess the dynamics of this resource. What is the effect of this diversity on the vegetation on the agricultural use value (production patterns and levels, feed value) ? The functional composition of the pastures, based on the grouping of the pastures into four types, together with the identification of the dominant type, gives a classification of the pastures according to the dates of the growth peaks and the digestibilities of the leaves and stems. The dominant type depends on the level of competition among the various species, generated by the mineral nutrition level and by the management. The functional diversity (types of grasses and proportion of dicots) is correlated with the specific diversity. In a second part, we show how to utilize these results to create typologies of agricultural and environmental use value based on descriptors of the vegetation (types of grasses and relative abundance of dicots) or else on the knowledge of the practices and their effects.