A functional classification of 63 common Poaceae in the "Campos" grasslands of South America

The natural grasslands that form part of the "Campos" of South America contain a large number of species at the paddock level (high a diversity), but little differentiation among paddocks (low p diversity). Thus, forage resources at the farm level have slightly different seasonal growth peaks, in part due to the low frequency of fertilization1 the lack of differential grazing management and mowing of these plant communities. To stimulate diversification of these forage resources, it is possible to take advantage of differential responscs of each type of plant community to changes in their use. Characterizing species by functional traits allows to orient the use of forage resources according their functional composition, thus increasing the.diversity of vegetation types, which favors differentiation of growth peaks among paddocks. After an initial division between C and C species1 63 Poaceae species were classified into eight groups or plant functional types (PFT) according to their preferred degree of soli fertility and use intensity. Based on the leaf dry matter content (LDMC) measured in experiments in Brazil, Uruguay and Argentina, we distinguished four PFT, hvo for C species and rn·o for C species, with LDMC less than or equal to 300 mg/ g. The species of these four PFT are adapted to fertile environments and intensive defoliation. Fertilizing and using more intensively vegetation dominated by species with these low LDMC can diversify the use value of paddocks, thus facilitating use of forage resources at the farm leveL Les prairies naturelles qui font partie des "champs" de l'Amérique du Sud se caractérisent par un grand nombre d'espèces de pâturages (forte diversité α) et une différenciation relativement faible entre les pâturages (faible diversité β). Cela signifie qu’au niveau de la ferme, il existe un ensemble de ressources fourragères avec des pics de croissance saisonnière peu différenciés. Ceci est en partie une conséquence de la faible utilisation de pratiques de fertilisation différentielles, de la gestion des pâturages et de la coupe de ces communautés végétales. Afin d'encourager la diversification des ressources fourragères (augmentation de la diversité β), la réponse différentielle des prairies peut être exploitée contre les modifications de leur utilisation. Caractériser l'espèce par ses caractéristiques fonctionnelles permet d'orienter l'utilisation de la ressource en appliquant le traitement approprié à sa composition, en augmentant la