On the overlap between effect and response plant functional types linked to grazing

The question addressed in this paper is whether plant traits and plant functional types related to forage selection by grazers are also related to those expressing short-term community response after grazing. Vegetation of natural campos grassland in south Brazil was examined for species composition and locally described for seven morphological traits before and after a controlled grazing period by bovine cattle. An optimization algorithm was used for the identification of plant functional effect types (PFcfT) and plant functional response types (PFrcT) - in this case, groups of plants similar in a given set of traits (assessed before and after one grazing short period, respectively) and in their association to grazing intensity. The results have shown that plant traits optimally defining plant types related to forage selection (PFcfTs) were the same traits optimally defining short-term community response to grazing (PFrcTs); also similar trends of plant morphological variation were observed among populations before and after grazing, based on the traits' correlation structure. However, at the community level the correlation vanished, since similar communities described by the performances of PFcfTs were not as similar when described by PFrcTs. Hence, whether plant functional types related to forage selection (effect types) are also related to community response to grazing may depend on the level of organization considered. The paper advances on the operational definition of possible overlaps between effect and response plant functional types.