Impacts of disturbance intensity in functional traits patterns in understories of seasonal forests

Abstract

Environmental disturbances alter the functional structure of forests, mainly in the understory, the layer which is most sensitive to disturbance. This study evaluated the patterns of leaf phenology and seed dispersal syndrome of tree species in ten understories of seasonal semideciduous forests under different stages of disturbance, and tested the hypothesis that an increase in disturbance intensity directly affects the representativeness of these two functional traits in the understory. The classifications of leaf phenology and seed dispersal syndrome were based on the literature and were compared between the understory and upper strata in each area, among ten understories and among understories under different intensities of disturbance. Comparisons of leaf phenology and dispersal syndrome showed a very low proportion of deciduous and anemochoric species in the understory compared to the upper strata. In comparisons of these traits among understories, there was a significant increase in the proportion of deciduous species in more disturbed stadiums, but not in the proportion of anemochoric species. The results showed that even with very distinct floristic diversity it was possible to establish functional patterns related to leaf phenology and dispersal syndrome in the understories of seasonal semideciduous forests. It is suggested that analysis of these traits can help as a parameter for the classification of successional stages of seasonal semideciduous forests in a global comparison.