The role of Baccharis (Asteraceae) shrubs in the short-term restoration of Atlantic rainforest

Abstract

The introduction of nurse species on degraded sites of Permanently Protected Areas represents a useful strategy for vegetation recovery in riparian forest. Species of the genus Baccharis (Asteraceae) have been documented as potential nurse plants being able of restructuring the native plant community. This study was aimed to evaluate the potential nursing role of Baccharis dracunculifolia in the recovery of a native plant community of a degraded Atlantic rainforest in a short-time period. The study was developed in two abandoned pasture areas in a riparian forest in the River Piranga basin, one in which B. dracunculifolia was planted (Restored treatment) to promote restoration, and a second area with no intervention (Degraded = Control treatment). Sampling took place 18 months after the planting of B. dracunculifolia. We set up 20 plots of 2 × 2 m in each treatment type (n = 40 plots), where all plant species were recorded (with the exception of the introduced Baccharis individuals and grasses), classifying them as native, ruderal, or alien. Plant richness was twice higher in the Restored treatment than the Degraded treatment. Furthermore, the observed values of alpha, gamma and beta diversity were also higher in Restored treatment. Restored treatment had 17 exclusive native species, while the Degraded treatment had only three non-exclusive native species. In addition, fewer ruderal and alien species were recorded in the restored plots with B. dracunculifolia compared to degraded plots. We concluded that, even in a short time period, planting B. dracunculifolia had a positive effect on promoting the assembly of the native plant community and possibly decreasing the chances of invasion by alien species.