Natural Regeneration in Plantations of Native Trees in Lowland Brazilian Atlantic Forest: Community Structure, Diversity, and Dispersal Syndromes

Plantations of native-tree species are often recommended for ecological restoration, but the understanding of how these techniques catalyze natural ecological processes is limited. We investigated natural regeneration in five plantations of native trees in the Poco das Antas Biological Reserve (PABR) in the state of Rio de Janeiro, Brazil. The plantations were 9-11 years old, and contained 8-14 native-tree species with different compositions and relative density of species. We analyzed floristic composition, structure (density and basal area) of overstory and understory strata, as well as other ecological attributes (dispersal syndromes, fruit or seed size, and the availability of fruit for frugivores). Zoochorous species comprised 77% of the community, with a prevalence of the two smallest size classes of propagules (< 0.6 and 0.6-1.6 cm) in natural regeneration. The density of zoochorous plants in the understory was positively correlated with their density in the overstory, indicating their influence on natural regeneration (r2 = 0.36; p < 0.0002). Fruit availability for frugivores (density and richness of plants fruiting during the year) was also positively correlated with the density of stems in the understory. Therefore, attributes such as dispersal syndrome and fruiting season should be considered in selecting species to be planted. The differences in natural regeneration observed in each of the native-tree plantations indicated that the performance of plantations as a restoration strategy may differ, depending on initial species composition, planting density, and site conditions.