Natural regeneration, composition and structure in a secondary Atlantic Forest fragment and in an abandoned Eucalyptus saligna Smith. (Myrtaceae) commercial plantation / Regeneração natural, composição e estrutura em um fragmento em sucessão secundária de Mata Atlântica e em reflorestamento comercial de Eucalyptus saligna Smith. (Myrtaceae) abandonado à regeneração

Abstract

The litter horizon on forests ecosystems acts on the nutrient cycling and on the soil’s microclimate conditions. However, to reforestation ecosystems the litter attributes can conduct to alterations that can diminish the seedling establishment, as well can act on the herbivory rates. In this context, this study aimed to verify the differences and relationships between woody species diversity, the herbivory index, the litter attributes, and the canopy openness among a fragment of Atlantic Forest on secondary succession and commercial plantation of Eucalyptus saligna Smith abandoned to regeneration. This study was conducted at the Klabin’s Company “Ecological Reserve”, at Telêmaco Borba – PR, Brazil. There weren’t observed differences on the species richness and abundance among the studied sites. Litter mass and thickness were higher in E. saligna environment. However, the litter attributes only presented relationship with the woody vegetation at the Atlantic Forest site, such as abundance and species richness with litter mass (r2=0.53 and r2=0.40, respectively) and abundance with litter thickness (r2=0.63). The herbivory index was greater on the forest patch. The canopy openness was superior in the E. saligna site. At this site, the herbivory index presented a positive relation with the canopy openness (r2=0.48) and a negative with abundance (r2=0.48). Abundance also presented a negative relation with the canopy openness (r2=0.58) in the E. saligna environment. The litter horizon on the E. saligna plantation doesn’t seem to offer restrictions to regeneration of the woody vegetation. However, at this site, the higher canopy openness and the herbivory pressure over the woody vegetation may lead to a lower rate of secondary succession compared to the Atlantic Forest fragment.