The role of secondary forest in the survival and growth of native species: Tree planting field experiment in the delta of the Paraná River (Argentina)

Abstract

Secondary forests constitute 74% of the world's natural forests and, while the conservation value of primary forests is irreplaceable, secondary forests can provide important biological conservation services and secure the future of many species. In the frontal zone of the Paraná River delta (Argentina), post-abandonment secondary forests are developed, composed of exotic species, but in which regeneration of native plant species is observed. The objective of this study was to evaluate the role of secondary forest in the conservation of native trees. For this, the survival and growth of 60 seedlings, belonging to four native tree species and planted inside and outside a secondary forest, were analyzed for one year. Results indicates that the average survival within the secondary forest (89%) is significantly higher than outside it (66%) and that, in the range studied (6 to 41 cm), the survival odds increase by 10% with each centimeter that the seedling's initial height increases. Height growth of seedlings is, on average, 144% higher in the absence of forest cover and differs according to species, with Allophylus edulis and Myrsine parvula being the species with the highest growth and Lonchocarpus nitidus the lowest. After one year monitoring, it is noted that the secondary forest is an environment conducive to the survival of native tree seedlings, although it imposes growth limitations typical of environments with forest physiognomy. Also, that the planting of native trees can constitute an adequate ecological restoration technique for the recovery of native riparian forest in the frontal zone of the Paraná River delta.