Passive restoration in Araucaria Forest: useful ecological indicators in monitoring successional advancement in exotic tree plantation landscapes

Monitoring successional advancement is a complex field involving a constant search for applied ecological indicators which facilitate monitoring of secondary forests for both active and passive restoration. In this study, the authors investigate the successional advancement of floristics and tree structure within Araucaria Forest (AF) fragments under passive restoration in a context where exotic tree plantations (mainlyPinusL. genus) dominate the landscape. The ecological indicators used were floristic dissimilarity (beta-diversity inferences), indicator species, ecological groups of species, basal area, and species abundance distribution (SAD) models (alpha-diversity inferences). A total of 182 tree species belonging to 91 genera and 43 botanical families were identified. A high beta diversity was verified for which each site has indicator species (for the locations CD-Dicksonia sellowiana; CO-Cryptocarya aschersoniana; and PG-Pinus taeda), where pioneer species contributed to much of the abundance. Different SAD models are useful for describing passive restoration sites in exotic tree plantation landscapes, namely Lognormal, Mandelbrot, and Zipf. SAD models together with basal area, taxonomic group (e.g. Myrtaceae assemblage), and tree abundance in ecological groups are strategic ecological indicators for monitoring successional advancement in AF.