Twenty-Five Years of Restoration of an Igapó Forest in Central Amazonia, Brazil

Abstract

This chapter describes a 25-year experience of restoration of a vast area impacted by a bauxite tailings spill over Lake Batata and its marginal igapó vegetation in Central Amazonia. It reviews papers and theses produced during this period and aims to provide a view of the restoration process from the past into the future. The main conclusions of this long-term restoration effort are: (1) Despite the sterility and difficult penetrability of the consolidated tailings substrate, igapó plants have been capable to establish and grow spontaneously in these areas, reaching reproductive stage and completing full life cycles; (2) Wherever natural regeneration was not possible, either due to topographic reasons or to water movements, human intervention by planting seedlings was also viable; (3) In areas subjected to longer term flooding (>8–9 months a year), planting is either physically not possible or, whenever possible, saplings die; (4) Natural regeneration and planting, altogether, were responsible for returning species richness and diversity to impacted areas, but floristic similarity with native, nonimpacted sites was moderate to low; this established vegetation produces shade, litter, organic matter and thus create new habitats and organic substrate for other species to establish naturally; (5) Recuperation is variable depending on site characteristics (annual length of flooding, species introduced, etc.) but often slow and in worse case scenarios new forests may take more than 75 years to converge to similarity with native nonimpacted igapó; thus, additional interventions are necessary to further forest growth, structure and diversity; (6) Despite the challenges posed by the scale of this enterprise, relevant actions to speed up successional trajectory are feasible, necessary and include continuous monitoring and evaluation, litter and seed addition, and selection of framework species for replacements.