Açaí palm intensification and the reorganization of woody plant assemblages at multiple spatial scales in an Amazonian estuarine forest

Abstract The exploitation of non-timber forest products has been proposed as a sustainable way to exploit tropical forests, but such an opportunity remains to examined case-by-case. We examine the impact by the intensification of the açaí palm (Euterpe oleracea) management for fruit production via increments on palm clumps/stems density on the woody plant assemblages (adult and regenerating) in an estuarine forest landscape in the eastern Amazon region, Brazil. Across 30 forest stands açaí clumps density correlated negatively with stem density and taxonomic diversity considering both adult and regenerating woody plant assemblages, but it posed a positive effect on beta diversity via species turnover. Soil fertility and forest stand accessibility played a complementary role. Moreover, açaí clump density affected the abundance of particular woody plant species, including a set of species declining before the 400-açaí clump density threshold imposed by current regulation. Accordingly, açaí clump density influenced the taxonomic organization of woody plant assemblages at landscape spatial level. Finally, it is worth mention a group of 105 species, which were recorded across the regenerating assemblages but not in the adult assemblages. Among them, a large number of small-statured woody plant species typical from the forest understory (i.e., the shade-tolerant flora) such as those from Miconia, Piper, Bactris, Anonna and Geonoma genus among many. As intensification is still spreading it can be considered a threat to the integrity of the Amazon estuarine forest. It questions the ecological sustainability the current Amazonian “black gold” is produced.