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The exploitation of non-timber forest products has been encouraged in order to reconcile economic uses, biodiversity conservation and the provision of ecosystem services. In this paper we investigate how increments on the açaí palm density (Euterpe oleracea) via forest management change tree assemblages across 47 plots in the Amazon estuarine forest (Brazil). Assemblage attributes were confronted to açai clump density, soil fertility, canopy openness and elevation. Both tree species density and richness were negatively affected by acai, but species richness was also affected by tree abundance. Species-accumulation curves also indicated higher alpha and beta diversity across low-intensity forest patches with high-intensity patches lacking half of the tree species. A small set of species dominated forest patches, but açaí density did not correlate with the abundance of valuable species. Explanatory variables, including açai density, explained a small fraction of the variation on the functional profile of tree assemblages, but functional richness was reduced by a half across forest stands exceeding 600 açaí clumps per ha. Our results suggest that açaí intensification alters the structure of woody plant assemblages in estuarine forest. Tree abundance and species richness consistently declines as açaí clump density increases, with some forest stands being dominated by açaí and almost lacking any tree species. Accordingly, landscapes dominated by high-intensity forest stands are largely impoverished in terms of understory, canopy and emergent tree species. These findings question the current legal regulations and thresholds adopted for açai management, while alert for potential disasters caused by poorly-regulated extractions of NTFPs. • Açaí intensification for enhancing fruit yield represents a complete reorganization of the estuarine forest. • Landscapes dominated by high-intensity forest stands are largely impoverished in terms of understory, canopy and emergent tree species. • Current legal regulations on açaí intensification fail to protect forest integrity and biodiversity. • Açaí represents a key economic opportunity for locals but a real threat for the estuarine forest. [ABSTRACT FROM AUTHOR]

Tropical forests are the global cornerstone of biological diversity, and store 55% of the forest carbon stock globally, yet sustained provisioning of these forest ecosystem services may be threatened by hunting-induced extinctions of plant-animal mutualisms that maintain long-term forest dynamics. Large-bodied Atelinae primates and tapirs in particular offer nonredundant seed-dispersal services for many large-seeded Neotropical tree species, which on average have higher wood density than smaller-seeded and winddispersed trees. We used field data and models to project the spatial impact of hunting on large primates by ~1 million rural households throughout the Brazilian Amazon. We then used a unique baseline dataset on 2,345 1-ha tree plots arrayed across the Brazilian Amazon to model changes in aboveground forest biomass under different scenarios of hunting-induced large-bodied frugivore extirpation. We project that defaunation of the most harvest-sensitive species will lead to losses in aboveground biomass of between 2.5-5.8% on average, with some losses as high as 26.5-37.8%. These findings highlight an urgent need to manage the sustainability of game hunting in both protected and unprotected tropical forests, and place full biodiversity integrity, including populations of large frugivorous vertebrates, firmly in the agenda of reducing emissions from deforestation and forest degradation (REDD+) programs. [ABSTRACT FROM AUTHOR]