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Due to the increasing human impact on natural resources, we assessed the harvesting of non-timber forest products (NTFP) to verify demographic changes in populations of native palm trees. Euterpe edulis is native to the Atlantic Forest in Brazil, characterized by high deforestation and fragmentation. This palm is also targeted for palm heart and fruit harvesting. The threats posed by such factors motivated this study, as they might lead to a decrease in natural populations. The viability of sustainably harvesting the species in small fragmented areas is unknown. We performed simulations for palm heart and fruit harvesting in three small populations (entitled: SH, AJ, and ES) sampled in a 1-year interval (2010–2011) to verify whether these practices were sustainable. Different harvesting scenarios were simulated: (1) no harvesting; (2) harvesting of palm heart of reproductive individuals; (3) harvesting of palm heart of large individuals (diameter at ground level > 65 mm, including reproductive or not). and (4) fruit harvesting. Each scenario was simulated at different harvesting intensities (percentage of individuals or fruits harvested). Integral projection models were used to calculate two demographic parameters, namely, population growth rate (λ) and elasticity. In the no harvesting scenario, the populations had λ > 1 (SH = 1.0655, AJ = 1.0184, and ES = 1.0862). Palm heart harvesting proved to be sustainable in both scenarios, but at a higher intensity in scenario (2) (SH = 83%, AJ = 14%, and ES = 35%) than in scenario (3) (SH = 17%, AJ = 4%, and ES = 16%). Fruit harvesting was sustainable at any intensity for all three populations. As the survival of large individuals has a high impact on λ, palm heart harvesting was in most cases sustainable only at low intensities. In contrast, as fecundity and seedling survival have a low impact on λ, fruit harvesting still proved sustainable at high intensities. Although the populations are tolerant to harvesting to some degree, it must be conducted carefully. As populations are fragile due to the current condition of reduced population size, the removal of palms at any rate can affect population persistence and generate possible cascade effects on the forest.
Palms species (Arecaceae) are abundant in tropical forests and influence ecosystems in important ways. Moreover, they are a relevant feature in the Atlantic Forest biodiversity hotspot. In this study, we seek to better understand the distribution of palm richness in Rio de Janeiro state, Brazil, with the aim to support conservation decisions and actions. Maps for 15 palm species were generated through species distribution modeling and then stacked into a palm richness map, which was further combined with current land-use and protected area maps to generate a realistic portrayal of the current situation of Arecaceae in the state. Our results revealed an increasing inland-to-coast pattern of richness that matches the biogeographical subdivision of the Atlantic Forest. Considering the land-use information, the palm species potential distribution is drastically reduced, especially for some species which already have a restricted distribution in the state. We also identified the most relevant protected areas for the conservation of palms in the state and those which might have been overlooked in floristic inventories, thus requiring more detailed investigation. Moreover, we point out those species with few points, for which species distribution models could not be built, and argue that they are the ones more likely to be threatened by habitat loss and should be the focus of specimen collection and recording. Finally, we draw attention to a large medium-richness remnant located between two protected areas which probably functions as a connection between them and should be a priority area for conservation.
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