Consistent patterns of common species across tropical tree communities.

Trees structure the Earth's most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1-6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth's 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world's most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.

Palmas de comunidades ribereñas como recurso sustentable en la Amazonía brasileña / Palms of riverine communities as a sustainable resource in the Brazilian Amazon

En la Amazonía, el 30% de la población se encuentra representada por pequeños núcleos poblacionales aislados. Uno de los problemas más graves para el desarrollo de estas poblaciones es el relacionado con la disponibilidad de energía eléctrica, porque su ausencia o constante racionamiento no permiten la instalación de agro-industrias para el aprovechamiento de los recursos naturales, lo que podria proprocionar valor agregado de los productos regionales renovables. En consecuencia, la búsqueda por mejores condiciones socio-económicas tiene como única alternativa la extracción depredadora y rápida de las riquezas naturales, llevando a la destrucción acelerada de los ecosistemas. Las plantas oleaginosas, destinadas principalmente a la alimentación básica de la población, también pueden constituir la base de un modelo de desarrollo tecnológico industrial auto-sostenido, ya que presentan la ventaja de ser recursos en áreas antrópizadas de la Amazonia; y que posibilitan la retención del hombre en el campo y evitan con esto la degradación de los ecosistemas naturales. En el presente estudio se da a conocer el conjunto de actividades que facilitaron la determinación del potencial de biomasa del “huasaí” (Euterpe precatoria Mart.) y otras oleaginosas disponibles en comunidades ribereñas del Estado de Amazonas (Brasil); éstas actividades estuvieron asociadas a las posibilidades de sumanejo sostenido para la generación de energía eléctrica. De esta forma, se presentan datos que sugieren condiciones del uso sostenible de la oferta de biomasa como fuente energética alternativa para desarrollar un programa de universalización de la energía eléctrica en la Amazonia brasileña.

In the Amazon, approximately 30% of the population is agglomerated in small villages or isolated areas. One of the most serious problems is the lack of electricity, where reduced supply and frequent rationing reduce life quality and prevent the instalation of industries that could raise the value of renewable regional products. Consequently, the pursuit of better socioeconomic conditions promote the quick depletion of natural resources, which invariably results in the accelerated destruction of local ecosystems. Oil palms, that are mainly used forbasic nutrition of local populations, could also form the basis for models of self-sustained technological and industrial development. A quantitative survey of native species of oil palms offers an alternative for sustained development based on a technological and industrial model because this resource occurs in populated areas inthe Amazon, which facilitates retaining the people in the field, preventing the depletion of natural ecosystems.This study presents the activities that were used to identify the potential of biomass of Euterpe precatoria Martand other oil palms available in riverside communities in the state of Amazonas (Brazil). These activities are associated with the possibilities of using palm species for sustainable development of energy generation. It was possible to identify the conditions for a sustainable supply of biomass as an alternative energy source which contributes to the Energy Universalization Program in the Brazilian Amazon.