A New Species Of Platycarpum (rubiaceae, Henriquezieae) From Peruvian Amazon

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The new species Platycarpum loretensis (Rubiaceae) is endemic to the Loreto Department, Peru, and restricted to white sand forests (varillal), palm swamps, and peatlands. It is similar to P. orinocense from which can be separated by the oblanceolate leaves with prominulous intersecondary veins (vs. elliptic to ovate, without intersecondary veins), corollas 1.9-3 cm long (vs. 1.2-2(-2.2) cm long), and fruits 4.7-5.5 x 3.6-4.9 cm (vs. 3-3.5 x 2.8-3.5 cm).2603276282Coordenacao de Aperfeicoamento Pessoal de Nivel Superior (CAPES)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Platycarpum vriesendorpiae sp nov., a second new species of Tribe Henriquezieae (Rubiaceae) from nutrient-poor soils in the Peruvian Amazon

The new species Platycarpum vriesendorpiae N. Davila (Rubiaceae, Henriquezieae) is described from Peru, where it is restricted to white-sand forests and peatlands in the Tapiche and Blanco River watersheds in southeastern Loreto Region. The new species is generally similar to P. acreanum Rogers of western Brazil in its phyllotaxy, leaf pubescence, and fruit shape and size. However, P. vriesendorpiae differs in its triangular stipules that are 2- or 3-angled at the base and in its smaller corolla366CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPE

Does the disturbance hypothesis explain the biomass increase in basin-wide Amazon forest plot data?

Positive aboveground biomass trends have been reported from old-growth forests across the Amazon basin and hypothesized to reflect a large-scale response to exterior forcing. The result could, however, be an artefact due to a sampling bias induced by the nature of forest growth dynamics. Here, we characterize statistically the disturbance process in Amazon old-growth forests as recorded in 135 forest plots of the RAINFOR network up to 2006, and other independent research programmes, and explore the consequences of sampling artefacts using a data-based stochastic simulator. Over the observed range of annual aboveground biomass losses, standard statistical tests show that the distribution of biomass losses through mortality follow an exponential or near-identical Weibull probability distribution and not a power law as assumed by others. The simulator was parameterized using both an exponential disturbance probability distribution as well as a mixed exponential-power law distribution to account for potential large-scale blowdown events. In both cases, sampling biases turn out to be too small to explain the gains detected by the extended RAINFOR plot network. This result lends further support to the notion that currently observed biomass gains for intact forests across the Amazon are actually occurring over large scales at the current time, presumably as a response to climate change. (Résumé d'auteur