Allpahuayo: floristics, structure, and dynamics of a high-diversity forest in Amazonian Peru.

This paper describes the results of a floristic inventory at the Allpahuayo Reserve, near Iquitos in Amazonian Peru. Two long-term one-hectare plots were established using a pre-determined sampling grid, with each individual tree and liana over 10 cm diameter collected at least once, except for palms. The plots were re-censused after 5 years to quantify forest dynamics. Floristic analysis shows that the Allpahuayo forest is among the most diverse site yet inventoried, with 281 to 311 species per hectare, and at least 466 species and 61 families in the 1277-stem two-hectare sample, confirming that upper Amazonia is a world center of tree biodiversity. The ecologically most dominant and speciose family in the plots is Fabaceae sensu lato, with 231 stems and 89 species; no other family represents more than 7% of the species or 10% of the stems. In contrast to the exceptional floristic diversity, both the structure and the dynamics of the Allpahuayo forest are similar to those recorded from other old-growth neotropical forests. Many tree and liana canopy species were previously unknown to both the Iquitos area and to Amazonian Peru, which demonstrates the significance of Amazon ecological studies to systematic botany.