A floristic inventory was carried out in an area of palm-dominated creek forest in Jenaro Herrera, in the northeast of Peru. All trees ≥ 10 cm dbh were surveyed in a one-hectare permanent plot using the standard RAINFOR methodology. There were 618 individuals belonging to 230 species, 106 genera and 43 families. The results showed that the total basal area of the trees in the plot was 23.7 m2. The three species with the highest importance value indexes were Iriartea deltoidea Ruiz & Pav., Oenocarpus bataua Mart. (Arecaceae) and Carapa procera DC. (Meliaceae). The five most dominant families in order of importance were Arecaceae, Fabaceae, Meliaceae, Euphorbiaceae and Sapotaceae. Although the soil of this plot was poorly drained, the number of trees and the diversity of the plot were typical for terra firme forest in the western Amazon.

A variety of processes have been identified as playing a key role in maintenance of hyper-rich tropical forest, among which ecological sorting caused by niche partitioning challenges stochastic dispersal processes. However, demographic responses to spatio-temporal resource variation that could result in biased species distributions are still little studied. In this paper we investigate from two censuses, c. 15 y apart, of a 12-ha permanent forest sample in French Guiana, how tree recruitment and mortality rates vary among hydrological soil types known to affect species habitat preferences and among ecological guilds related to species light requirement. The results indicate that both recruitment and mortality vary significantly with respect to these factors. While the mean instantaneous mortality and recruitment rates are estimated to 0.98 and 0.81%, respectively, pioneer species, canopy trees and hydromorphic bottomland soils depart significantly from these values. In particular, the pioneers, regenerating either from the soil seed bank or from post-opening seed rain, show faster dynamics than other species. These two guilds harbour probabilities of mortality elevated by a factor of 1.9 and 3.2, respectively, and probabilities of recruitment elevated by a factor of 4.9 and 3.1, respectively. Conversely, canopy trees show slower dynamics, with probabilities of mortality and recruitment lowered by a mean factor of about 0.5 with respect to other species. We also observe that trees growing in hydromorphic bottomlands prove to have significantly higher mortality and recruitment probabilities, by a factor of about 2 with respect to those growing in terra firme.