Demography of Oenocarpus bataua and implications for sustainable harvest of its fruit in western Amazon

Oenocarpus bataua is the seventh most abundant tree in the Amazon and one of the most used palms in the region. The main resource obtained from the species is the fruits that are harvested from wild populations for human consumption. Across its distribution area adults are most frequently felled to obtain the racemes, which may affect the palm's populations. In this paper we studied the demography of two populations of Oenocarpus bataua to assess the harvest potential of its fruits and the density variation in different habitats in the western Amazon to estimate fruit yields in different forest types. Non-inundated lands held the greatest densities with an average of 11 adults ha(-1) (0-132 adults ha(-1)). The population finite growth rate (lambda) in Amacayacu, Colombia, was 0.9103 because of slow growth and low survival of stemless individuals and low recruitment. On the contrary, in Yasuni, Ecuador, we found a growing population with lambda = 1.0368. According to our simulations, adult felling reduced transient population growth (lambda (t) ) in both populations, especially when harvest was frequent even at low intensities. In Amacayacu a simulated harvest of 60 % year(-1) of the fruits by climbing did not modify lambda (t) substantially, while in Yasuni, a regime of 80 % of annual harvest did not diminish lambda (t) below one and the initial number of adults. The results help to understand the demography of useful palms and to address sustainable management. For instance high yields can be obtained by shifting to non-destructive harvest techniques that can meet the increasing demand and maintain the populations.