Spatial distribution and environmental preferences of the piassaba palm Aphandra natalia (Arecaceae) along the Pastaza and Urituyacu rivers in Peru

Aphandra natalia (Balslev and Henderson) Barfod, an economically important fibre producing palm, is common in rainforest on low terraces along the Pastaza and Urituyacu rivers in Amazonian Peru. The aim of this study was to investigate the spatial distribution and environmental preferences of Aphandra in old-growth terrace forest to which it is limited in this region. Densities of immature and mature individuals were 507 ± 212 (S.D.) ha−1 and 19 ± 8 ha−1, respectively, in 11 (5 × 500 m) transects placed in old growth terrace forest near four villages and 739 ± 188 ha−1 and 96 ± 49 ha−1, respectively, in six irregular transects placed in what the local villagers considered dense Aphandra stands. We examined environmental and spatial correlates of Aphandra occurrences using stepwise multiple autologistic regressions. Site, soil moisture, slope inclination, and topographic position influenced the spatial distribution of Aphandra. Furthermore, the distribution was strongly clumped, independently of environmental factors, with particularly the concentration of immature individuals around adults pointing to dispersal limitation as the likely causal mechanism.