COMPOSITION, DENSITY, AND FRUITING PHENOLOGY OF ARBORESCENT PALMS IN AN AMAZONIAN TERRA-FIRME FOREST

The composition, density, and fruiting phenology of arborescent palms were examined in a remote term firme forest site near the upper Urucu river, Amazonas, Brazil. A total of 248 individuals with a diameter at breast height (DBH) greater-than-or-equal-to 10 cm, including 8 single-stemmed and 1 multistemmed species, occurred within a 5-ha area (twelve 0.25-ha plots and two 1-ha plots). Using a point-quadrant method, an additional 75 palms were tagged along 4.9 km of transects. Arborescent palms accounted for 7 percent of 4915 trees, and comprised the sixth most abundant tree family. The combined density of all palm species was substantially greater in relatively patchy areas of poorly drained to waterlogged soils within creekside forest (81 ind./ha) than on well-drained, high forest soils (36 ind./ha). Palm species appeared to segregate according to habitat topography, resulting in two relatively distinct subcommunities. Jessenia bataua, the most common species, accounted for 42 percent of the arborescent palms. Immature and mature fruits of this and other palm species were available throughout the year, and represented an important food source for frugivores during the dry season, when ripe fleshy fruits of nonpalm trees became rare or nonexistent. The reproductive phenology of arborescent palms is discussed in terms of its role in sustaining frugivores through periods of generalized ripe fruit scarcity.