Local extinction of an important seed disperser does not modify the spatial distribution of the endemic palm Astrocaryum aculeatissimum (Schott) Burret (Arecaceae)

Abstract

Spatial pattern of the palm Astrocaryum aculeatissimum was investigated in an urban Atlantic Forest fragment (Tijuca National Park, Brazil) where its main seed disperser, the red-rumped agouti Dasyprocta leporina, is locally extinct. A 120 × 130 m plot (1.56 ha) was established in which all A. aculeatissimum individuals were quantified, georeferenced, and classified by ontogenetic stages, namely, seedling, infant, juvenile, immature individual, and adult. Analyses were performed using Ripley’s K function. We recorded 376 individuals, most of which were in the juvenile stage (n = 228). The spatial pattern was aggregated as observed for other palm species. Seedlings and infants were not associated with adults, whereas juveniles and immature individuals were observed closer to adults than expected. The distance between each seedling and the nearest adult ranged from 3 to 30 m (mean ± sd = 11.8 ± 7.8), which is similar to the agouti dispersal distances reported in other studies. Despite the importance of agoutis for the seedling recruitment of A. aculeatissimum, their short-term absence does not affect the spatial distribution of this palm in the studied area.