Seed shadows, seedling survival and spatial distribution of the palm Oenocarpus bataua, in a forest of the Colombian Andes

Abstract

The objective of this work was to quantify some aspects of the demography of a population of the Oenocarpus bataua palm such as seed shadows, seedling survival, density and spatial distribution of seeds, seedlings, juveniles and adults, in a premontane humid forest of Antioquia (Colombia), using circular plots and others of half hectare and one hectare. This palm of canopy and sub-canopy produces fruits of great size consumed by frugivores. The abundant production of fruits and the short distances of dispersion generate spatially restricted seed shadows, in spite of the high rates of removal, which produces an aggregated distribution of seedlings and juveniles. It can be related to defaunation of these forests by transformation of habitat and hunting, which reduce the quality and abundance of long-distance dispersers like large birds and mammals. Nevertheless, squirrels (Microsciurus mimulus y Sciurus granatensis) and agoutis (Dasyprocta punctata) contribute to short-distance dispersal, although to a lesser degree they performed dispersal to greater distances (53-62 m). In contrast to juveniles, the adults showed a random distribution pattern that could be explained by density-dependent mortality of the seeds, seedling and juvenile stages. In spite of limited dispersal, the large seeds of this palm generate robust seedlings and successful regeneration, to the point that O. bataua is one of the dominant species in the forest. These kinds of studies are important for the management and conservation of this promissory palm, whose abundance has declined due to intensive exploitation and transformation and reduction of its natural forest habitat.