Effects of the spatial distribution of trees, conspecific epiphytes and geomorphology on the distribution of epiphytic bromeliads in a secondary montane forest (Cordillera Central, Colombia)

Abstract

The spatial organization of epiphytes has come under increasing attention. This kind of information is necessary for the general understanding of their ecology and for the design of sustainable harvesting methods. In this study, the small-scale (local) distribution of epiphytic bromeliads was studied using correlograms and permutational regression on distance matrices. Fieldwork was carried out in a young secondary forest stand in the central cordillera of Colombia at 3150 m asl. A complete census of the bromeliads in this plot was made, using a lattice with 400 quadrats. Six species of bromeliad were found (1008 individuals). All of these except one showed an aggregated spatial pattern. This pattern was independent of the position of the trees in the sampled plot. The distribution of the bromeliads was determined by the availability of substrate (branch surface area per quadrat), the proximity of conspecifics and the geomorphology of the terrain. The structure of the forest surrounding an epiphyte had an influence on the position of the epiphyte in the tree (height measured as distance from the canopy). The use of two-dimensional, lattice-based sampling strategies is discussed as a possible method for comprehensive surveys of epiphyte populations in natural forests.