Biotic Factors Affecting the Abundance of Vascular Epiphytic Bromeliads Growing in Cloud Forest in Reserva Biologica Los Cedros, Ecuador

Abstract

Aims: In this paper we investigate whether the abundance of epiphytic bromeliads growing in cloud forest was affected by: (1) phorophyte family; (2) phorophyte size; and (3) the abundance of other epiphytes. Study Design: The abundance of bromeliads was compared on 35 random trees from each of the three most abundant tree families (Burseraceae, Moraceae and Clusiaceae) present within a study site consisted of a 25 m x 25 m riverine area, situated along the Rio Los Cedros, within the Reserva Los Cedros Biological Reserve. All trees and bromeliad species within the study area had previously been identified by staff from the National Herbarium of Ecuador and this information was made available to the authors. Verification of botanical identification was further supported on-site. Place and Duration of Study: A one month study at Reserva Biologica Los Cedros, near the town of Chontal, Pichincha Province NW Ecuador. Methodology: For each of the 105 trees sampled we recorded the following data: total number of bromeliads, number of each of the five most abundance species of bromeliads in the study area; tree family, tree diameter at breast height (DBH), tree height, percent cover of vascular epiphytes; percent cover of non-vascular epiphytes. Data were collected non-invasively from ground level by using binoculars. Results: The results showed no evidence of phorophyte specificity amongst epiphytic bromeliads. However, larger phorophytes held more bromeliads irrespective of phorophyte family and even when supporting high abundances of other vascular epiphytes. Conclusion: We conclude that it is tree size and not the phorophyte species that is most important in driving high abundance and diversity in bromeliad communities. We also conclude that the bromeliad component of epiphyte communities is not affected by competition from other co-occurring epiphytes. Further research is needed to understand how species interactions within epiphyte communities drive epiphyte community assembly, dynamics and diversity.