Local and regional coexistence of atmospheric bromeliads in epiphyte communities: unraveling intra and interspecific mechanisms of competition among species with highly overlapping niches

Abstract

The coexistence among species is often due to environment heterogeneity and trade-offs generated by differences in species' life history, as those related to dispersion capacity and competitive skills. Epiphytic communities are one of the best examples of the space as limiting resource in tropics, due to the massive amount of these plants on tropical canopies. Communities dominated by atmospheric bromeliads, in special, could be a good model to test relations of coexistence and intra and interspecific competition, due firstly to the occurrence of massive populations of some species on a few trees, and secondly to they unabsortive and, consequently, uncompetitive roots, excluding the bias of belowground competition. The aim of this study is to unravel the competitive strategies of three common atmospheric bromeliad species with distinct life histories that have a wide distribution in South America and coexist massively in natural and human-impacted areas of the Brazilian Cerrado domain. We will study the interactions among these species in two hierarchical levels: local (on a single tree) and regional (on a group of trees) using natural communities, controlled experiments and Individual Based Models (IBMs). With these models, will test the significance of the empirical patterns under distinct densities of each species and many generations. We also aim to calculate, on regional level, the effects of distinct functional types of host trees, with distinct tree densities (i.e. habitat amount) and composition (i.e. habitat heterogeneity), on the dynamic of a metacommunity dominated by atmospheric bromeliads. With these relatively new and modern approaches, we intend to achieve interesting results in a poorly explored topic of ecology (i.e. competition among epiphytes) which could provide important insights regarding plant interaction overall and also on conservation ecology of tropical forests. (AU)