Copepods and ostracods associated with bromeliads in the Yucatán Peninsula, Mexico

A substantial fraction of the freshwater available in the Neotropical forests is enclosed within the rosettes of bromeliads that form small aquatic islands within a terrestrial landscape. These aquatic oases provide shelter, water, nutrients and resting of aggregation sites for several aquatic organisms, among them crustaceans. However, in comparison with the multitude of studies on open aquatic systems, our knowledge on crustaceans inhabiting semi-terrestrial habitats and phytotelmata is limited and their presence in such environments is poorly understood. The present study was carried out in two natural protected areas of the Yucatán Peninsula aiming to understand the diversity and dispersal strategies of crustaceans living in bromeliads. Sediment and water contained in four species of bromeliads have been collected in order to understand the diversity and dispersal strategies of crustaceans living in such habitats. From a total of 238 bromeliads surveyed, 55% were colonized by crustaceans. Sixteen copepod, three ostracod and one branchiopod species were recorded during this study, however only seven species are considered as true bromeliad inhabitants. Different degrees of association between crustaceans and bromeliad species were assessed with an indicator species analysis, where significant associations were found for all crustaceans. We found significant differences between bromeliad species and reserves and their associated fauna. In order to analyze the genetic diversity of this fauna, we sequenced several individuals of each species with two genetic markers (18S rRNA and COI mtDNA). Bayesian analyses and the Generalized Mixed Yule Coalescent method (GMYC), delimited 7 well supported species. A comparison of the dispersal strategies used by different species, including passive dispersal, phoretic behavior and active dispersal, is included. This study stresses the need of studying meiofauna of phytotelms, which could be used as an indicator of local diversity in Neotropical forests.