CRUSTACEAN ZOOPLANKTON IN CHILEAN EPHEMERAL POOLS: AN EXAMPLE FOR THE STUDY OF METAPOPULATIONS AND METACOMMUNITIES
- The ecological concepts 'metapopulation' and 'metacommunity' encompass the existence of integrated systems of populations and communities, as units that experience continuous exchange of individuals through migratory activity. These concepts could be applied to crustaceans that inhabit systems of pools situated closely to each other. This study presents field observations of species associations of planktonic Crustacea sampled from shallow water bodies in the Patagonian plains (38-53 degrees S). A species presence-absence matrix was created for calculating the Jaccard Index of community similarity and for testing null models of species associations, with the aim of determining whether species associations are random or not. The results of the calculations for the Jaccard Index indicated the existence of distinct groups according to the geographical zones involved, i.e., the pools of Ron-Aiken, Balmaceda, and Puaucho. The groups of pools thus recognized showed similarities between the Kon-Aiken and Balmaceda assemblages. The results of the null model analysis exhibited the presence of regulating factors in all simulations that are designed to discover an absence of regulating factors in species associations. The Jaccard indices and the significant outcomes of the null model analysis all agree with previous ecological observations. The ecology and biogeography of the communities studied are also discussed.