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  • Author or Editor: Patricio De los Ríos-Escalante x
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The zooplankton assemblages in Chilean lakes are characterized by their markedly low species numbers and dominance of calanoid copepods. Nevertheless, the effects of zooplanktivorous fish predation on zooplankton size in these communities have not yet been studied in detail. The aim of the present study was to analyse the total length in the main groups of zooplanktonic crustaceans in Chilean lakes: Copepoda: Calanoida, and Cladocera: Daphniidae, as well as “small cladocerans” (specifically the families Bosminidae and Chydoridae). The results revealed that in the presence of fish, total body length decreased significantly for calanoid copepods, whereas for other groups that presence has no significant effect. In sites with fishes, daphniids are significantly larger in comparison with the other groups of the zooplankton community, whereas in sites without fishes calanoids are significant larger in comparison with those other groups. These results would indicate that calanoids would be the main prey for zooplanktivorous fishes in Chilean lakes. Similar results have been reported for Argentinean Patagonian lakes.

In: Crustaceana

The inland water bodies of northern Chile (18-27°S) are characterized by high salinity levels and impoverished species richness. This study presents field observations of species associations sampled from shallow water bodies in the Antofagasta region of northern Chile (23°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 Jaccard Index calculations indicated the existence of defined groups, including three sites with Artemia franciscana, two sites with Boeckella poopoensis, and a sixth site only containing the ostracod Sarscypridopsis aculeata. The results of the null model analysis denoted the presence of regulating factors only in fixed-fixed simulation, that is the most robust in comparison to the other two simulations that denoted absence of regulator factors in species associations. The Jaccard indices and significant null model analysis agree with previous ecological descriptions of salinity as a determinant of species associations, whereas the non-significant results of the other two simulations could be due to the low number of species reported. The ecology and biogeography of these communities are also discussed.

In: Crustaceana
In: Crustaceana

The Chilean fairy shrimp species are represented by the Branchinecta genus, which are poorly described, and mainly occur in shallow ephemeral pools in the Atacama Desert of northern Chile and the Southern Chilean Patagonian plains. The aim of the present study was to perform an initial ecological characterization of Branchinecta habitats and its associated communities in the Chilean Southern Patagonian plains (45-53°S) using null models (co-occurrence, niche sharing and size overlap). The results of the co-occurrence analysis revealed that the species’ associations are structured, meaning that at different kinds of Branchinecta habitats, the associated species are different. I did not find niche sharing, which means interspecific competition is absent. Finally the size overlap analysis revealed structured patterns, which are probably due to environmental homogeneity or colonization extinction processes. The habitats studied are shallow ephemeral pools, with extreme environmental conditions, where continuous local colonization and extinction processes probably occur, which would explain the marked Branchinecta species endemism.

In: Animal Biology
In: Crustacean Zooplankton Communities in Chilean Inland Waters
In: Crustacean Zooplankton Communities in Chilean Inland Waters
In: Crustacean Zooplankton Communities in Chilean Inland Waters