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Abstract

The presence of the calanoid copepod Boeckella gracilis (Daday, 1902) in Chilean seasonal pools has been only poorly studied as yet. The aim of the present study thus is to investigate the role of conductivity and temperature on the relative and absolute abundance of B. gracilis in seasonal coastal pools in the Araucania region (38°S, Chile). The results of correlation analysis revealed the presence of a significant inverse correlation between conductivity and relative abundance, whereas no significant correlations were found between conductivity and absolute abundance, between temperature and absolute abundance, and between temperature and relative abundance. These results agree partially with similar observations for mountain pools in the same region, but they would not agree with observations for calanoids of saline and subsaline inland waters in the northern and southern extremes of Chile. Considering this scenario, the species would show different populational responses to environmental stress in different situations, which phenomenon deserves to be studied more extensively and in more detail.

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

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 crustacean zooplankton of Chilean inland waters has been studied mainly in large Patagonian lakes, while that plankton in other Chilean water bodies has as yet been insufficiently investigated. The species actually reported upon herein require revision as regards their taxonomy and biogeography. On the basis of studies in the Patagonian lakes, oligotrophy has been determined as the main factor regulating zooplankton assemblages, whereas in southern shallow ponds the main regulating factors are oligotrophy and conductivity combined. No detailed studies for other Chilean water bodies are available to date.
This book provides a checklist with updated information of the species of crustacean zooplankton in Chilean inland waters, while the results of an ecological study offer data for understanding the distribution and abundance of those faunal elements in the area.