Search Results

You are looking at 1 - 10 of 52 items for

  • Author or Editor: Patricio De los Ríos-Escalante x
Clear All Modify Search

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.
In: Crustaceana

Crustacean communities in saline lakes are regulated mainly by salinity, and a significant inverse correlation can be found between salinity and species richness. The aim of the present study is to compare the carcinological diversity of two distinct arid regions of the world: Algerian saline lakes, locally called “chotts” and “sebkhas”, and their Chilean Altiplano counterparts, and to determine if there are similar regulator patterns that influence the composition of those communities. The main halophilic taxon common to both regions was the anostracan Artemia at high salinities. However, many other halotolerant crustaceans may occur in Algerian chotts and sebkhas, such as Phallocryptus spinosa, Branchinectella media, Moina salina, Cletocamptus retrogressus, Arctodiaptomus salinus and Heterocypris sp. In Chilean saline lakes the calanoid copepod Boeckella poopoensis was an important component of zooplankton at high salinities, while ostracods were totally absent. The results of correlation analysis revealed a significant inverse correlation between salinity and species number (Algeria, τ=0.39039, z=2.9402, p-value = 0.0032; Chile, τ=0.5868, z=2.3973; p-value < 0.0165). The results of null model analysis describing species co-occurrence showed that the species communities are random for Algerian saline lakes due to the presence of many halotolerant species. For Chilean saline lakes, the species communities are structured.

In: Crustaceana

The distribution of crustaceans of inland waters in southern Patagonia is characterized by the presence of sub-Antarctic and southern South American species. The aims of the present study were to study the geographical distribution of the calanoid copepod Boeckella brevicaudata (Brady, ) and the community structure of the zooplankton assemblages in which this species occurs. This last purpose was approached by applying null-models analyses based on species co-occurrence and niche-sharing. The species itself inhabits sub-Antarctic islands as well as southern South America. The results of the co-occurrence null model analysis revealed that the communities with this species have no regulating factors, whereas the niche overlap null model analysis revealed that these species share the same ecological niche. We thus found low abundances for all species, with specifically low B. brevicaudata abundance, at low mineral contents of the water. The results obtained were similar among sites in southern Argentinean and southern Chilean Patagonia, and on sub-Antarctic islands of which data were available.

In: Crustaceana