Species co-occurrences based on a presence/absence null model for Copepoda and cladocerans in Patagonia and Tierra del Fuego lakes and ponds

Abstract

Abstract:The zooplankton assemblages in southern Chilean Patagonia are characterized by calanoid dominance and low species number that is observable under oligotrophic status and wide conductivity values, whereas at mesotrophic status the daphnids are dominant with high species number, and finally at hyper-saline environments halophilic species such as Artemia persimilis and/or the calanoid Boeckella poopensis predominate. In the present study data of different lakes and ponds between 45-53• S were analyzed, with the aim to determine potential structures at different sites. For this purpose a null model based in guild structure was applied, considering each guild a different kind of water body (lake, small lake, permanent pond, ephemeral pond, and saline lake). The results revealed in two simulations that guild are structured. These results are similar with other descriptions on the basis of null models that revealed a random pattern of species associations for similar ecosystems due to many species repeated in all or practically all studied sites or similarities of ecological features. Ecological and biogeographical topics were discussed.

Inland water microcrustacean assemblages in an altitudinal gradient in Aysen region (46° S, Patagonia Chile)

“…It is due to the presence of few species repeated in all or practically all sites (De los Ríos et al 2008a, b, c;De los Ríos 2008). This pattern of species repetition by site in spite of environmental heterogeneity was observed for lakes and ponds in Torres del Paine National Park at 51° S (De los Ríos & Soto, 2009), and in large scale in lakes and ponds in Magallanes region between 51-53°, including Torres del Paine National Park and Tierra del Fuego island (De los Ríos et al, 2010b).…”