Use of null models to explain crustacean zooplankton assemblages in waterbodies of Alerce Andico National Park (41°S, Chile)

Patricio de Los Ríos, Enrique Hauenstein, Mario Romero and Patricio Acevedo A.
CRUSTACEANA 85, 6 (2012)


The zooplankton assemblages in deep, mostly oligotrophic northern Patagonian lakes are
characterized by low species numbers and a marked dominance of calanoid copepods. In the present
study, data collected in field work on six water bodies located in Alerce Andino National Park
(41°S) were analysed using the Jaccard Index of community similarity and a co-occurrence of null
models, and such with the aim of determining potential regulating factors for the observed crustacean
assemblages, using a presence-absence matrix. A significant correlation between species number and
surface area was found. The null model used species co-occurrence, and the basis of this model is
that the species associations observed are random. The results revealed the absence of regulating
factors and indicate that the sites are relatively homogeneous, with low species numbers and similar
plankton assemblages at all studied sites. This finding is in accordance with similar descriptions for
zooplankton assemblages in other Chilean Patagonian lakes.


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