Revista Chilena de Historia Natural 82 (3): 425-442, 2009
RESEARCH ARTICLE
Spatial distribution patterns of benthic macroinvertebrates assemblages in an Andean
Patagonian fluvial system
In January of 2006 we studied the distributional patterns of benthic macroinvertebrate
communities of the Baker river basin (45º50’ O and 47º55’ S) and their main controlling factors trying to cover the greater variety of the
lotic ecosystems. To carry out the study, 27 sampling stations were located in the different sub basins of the river. In each station,
physical-chemical parameters of the column of water were quantified (conductivity, dissolved oxygen, pH, temperature and turbidity),
and documented characteristics of the segment (e.g. wide of the channel and sediment type) and cartographic information using a
geographic information system (GIS) and complemented with cartographic information using GIS. Identified a total of 51 taxa, are
mostly insect larvae (80 %). The groups most richness were orders Ephemeroptera (15 taxa), Plecoptera (8 taxa) and Trichoptera (8
taxa). The classification and ordination analyses carried out with the data of abundance, allowed to recognize seven groups stations
(A-F) statistically significant (P < 0.05). The multiple regression analysis, showed that the environmental variable that accounts for
the observed biological patterns, was coverage cobble, explaining 45.1 % the variance of the biological data (r<sup>2</sup>
= 0.44 P < 0.05).
Key words:
Baker river basin,
benthic macroinvertebrates, fluvial habitat, Froude number, Patagonian rivers
