Short Research Note Invertebrate colonization patterns in a Mediterranean Chilean stream

The macrozoobenthos colonization process on artificial substrata in lotic environments was evaluated. Two seasonal periods, autumn–winter and spring–summer, of a relatively undisturbed fluvial system, the Estero Nonguén (VIII Region, Chile), have been studied. Five stations, two in riffles and three on sandy bottoms, extending from a head water stream to 5 km down river, were sampled. For all stations and for each season the results were as follows: (a) 32 % of the total number of taxa found in this study colonized the artificial substrata on the first day of exposure, (b) the taxa that colonized sandy bottoms were typical for riffle, (c) the colonization process showed the same abundance, specific and cumulative richness and diversity pat-terns over time, and (d) equilibrium was reached approximately 2 weeks after initial exposure. This suggests that ‘‘Estero Nonguén’ ’ stream presents a nearly pristine condition and can be considered as a reference site to carry out biodiversity and ecosystem functionality studies, and giving information on time recovery for sectors previously disturbed