Colonization by benthic macroinvertebrates in artificial and natural substrates in a mountain stream from Itatinga, Sao Paulo, Brazil

摘要

The artificial and natural substrates were compared regarding the colonization process by macroinvertebrates. At 1~(st), 3~(rd), 7~(th), 13~(th), 21~(st), 31~(st) and 42~(nd) sampling days the macroinvertebrate richness and abundance were analyzed. Chironomidae larva was the most abundant on both substrates during the whole sampling period (53% on each substrate), followed by Oligochaeta (17 in artificial and 18 % in natural), Ephemeroptera (16 and 11%) and Trichoptera juveniles (10 and 11%). The ecological succession process was similar on both substrates, with Oligochaeta as an important colonizer in earlier stages of the successional process. Other similarity between the substrates was the appearance of Ephemeroptera-Leptohyphidae at the 7~(th) sampling day, after what other groups started fluctuations on their abundance. In conclusion, the artificial substrate was appropriated for the macroinvertebrate colonization, showing similarity of the community structure and the process of ecological succession when compared to the natural one. For both substrates a stabilization period of the community composition happened between the 7~(th) and 13~(th) samplings days.