Macroinvertebrate community dynamics in the Potrerillos stream (Colombia): Response to seasonal ƀow changesBetween January and December 2006 monthly samplings of benthic macroinvertebrates in two sampling stations were conducted in the Potrerillos stream.This article presents the analysis of the spatial and temporal changes in the composition and structure of this community as a function of the seasonality of rains in a drywood tropical region.It was determined that the periods of scant and moderate rains were beneſcial to processes of colonization and development of different taxa, as these periods presented the highest values of abundance, richness and diversity (H ).This last concept was related to a continuous ƀow of low variability, which favored the heterogeneity of habitats, favorable levels of physical and chemical variables, and the availability of higher food supply.During the dry season, the ƀow ceased and several isolated ponds were formed, habitats and food were lost, physical and chemical conditions were altered, many taxa disappeared and the taxa best adapted to lenitic zones and moist substrates were dominant.The abundant rains brought new hydrologic dynamics, which, though they generated unstable habitats and microhabitats, allowed for the colonization of organisms, mainly those with winged instars, which increased richness and diversity.Despite that disturbances caused by drought and abundant rains caused ƀuctuations in the habitats' characteristics and in the composition and structure of the community, the ecosystem was stable and resilient with reference to these community attributes.