We explored the colonization of a patchy ecosystem by two neutrally labeled, but otherwise isogenic, strains of Escherichia coli. One-dimensional arrays of habitat patches linked by connectors were inoculated at opposite ends by two fluorescently-labeled strains, and the colonization was studied by time-lapse microscopy. We focussed on the degree of reproducibility of the resulting colonization patterns and on the interactions between the two populations during the colonization process.