The Amazonian Campina is a woodland, with emergent trees of about 10 m, found in patches in the Amazonian rain forest. It usually has open areas with a white sand soil directly exposed to sun, and shaded areas with a more dense vegetation. I sampled the dragonfly assemblage in this system counting every dragonfly at pre-determined points, at 5 min intervals, between 7:00 and 18:00 h. Erythrodiplax lativittata, Miathyria marcella and Erythemis vesiculosa were the most abundant spp. The frequency data by point revealed an association of E. lativittata (percher) with shaded habitats, and M. marcella and E. vesiculosa (fliers) with open habitats. The characteristics of thermoregulation of fliers and perchers seem to explain this microhabitat selection. Due to high productivity and density of small insects, the Campina is probably an excellent habitat for foraging. It is suggested that in these foraging habitats the spatial species arrangement is mostly determined by behavioural-physiological traits, which may help to explain the community faunal composition.