Because wildfires alter plant communities, we describe the effects of a single fire event on the composition and diversity of Amazonian ferruginous savannas, locally known as cangas. We installed 20 observation plots in burned and unburned parts of a homogeneous canga site from the Carajás Massif. The single fire event shifted community composition slightly, increased functional richness and the abundance of anemochoric and subshrub species, but did not influence the number of phanerophyte species, highlighting the importance of both seeding and resprouting strategies in the post-fire scenario. In contrast, neither taxonomic nor phylogenetic diversity was affected by the fire event. The absence of differences in the phylogenetic community structure indicated that specific adaptations to fires are widespread within the canga phylogeny, although fires are not an eminent part of these ecosystems, as in other neotropical savannas. As diversity metrics were not negatively affected by a single fire event and only small shifts in species composition were observed, our data indicate maintenance of important ecosystem properties despite an occasional wildfire event in the analysed canga shrubland. Further research should outline how different physiognomies are affected and how different fire regimes influence communities to assist in the design of effective management plans for this ecosystem.