An ecological evaluation of habitats on the Maracá Island, Roraima, Brazil, is proposed, based on the comparative study of mammalian ectoparasite fauna. Habitats were clustered into groups with similar fauna, based on the richness, diversity, abundance, prevalence and interchange of ectoparasites and analyzed phenetically using ectoparasites as characters. A phenogram indicated two spatial groups: natural habitats, represented by the forest and the Curatella/Byrsonima savanna at Santa Rosa and modified or mixed habitats represented by the seasonally flooded savanna, the Ecological Station and the area around the Ecological Station water tank. Interchange of ectoparasites between hosts showed a higher impact of the forest on the Santa Rosa savanna than vice versa, indicating that currently the savanna is suffering retraction.