We conducted an aerial survey of the marsh deer population Blastocerus dichotomus (Illiger, 1815) in the Ilha Grande National Park and its surroundings, on the border between the states of Paraná and Mato Grosso do Sul, Brazil, during the dry season. We used the double-counting technique, resulting in a population estimate of 1079 ± 207 marsh deers in a sampled area of 1081 km², corresponding to an estimated density of 0.998 ± 0.192 ind/km². The population was mostly concentrated inside the park, but also occupied altered wetlands outside its limits. The results should be used to support population management and conservation measures at the national park and its surroundings, due to the enormous anthropogenic pressure upon the marsh deer population in the region.
Aerial survey; double-count technique; marsh deer; Blastocerus dichotomus; Ilha Grande National Park
