Site occupancy of Dasypus novemcinctus (Mammalia, Cingulata) and daily activity of four armadillo species in the Uruguayan Savanna and southern Atlantic Forest

Abstract

Site occupancy and daily activity remain mostly unknown for many species of armadillo. Seeking to address this issue for four cooccurring species (Cabassous tatouay, Dasypus novemcinctus, D. septemcinctus, and Euphractus sexcinctus) we deployed camera traps for 60 days in 162 sites across northern Uruguay and southern Brazil. This area encompasses two phytogeographic domains: the Uruguayan Savanna and the southern Atlantic Forest. Most records belonged to D. novemcinctus. We modelled the site occupancy probability of this species as a function of environmental covariates (i.e., distance to water, distance to urban areas and site occupancy of exotic species). Models revealed that site occupancy probability increased with the distance to urban areas. However, when analyzing either domain separately, no covariates influenced site occupancy. To understand the daily activity patterns of armadillos, we measured the nocturnality of each species. All showed highly nocturnal activity, averaging between 22:00 and 00:00. This was unexpected for D. septemcinctus and E. sexcinctus, regarded as mostly diurnal in scientific literature. Then, we estimated the temporal overlap between D. novemcinctus records in either domain and between D. novemcinctus, other armadillos and the exotic species Canis familiaris and Sus scrofa. Dasypus novemcinctus activity did not vary between domains, showed high overlap with that of other armadillos, intermediate overlap with S. scrofa and low overlap with C. familiaris. These results add to our understanding of armadillo ecology, especially that of D. novemcinctus, while also providing valuable insights into threats to this species’ conservation, particularly the urbanization of its natural habitat.