Influence of topography on the location and density of armadillo burrows (Dasypodidae: Xenarthra) in the central Amazon, Brazil

Abstract

Armadillos (Dasypodidae: Xenarthra) are the principal group of burrow-excavating mammals in Amazonian forest. Little is known about how the landscape's physical characteristics influence where these organisms choose to construct their burrows. We measured topographic characteristics of armadillo burrow placement and evaluated whether these variables affect overall burrow density. Our study took place on the study sites of the Biological Dynamics of Forest Fragments Project in the central Amazon, Brazil. To determine if armadillos exhibit habitat use preferences in constructing their burrows, we quantified the declination and elevation of available terrain along transect lines on our study sites and compared this with the characteristics of areas containing burrows. We also tested whether topographic variables were related to burrow density. Armadillos preferentially build burrows on low elevation, inclined terrain, and declination was positively related to burrow density. Low, inclined areas correspond to slopes next to stream basins. It may require less effort for armadillos to excavate these areas, while also providing proximity to water. The results of this study indicate that topographic information is important to consider when using burrows to estimate habitat use and density of armadillos in terra-firme forests of the central Amazon.