Habitat use
We used infrared images (Carta 2005 Project, National Program for Aerospace Missions
and Remote Sensing) to delineate each habitat type on the landscapes where sloths were
located. Global Positioning System (GPS) points were plotted for each relocation of a
specific animal in a specific habitat. In addition to providing the data for home range
estimates, these relocations also facilitated the estimation of ‘potential available habitat.’
To establish ‘potential available habitats’, radio telemetry locations of all animals for each
species were mapped onto the landscape and the vegetation cover map was superimposed
to generate a set of buffers of 30 m radius using ‘‘Xtool’’ (www.esri.com) of ArcView 3.3.
Thirty meters was considered the margin of error for the reading with GPS equipment. The
area delineated by this buffer was considered the ‘potential available habitat’ for each sloth
species. The ‘potential available habitat’ for the two sloth species differs slightly because
the home ranges established using telemetry data only partially overlapped (Figs. 1 and 2).
The ‘expected use’ for each habitat type was estimated as the percentage of each habitat
type that occurs on the entire landscape (Biotas software, version 1.03.1 Alpha, Ecological
Software Solution). The total number of observed animal-location points within a habitat
type was compared with that expected if occurrence in any habitat is random using
Chi-square goodness-of-fit tests (Neu et al. 1974; White and Garrott 1990).