Use of space by small mammals in a semiarid area in northeastern Brazil

The use of spool-and-line provides information about the movement, vertical stratification and use of shelters and nests by animals. This study evaluated the area of daily use and selection of microhabitat by the marsupialGracilinanus agilisand the rodentWiedomys pyrrhorhinusin northeastern Brazil. The study was conducted using the spool-and-line technique in areas of shrubby arboreal Caatinga and data were obtained on daily use, tortuosity of movement, use of the ground and vertical strata for each individual. The microhabitat was sampled through the ground cover and canopy and the vertical leaf obstruction only during the dry season. A total of 44 trajectories, totaling 2451.42 m, were evaluated. No differences were found in the movement variables between males and females of these species. The species differed only in their use of vertical strata.Gracilinanus agilisshowed area of daily use values that were greater than those ofW. pyrrhorhinus, and low tortuosity values could be associated with the low local population density of these species. The difference in the use of vertical strata was expected, becauseG. agilisis known to be a scansorial species whileW. pyrrhorhinusis preferably arboreal. The absence of habitat selection suggests that these species may be performing this selection on the scale of mesohabitat.