Return to preferred habitats (edges) as a function of distance in Akodon azarae (Rodentia, Muridae) in cropfield-edge systems of central Argentina

Abstract

We studied the ability of Akodon azarae (Rodentia, Muridae) to return to their preferred habitat, when released at a perpendicular distance (25, 50 or 75 m) from the edge towards the cropfield, and a parallel distance (100 m) away from the site of first capture within the edge habitat. Return success was estimated as the proportion of animals recovered in edges. The recapture rate between the field and the border was significantly higher than the recapture rate estimated according to successive captures in the border. Successful returns did not decrease significantly with increasing release distance, but animals released at 50 m from edges were less successful in returning to borders than the other release-distance groups. Although the median time taken to the first recapture in edges did not differ among the release-distance groups, rodents released at 25 m and 50 m returned to edges faster than those released at 75 m. A. azarae showed both a successful return to the edge and a trend to return to the home range area. We conclude that A. azarae can return to edges from cropfields at distances that are larger than those they usually travel, allowing the use of fields when they present good conditions for reproduction and survival. Successful return is probably the result of direct movements rather than random wandering.