Spatial ecology of the Pampas fox, Pseudalopex gymnocercus, in the Argentine Pampas grassland.

LUENGOS VIDAL, E.M.; LUCHERINI M.; CASANAVE E.B.

Mendoza, Argentina, 9-14/8

Congreso; X-IMC; 2009

IADIZA; IFM, SAREM

The Pampas fox, Pseudalopex gymnocercus, is a medium-sized South American fox, actively persecuted by men for preying upon livestock. In spite of its wide distribution and relative abundance, the knowledge on social and spatial organization of this canid is extremely scarce. The spatial ecology of pampas fox was examined from February 2001 to May 2007 in two study areas in the southwest of Buenos Aires Province, central Argentina. The first area was located in the Tornquist Provincial Park (PPET), a protected mountain grassland area with a high density of wild horses, and the second area was near the village of Aparicio (APA), a typical cropland and cattle ranching region. Twenty six foxes were radio-tracked (16 at PPET and 9 at APA). The average annual home range size (HR), estimated by the minimum convex polygon, was 213.3±136.8 ha. HR size varied more among individuals than between areas and sexes. Nevertheless, at PPET HRs tended to be smaller and their sizes decreased more than at APA when the 5% most external positions were excluded. Breeding pairs used overlapping HRs, remained stable for several years and showed strong site fidelity. At both areas, HR overlap was larger intersexually (29.8±41.1) than male intraxesually (16±10.4). However, while female core areas overlapped 73.2% at PPET, no overlap between females was observed at APA. Foxes spent 38.5% of their time active. Nocturnal activity (35.6%) was significantly greater than during the rest of the day (range 14.4%-27.3%), but activity patterns were flexible: foxes were almost exclusively nocturnal at APA and showed diurnal activity at PPET, where hunting is prohibited. Monogamous breeding pairs appear to be the basic component of the social organization in Pampas foxes, but flexibility was observed in the degree of interindividual tolerance, group size, HR size and strength of territoriality.