FACTORS AFFECTING SMALL CAT ABUNDANCE IN THE HIGH ANDES OF ARGENTINA

LUCHERINI M.; LUENGOS VIDAL E.; REPPUCCI J.I.

Mendoza

Congreso; 10th International Mammalogical Congress; 2009

The ecological factors affecting the distribution and abundance of both species of small cats occurring in the High Andes, the Andean cat Leopardus jacobita and the Pampas cat L. colocolo, have not been explored. We examine here the patterns of relative abundance of these cats in Argentina as a function of topography, prey availability and other habitat characteristics. Cat signs of presence were counted while walking 400 m-long line transects and their relative abundance was estimated as the number of cat sites/km. For each transect (n=121, in 10 areas) we also recorded the presence of Mountain vizcachas Lagidium viscacia, small cats’ main prey, and of other carnivores, as well as altitude, slope, terrain ruggedness, habitat composition, human activity at 2721 sampling points along transects. The average (±SD) number of cat sites/km was 3.02±4.71. As expected, cat site abundance increased with that of their prey (R2=.122, p=.0001), estimated through 4 categories of visually-estimated fecal pellet abundance. Nevertheless, this regression had a lower predictive value than that with terrain ruggedness as independent variable (R2=.316, p=.0001). Using all variables in a stepwise procedure, only ruggedness, prey abundance and mean slope had significant (p<.1) contributions, and the resulting model explained only a slightly larger proportion of data variability (R2=.369, p=.0001). The values of indices for terrain ruggedness and abundance of Mountain vizcachas were 1.7 and 1.6 times greater in the areas of cat high density (defined as those with > 4 cat sites/km, n=23 transects) than in low abundance areas (no cat sign recorded, n=47). Although it cannot be excluded that ruggedness is indicative of patches preferred by cats as defecation sites, we suggest that this parameter is related to vizcacha preferred habitats and thus that prey abundance and availability would be the key environmental variables affecting cat abundance in the High Andes.