LOWLAND AND UPLAND CARNIVORES FROM THE SOUTHERN CONE OF SOUTH AMERICA

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

Mendoza

Congreso; 10th International Mammalogical Congress; 2009

Two contrasting hypotheses have been proposed about the competitive ability of widespread vs. geographically restricted species.  One maintains that widespread species have become widespread because they are competitively dominant over related, geographically restricted species.  The alternative hypothesis is that narrow-ranging species are ecological specialists that competitively dominate specific habitats/resources.  Through radiotracking, live and camera trapping we compared intraguild niche overlaps and population abundances of medium-sized carnivores in three areas, one located in the High Andes deserts and composed by the culpeo fox (Lycalopex culpaeus), Andean cat (Leopardus jacobita) and Pampas cats (L. colocolo) and two in central Argentina, in the Pampas grassland and Monte ecoregion, and comprising the Pampas fox (L. gymnocercus), Geoffroy’s cat (L. geoffroyi) and Pampas cat.  In both guilds, the puma was the only large carnivore. Several lines of evidence suggest that in the Pampas guild composition was altered by human disturbance, which affected primarily the puma and, possibly, the felid/canid abundance ratio, favoring the more adaptable foxes.  As expected, in both guilds niche overlap was the largest between the most similar species (i.e. small cats), but we found evidences of trophic, spatial and temporal segregations, which probably facilitate species coexistence.  Although specialized, restricted species could be more efficient resource exploiters and still have smaller populations because they use rarer resources, the lower abundance of Andean cats, a trophic specialist, than the more widespread Pampas cats in areas where the main prey of Andean cats is abundant suggests that Pampas cats were competitively dominant. Interestingly, while the Pampas cat was the most abundant felid in the High Andes, it was less common than the Geoffroy’s cat in the Pampas.  While we cannot exclude that Geoffroy’s cats are more efficient competitors, we suggest that species-specific habitat association may affect the competitive ability of carnivores.