Revista Chilena de Historia Natural 76 (2): 313-321, 2003
RESEARCH ARTICLE
Effects of livestock on the feeding ecology of endemic culpeo foxes (Pseudalopex
culpaeus smithersi) in central Argentina
Livestock can affect the feeding ecology of carnivores either directly, by becoming
potential prey, or indirectly, by modifying selection of other prey. Selection of other prey is modified through the negative effects of
livestock on food and cover, which reduces density and increases vulnerability of wild prey. Pseudalopex culpaeus smithersi
is an endemic subspecies of culpeo fox of central Argentina that is persecuted due to predation on livestock. We studied the
direct and indirect effects of livestock on P. c. smithersi’s feeding ecology by evaluating its diet, prey availability, and prey
selection in two areas with different livestock abundance—a national park and an adjacent sheep and cattle ranch in the Achala
grassland plateau. We studied diets from feces and used conversion coefficients to estimate prey numbers and biomass consumed.
Culpeos preyed primarily on native rodents (cavies and cricetines) according to both prey numbers and biomass. The differences in
culpeo diet, prey availability, and prey selection between sites were strongly associated with effects of livestock. Culpeos consumed
more livestock carrion and birds at the ranch, and tucos (Ctenomys sp.) only at the park. Livestock density was high at the
ranch and low at the park, cricetine and tuco densities were significantly higher at the park, and European hare (Lepus
europaeus) densities were similar between sites. According to prey numbers consumed culpeos did not appear to be selective,
but according to biomass they consumed cricetines more and hares less than expected at both sites and sheep more than expected
at the park. Livestock may reduce densities and increase vulnerabilities of cricetines and fossorial tucos in Achala by soil trampling that
destroys burrows, competition for forage, and reduction of grass cover.
Key words:
culpeo, livestock
effects, prey selection, prey availability Pseudalopex culpaeus smithersi
