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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. RESUMENEl ganado puede afectar la ecología trófica de los carnívoros en forma directa, siendo una presa potencial, e indirecta, modificando la selección de otras presas. La selección de otras presas es modificada a través de efectos negativos del ganado sobre el alimento y la cobertura, reduciendo la densidad e incrementando la vulnerabilidad de presas silvestres. Pseudalopex culpaeus smithersi es una subespecie endémica de zorro culpeo del centro de Argentina que es perseguida debido a su depredación sobre ganado. Estudiamos los efectos directos e indirectos del ganado sobre la ecología trófica de P. c. smithersi evaluando su dieta y disponibilidad y selección de presas en dos sitios con diferente abundancia de ganado-un parque nacional y una estancia adyacente de ovinos y vacunos en el pastizal de Pampa de Achala. Estudiamos la dieta a partir de heces y utilizamos coeficientes de conversión para estimar el número y biomasa de presas consumidas. Los culpeos depredaron principalmente sobre roedores nativos (cuises y cricétidos) de acuerdo con el número y la biomasa de presas consumidas. Las diferencias en consumo,...

A total of 111 samples (43 faeces and 79 gastrointestinal tracts) of 14 wild carnivore species from 12 Argentine provinces were analyzed. Helminth eggs were identified in 73% of the faecal samples and adult worms were recovered from 81% of the gastrointestinal tracts. We found 19 helminth species. Among the most frequent findings were parasites of domestic carnivores, namely Toxocara canis, Toxocara cati, Toxascaris leonina, Ancylostoma caninum, Ancylostoma tubaeforme and Uncinaria stenocephala. In addition, new hosts are reported for 6 nematode species and 5 helminth species are recorded for the first time in Argentina: Aonchotheca putorii, Molineus brachiurus, Cyathospirura chevreuxi, Physaloptera praeputialis and Oncicola martini.

This study presents the first data on the diet of the puma ( Puma concolor ) and an endemic culpeo fox ( Pseudalopex culpaeus smithersi ) in the high mountains of central Argentina, based on scat analysis. Trophic interactions of both carnivores were examined from 2003 to 2008 inside a protected area after livestock removal. A total of 604 scats were analyzed. Native species (small cavids and cricetine rodents) were most frequently consumed (58 % -100 % ) by both carnivores. Exotic prey were consumed more in 2003 than in other years by both carnivores. Culpeo foxes consumed a higher number of prey items and a lower mean weight of mammalian prey than pumas. Niche breadth was high for pumas in 2003 and for culpeo foxes in 2004, decreasing in subsequent years with the same tendency in both carnivores. Diet overlap was high in all years. Pumas seemed to prey on available prey items, suggesting a trend toward diet specialization in small prey in both carnivores. Native prey are the most important food items for both carnivores inside the park; these results are encouraging in terms of the resilience of at least some components of the predator-prey assemblage in the high mountains of central Argentina.

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