Estela M. Luengos Vidal

Lycalopex Gymnocercus (Carnivora: Canidae)

Abstract Lycalopex gymnocercus (Fischer, 1814) is a canid commonly called the Pampas fox. A sexually dimorphic fox-like carnivore of medium size with reddish coloration on sides and white on the ventral surface, it is 1 of 6 species in the genus Lycalopex. It occurs in eastern Bolivia, western and central Paraguay, Uruguay, north and central Argentina, and southeastern Brazil. It prefers open habitats but also occurs in areas of Pampas grassland modified by extensive ranching and agriculture activities. It has been assigned to the “Least Concern” category of the International Union for Conservation of Nature and Natural Resources.

Interindividual interactions of Molina's hog-nosed skunks Conepatus chinga in the Pampas grassland of Argentina

During one year, we radiotracked two female and two male Molina’s hog-nosed skunksConepatus chinga (Molina, 1782), a little studied mephitid, in the Pampas of central Argentina, to analyze the static and dynamic interactions between individuals. Mean home range overlap was large (44.5%), but males shared a smaller proportion of their home ranges than females. The average percentage of localizations in the overlap area (39.3%) indicates that these areas were not marginal sections of individual home ranges, but this value was greater for individuals of different genders than intrasexual dyads. The Coefficient of Spatial Association confirmed that the distances between individuals of different sexes were smaller than between animals of the same sex. During simultaneous locations, females were closer than males, but reciprocal distances between individuals varied over the time. These patterns are congruent with those described as typical for mustelids and mephitids. Our results confirm that an analysis of home range overlap should not be considered complete without the study of dynamic interactions among individuals and their temporal variations, which are necessary to overcome the limitations of spatial overlap analysis.

Field Immobilization of Molina’s Hog-nosed Skunk (Conepatus chinga) Using Ketamine and Xylazine

We injected 27 adult Molina’s hognosed skunks (Conepatus chinga) intramuscularly by hand with ketamine hydrochloride (KH) and xylazine hydrochloride (XH) in the Pampas grassland of Argentina. Skunks were immobilized with a mean (±SD) dosage of 24.9±6.5 mg/kg KH and 1.9±0.6 mg/kg XH. The mean effective dosages of KH (27.6 mg/kg) and XH (1.7 mg/kg) were higher and lower, respectively, than those reported in skunks previously. Mean induction and recovery time were 5.3±1.9 min and 47.7±18.5 min, respectively. Hypothermia was the only problem detected in field immobilization and occurred in winter but did not appear to be associated with to drug doses. We conclude that KH/XH is a safe immobilizing drug combination for Molina’s hog-nosed skunk.

How rare is the rare Andean cat

Abstract Although rareness is the main criterion used to list the Andean cat Leopardus jacobita as endangered, information on its population abundance is lacking. During 14 expeditions to north-western Argentina, we recorded the culpeo Lycalopex culpaeus at all sites where we interviewed local people, the Pampas cat Leopardus colocolo at 85.2% of sites and Leopardus jacobita at 66.7% of sites. Encounter rates for indirect signs of small cats and foxes were similar. DNA genotyping showed that only 4.9% of faecal samples from small cats were from L. jacobita. Camera trapping recorded culpeos in 85.7%, Pampas cats in 71.4%, and Andean cats in 42.9% of the areas. The mean capture rate for culpeos was more than twice that for Pampas cats and five-fold that for Andean cats. Direct signs of L. culpaeus were the most abundant, whereas those for L. colocolo and L. jacobita were similar. Culpeos are more widespread and abundant than small cats in the High Andes. Populations of L. jacobita are less homogeneously distributed than those of L. colocolo, but clear differences in abundance of sympatric populations were not detected. Our results support the need for conservation measures for L. jacobita, an endemic of the High Andes.

Feeding habits of Molina’s hog-nosed skunk in the Pampas grassland of Argentina

Abstract We studied the feeding ecology of Molina’s hog-nosed skunk (Conepatus chinga) in a protected area of the Pampas grassland by comparing the content of scats (140 samples) to prey abundance (estimated by invertebrate capture rates from 38 pitfall trap grids). Fecal analysis supported a largely insectivorous diet, with small vertebrates and carrion representing minor alternative resources. Almost all invertebrate prey was significantly more abundant in the warm period than the cold period, whereas skunk diet did not vary seasonally. Even though Molina’s hog-nosed skunks were considered to be opportunistic foragers due to their wide trophic niche, our results indicate that despite their trophic generalism, they consumed several prey items in proportions differing from those expected by their respective availabilities.

Home range size and habitat selection of Geoffroy’s cat (Leopardus geoffroyi, Felidae, Carnivora) in the pampas grassland

Abstract This study examined the spatial ecology of Geoffroy’s cats, Leopardus geoffroyi, living in a protected area surrounded by croplands in the Argentine grasslands. A total of six different adults were marked with 14 radio-collars from 2001 to 2005 but only three (one female and two males) produced a meaningful amount of data (54–135 positions). Total home range size was 8.83±1.58 km2 (100% Minimum Convex Polygon) and 7.27±2.23 km2 (90% Fixed Kernel). Core areas averaged 1.46±0.84 km2. Geoffroy’s cats most frequently used Exotic Woodland areas followed by Rocky and Agricultural areas. All cats clearly avoided natural habitats and selected Exotic Woodland at the two levels of selection examined: within the study area and within home ranges. In our study area, Geoffroy’s cats’ home ranges were larger than all those previously recorded in natural areas. The Geoffroy’s cat preference for Exotic Wood patches and avoidance of natural grasslands was likely due to the degradation of natural habitats caused by a dense population of feral horses. We also argue that woodlands can play an important role in the ecology of this species, either as refuge, hunting area or for territorial marking, regardless of their origin.

Habitat selection of Molina's hog-nosed skunks in relation to prey abundance in the Pampas grassland of Argentina

Abstract We radiotracked 16 (6 males, 10 females) adult Molinas hog-nosed skunks (Conepatus chinga) to examine habitat selection using compositional analysis at 2 spatial scales in a protected area and a landscape fragmented by agriculture. To aid in understanding the habitat use of skunks, the abundance of invertebrates was estimated in each habitat. Habitat use and selection varied between the 2 study sites. Skunks selected habitat at landscape level but not at home range level in the protected area. In the cropland area skunks showed overall habitat selection at both scales, although at landscape level we did not detect a significant ranking of habitats. In both sites, when we found a significant selection grassland patches ranked first. Although this habitat does not reach 10% of the total area, it presented the highest abundance of Coleoptera. Because Coleoptera are the main prey item of this mephitid, these results support the hypothesis that habitat selection in C. chinga is highly related to food availability. We conclude that the preservation of grassland patches may be essential for managing C. chinga populations in the highly human-modified landscapes of the Pampas.

Morphometrics of Pampas foxes (Pseudalopex gymnocercus) in the Argentine Pampas

No abstract available

Characterization of puma–livestock conflicts in rangelands of central Argentina

Livestock predation is one of the major causes of conflicts between humans and pumas (Puma concolor). Using data from interviews with ranchers and kill-site inspections, we characterized puma–livestock conflicts in Villarino and Patagones counties of central Argentinean rangelands. Depredation was considered the major cause of livestock losses, and puma attacks were reported in 46.6% and 35.4% of ranches in Villarino and Patagones, respectively. The majority of ranches underwent losses smaller than 1000 USD. The proportion of livestock lost to predation (0.1–10.4%) and financial losses (5.3–1560.4 USD) per ranch/year varied across ranches, and small sheep ranches in Villarino were affected the most. Depredation was recorded only at night and preferentially in grassland with shrubs and cropland habitats. Although nocturnal enclosures appeared to decrease sheep losses, puma hunting was considered the most effective form of reducing depredation and was implemented by most ranchers. Mortality rates were 3.7 and 1.1–1.56 individuals/year × 100 km2 for sheep and pumas, respectively. Nocturnal fencing, shepherding and spatial separation from predators may efficiently reduce sheep losses. However, the poor association between the intensity of puma persecution and puma-related livestock losses suggests that conflict mitigation in central Argentina is not only about reducing damage but also about increasing tolerance.

New data on the distribution and natural history of the lesser grison (Galictis cuja), hog-nosed skunk (Conepatus chinga), and culpeo (Lycalopex culpaeus) in northwestern Argentina

Abstract We present a total of 190 new distribution records of three little-known mammalian carnivores (Conepatus chinga, Galictis cuja, and Lycalopex culpaeus) obtained using camera trap techniques and direct observation in the highlands of Jujuy province, northwestern Argentina. These new records extend the present known distributions of these three species to the west of the province and to higher altitudes, and provide additional information on habitat association and activity patterns.