Livestock depredation by puma (Puma concolor) in the Argentine Espinal, Southern Buenos Aires province

FRANCHINI, MARCELLO; GUERISOLI, MARIA DE LAS MERCEDES; CARUSO, NICOLÁS

Cesena

Congreso; Congresso Nazionale Fauna Problematica; 2016

Livestock depredation is one of the most frequent sources of conflict between humans and carnivores throughout the world, representing a serious problem for carnivore conservation. We investigated the conflict between puma (Puma concolor) and livestock ranchers in the two southernmost counties of Buenos Aires Province (Argentina), an area of 25,000 km2. During the last decades, the natural habitats of this region have been dramatically changed by the expansion of livestock farming and agriculture, which are the principal sources of income for local people. This study aims to characterize puma predation and describe its effects on the revenues of the ranchers living in this region. Data were collected from 2007 to 2015 through two different techniques: interviews to local residents and kill site inspections. Sheep were the most common species (77.3%) in the ranches which suffered depredation whereas cattle were less abundant (22.7%). In the whole study area, if we consider only those ranches (n=83) where we know the exact numbers of individuals present and predated, the total number of livestock heads (both cattle and sheep) killed by pumas (n=1,977), represented the 8.83% of the total stock (n=22,378). In both counties, sheep were the most predated livestock (10.8% of the sheep bred in the ranches with predation), while depredation on cattle was less frequent (2.1%). Consequently, the economic loss produced by puma predation on sheep (totalling 60,134 USD in our sample of 44 ranches) was greater than for cattle (9,290 USD, n=4 ranches) and equalled to 13.4% of the total economic damage. For individual ranches affected by predation the loss averaged 1,251 USD and ranged from 17 to 12,700 USD. Most predation events (98%) occurred during night time and far from anthropic areas (roads and villages; mean distance ± SD: 32.01 ± 16.7 km). No temporal predation pattern was observed on domestic sheep, whereas predation on cattle was concentrated during the calving period (from September to December). An intensive field survey realized in a small area of Patagones county (537 km2) during 24 months showed that predation events (n=15) occurred most in cropland (33.3%), followed by woodland (26.7%) and grassland with shrubs (26.7%). Grassland was the least represented habitat in predation sites (13.3%). The proportion of predation events in cropland was greater than the availability of this habitat in the area, probably due to a greater presence of sheep in cropland areas. The mean number of livestock killed for each predation event differed according to the method we used to collect the data. For example, in Patagones (the only county for which we have enough field data) this number was 26.3 individuals for the data from interviews and 4.6 when we used only data collected directly by field operators through kill sites inspections. In this sense, interviews to ranchers may result in an overestimation of their livestock losses due to puma attacks. Interviews and kill site inspections showed that local people and pumas have a coexistence conflict in the study area, due to puma attacks on livestock. Sheep are the most common predated species and their predation produced a higher economic loss than for cattle. These results confirm that sheep are an easier prey for pumas than cattle, probably due mostly to their smaller body mass. This conclusion is also supported by the fact that sheep predation showed no monthly pattern while cattle predation is concentrated during the calving season. The fact that most predation events occurred at night and far from anthropic areas suggests that pumas tend to avoid humans. Our results indicate that the information we collected throughout interviews, in conjunction with our analysis on puma kill sites, produced valuable data to understand carnivore-livestock conflicts and, therefore contribute to design management measures to decrease conflicts. In particular, they show that although the losses caused by puma predation can be important for some ranchers, they are often reduced. We conclude that although their true relevance may be overestimated by ranchers, conflicts should be considered by local livestock production and wildlife management plans.