Relationships between livestock grazing intensity and mammal predator-prey: A study case in Copo National Park in the dry Chaco forests

MAURICIO M. NUNEZ REGUIRO; CARUSO, MARÍA FLAVIA; GUSTAVO MARAS ; MARÍA SOLEDAD ANDRADE-DÍAZ; ENRIQUE J. DERLINDATI; CARLOS TRUCCO; CAROLINA B. TRIGO; ANDRES TALAMO

JOURNAL FOR NATURE CONSERVATION

ELSEVIER GMBH

Año: 2022

1617-1381

Extensive livestock ranching is one of the main drivers of habitat degradation in terrestrial communities in thedry Chaco forest (Argentina). Grazing intensity could differentially affect native mammals and their interactions,which could impact both, native mammal communities and livestock production systems. Here, we determinedhow the activity index of grey foxes Lycalopex gymnocercus and capture abundance and richness of smallmammals vary along a grazing intensity gradient in a particular region of the dry Chaco forest (Copo NationalPark, Argentina). Track plots were used to estimate the activity index of foxes and cattle, and Sherman traps forsmall mammals. Fresh scats were collected to analyse the diet of foxes and to assess possible changes in predatorpreydynamics. Fruit availability and shrub density were measured in 6 plots of 2 m × 50 m. We used generalizedlinear mixed models, Spearman?s nonparametric rank correlation, Chi-squared test, and Spearman?s partialcorrelation coefficient to analyse the potential effects of grazing intensity. We found that the activity index offoxes increased (0.06 ± 0.018) while small mammal abundance (-0.08 ± 0.024) and species richness decreased(rs = -0.94) with increasing grazing intensity. However, the proportion of scats with mammalian remainsdecreased with increasing grazing intensity. Also, we did not find a strong partial correlation between foxes andsmall mammals when we controlled for grazing intensity. This suggests that the abundance and diversity of smallmammals in the study area are determined more by grazing intensity than by predator-prey interactions. Grazingintensity could negatively affect small mammals, but not through changes in fruit availability or shrub density,but possibly by affecting grass cover. Consequently, foxes? activity could increase to meet caloric intake requirements.Our results suggest that specific cattle management recommendations depend on the wildlife speciesthat serves as a conservation target. We recommend testing whether reducing cattle load can make this productiveactivity compatible with wildlife conservation in dry Chaco forests.