Diurnal pastoralism does not reduce juvenile recruitment nor elevate allostatic load in spotted hyenas

Abstract

Abstract Anthropogenic activity can have substantial effects on wildlife. These effects may vary according to the characteristics of the activity and the species involved. Although effects on behaviour are well studied, studies of effects on fitness and physiology are scarce, particularly for group‐living species. We exploited a natural experimental setup to investigate the effect of diurnal pastoralism on juvenile recruitment and allostatic load in a population of free‐ranging spotted hyenas in the Ngorongoro Crater, Tanzania, over a 24‐year period. Pastoralism was restricted to the territories of two of the eight study clans, allowing us to compare juvenile recruitment in exposed and unexposed clans. We also compared faecal glucocorticoid metabolite concentrations (fGMC)—a biomarker of an organism's allostatic load—between exposed and unexposed clans using 975 faecal samples from 475 hyenas. We found no detectable difference in juvenile recruitment nor fGMC between the exposed and unexposed clans, indicating that the pastoralism had no substantial deleterious effect on the spotted hyenas. The lack of a deleterious effect likely stems from the combined effect of the predictable and undisruptive nature of the pastoralism, the socio‐ecology of spotted hyenas and the Ngorongoro Crater's consistently abundant prey. Our findings demonstrate that exposure to anthropogenic activity may be compatible with the persistence of certain group‐living species, especially if the overlap between the species' critical behaviours and the activity is limited. Our study thereby provides new perspectives for ecologists, conservation biologists and stakeholders who seek to assess human–wildlife conflicts and balance the needs of local human communities and wildlife.