Ecological factors rather than tourism pressure primarily affect the stress-related endocrine response of four ubiquitous mammal species in a small South African reserve

Abstract

Wildlife tourism is a growing global industry with notable economic and conservation value, yet its potential impact on animal welfare is a critical concern. Traditional behavioural studies have been used to assess these effects, but non-invasive physiological measures, such as faecal glucocorticoid metabolites (fGCMs), provide direct insight into stress-related coping mechanisms. This study presents a multispecies assessment of fGCM alterations associated with tourism and season in four ungulates—impala (Aepyceros melampus), zebra (Equus quagga), blue wildebeest (Connochaetes taurinus) and giraffe (Giraffa camelopardalis)—within a small South African nature reserve. Using established species-specific enzyme immunoassays, 533 faecal samples collected during the wet and dry seasons were analysed, considering season, sex and tourist activity levels. The results revealed species-specific endocrine responses primarily to ecological factors, but also in some cases to anthropogenic factors. Blue wildebeest showed elevated fGCMs during the wet season, likely linked to reproductive events and social changes. Zebra and impala exhibited higher fGCMs during the dry season, coinciding with resource scarcity and increased tourism, with impala fGCMs significantly higher on weekends, suggesting an interaction between ecological and tourism-related stressors. Giraffe showed no seasonal or tourism-related effects, although females had higher fGCMs, likely reflecting pregnancy-related endocrine changes. These findings underscore the value of a multispecies approach to evaluate physiological impacts of wildlife tourism. Identifying differential sensitivities among species highlights the need for tailored management strategies to minimise welfare impacts, particularly during ecologically sensitive periods. As nature-based tourism expands, evidence-based practices will be essential to balance visitor experiences with conservation and animal welfare objectives.