Ecological and Anthropogenic Determinants of Ungulate and Large Carnivore Occupancy and Habitat Use in Niokolo-Koba National Park (Senegal)

Abstract

In the face of increasing ecological degradation and anthropogenic pressures, between 1970 and 2005, African large mammal population sizes have declined by 60%. While large ungulates are primarily threatened by habitat destruction and fragmentation, large carnivores also suffer from decreased prey availability and are often involved in conflicts with local human populations. In West Africa, this population decline reaches 85% over the same timeframe, highlighting the need for conservation actions and sustainable resource management. Senegal’s Niokolo-Koba National Park (NKNP) boasts a wide variety of ecosystems and unique biodiversity but faces heavy anthropogenic pressures. It is therefore critical to better understand large mammal’s decline in this area. With the purpose to enlighten how ecological and anthropogenic factors affect the occupancy and habitat use of large mammals in NKNP, we developed occupancy models for eleven ungulate and four large carnivore species, using data from a 105-day camera trap survey. We discovered that proximity to permanent water resources is significantly positively associated to ungulate and carnivore occupancy in the park. Our results have also highlighted the importance of gallery forests for many ungulates, as well as for leopards which were associated with forested areas more than any other carnivore. Prey occupancy acted as a driver of habitat use for lions, spotted hyaenas and wild dogs, reflecting their role in trophic chains. Anthropogenic factors had species-specific effects on small ungulate and lion occupancy, which overall were negatively associated to areas with illegal human activities and pastoralism, mainly concentrated in the park’s periphery. These finding directly support evidence-based conservation strategies and management decisions to mitigate the rapid decline of ungulates and large carnivore populations in West Africa. Ensuring permanent water access, preserving gallery forests and strengthening anti-poaching control in NKNP will be crucial for the long-term viability of ungulates and large carnivores. Furthermore, regulating illegal pastoralism in NKNP’s periphery would reduce its impact on human-wildlife conflicts and range contractions in prey species. This thesis lays the groundwork for further studies to be conducted in the park, comparing future findings to those obtained through this study and provides modeling tools to monitor the impacts of management and conservation on wildlife over time, in conjunction with NKNP surveys. Key words: Occupancy modeling, Habitat use, Ungulates, Large Carnivores, West Africa.