Sympatric large carnivores in Senegal 665


heightened by the rise of terrorism (Lhoest et al., 2022). The situation for the leopard Panthera pardus is also serious; this species has been described as the most persecuted felid glo- bally (Hunter & Balme, 2004) and has lost 86–95% of its historic West African distribution since 1750 (Jacobson et al., 2016). In contrast, the spotted hyaena Crocuta crocuta has a broader regional distribution and persists in some of the human-altered landscapes of Senegal (Mills & Hofer, 1998). Many large carnivores are the target of the illegal trade in skins and body parts, which are used for cultural practices in line with various local belief systems (Adeola, 1992). Retaliatory persecution by herders because of real or perceived predation on livestock is also driving carnivore declines (Gueye et al., 2022). West African large carnivores are generally geographically


isolated from the rest of the continent and are (or are sus- pected to be) distinct subspecies (Henschel et al., 2010; Anco et al., 2018; Woodroffe & Sillero-Zubiri, 2020), except for the spotted hyaena, for which data on its genetic status are lacking (Gueye et al., 2022). Niokolo-Koba National Park holds a nearly intact guild of large carnivores—only missing the historically present Northwest African cheetah Acinonyx jubatus hecki—which makes it a crucial landscape for the conservation of these species in West Africa. Yet little is known about the population status and ecology of large car- nivores within the Park, and in the region more broadly. We present the first insights into the distribution and spatio-temporal interactions of the sympatric large carni- vores occurring in Niokolo-Koba National Park. Our specif- ic aims were to identify factors driving spatial use by large carnivores within the study area, explore how these species spatially coexist and determine their activity patterns and overlaps. Robust data on the ecology and distribution of large carnivores in Niokolo-Koba National Park could in- form conservation planning and management efforts by providing insights into which habitats and resources are crucial to their persistence. This baseline information could then be used to develop conservation strategies in- cluding restoration and management of habitats and prey populations, targeted anti-poaching patrols and conflict mitigation measures (Ripple et al., 2014). Our work thus forms the basis to improve our knowledge of large carni- vores in Niokolo-Koba National Park and guide the long- term conservation and monitoring of these species in the re- gion (Bauer et al., 2021).


Study area


Niokolo-Koba National Park, the largest terrestrial pro- tected area in Senegal, covers c. 9,130 km2 in the Western Sudanian savannah ecoregion (Fig. 1) and has monthly tem- peratures ranging from 28.0 °C in December to 34.5 °C in April (Arbonnier et al., 2019). Annual rainfall is 900–


1,200 mm, with 78% falling during the rainy season (June– October; Dagorne et al., 2020). The Gambian River is the largest and only permanent river in the Park, but waterholes can be found in its two tributaries (Niokolo-Koba and Koulountou) during the dry season. The landscape com- prises a mosaic of habitats such as grassy savannahs, shrub savannahs,wetlands, dry forests, gallery forests and bamboo groves (Arbonnier et al., 2019). The terrain is largely flat, ex- cept in the south-west, where Mont Assirik, the highest point in the Park, culminates at an elevation of 310 m.


Methods


Camera-trap survey Weconducted a camera-trap survey during the 2021 dry sea- son (12 March–27 June), with the primary objective of esti- mating leopard density and the secondary objective of obtaining baseline information on the distribution of key species in the National Park. We used 139 cameras (44 PantheraCam V6 and 94 PantheraCam V7, Panthera, USA; and one infra-red Browning BTC-6HDX, Browning Trail Cameras, USA) deployed in 72 stations, 63 of which were paired. The survey covered just under one-fifth of the National Park (1,523 km2). We used a grid of 5-km2 cells and deployed a camera-trap station within each cell (mean inter-station distance = 3 km). We selected macro- placement remotely through satellite imagery, focusing on the road network (Fig. 1), gallery forests and proximity to permanent water sources (Tanwar et al., 2021). We chose micro-placement to maximize large carnivore detection by identifying areas with large carnivore spoors, scats and prey carcasses, amongst other factors. When no sign of presence could be found, we deployed cameras along vehicle tracks and at the intersections of wildlife trails (Kolowski & Forrester, 2017). We placed the camera traps c. 30–45 cm above the ground on trees, orientated perpendicular to ani- mal tracks (TEAM Network, 2011). We programmed the cameras to take a single picture each time the sensor was triggered by movements, with a 1-s delay between triggers. We treated photographs of the same carnivore species at the same station as independent events if they were sepa- rated by at least 30 min (Meek et al., 2014).


Data analyses


Relative abundance index and non-metric dimensional scal- ing analysis To visualize dissimilarity amongst species based on their presence or absence at different camera-trap stations, we used non-metric dimensional scaling (nMDS; Woese et al., 1990). We computed nMDS from the relative abundance index (RAI) of each species at each station


Oryx, 2024, 58(5), 664–675 © The Author(s), 2024. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605323001746


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