Sympatric large carnivores in Senegal 671


TABLE 2 Parameter estimates, standard errors and P-values for de- tection probability (ρ) and site use (ψ) for the best model for each species of large carnivore surveyed in Niokolo-Koba National Park, Senegal, during the dry season of 2021.


Species


Spotted hyaena


Parameters1 ρ Effort


Leopard Lion


Wild dog


Leopard Lion


Wild dog


ψ NDVI ρ Hyaena


Estimate ± SE P


0.108 ± 0.041 7.87 × 10−3 0.618 ± 0.253 1.48 × 10−2 0.606 ± 0.350 8.32 × 10−2 1.286 ± 0.606 3.37 × 10−2


RAI_Leopard 0.975 ± 0.534 6.80 × 10−2 0.641 ± 0.260 1.39 × 10−2


−0.999 ± 0.388 1.01 × 10−2


ψ Dist_Road −1.083 ± 0.363 0.002 ψ NDVI


Dist_Gambie −1.006 ± 0.443 0.023 RAI_Leopard 0.494 ± 0.339 0.145


−0.910 ± 0.418 0.029


ψ Dist_Road −0.743 ± 0.645 0.249 RAI_Hyaena 1.542 ± 0.765 0.043


RAI_Lion RAI_Leopard −0.693 ± 0.891 0.437 −2.856 ± 2.292 0.212


1NDVI, normalized difference vegetation index; RAI, relative abundance index.


leopard presence and RAI, respectively (Table 2). Despite their hunting skills (Kruuk, 1972), spotted hyaenas are well- known for their kleptoparasitism (Périquet et al., 2015), which could explain the positive association of their detec- tion with the presence of leopards, lions and African wild dogs (Table 2).However, despite evidence of positive spatio- temporal interactions, the occupancy probabilities of leo- pards and spotted hyaenas were driven by different habitat characteristics. Our results suggest that spotted hyaenas pre- ferred open, less vegetated habitats (probably related to their prey searching behaviour; Watts & Holekamp, 2007), whereas leopards were more likely to occur on roads, cor- roborating findings of earlier studies (Mann et al., 2014; Cusack et al., 2015). Lion site use was concentrated in the core area of the


Park, close to the Gambian River. Prior research found that lions tend to use areas near water sources during the dry season, probably because of the higher prey biomass and water availability in these areas (Valeix et al., 2010; Kittle et al., 2016). This relationship between prey biomass and lion site use has been observed previously in Pendjari National Park (Henschel et al., 2016). Poachers often target areas near permanent water, with most such poaching activ- ity occurring during the dry season when surrounding crop fields lie fallow and people are thus not occupied with farm- ing work, and because accessibility of the Park and visibility across the terrain are improved during this period relative to the wet season (Compaore et al., 2020). These findings em- phasize the need to focus anti-poaching patrols around the Gambian River and other riverine areas in the Park during the dry season to better protect lions and their prey species.


However, although these results were corroborated by the nMDS analyses (Fig. 2), limited data availability and poor model fit hinder further interpretation, and we recommend further research on lion occupancy in the Park. African wild dogs are the smallest and most subordinate


species amongst the four large carnivores in Niokolo-Koba National Park (Darnell et al., 2014). We showed that they had a low overall site use probability that was negatively as- sociated with distance to roads and leopard and lion RAIs, a finding that is widely attested to in the literature (Darnell et al., 2014; Henschel et al., 2020; Madsen & Broekhuis, 2020). The low detection rates for both lions and African wild dogs may be linked to their low densities in the Park, resulting in large confidence intervals for site use, overdis- persion for the lion model and potentially biased activity patterns (Ridout & Linkie, 2009). However, our results match the literature (Saleni et al., 2007; Darnell et al., 2014) and are the first to be published for these emblematic species in Niokolo-Koba National Park. Providing baseline information on the spatio-temporal


ecology of threatened large carnivores is crucial to identify key habitats that are important for their long-termsurvival, notably for the species with low site use (lion and African wild dog) in a context of recovery; ongoing surveys suggest that the lion population has doubled since the first survey conducted in the Park in 2011 (P. Henschel, pers. comm., 2021). We show that leveraging data from camera trapping designed for a single species (i.e. leopard) can be used successfully to explore the spatio-temporal patterns of so-called bycatch (i.e. non-target) species. It is important to note that when using such data in the study of wide- ranging species, particularly those with large home ranges that encompass multiple camera-trap stations, there is an increased probability of spatial autocorrelation (Guélat & Kéry, 2018). Therefore, it is important to exercise caution when interpreting our results. Furthermore, the size of the Park and limited accessibility by road presented logis- tical challenges, so we focused on the core area, which is better protected and where carnivores are most likely to be detected. Thus, our results only apply to the study area and should not be extrapolated to the entire Niokolo-Koba National Park. In the present context of lion recovery, it is crucial to


monitor interactions between species. Co-occupancy models (Rota et al., 2016) are generally recommended for this purpose, but because of data scarcity (MacKenzie et al., 2002) we opted to use single-species occupancy mod- els to compare our results to the existing literature (Everatt et al., 2014; Spencer et al., 2020; Broekhuis et al., 2022). The results of our study provide insights into the eco-


logical needs of the large carnivores in the study area, en- abling authorities to prioritize anti-poaching effortswithin the Park. Specifically, we recommend strengthening anti- poaching patrols around waterholes and the Gambian


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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