Project Introduction

The historical distribution of the African lion (Panthera leo) encompassed majority of the African continent, except the interior of the Saharan desert and regions dominated by dense tropical rainforest (Nowell & Jackson 1996; Schaller, 2009). Unfortunately, the population’s decline began in the mid-1800s as a result of various anthropogenic factors, such as retaliatory or indiscriminate killing (using spears, guns and poisoning), prey base depletion, bushmeat poaching, excessive or poorly monitored trophy hunting and loss, of habitat.  

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Extant Lion range in 2023 is approximately 1,566,529.59 km², only 7.4% of its historical range, with an estimated ~23,000 free-ranging lions remaining in Africa, and it is rapidly decreasing in abundance (Nicholson et al., 2023). Within their native range, existing populations are small and isolated; for example, of the approximately 67 areas in Africa where resident lion populations are known, 26 (39%) contain fewer than 50 individuals (McDermid et al., 2017).

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Despite this, many viable populations are now restricted to protected areas (including Northern Tuli Game Reserve) that are geographically isolated from each other (Bauer & Van Der Merwe, 2004; Slotow & Hunter, 2009). However, populations in protected areas are still exposed to legal and illegal activities, such as hunting and roadkill (Woodroffe & Ginsberg, 1998; Woodroffe, 2000), compromising their viability and likelihood of survival. This introduces difficulties for conservation managers, as small populations are slower to recover from stochastic events and genetic diversity is often limited (Hayward et al., 2007).

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With so many small and isolated lion populations, the conservation and protection of these populations are important. Populations, such as those in the Northern Tuli Game Reserve, were almost extirpated from the reserve by the late 1960s (McKenzie, 1990) but increased in the early 1970s (Lind, 1974). However, surrounding human habitations have led to human-carnivore conflict, persecution, and a previous dramatic population decline as a result of illegal activities such as snaring, poisoning and shooting (Snyman et al. 2014). For example, a 2014 study calculated the potential population level based on the available biomass of lions' preferred prey species within the Northern Tuli Game Reserve (Snyman et al. 2014; Hayward, O’Brien and Kerley, 2007). The lion population was estimated at 73 individuals and was exposed to human-caused mortalities, primarily occurring close to the Reserve boundary, indicating the intensity of edge effects in the absence of predator-proof fencing (Snyman et al. 2014).

The Northern Tuli Game Reserve lion population is currently experiencing some immigration and emigration with adjacent areas of South Africa and Zimbabwe. However, a study by Snyman et al. 2014 reported several cases of mating between close relatives, such as mother and son, due to the low dispersal rate of subadults and lack of male coalitions. These examples indicate that processes that lead to inbreeding depression are likely to occur in small lion populations affected by human persecution.

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Given the rapid decline in lion numbers in Northern Tuli, protecting extant populations is critical, and it is important from a conservation standpoint to identify and effectively monitor lion populations to help ensure the long-term biological and economic viability of these populations. To this end, several indirect measures (camera arrays, radio collaring and tracking, running transect lines and tracking) are being implemented, including the current preferred indirect method in East Africa is call-ups (Ogutu, Bhola & Reid, 2005; Whitman et al., 2006; Kiffner et al., 2009) to estimate relative lion abundances, density, and distribution.

 

Reference list:

Bauer, H. and Van Der Merwe, S. (2004). Inventory of free-ranging lions Panthera leo in Africa. Oryx, 38(01). doi:https://doi.org/10.1017/s0030605304000055.

Brink, H., Smith, R.J. and Skinner, K. (2012). Methods for lion monitoring: a comparison from the Selous Game Reserve, Tanzania. African Journal of Ecology, 51(2), pp.366–375. doi:https://doi.org/10.1111/aje.12051.

Hayward, M.W., O’Brien, J. and Kerley, G.I.H. (2007). Carrying capacity of large African predators: Predictions and tests. Biological Conservation, 139(1-2), pp.219–229. doi:https://doi.org/10.1016/j.biocon.2007.06.018.

Kiffner, C., Meyer, B., Mühlenberg, M. and Waltert, M. (2009). Plenty of prey, few predators: what limits lions Panthera leo in Katavi National Park, western Tanzania? Oryx, 43(01), p.52. doi:https://doi.org/10.1017/s0030605307002335.

Kitchener, A.C., C Breitenmoser-Würsten, E Eizirik, Gentry, A., Lars Werdelin, Wilting, A., Yamaguchi, N., Abramov, A., Christiansen, P., Driscoll, C.A., Duckworth, J.W., Johnson, W.E., Luo, S.J., Meijaard, E., P O’Donoghue, Sanderson, J., Seymour, K., Bruford, M.W., Groves, C. and Hoffmann, M. (2017). A revised taxonomy of the Felidae. The final report of the Cat Classification Task Force of the IUCN/SSC Cat Specialist Group.

Lind, P. (1974). Shasi-Limpopo Ranger’s Report 1973/1974. Unpublished Report for the Management and Landowners of the Northern Tuli Game Reserve.

McDermid, K.R., Snyman, A., Verreynne, F.J., Carroll, J.P., Penzhorn, B.L. and Yabsley, M.J. (2017). SURVEILLANCE FOR VIRAL AND PARASITIC PATHOGENS IN A VULNERABLE AFRICAN LION (PANTHERA LEO) POPULATION IN THE NORTHERN TULI GAME RESERVE, BOTSWANA. Journal of Wildlife Diseases, 53(1), pp.54–61. doi:https://doi.org/10.7589/2015-09-248.

McKenzie, A.A. (1990). Co-operative Hunting in the black-backed Jackal (Canis Mesomelas schreber). [PDF] Available at: https://repository.up.ac.za/bitstream/handle/2263/24492/08summary.pdf?sequence=10 [Accessed 8 Feb. 2024].

Nicholson, S., Bauer, H., Strampelli, P., Sogbohossou, E., Ikanda, D., Tumenta, P.F., Venktraman, M., Chapron, G. and Loveridge, a (2023). Panthera leo, Lion. [online] The IUCN Red List of Threatened Species. The IUCN Red List of Threatened Species. Available at: https://dx.doi.org/10.2305/IUCN.UK.2023-%201.RLTS.T15951A231696234.en [Accessed 9 Feb. 2024].

Ogutu, J.O., Bhola, N. and Reid, R. (2005). The effects of pastoralism and protection on the density and distribution of carnivores and their prey in the Mara ecosystem of Kenya. Journal of Zoology, 265(3), pp.281–293. doi:https://doi.org/10.1017/s0952836904006302.

Paolo Strampelli, Searle, C.E., Smit, J., Henschel, P., Lameck Mkuburo, Ikanda, D., Macdonald, D.W. and Dickman, A. (2022). Camera trapping and spatially explicit capture–recapture for the monitoring and conservation management of lions: Insights from a globally important population in Tanzania. 3(1). doi:https://doi.org/10.1002/2688-8319.12129.

Schaller, G.B. (2009). The Serengeti Lion. University of Chicago Press.

Slotow, R. and Hunter, L.T.B. (2009). Reintroduction Decisions Taken at the Incorrect Social Scale Devalue their Conservation Contribution: The African Lion in South Africa. [online] www.infona.pl. Available at: https://www.infona.pl/resource/bwmeta1.element.wiley-bseries-3237543789-o9781444312034-ch3 [Accessed 9 Feb. 2024].

Snyman, A., Jackson, C.R. and Funston, P.J. (2014). The effect of alternative forms of hunting on the social organization of two small populations of lions Panthera leo in southern Africa. Oryx, 49(4), pp.604–610. doi:https://doi.org/10.1017/s0030605313001336.

Whitman, K. (2006). Modelling, Monitoring and the Sustainable Use of Lion Populations in Tanzania. [online] Available at: https://www.researchgate.net/profile/Henry-Brink-2/publication/236733774_Methods_for_lion_monitoring_A_comparison_from_the_Selous_Game_Reserve_Tanzania/links/5c67c50e299bf1e3a5abf428/Methods-for-lion-monitoring-A-comparison-from-the-Selous-Game-Reserve-Tanzania.pdf [Accessed 8 Feb. 2024].

Woodroffe, R. (1998). Edge Effects and the Extinction of Populations Inside Protected Areas. Science, 280(5372), pp.2126–2128. doi:https://doi.org/10.1126/science.280.5372.2126.

Woodroffe, R. (2000). Predators and people: using human densities to interpret declines of large carnivores. Animal Conservation, 3(2), pp.165–173. doi:https://doi.org/10.1111/j.1469-1795.2000.tb00241.x.