Reviewing Conservation Priorities : A case study on African Lions.

By Penthai Siriwat

Conservation is hard. Even after pouring in a lot of time and money, achieving results is never as straight-forward as you imagine. This is because natural ecosystems that we want to conserve are complex; species interactions occur on a multitude of levels with both biotic and abiotic factors. It could be argued that the fundamental goal of conservation is to maintain a diverse ecosystem, however, there tends to be a bias in what we prioritise and choose to conserve. One of the front-runners in the world of conservation is the African lion (Panthera leo). Not only are they one of the ‘big bosses’ or apex-predator in this Savannah ecosystem, but their majestic and charismatic nature also has a special appeal to the hearts of the general public, ultimately making them a key pillar to the culture of conservation.

Screen Shot 2013-12-06 at 00.51.23

Source: Steve Garvie (2013)

The continental decline of these lions has therefore caused great concern. The main reasons have been attributed to habitat loss and fragmentation, human-wildlife conflict, trophy hunting and disease. It was predicted that in the next 40 years, nearly half of Africa’s free-roaming lions could potentially decline to near extinction1. This has led to the formulation of different management and conservation plans. However, as  ecosystems are an interactive web, there could be inadvertent effects on non-target species. As a big fan of lions, I have no intention to discredit any form of conservation that aims to save these regal cats. Nevertheless, I believe that conservationists, land-managers and policy-makers must also be aware of this conservation bias.  I will highlight two different lion management plans to show that before investing on a single species, the priority must be to evaluate the effects that may occur on the ecosystem-level as well.

Lions behind protected fences – Source: Dan Bodenstein (2008)

Firstly, human-lion conflicts has intensified greatly due to habitat fragmentation; lions roam and kill livestock, which causes villagers to retaliate. As human populations grow, the overlap between lion and humans will increase and confrontation will be inevitable. To deal with this problem, a study was carried out evaluating lion population trends and densities with different management techniques from 42 African reserves and suggests that fences should be established to more game reserves and parks in order to protect these top-level predators1. The study suggests fenced reserves can sustain higher carrying capacities and is more cost-effective per lion and per management expenditure.

The paper was  counteracted by another study2 which critiques Packer’s study and indicates that fenced population are not as effective as previously calculated. More importantly, they emphasise that lion conservation should not be financially driven, and that lions can do well in some fenced areas but usually at the expense of other species. In addition to genetic isolation and further fragmentation, nomadic and migratory wildlife could also be prevented from dispersing, foraging and migrating, such as reduced accessibility and routes to water and grazing areas2. Wide ranging species like the endangered African wild dogs will also inevitably be affected as they require huge territories within and outside protected areas. Additionally, fencing can increase pressure on vegetation leading to overgrazing and possibly starvation of many ungulates in reserves. Furthermore, humans may exploit fencing material, as evident in Zambia where standing fence wires were stripped to make bushmeat snares for poaching. Thus, although fencing is economical, it would further literally divide areas up which actually further aggravates the initial issue of habitat fragmentation in the first place.

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Source: Steve Garvie (2012)

Another aspect of human conservation intervention is disease management, such as control of animal movement and vaccinations. In 1994, an outbreak of Canine Distemper Virus (CDV), led to a loss of a third of the lion population in the Serengeti which took four years to recover3. The ‘Project Life Lion’ was launched in 1996 to vaccinate dogs in Serengeti villages to save local lion and wild dog populations.  However, the conservation conflict arises as long-term studies on these two predator species population suggests that lion populations inversely correlates with the cheetah populations within the region. Lions are responsible for approximately 80% of total cheetah cub deaths by predation, thus it effectively maintains the cheetah population at low levels. This could imply that if lions populations are successful, the future for cheetahs could be grim. 

Figure 1: Probability of extinction of Serengeti plains Cheetahs for different rates of CDV outbreaks. Source: Chauvenet et al. (2011)

Models constructed from interacting populations between lions and cheetahs over 60 years, suggested that a successful programme of lion vaccination and no CDV outbreaks might increase the probability of cheetah extinction to 39.2%. Without vaccination and two CDV outbreaks, the extinction risk decreases to 23.5% [figure 1]. It should be noted that the model assumes an isolated cheetah population, which is not the case at present. However, the researchers concluded that vaccinations and control of CDV could double the probability of cheetah extinction. Although there are limitations and assumptions in the model, it underlines that disease eradication might not be ideal for everyone. The scenario of saving a predator at the expense of another is not inconceivable; the efforts to protect tigers in India have evidently led to an unforeseen decrease in leopard population.  Thus, the predicament of the situation is seemingly realistic and requires long-term-monitoring to track both populations.

Therefore, using two examples from different lion management approaches, we see conflicts within conservation and how our interventions may have inadvertent by-products that could perturb trophic interactions and ultimately shift ecosystems, which can then render the invested time and money ineffective. Although making trade-offs is unavoidable, it would be a shame to put ourselves in a lose-lose situation with either doing nothing and losing one or several species, or alternatively, to guarantee safety of one or a few whilst effectively allowing others to face the brutal demise of extinction. Clearly, how we choose to see our wildlife in the future determines how we manage them today. I believe we have the technologies, be it medicinal vaccines, or improved abilities to track and monitor populations, which can allow us to shift conservation focus from single-species level to an ecosystem-level. Rather than building fences that simply separates human and wildlife, funds should alternatively be invested  in education and mitigation of local communities and rangers to tighten and improve the relationship between humans and wildlife.

Cover picture – Source: Steve Garvie (2013).

References

[1] Packer, C., Loveridge, A., Canney, S., Caro, T., Garnett, S. T., Pfeifer, M., Zander, K. K., Swanson, A., Macnulty, D., Balme, G., Bauer, H., Begg, C. M., Begg, K. S., Bhalla, S., Bissett, C., Bodasing, T., Brink, H., Burger, A., Burton, a C., Clegg, B., Dell, S., Delsink, A., Dickerson, T., Dloniak, S M., Druce, D., Frank, L., Funston, P., Gichohi, N., Groom, R., Hanekom, C., Heath, B., Hunter, L., Deiongh, H. H., Joubert, C. J., Kasiki, S. M., Kissui, B., Knocker, W., Leathem, B., Lindsey, P. a., Maclennan, S. D., McNutt, J. W., Miller, S. M., Naylor, S., Nel, P., Ng’weno, C., Nicholls, K., Ogutu, J. O., Okot-Omoya, E., Patterson, B. D., Plumptre, A., Salerno, J., Skinner, K., Slotow, R., Sogbohossou, E. a., Stratford, K. J., Winterbach, C., Winterbach, H. and Polasky, S. (2013) Conserving large carnivores: dollars and fence. Ecol. Lett. 16, 635–41.

[2] Creel, S., Becker, M. S., Durant, S. M., M’soka, J., Matandiko, W., Dickman, a J., Christianson, D., Dröge, E., Mweetwa, T., Pettorelli, N., Rosenblatt, E., Schuette, P., Woodroffe, R., Bashir, S., Beudels-Jamar, R. C., Blake, S., Borner, M., Breitenmoser, C., Broekhuis, F., Cozzi, G., Davenport, T. R. B., Deutsch, J., Dollar, L., Dolrenry, S., Douglas-Hamilton, I., Fitzherbert, E., Foley, C., Hazzah, L., Henschel, P., Hilborn, R., Hopcraft, J. G. C., Ikanda, D., Jacobson, A., Joubert, B., Joubert, D., Kelly, M. S., Lichtenfeld, L., Mace, G. M., Milanzi, J., Mitchell, N., Msuha, M., Muir, R., Nyahongo, J., Pimm, S., Purchase, G., Schenck, C., Sillero-Zubiri, C., Sinclair, a R. E., Songorwa, a N., Stanley-Price, M., Tehou, C. a., Trout, C., Wall, J., Wittemyer, G. and  Zimmermann, A.  (2013) Conserving large populations of lions – the argument for fences has holes. Ecol. Lett. 16, 1413–e3.

[3] Chauvenet, A. L. M., Durant, S. M., Hilborn, R. & Pettorelli, N. (2011) Unintended consequences of conservation actions: managing disease in complex ecosystems. PLoS One. 6, e28671.

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