Lions are losing out on the savannahs of Africa

There may be as little as 32,000 lions left in the wild in Africa, and their savannah home is shrinking rapidly in the face of human population expansion. This is the grim message of the wild cat charity Panthera and a team of scientists from across the globe.

The habitable area for lions in the African savannah is now only 3.4 million square kilometers, 25% of the amount potentially available to them. The lion’s plight is even worse than this number suggests, as much of the territory available to them is not in one accesible area, but fragmented into around 67 small ‘islands’ of habitability. The ‘oceans’ in between each island prevent populations from interacting, raises the likelihood of deleterious inbreeding and puts each subpopulation in greater danger of dying out.  This situation is also occuring in Asia, where a subspecies of lion - Panthera leo persica - has diminished to a population of just 400 individuals, all descended from a dozen individuals. Some islands in Africa have less than 50 lions, and are isolated by hundreds of miles.

 

The team took the most up-to-date estimates for lion populations in the continent. Then using high resolution satellite maps of the continent, they overlaid as much useful information as they could. Protected areas, hunting grounds, national parks, human habitation, and more were all overlaid. From this, the team could deduce where lions were most likely to be found, and in how many numbers. The figures are obviously not definite, but good working estimates that can be used to help guide future decisions into the lions’ welfare.

Like the Asiaitic lion, lions in Africa are currently classified as ‘vulnerable’ by the International Union for Conservation of Nature, meaning there is a significant risk of them becoming extinct in the wild in the near future.

The greatest threat to the survival of the lions is their shrinking habitat, caused almost entirely by humans. Since 1960, dense human populations have expanded into 2.2 million square kilometers of savannah. With growing population numbers, and a heavy political motivation for development, huge swathes of land are being turned over to agriculture and industry.

This new research shows that, while a population of 30,000 or so lions is not in immediate danger, this is only the case if the population is geographically cohesive. Populations are stronger and more resilient together. Apart they are much more likely to fall. Of all the areas the team of scientists found, only 67 has large and stable populations – so called lion strongholds.

Panthera’s Lion Program Survey Coordinator, Dr. Philipp Henschel said:

“Lions have been hit hardest in West Africa, where local governments often lack direct incentives to protect them. While lions generate billions of tourist dollars across Eastern and Southern Africa, spurring governments to invest in their protection, wildlife-based tourism is only slowly developing in West Africa. Currently lions still have little economic value in the region, and West African governments will require significant foreign assistance in stabilizing remaining populations until sustainable local conservation efforts can be developed.”

A conservation idea that has had success in other areas – including the increasingly deforested Borneo rainforest – is that of the ‘conservation corridor’. As a result of some disturbance – say a new road or settlement – a population of animal can easily be split in two, with each sub population threatened as a result. Building some sort of link between the two, such as a path of protected ground can effectively reunite the populations.  If such an initiative could be undertaken to link lion strongholds together, it could give the populations a fighting chance.

On the ground fieldwork has to be carried out. Population estimates using satellite maps are useful, but can only go so far. Many areas of Africa are still unexplored in terms of lion censusing. Only with more information can a viable plan to save this most majestic of cats be formulated.

The article, published in the journal Biodiversity and Conservation, is open access, and can be viewed here.

You can help out Panthera with their important work in conservation and find out more at their website. 

ResearchBlogging.orgRiggio, J., Jacobson, A., Dollar, L., Bauer, H., Becker, M., Dickman, A., Funston, P., Groom, R., Henschel, P., Iongh, H., Lichtenfeld, L., & Pimm, S. (2012). The size of savannah Africa: a lion’s (Panthera leo) view Biodiversity and Conservation DOI: 10.1007/s10531-012-0381-4

Charlie

Charlie is a science writer from London. He tweets @UnpopSci.

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