Lion populations are becoming increasingly fragmented within insular reserves, closed to natural immigration [1-2]. Whereas previously natural re-colonization had been possible, the opportunities for such events today are greatly reduced or non-existent. This trend increasingly applies even within countries with previously substantial lion populations outside protected areas. Natural re-colonization thus increasingly requires emigration from an occupied area through an inhospitable habitat matrix .
An interventionist approach to species management, including lion conservation, has increasingly been adopted through translocation and reintroduction [4-11]. The reintroduction of lions has well-practiced techniques [4, 12-13] although small numbers of animals have been involved. Over thirty sites in South Africa have reintroduced lions over the past two decades  with methods being adopted in other countries undergoing land-use changes, such as Namibia . Many of these reintroductions however have added little to the conservation of the species as they have been conducted at the incorrect social scale with failures to manage non-viable reintroduced populations within a meta-population framework .
Reintroductions may be suitable in protected areas where lions have been extirpated or where extant populations have become genetically non-viable and natural re-colonization is unlikely. Examples could include countries recovering from civil war such as Angola, Mozambique, Rwanda and Uganda , or where closed populations would benefit from an infusion of genetic material, such as in the Ngorongoro Crater . There, while lions recovered from a severe disease epizootic in 1963, three subsequent outbreaks between 1994 and 2001 occurred in such rapid succession that this isolated population has been unable to recover. Kissui and Packer  consider that the Crater population may have become usually vulnerable to infectious disease in recent years owing to its close proximity to a growing human population (including their domestic dogs) and a history of inbreeding. The Crater lions may therefore provide important insights into the vulnerability of many isolated lion populations.
Since the lion population has dropped so rapidly during the past few decades we do not know how drastic a measure might have to taken a decade from now to ensure the survivability of lion populations in Africa. However, reintroduction will become increasingly more important as affirmed by the IUCN  due to the rapid increase in the number of small and even large resurrected reserves  and the expansion of threats to wildlife. In addition, small populations will require active management to maintain genetic diversity . A question exists therefore on the possible sources of lions for such reintroduction programs.
Whenever possible, reintroductions should include the release of young adult wild lions captured for the purpose of translocation. These can be released into areas which are known to support adequate wild prey, and where effective programs to mitigate threats to reintroduced populations are underway. In such cases wild caught animals will be maintained in large pens within the release area for several months (“soft release”) to reduce their tendency to return to the area from which they originated.
“The reality of the current situation is that it will not be possible to ensure the survival of an increasing number of threatened taxa without effectively using a diverse range of complementary conservation approaches and techniques including, for some taxa, increasing the role and practical use of ex situ techniques. If the decision to bring a taxon under ex situ management is left until extinction is imminent, it is frequently too late to effectively implement, thus risking permanent loss of the taxon.” IUCN Technical Guidelines on the Management of Ex-Situ Populations for Conservation (2002) (pdf)
If the reintroduction of wild caught lions is not possible, desirable, or if the results are poor, we can attempt multi-stage programs to reintroduce lions bred from wild-living individuals. Suitable lions would be bred in large fenced areas, along with natural game, carefully shielded from human contact. The resulting cubs, not habituated to humans and taught to hunt by their wild-living parents, would then be reintroduced into suitable wild areas. After their release, the next generation of cubs would then be reared.
Founder populations for the multi-stage program may originate from captive individuals. Suitable disease-free captive lions, which lack hunting skills, are bred and their offspring raised around humans; entering stage one of the African Lion Rehabilitation & Release into the Wild Program. Later, once these offspring mature they are used to form prides that are released into semi-wild environments with natural game, and human contact removed. Their non-human habituated cubs born in these areas are then released, at an appropriate age, into the wild after pre-release training by their parents. In some areas the release of the re-wilded captive bred individuals or prides may also be possible and desirable.
The semi-wild environments provide opportunities for well-controlled experiments on all aspects of the captive versus wild situations, and refinement of proposed reintroduction protocols. For instance, should captive-reared youngsters not learn to hunt well, we might try adding experienced, wild-caught individuals to the captive-reared group, recognizing that integration into the existing social mix might be challenging. With properly designed holding facilities, we will have the flexibility to try different approaches to group formation. Rearing them in captivity would also permit experiments in aversive conditioning to avoid livestock. Finally, an important part of this approach is that the Walk with Lions Program raises tourism funding to contribute to the costs of this program, but also many other conservation projects. It also creates many jobs for the local community. Thus it becomes an integral part of a self-sustainable conservation model that gives local communities a reason to not only protect wildlife populations, but also to encourage their growth.
By taking the above multi pronged approach we can scientifically study each of them to determine which program, or combination of programs, is most appropriate under specific conditions. While some may say there is no need to study captive breeding programs since there are still many wild lions, we want to study all approaches, and combinations of them, to get a better scientific understanding of each and their differences under controlled scientific conditions. ALERT will seek expertise from successful felid introduction programs such as those involving private reserves in South Africa, and other actual reintroduction programs.
This project of studying all approaches is funded through external sources and the development of ecotourism operations around as many elements of the program as are possible. Crucially, by ensuring that local communities living near the program's conservation areas are fully involved in the revenue generating potential, the development of relevant sustainable support for conservation is achieved.
Further, all elements of the program seek to address the broader issues in lion conservation at each project site. This includes the complete rejuvenation of the wildlife area including all environmental and biotic factors, habitat protection and mitigation of the reasons why local lion populations declined in the first place.
Providing adequate protection for prey resources in a large area is a major undertaking, requiring considerable effort and political will on the part of national and local government and neighbouring human communities. ALERT supports the training and equipping of park guards, anti-poaching units, and resource assessment teams. Park infrastructure needs to be renovated, tourism facilities built and support staff trained. We also help surrounding communities improve farming and livestock-rearing practices in order to end their reliance on bushmeat, thereby allowing prey populations to recover. We also work with them to secure livestock from attacks by lion populations. Wildlife-based enterprises and other tourism operations are established in order to provide financial sustainability to programs and improve the livelihoods of neighbouring communities through benefit sharing. Underlying all development efforts is the understanding that local communities must see wildlife as essential to their economic well-being if they are to protect it.
The long-term viability of current lion conservation strategies: A role for ex situ reintroduction
A framework for the ex situ reintroduction of the African Lion
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