We define African savannahs as being those areas that receive between 300 and 1,500 mm of rain annually. This broad definition encompasses a variety of habitats. Thus defined, savannahs comprise 13.5 million km 2 and encompass most of the present range of . The comparable area shrank to 9.7 million km 2 by 2000. Areas of savannah Africa with few people have shrunk considerably in the last 50 years and human population projections suggest they will likely shrink significantly in the next 40. The current extent of free-ranging lion populations is 3.4 million km 2 or about 25 % of savannah area. Habitats across this area are fragmented; all available data indicate that between 32,000 and 35,000 free-ranging lions live in 67 lion areas. Although these numbers are similar to previous estimates, they are geographically more comprehensive. There is abundant evidence of widespread declines and local extinctions. Under the criteria we outline, ten lion areas qualify as lion strongholds: four in East Africa and six in Southern Africa. Approximately 24,000 lions are in strongholds, with an additional 4,000 in potential ones. However, over 6,000 lions are in populations of doubtful long-term viability. Lion populations in West and Central Africa are acutely threatened with many recent, local extinctions even in nominally protected areas.

African lions (Panthera leo) are in decline across many parts of the continent with retaliatory killing of lions for attacks on livestock being an important cause. In East Africa, projects are fortifying bomas to reduce large carnivore conflicts with the specific goal of preventing the indiscriminate killing of lions. A lack of evidence-based studies evaluating the impact of these efforts means their efficacy for lion conservation is not yet scientifically verifiable. We evaluated fortified bomas by comparing large carnivore attack rates at 84 unprotected bomas and 62 fortified bomas called Living Walls. The latter were 99.9 % successful in preventing nighttime carnivore attacks over 1,790 boma-months. Following Living Wall installation, there were no lion deaths at fortified bomas. Our results demonstrate the importance of predator-proof enclosures as a tool for lion conservation across the continent in areas where they inhabit human-and livestock-dominated landscapes. This study also contributes more broadly by highlighting the importance of scientifically evaluating conservation efforts.