A species population reduction of approximately 30% is suspected over the past two decades (= approximately three Lion generations). The causes of this reduction (primarily indiscriminate killing in defense of life and livestock, coupled with prey base depletion: Bauer 2008), are unlikely to have ceased. This suspected reduction is based on direct observation; appropriate indices of abundance; a decline in area of occupation, extent of occupation and habitat quality; and actual and potential levels of exploitation.

Estimating the size of the African Lion population is an ambitious exercise involving many uncertainties. The three main efforts (Ferreras and Cousins 1996; Chardonnet 2002; Bauer and Van Der Merwe 2004) all use different methods. The African Lion Working Group compiled individual population estimates primarily from protected areas (23,000 Lions: Bauer and Van Der Merwe 2004). In 1980, Ferreras and Cousins (1996) predicted 18,600 Lions to occur in protected areas. This was probably an underestimate as not all protected areas inhabited by Lions at that time were included. Still, the comparison suggests that the number of Lions in African protected areas has remained stable or possibly increased over time. But Ferreras and Cousins (1996) predicted that most Lions in 1980 were found outside protected areas. Chardonnet (2002) finds that unprotected areas still comprise a significant portion (half) of the Lion's current African range. Comparison of Ferreras and Cousin's (1996) prediction of 75,800 Lions in 1980 (roughly three Lion generations ago) to Chardonnet's (2002) estimate of 39,000 Lions yields a suspected decline of 48.5%. This calculation suggests a substantial decline in Lions outside protected areas over the past two decades. Ferreras and Cousins (1996) may have over-estimated the African Lion population in 1980, as their number was derived from a model rather than actual Lion counts, and so it is possible that the rate of decline of the African Lion population may be lower. A group exercise led by WCS and the IUCN SSC Cat Specialist Group estimated that 42% of major Lion populations were declining (Bauer 2008). The rate of decline is most unlikely to have been as high as 90%, as reported in a series of news reports in 2003 (Kirby 2003, Frank and Parker 2003).

In Sub-Saharan Africa, the Lion conservation community works in the context of four regions: West, Central, East and Southern. The Lion population is classified as regionally Endangered in West Africa (Bauer and Nowell 2004). It is isolated from Lion populations of Central Africa, with little or no exchange of breeding individuals (Chardonnet 2002, Bauer and Van Der Merwe 2004). The number of mature individuals in West Africa is estimated by two separate recent surveys at 850 (Bauer and Van Der Merwe 2004) and 1,163 (Chardonnet 2002). Both estimates are well below the Endangered criterion level of 2,500. Lions in West Africa are grouped into three isolated subpopulations by Chardonnet (2002) and approximately seven by the African Lion Working Group (Bauer and Van Der Merwe 2004). Chardonnet?s (2002) three subpopulations consist of 18 different individual populations, between which there may be some interchange of individuals, although this is unknown. There is disagreement over the size of the largest individual population in West Africa: the African Lion Working Group (Bauer and Van Der Merwe 2004) estimates 100 Lions in Burkina Faso?s Arly-Singou ecosystem, while Chardonnet (2002)