A review of field techniques to estimate lion presence and abundance

1. Since the 1990s, the number of lions (Panthera leo) has declined by about 43% across African range states. Reliable lion population estimates can contribute to effective management and inform local and international conservation policies. Though many survey methods have been used to estimate lion abundance, an assessment of their usefulness and effectiveness is lacking.2. We reviewed and identified available methods used to estimate lion populations, then investigated their feasibility, cost-effectiveness and suitability to achieve primary objectives.3. We identified 12 methods in two categories: direct (minimum counts, call-in surveys, capture-recapture, opportunistic sightings, remote cameras, distance-based and aerial counts) and indirect (track counts, secondary information, prey-based, genetic samples and roar counts).4. We identified 48 studies (57%) in which lion population estimation was not repeatable. Additionally, 38% did not provide any measure of precision. About 28% of the studies were conducted specifically for management purposes, while remaining studies focused on population estimates and dynamics.5. Because data from these studies have influenced local management and global lion conservation policies, we recommend basing future policies and management on repeatable, precise and accurate population estimates supported by appropriate and cost-effective experimental designs. In most cases, these estimates are obtained through actual lion counts derived from direct observation methods including call-in, capture-recapture and remote camera surveys or through reliable animal signs such as genetic samples.