Estimation of tiger densities using photographic capture-recapture

This methodological breakthrough applied camera trapping and capture-recapture statistics to estimate tiger density from the unique stripe patterns that identify individuals. By treating photographs as captures, the authors derived rigorous, statistically defensible density estimates with measures of uncertainty, replacing unreliable pugmark counts. The approach accounted for the probability that a tiger present in an area might not be photographed, a crucial correction that earlier methods ignored. The study transformed tiger monitoring worldwide, providing a repeatable, scientifically sound way to track populations and evaluate conservation interventions. It became the template for camera-trap surveys of striped and spotted cats globally. For anyone following tiger conservation, this paper underpins the population numbers reported for reserves across Asia and the methods used to detect whether tigers are increasing or declining.