Beyond numbers: Prioritizing population health in the next era of wildlife conservation

Conservation efforts have led to significant recoveries in the population numbers of many endangered species, including the Siberian crane (Leucogeranus leucogeranus). However, how to accurately evaluate conservation effectiveness has become a new global challenge. A persistent misconception in conservation practice is the overemphasis on population numbers while overlooking population health. In this perspective, we argue that population numbers alone is an insufficient indicator of conservation success. Using the case of the Siberian crane at Poyang Lake, we highlight emerging concerns: although population numbers have increased substantially, the species now faces high ecological and health risks due to habitat degradation, artificial land use, and increased disease exposure. A growing proportion of the population is now concentrated in agricultural habitats, such as rice paddies and lotus ponds, where exposure to pesticides, microplastics, and cross-species pathogens is elevated. We propose a multidimensional framework for assessing population health, integrating physiological, genetic, demographic, disease-related, behavioral, and environmental indicators. This paradigm shift is essential to ensure that endangered wildlife populations are not only numerically recovering but also resilient and viable in the face of growing environmental challenges.