Using apex predators, charismatic species, and animal diversity as a proxy for biodiversity.

Abstract

Due to logistical, financial, and methodological constraints, comprehensive monitoring of all species within ecosystems is often impractical, leading conservation science to rely on proxy indicators of biodiversity. Among the most widely used proxies are apex predators, charismatic species, and animal diversity metrics. This literature review synthesizes empirical evidence published between 2021 and 2025 to evaluate the effectiveness, limitations, and ecological validity of these three proxy approaches across terrestrial, freshwater, and marine ecosystems. The review compares how well apex predators and charismatic species reflect broader biodiversity patterns relative to direct measures of animal diversity, including species richness, functional diversity, phylogenetic diversity, and behavioural or trophic metrics. Findings indicate that apex predators can be reliable indicators of trophic integrity and habitat quality in relatively intact, large-scale ecosystems, but their proxy performance weakens in human-modified landscapes and when assessed using simple presence–absence measures. Charismatic species are effective for public engagement and conservation awareness but exhibit strong taxonomic, geographic, and detection biases that limit their ecological representativeness. In contrast, animal diversity metrics—particularly those incorporating functional, phylogenetic, and behavioural dimensions—consistently demonstrate greater sensitivity to ecological change and provide earlier warning signals of biodiversity loss. Overall, the review highlights that no single proxy is sufficient for biodiversity monitoring. Instead, multi-metric and context-specific approaches that integrate proxy species with direct biodiversity measures are essential for effective conservation planning and decision-making under accelerating global environmental change.