Space use and survival of reintroduced Persian onagers

Abstract Reintroduction is a conservation priority aimed at restoring native species to parts of their historical range through the release of wild or captive‐bred individuals. However, little is known about how reintroduced populations respond to habitat features and management interventions, such as the placement of ranger stations or the use of individuals from different origins. We evaluated the reintroduction of the Critically Endangered Persian onager ( Equus hemionus onager ) in Kavir National Park, Iran, a desert ecosystem largely devoid of human disturbance. We conducted daily foot surveys (2022–2023) and collected demographic data from 2018 to 2024. Using Bayesian occupancy models and demographic analyses, we addressed two questions: (i) How is onager occupancy influenced by trade‐offs between habitat characteristics and proximity to ranger stations? and (ii) to what extent do interventions, such as periodic restocking, affect survival and population growth over time? Occupancy was positively associated with Artemisia–Zygophyllum shrub communities and proximity to ranger stations, highlighting the importance of habitat quality and law enforcement. These shrublands, largely confined to central and eastern regions of the park and isolated by unsuitable vegetation and salt plains, appear to constrain broader range occupancy. Demographic analyses revealed high initial mortality linked to translocation stress and social aggression within the acclimatisation site, and none of the wild‐born individuals were likely to have survived. Cumulative survival declined over time, suggesting that repeated mortality events may threaten long‐term population viability. Practical implications: These findings highlight the need for adaptive reintroduction strategies, including optimising group composition, reducing translocation‐related stress and social aggression, and adaptive post‐release monitoring to improve survival and long‐term population persistence.