Reproductive Collapse of Golden Eagles in Oman’s Hyper-Arid Desert: Conservation Implications for Marginal Populations in Extreme Environments

Abstract Hyper-arid ecosystems operate close to physiological tolerance limits, such that relatively small increases in temperature may trigger abrupt and non-linear demographic responses once critical thresholds are exceeded. We analysed long-term climatic trends (1980–2026) and reproductive dynamics of the Golden Eagle ( Aquila chrysaetos ) in the hyper-arid central desert of Oman, one of the southernmost and most climatically marginal populations of the species. Reproductive and occupancy data were derived from repeated surveys conducted at a minimum of 21 confirmed breeding territories (144 survey visits), complemented by an independent long-term observational dataset (1975–2020; 675 records). Mean annual temperature increased by more than 2 °C over the study period, while precipitation remained persistently low (<40 mm yr◻ 1 ). Confirmed reproductive activity declined sharply and collapsed to near zero beyond a narrow thermal threshold (∼28.3–28.6 °C), despite intermittent adult presence. Reproductive activity was strongly negatively correlated with temperature, whereas precipitation showed a secondary effect that did not rescue reproduction once thermal limits were exceeded. Independent demographic observations revealed progressive loss of juveniles and immatures and dominance of isolated adults. Together, these results provide strong evidence for climate-driven functional extinction sensu reproductive failure, with demographic erosion occurring well before adult disappearance, highlighting extinction-debt dynamics in long-lived desert raptors under ongoing climate warming. This study has implications for climate adaptation policies in arid regions of the Arabian Peninsula.