Factors affecting populations of the endemic Iberian hare (Lepus granatensis) after the first myxomatosis outbreaks in Central Spain

Abstract

The Iberian hare (Lepus granatensis) is an endemic species distributed in Spain and Portugal. Myxomatosis outbreaks affecting this species were detected in 2018 in Central and Southern Spain, spreading afterward. Aiming to evaluate factors affecting the status of hare population after the arrival of myxomatosis, we conducted 108 nocturnal hare counts in Central Spain during two study periods (winter/spring and summer/autumn) in 54 different hunting grounds, covering 1071 km and observing 884 individuals. The mean density in winter/spring was 7.66 hares/100 ha, (range 6.14–9.54/100 ha), while in summer/autumn, it was 3.4 hares/100 ha (range 2.6–4.4/100 ha). Densities of hares were not affected by the dominant habitat and the presence/absence of myxomatosis outbreaks. Hares were more abundant at hunting grounds at a higher altitude and in those conducting targeted management, while detection of myxomatosis was related to lower altitude and higher levels of game management. A MaxEnt model used to generate a risk map for myxomatosis occurrence showed that the temperature annual range was the most important predictor, which suggests that environmental factors affecting myxomatosis vectors (mosquitoes, fleas, and ticks) could play a key role in disease transmission. As myxomatosis in hares is becoming endemic, hare densities may be improved by game management and the monitoring and surveillance of this emerging disease. These surveillance programs could be the basis of effective collaborations between hunters, researchers, and environmental managers.