 This scheme includes these desert ecoregions in the Palearctic realm; other biogeographers identify the boundary between realms as the transition zone between the desert ecoregions and the Mediterranean basin ecoregions to the north, which places the deserts in the Afrotropic, while others place the boundary through the middle of the desert.Gazelles, oryx, sand cats, and spiny-tailed lizards are some of the desert-desert-adapted species that survive in this extreme environment.Many species, such as the striped hyena, jackal and honey badger have become extinct in this area due to hunting, human encroachment and habitat destruction.