Threat or threatened species? A paradox in conservation biology

The introduction of alien species is one of the main threats to conservation. However, the same species may be threatened and be a threat in nearby areas. This is the case of the Barbary sheep (Ammotragus lervia) and mouflon (Ovis orientalis), which greatly hinder the management and conservation of biodiversity outside their native range. To prevent the extinction of many endemic plants, it is necessary to overcome several methodological difficulties.