Misconception and mismanagement of invasive species: The paradoxical case of an alien ungulate in Spain

Scientific evidence should dominate in any management decision dealing with alien species. It is also essential for all stakeholders to agree on the terminology used to avoid undesirable misinterpretations. A well-known example is the use of the term "invasive," which has two basic meanings, one as a biogeographic criterion and the other as an impact criterion. The aoudad (Ammotragus lervia) is a North African ungulate introduced in Spain, which was labeled "invasive" by Spanish authorities due to misreading of the term used by early studies. Indeed, to date, there are no conclusive empirical data showing negative effects of the aoudad on native flora and fauna. Recent studies have shown that its closest native ungulate, the Iberian ibex (Capra pyrenaica), has expanded throughout territories already occupied by the aoudad, without any apparent conflict. Aoudad diet selection studies also show them to be markedly grazers, so its role in the Mediterranean trophic network might be similar to that of extinct wild ungulates that fed in natural meadows, maintaining landscapes heterogeneous. New opportunities for its study are opening, particularly in Iberian semiarid lands. Unfortunately though, its current simplistic definition as an invasive species keeps in suspense its eventual eradication throughout the country.