Study shows Barbary sheep do not compete with mountain goats and questions its status as an invasive species

A study published in the journal Animals shows that the Barbary sheep (a species of African origin introduced into the peninsula in the 1970s) and the mountain goat (native) have clear differences in their feeding habits, allowing them to share habitat without competing directly for the same resources.

The research, a collaboration between the Universitat Autònoma de Barcelona (UAB), the Spanish National Research Council (CSIC), and the Polytechnic University of Madrid (UPM), provides the first empirical evidence of apparent dietary compatibility between an exotic species and a native species within the Spanish territory, and questions the classification of the Barbary sheep as an invasive species.

“This study shows that the Barbary sheep, despite being classified as invasive, can coexist with the mountain goat without displacing it, thanks to a clear differentiation in their diets”, explains Jorge Cassinello, researcher at the Arid Zones Experimental Station (EEZA-CSIC) and lead author of the study. “Our results question the scientific basis for including it in the Spanish Catalogue of Invasive Alien Species”, he adds.

The analyses show that the Barbary sheep behaves mainly as a grazer, since 57% of what it consumes is herbaceous, while the mountain goat is primarily a browser, with 63% of its diet based on shrubs. When they coexist, the Spanish ibex adjusts its diet by increasing its consumption of herbaceous plants, while the Barbary sheep increases the proportion of woody plants in its diet during the summer, reflecting adaptive flexibility mechanisms that favor the coexistence of these two species.

“The differences in feeding habits we have detected are clear: the Barbary sheep maintains its grazing behavior, while the mountain goat prefers scrubland. This segregation greatly reduces direct competition between the two species”, says Jordi Bartolomé, professor in the Department of Animal and Food Science at the UAB and co-author of the study.

To reach these conclusions, researchers analysed more than 300 fecal samples using two complementary techniques: microhistological analysis and near-infrared spectroscopy (NIRS). “The use of NIRS has allowed us to increase the number of samples and statistically validate the results, which reinforces the robustness of the conclusions”, says Elena Albanell, professor in the same department at the UAB and specialist in this technique.

Sampling was carried out in several mountain ranges in Murcia inhabited only by Barbary sheep, only by mountain goats, or by both species in sympatry, i.e., sharing the same territory. “In the field, we have observed on several occasions the spontaneous formation of mixed groups of Barbary sheep and mountain goats grazing in close proximity without any signs of conflict,” says Sergio Eguía of MendiJob, the company responsible for selecting study areas and collecting samples.

Beyond the interaction between the two species, researchers highlight the positive role of wild herbivores in the dynamics of Mediterranean ecosystems. “The maintenance of a diverse and open landscape, rich in grasslands and clearings, depends largely on the action of large grazing herbivores, a role that the Barbary sheep can perfectly fulfill”, states Alfonso San Miguel, lecturer at the UPM and co-author of the study.

The authors conclude that the available evidence does not justify considering the Barbary sheep an invasive species on the Iberian Peninsula and propose reviewing its legal status in light of the results.

The study was funded by the Government of Murcia through the Artemisan Foundation.

Reference article: Cassinello, J., Albanell, E., Eguía, S., Roverso, A., San Miguel, A. & Bartolomé, J. (2025). When the evidence points to the non-invasive nature of an allegedly invasive alien species: the case of the aoudad in mainland Spain. Animals 15, 2683. https://doi.org/10.3390/ani15182683