The Barbary sheep ( Ammotragus lervia ) was introduced to Spain in 1970, in the Sierra Espuña Natural Park, in Murcia, for one reason: to serve as a hunting animal . Since then, it has spread throughout the provinces of Alicante, Almería, Granada, Jaén, Cuenca, Ciudad Real, Badajoz and Cáceres, in some cases due to the same expansion of the species in its colonization process, and in others, by subsequent introductions for hunting use.
In addition, in 1972, 16 specimens were released, with identical intentions, in La Palma, where it successfully settled and spread throughout the La Caldera de Taburiente National Park, and along the eastern and northeastern slopes of the island.
Barbary as an invasive species
A species is considered invasive when, after being introduced by human hands into an ecosystem and successfully naturalizing, it begins to spread rapidly, crossing what is known as a dispersal barrier , and colonizing new environments beyond where it was introduced, and continues reproducing. The invasive behavior of the Barbary sheep is, therefore, more than proven, regardless of whether or not it caused impacts.
Fortunately, successive regulations met the scientific evidence and the Barbary sheep was classified as an invasive species by the Consell de la Comunitat Valenciana in 2009. Four years later, when the Spanish Catalog of Invasive Exotic Species was created in 2013, the Barbary sheep It was included from the first version. However, the regulations establish the population of the Region of Murcia as an exception . Something that is still ironic, since it was there where the first introduction took place, and from where its invasion began.
Barbary impacts
Although the mere fact of being an invasive species is enough for its regulation and therefore to use the necessary control measures, the truth is that the blueberry also has environmental impacts that should not be ignored.
They are voracious herbivores, which massively consume the herbaceous upholstery; this, together with the actions of trampling, favors erosion in soils that, in themselves, are more sensitive to these disturbances. This circumstance, in addition to reducing the availability of food for other species, can alter the structure of the ecosystem and favor its desertification .
It is true that in the peninsula no real competition has been reported on the native populations of mountain goats; but, in a scenario of climate change , where the distribution areas of the invasive barnacle are increasingly arid, and the
resources become more scarce, added to greater pressure from this exotic species, this scenario may change. In addition, the Barbary sheep, more gregarious than the goat, could act as a vector for scabies , a disease caused by mites, which goats and Barbary sheep share, and which can jump to humans in the form of zoonosis .
Its expansion into protected areas with endemic flora can put that flora at risk, so in this case, the most effective thing would be to avoid environmental damage before it occurs, through preventive actions. In fact, in the Canary habitat, its effect is much more destructive . Among the plants consumed by the Barbary sheep there are up to 21 endemisms , many with a very high level of threat, such as the Guanche rosebush ( Bencomia exstipulata) , the snowhead ( Cheirolophus santos-abreui) , the fire beak ( Lotus pyranthus ) or the species recently discovered in La Caldera de Taburiente, Helianthemum cirae .
What should we do?
A study carried out in 2007 by researchers from the Hunting Resources Research Institute (IREC) and the National Museum of Natural Sciences (MNCN-CSIC) already concluded that, observing the cumulative effects of the Barbary sheep in Iberian Mediterranean ecosystems, its presence « it should be considered a major problem for the ecosystem”, and that, despite the opposition of hunting groups, the optimal measure to take “should be the eradication of the species” from the areas where it is invasive. In this sense, “time is critical, and if action is not taken in the near future, the ongoing expansion of the species will reduce possible management alternatives.”
Since this study was conducted, the Barbary Sheep has continued to spread far beyond where it was initially found. And these actions must be launched not only where the management measures dictated by the Catalog require it, but also in the Region of Murcia , where the Catalog itself establishes an exception, solely based on the pressure of the groups that, for interest, oppose its eradication.
Experience tells us that every time actions aimed at the maintenance and conservation of ecosystems are violated or restricted by the interest of a few, the result does not usually turn out well. We have seen this with eucalyptus and cellulose extraction companies; or with the prickly pear and its cultivation; we have seen it with American mink and fur farms; It has also happened with certain invasive fish in our rivers and some groups of fishermen. With the barbary, we find ourselves in the same situation.
References:
Acevedo, P. et al. 2007. Invasive exotic aoudad (Ammotragus lervia) as a major threat to native Iberian ibex (Capra pyrenaica): a habitat suitability model approach. Diversity and Distributions, 13(5), 587-597. DOI: 10.1111/j.1472-4642.2007.00374.x
Blackburn, T. M. et al. 2011. A proposed unified framework for biological invasions. Trends in ecology & evolution, 26(7), 333-339. DOI: 10.1016/j.tree.2011.03.023
BOE. 2013. Royal Decree 630/2013, of August 2, which regulates the Spanish Catalog of invasive alien species. BOE, 185(Sec. I.), 56764-56786.
Vila, M. et al. (Eds.). 2008. Biological invasions. Superior Council of Scientific Research.
