Aoudad sheep, once brought to the American Southwest for hunting, are now thriving in its arid landscapes. Image Credits: Wikimedia Commons.
Because the same type of steep, arid country is occupied by desert bighorn sheep, including the protected Peninsular population of the Santa Rosa Mountains, in California, this matters. Because of their size, distinctive horns and hardiness in harsh conditions, wildlife managers introduced the animals in different areas. Aoudad, also known as Barbary sheep, are native to the mountains and deserts of northern Africa, but were introduced to parts of the American Southwest as exotic game animals. Aoudad were introduced into the Southwest for hunting and subsequently established wild populations, according to the National Park Service . However, once introduced, the aoudad became less reliant on management by humans.
Their ability to survive in dry, rugged terrain eventually brought them into contact with native species that depend on many of the same resources. In desert environments, their ability to tolerate heat, use rugged terrain and feed on a wide range of plants has allowed them to persist. From game animal to established population The introduction of aoudad to the American Southwest came through intentional releases. Their adaptability allowed them to establish themselves in landscapes that many large mammals struggled to inhabit.
The California Department of Fish and Wildlife says the Santa Rosa Wildlife Area covers about 101,500 acres and contains the largest herd of protected Peninsular bighorn sheep in the United States. They identified 88 plant genera consumed by the two species. The National Park Service describes aoudad as an introduced species that has become established in several parts of the Southwest, while noting that they can occupy habitat once used by native bighorn sheep. It raises the question of how an introduced sheep species fits into an ecosystem that already has a native one, especially when wildlife managers are trying to conserve scarce resources for both.
The Peninsular bighorn sheep exist in geographically isolated herds from the San Jacinto Mountains all the way down to the Mexico-California border, according to the California Department of Fish and Wildlife. Lamb survival may vary significantly among populations and seasons and may be affected by rain that influences the productivity of vegetation and diseases, according to CDFW. That adaptability is particularly important in desert ecosystems. The history shows how an introduction made for hunting can later become a wildlife-management problem. California’s Santa Rosa Mountains provide an important example of the habitat at stake. When two sheep use the same desert The issue stems from how similar the two species are. Both aoudads and desert bighorn sheep have adapted to living in mountainous and rocky areas in arid climates. Both species also rely on vegetation and water resources that are especially limited at certain times of year. The California Department of Fish and Wildlife further adds that Peninsular bighorn sheep inhabit a small geographical area at the base of the Peninsular Ranges. The distribution of this type of animal is influenced by such factors as topography, visibility, water sources, and the amount of forage available. Canyon bottoms, washes, and alluvial fans become particularly important since they provide water and forage sources. Research published in the Journal of Wildlife Management provides a closer look at what happens when the two species share the same landscape. Scientists analysed the diets of aoudad and desert bighorn sheep in the Sierra Vieja Mountains of West Texas using DNA metabarcoding of faecal samples. The diets were more similar during the warm-dry season, when forage was more limited, suggesting that periods of resource scarcity could increase the potential for competition. There was another important difference in their diets. Whereas bighorn sheep preferred higher-quality forage, aoudads had a more general diet and could use lower-quality food sources more efficiently. This finding does not prove that aoudad are displacing bighorns in California, but it helps explain why competition between the two species is a concern. Image Credits: Wikimedia Commons. A longer conservation challenge Competition with yet another herbivore is only one part of a broader conservation challenge for desert bighorn sheep. Desert bighorn sheep inhabit naturally limited regions, and the presence of water and suitable grazing areas determines the location and size of each herd. Migration between herds is important for reaching resources and maintaining genetic links between them. Environmental factors affect the animals in their natural habitat as well. The monitoring includes ground surveys and satellite and VHF collar tracking for the purpose of studying the movement patterns of the animals. Thus, the aoudad story goes beyond the species’ initial introduction as a game animal. Catch the latest World News and Live updates. Download the TOI app.
