Diets and Resource Sharing Among Livestock on the Saiq Plateau, Jebel Akhdar Mountains, Oman

摘要

A standard method of fecal plant cuticle analysis was used to determine the diets of goats, sheep and feral donkeys on the Saiq Plateau of Oman during a year of below average rainfall. Feces were collected monthly from 8 localities. Twenty-three thousand four hundred digital cuticle images of the feces and the plant reference collection were stored in a Microsoft Access~(C) database. This computer-assisted system greatly increased the speed and efficiency of plant identification, data manipulation and analysis. Goats, sheep and donkeys consumed 37, 32 and 30 species respectively, consisting mostly of plants that have high to moderate coverage in the community (Helianthemum lippii, Sideroxylon mascatense, Cymbopogon sp., Olea europaea, Teucrium mascatense, Juniperus excelsa). A few species with low coverage had a moderate occurrence in the diets (Farsetia sp., Eragrostris barrelieri, Cenchrus ciliaris). Goats and sheep ate more species of dicots than monocots, but donkeys consumed them in equal proportions. No notable seasonal changes occurred in the diets during the brief dry period. Diet overlap among goats, sheep and donkeys was high (median O_(jk) = 0.836) and asymmetrical; a moderate number of plant species eaten by donkeys are also eaten by goats and sheep (O_(jk) = 0.63), but most plants consumed by goats and sheep are also eaten by donkeys (O_(jk) = 0.85 and 0.82, respectively). Depending on stocking levels, this high degree of diet overlap may be decreasing the productivity and reproduction of the food plants as well as that of the goats and sheep, which commonly require supplemental feeding. Juniperus excelsa, a threatened tree, was moderately common in the diet of goats and sheep. Several possible impacts of domestic animals on wild species are discussed. Range productivity and stocking levels need to be quantified as a first step toward developing a sustainable animal industry on the Saiq Plateau.