Seasonal diets of sheep in the steppe region of Tierra del Fuego, Argentina

• Published in: Journal of range management Vol. 49; no. 1
• Main Authors: Posse, G. (CEVEG-CONICET, Buenos Aires, Argentina.), Anchorena, J, Collantes, M.B
• Format: Journal Article
• Language: English
• Published: 01.01.1996
• Subjects: ALIMENT POUR ANIMAUX; ARGENTINA; ARGENTINE; BIODIVERSIDAD; BIODIVERSITE; COUVERT; CUBIERTA DE COPAS; DIETA; ELEMENTO PRIMARIO DEL SUELO; ESTEPAS; FESTUCA; HERBAGE; OVIN; OVINOS; PIENSOS; PLANTAS LENOSAS; PLANTE LIGNEUSE; PRADERAS; REGIME ALIMENTAIRE; ROCHE MERE; SOL D'HERBAGES; STEPPE; SUELO DE PRADERAS; VARIACION ESTACIONAL; VARIATION SAISONNIERE
• ISSN: 0022-409X; 2162-2728
• DOI: 10.2307/4002720

Sheep diets were determined seasonally for large flocks grazing year-round in 2 landscape types of the Magellanic steppe of Argentina. A tussock-grass steppe of Festuca gracillima Hooker f. dominates the uplands of the whole area. On acid soils (Quaternary landscape), woody variants of the steppe prevail; on neutral soils (Tertiary landscape), woody plants are almost absent and short grasses and fortes are abundant. Principal taxa consumed throughout the year were: Poa L., Deschampsia P.Beauv., and "sedges and rushes". Consumption of woody species and of the dominant tussock-grass Festuca gracillima increased notably in winter. Despite the large proportion of species in common, diets differed significantly between landscapes. In the Quaternary landscape, which has a higher botanical diversity, diets were more dissimilar among seasons and had a higher annual diversity index. Because of their different composition of forage types the 2 landscapes differed in their overall grazing value. The Tertiary landscape, with a low floristic diversity but richer in highly preferred species as Poa spp. would be a more risky grazing area in winter, when an ice sheet or a snow cover limits harvesting of the lower layer of short grasses and forbs