To give you an idea of the productivity variations possible for brittle grasslands, here are some approximate figures on the amount of land required to support 1 large livestock unit (i.e., a producing cow) year-round under very good management. Bear in mind that productivity varies greatly within categories (across various cold steppes, for example).

• 35" (890 mm) high-rainfall tropical savanna in Zimbabwe: 2.5 acres (1 hectare)
• High-production brittle grassland, U.S.A.: 2-10 acres (0.8-4 ha)
• Medium-production brittle grassland, U.S.A.: 10-25 acres (4-10 ha)
• Low-production brittle grassland, U.S.A.: 25-100+ acres (10-40+ ha)
• High Lonesome (mild steppe): 50-60 acres (20-24 ha)
• Our place in Colorado (cold steppe): 30 acres (12 ha)
• Dave James's winter range in southeastern Utah (6" [150 mm] of very erratic and unreliable precipitation): 200 acres (80 ha)