Land-use intensity affects range condition in arid to semi-arid Namibia

Abstract

Range condition at sites of differing land-use intensity at a communal farm was assessed. Vegetation, soil and termite parameters were tested for their potential as indicators. The vegetation indicators did not discriminate between two sites of high and low land-use intensity. However, the soil fertility parameters provided interesting results. The phosphorus (P), nitrogen (N), organic carbon (OC), light fraction (LF), C:N and C:LF data indicate that nitrogen limitation is more critical under high land-use and grazing pressure. Organic carbon levels are generally low but reduced to critical levels under high land-use intensity; nutrients such as phosphorus and nitrogen are conserved in the system, whereas organic carbon losses are high and inputs low. The conversion of the ‘active carbon pool’ into the ‘slow pool’, a prerequisite for long-term soil resilience, is not taking place under high land-use intensity. Termites might play an important role in maintaining range condition.