Satellite based long-term assessment of rangeland condition in semi-arid areas: An example from Botswana

A methodology was devised for comparison of generalised range condition over time, irrespective of the nature of original imagery used. It was applied for range condition change mapping throughout Botswana through 1984-2000. Results showed that range degradation was most widespread during the 1980s drought when 25% of the country was affected, decreased to 6.5% in 1994 and increased to 9.8% in 2000. This suggests that these semi-arid rangelands are fairly resilient and can withstand “normal” droughts even under conditions of heavy grazing pressure. However, degradation that persists during normal or above average rainfall years is related to increasing livestock and other pressures on rangelands and may represent areas with severe range recovery problems. This application meets some requirements of a semi-arid developing country looking to improve range condition monitoring over relatively remote areas.