Plant species in arid environments are often widely spaced making population assessments difficult. In order to minimise observer bias we tested two repeatable simple methods during red data assessments in the southern Namib Desert. Both the transect-based and the quadrat-based method resulted in over-estimates of the true population size. However, because of case of application, the transect method warrants further development. Keywords: karoo, Namibia, Sperrgebiet, succulents.