The Devils in the Details—but So Are the Angels: Linear Density Estimates of Harpagophytum zeyheri (Devil's Claw) From the Zambezi Region, Namibia

Abstract

Harpagophytum zeyheri (devil's claw) tubers are manually harvested for its pharmaceutical properties (anti-inflammatory) in the sandier regions, especially the communal areas in north-eastern Namibia, with various authors having questioned the sustainability and viability of current harvesting practices. Although regulation in the form of a quota system is implemented, this is not based on scientifically established density estimates or sustainable harvesting quotas. There is a dearth of published data regarding density estimates for H. zeyheri from Namibia. The average linear density from the Zambezi Region (all areas; this study) is 22.4 plants/km while other estimates from Namibia for H. procumbens vary between < 1 and 2000 plants/ha. The aim of this study was to contribute to the poorly known distribution and density of H. zeyheri from the Zambezi Region where most of Namibia's resource for the export market originates from and to highlight the potential threat of not conducting scientifically based preharvest counts on sustainability of this valuable resource.