A preliminary botanical assessment of an isolated inselberg archipelago in the Namib Sand Sea, Namibia

The inselbergs of the Namib Desert serve as biodiversity refugia in a matrix of largely depauperate gravel plains or sand dunes. Despite their ecological importance and expected species richness, the biota of most Namib inselbergs has not been surveyed. An isolated and previously unexplored inselberg archipelago in the northeastern corner of the Namib Sand Sea was visited in December 2023. A preliminary botanical assessment recorded 42 plant species across three inselberg sites. The floristic survey was conducted by walk-over assessments and capturing photographic records that were uploaded to iNaturalist for public access. Euphorbia Koppie exhibited the highest diversity at 38 species, attributed primarily to its larger size and habitat heterogeneity, while the smaller Commiphora Koppie and Owl Koppie recorded 16 and 14 species respectively. Frequently recorded species across all three sites include Commiphora saxicola, Cleome angustifolia subsp. diandra, Caroxylon sp., Euphorbia glanduligera, Tephrosia dregeana, Tetraena cylindrifolia and Stipagrostis ciliata. This survey contributes valuable baseline data for future biodiversity assessments and conservation efforts in the Central Namib Desert at a time of increasing threat from tourism, infrastructure development, mineral prospecting, poaching and mining activities.