The 'oasis effect' of Welwitchsia plants on soil microbiota in the Namib Desert.

It is unclear how consistently desert and semi-desert plants are associated with a distinct soil biota. Previous studies have concentrated on the effects on soil microbiome around semi-desert angiosperms: we aimed to understand if similar effects could be found in the taxonomically isolated desert gymnosperm Welwitchsia mirabilis in the eastern Namib Desert. We took soil cores adjacent to the plants in environments ranging from extreme desert to arid shrubland, and in nearby control sites between the plants. Soil chemistry was analysed, and soil DNA was extracted and sequenced for the bacterial 16S region. Despite, the range of climates, the soil around Welwitchsia plants was consistently associated with a particular bacterial community composition, that was distinct between samples close to Welwitchsia plants, and those further away.