The arid central dune field of the Namib Desert is characterized by a pronounced rainfall gradient across its west-east, 160 km breadth, and a correlated increase in sand stability and grass community complexity. In addition to these macro-gradients, micro-gradients of sand stability and available moisture across each dune slope result in stratified grass communities on the dunes. The effects of abiotic factors and plant associations on the community structure of VA-mycorrhizal fungi in a naturally arid and unstable grassland could thus be investigated. Mycorrhizal fungal communities associated with five grass species were sampled at sites located across the gradients. Keywords: dune ecology, fungal diversity, moisture, mutualism, Namib Desert, Namibia, pulse-reserve paradigm, mycorrhiza.