“…The strongest environmental association of the Namib FCs is with mean annual precipitation, which ranges between approximately 50 and 150 mm (Cramer & Barger, 2013) and occurs where sparse grassland is dominated by Stipagrostis species on soils that are predominantly coarse-textured, aeolian-derived sands that have a high capacity for water and nutrient movement (Cramer et al, 2017;Ravi et al, 2017). The origin of these FCs in water-limited drylands has puzzled scientists for decades (Sahagian, 2017;van Rooyen et al, 2004). The hypotheses include (a) allelopathic influences of a plant that no longer occurs in FCs (Meyer et al, 2015;Theron, 1979); (b) seepage of carbon monoxide, hydrocarbons, or other volatiles from below ground that kills grass in regular patterns (Albrecht et al, 2001;Jankowitz et al, 2008;Naude et al, 2011); (c) an unspecified microbial effect (Eicker et al, 1982;Ramond et al, 2014;van der Walt et al, 2016); (d) faunal removal of grasses by termites (Becker & Getzin, 2000;Juergens, 2013;Moll, 1994;Vlieghe et al, 2015) or detrimental influence on grasses by ants (Picker et al, 2012); and (e) self-organized emergent vegetation patterning arising from competitive and facilitative interactions between grasses (Cramer et al, 2017;Cramer & Barger, 2013;Getzin et al, 2015aGetzin et al, , 2015bGetzin et al, , 2016Ravi et al, 2017;Tschinkel, 2012;van Rooyen et al, 2004).…”