Soil fungal community in patchy rangelands along an aridity gradient

In drylands, the cover of ground surface encompasses of shrubby vegetation patches, livestock trampling routes, and inter-patch spaces, altogether comprising a three-phase mosaic ecosystem. These microhabitats play a crucial role in determining surface- and soil-water redistribution, thereby regulating ecosystem functions. Soil fungi communities are integral to ecosystem processes. In drylands, their functional and taxonomic diversities are regulated by characteristic extreme abiotic conditions. Yet, their abundance, diversity, and composition have been relatively unexplored in such patchy ecosystems. This study aimed to assess the effect of microhabitats on the soil fungal community along an aridity gradient in southern Israel, covering semi-arid, arid, and hyper-arid sites in two opposing hillslope aspects (north vs. south) and in the three microhabitats. The results indicate that location along the gradient and hillslope aspect substantially influence fungal taxonomic richness, though they did not affect the composition of functional guilds. At the same time, the effect of microhabitat was not substantial. Overall, the study emphasizes the importance of aridity and hillslope aspect in shaping the composition, distribution, and functional groups of the soil fungal community. Dispersal was shown to decrease as aridity increases. Specifically, network analysis indicates that increasing aridity reduces microbial communities, likely due to decreased soil moisture.