Elevation-Associated Patterns of Soil Bacterial and Fungal Communities Along Mount Toubkal, North Africa’s Highest Mountain

High-mountain ecosystems are sentinels of global environmental change, yet the soil microbial communities of North Africa’s highest peak remain entirely unexplored. Here, we present the first comprehensive characterization of soil bacterial and fungal communities across a 3,600-meter elevational gradient on Mount Toubkal (500–4,165 m), Morocco, integrating next-generation sequencing (16 S rRNA and ITS1) with soil physicochemical and enzymatic analyses. Our findings reveal a fundamental divergence in biodiversity patterns: bacterial alpha diversity remained comparatively stable along the sampled transect, whereas fungal richness decreased toward higher elevations. Site-level analysis confirmed a negative association between fungal richness and elevation (ρ= -0.70, P = 0.036, n = 9). Fungal richness and Shannon diversity were positively associated with soil organic matter at the site level (ρ = 0.83, P = 0.005, and ρ = 0.77, P = 0.016, respectively), while bacterial richness was associated with available phosphorus, pH, and phosphatase activity. Bacterial and fungal community composition differed among the sampled elevation-sites. Actinobacteriota was the dominant bacterial phylum throughout the transect, while Ascomycota dominated fungal communities at most sites. Chytridiomycota became dominant specifically at 3,500 m. Bacterial and fungal community composition differed among sampled elevation-sites, although these patterns reflected both community-centroid and dispersion differences. Community dissimilarity increased with absolute elevation difference, indicating compositional turnover along the sampled transect. Microbial diversity and composition were associated with variation in soil organic matter, available phosphorus, and pH along the sampled transect. These findings establish the first soil-microbiome baseline across Mount Toubkal and expand current knowledge of microbial biogeography in North African mountain ecosystems.