Soil Bacterial Diversity and Community Composition Across Contrasting High-Andean Sites in Candarave, Southern Peru

High-Andean drylands are environmentally heterogeneous ecosystems, yet soil bacterial communities in southern Peru remain poorly characterized. This exploratory study examined bacterial communities in 23 soil samples collected from five sites in Candarave, Tacna, representing herbaceous-shrubland, succulent shrubland, and agricultural environments that also differed in elevation, soil pH, moisture, and historical aridity descriptors. Bacterial communities were characterized by 16S rRNA gene amplicon sequencing. Actinobacteriota, Chloroflexota, and Proteobacteria predominated across the sampled sites. Alpha diversity differed among sites (Kruskal-Wallis, p ≤ 0.009) and was highest at the two agricultural sites (P4 and P5; Shannon index, 11.33 ± 0.34 and 11.35 ± 0.17) and lowest at the herbaceous-shrubland site P1 (9.52 ± 0.75). ANCOM-BC indicated higher abundances of Azospirillales at both agricultural sites and of Blastococcus and Solirubrobacter mainly at P4, whereas Candidatus Udaeobacter and Conexibacter were more strongly represented at P3, the succulent shrubland site. Unweighted UniFrac analysis showed marked differences in bacterial community composition among the five sampling sites (PERMANOVA, pseudo-F = 4.67, p = 0.001), while multivariate dispersion did not differ significantly (PERMDISP, F = 0.686, p = 0.153). These results provide a descriptive baseline for soil bacterial diversity in an understudied high-Andean region and document substantial community heterogeneity among sites differing simultaneously in environmental conditions, vegetation, and land use.