Abstract:
To date, little research has been conducted on the landscape-scale distribution of soil microbial communities and the factors driving their community
structures in the drylands of Africa. We investigated the influence of landscape-scale variables on microbial community structure and diversity
across different ecological zones in Botswana. We used amplicon sequencing of bacterial 16S rRNA gene and fungal internal transcribed spacers
(ITS) and a suite of environmental parameters to determine drivers of microbial community structure. Bacterial communities were dominated by Actinomycetota (21.1%), Pseudomonadota (15.9%), and Acidobacteriota (10.9%).
The dominant fungal communities were Ascomycota (57.3%) and Basidiomycota (7.5%). Soil pH, mean annual precipitation, total organic carbon,
and soil ions (calcium and magnesium) were the major predictors of microbial community diversity and structure. The co-occurrence patterns of bacterial and fungal communities were influenced by soil pH, with networkspecific fungi–bacteria interactions observed. Potential keystone taxa were
identified for communities in the different networks. Most of these interactions were between microbial families potentially involved in carbon cycling,
suggesting functional redundancy in these soils. Our findings highlight the
significance of soil pH in determining the landscape-scale structure of microbial communities in Botswana’s dryland soils.
