Soil bacteria and fungi communities are shaped by elevation influences in Colombian forest and páramo natural ecosystems

ABSTRACT

The influence of elevation on natural terrestrial ecosystems determines the arrangements of microbial communities in soils to be associated with biotic and abiotic factors. To evaluate changes of fungi and bacteria at the community level along an elevational gradient (between 1000 and 3800 m.a.s.l.), physicochemical measurements of soils, taxonomic identifications of plants, and metabarcoding sequences of the 16S rRNA gene for bacteria and the ITS1 region for fungi were obtained. The bacterial taxonomic composition showed that Acidobacteriota increased in abundance with elevation, while Actinobacteriota and Verrucomicrobiota decreased. Furthermore, Firmicutes and Proteobacteria maintained maximum levels of abundance at intermediate elevations (1200 and 2400 m.a.s.l.). In fungi, Ascomycota was more abundant at higher elevations, Basidiomycota tended to dominate at lower elevations, and Mortierellomycota had a greater presence at intermediate sites. These results correlated with the edaphic parameters of decreasing pH and increasing organic carbon and available nitrogen with elevation. In addition, the Shannon index found a greater diversity in bacteria than fungi, but both showed a unimodal pattern with maximum values in the Andean Forest at 2400 m.a.s.l. Through the microbial characterization of the ecosystems, the elevational gradient, soil properties, and vegetation were found to exert significant effects on microbial communities and alpha diversity indices. We conclude that the most abundant soil microorganisms at the sampling points differed in abundance and diversity according to the variations in factors influencing ecological communities. (AU)