Elevation was the best predictor of variation in bacterial community composition along the two transects, even when considering other soil parameters. Elevation was itself highly correlated with mean annual temperature (MAT) and mean annual precipitation (MAP), suggesting that soil bacterial community composition on Mt. Halla is more strongly affected by climate than by geochemical or soil textural factors. The two transects showed certain consistent differences in bacterial phyla composition, with one transect having significantly higher abundance of Planctomycetes and Gemmatimonadetes than the other. Certain other phyla (e.g. Acidobacteria) also showed striking trends in abundance with elevation, but the trends differed between the two transects.
Bacterial diversity and richness were also most strongly correlated with elevation, MAT and MAP, although soil pH explained a part of the variation. Moreover, vegetation cover type, irrespective of elevation, had an effect on soil bacterial diversity and richness. We found a 鈥榙ip鈥?in diversity at lower mid elevations (700-1300聽m) in both transects; a trend which has not been found before. Our results, when compared with other studies, emphasize that no simple rule can be applied to mountain systems in general, but that climate itself is a major influence on community composition.