T-RFLP profiles were significantly correlated to
all studied soil variables, however, only correlation to
pH was significant after adjusting for site effect. This
suggested that soil pH influenced communities at a
small scale, while organic matter and soil moisture were
shaping communities at a larger scale (i.e., inter-site). In
many studies, soil pH acted at a rather large scale and
with broad range of pH values [13, 38], however, bacterial
community changes due to small differences (only 0.10)
in soil pH have been also previously observed [14, 7]. The
scale differences might be due to the complexity of soil
pH factor i.e. its correlation and functional relatedness to
other factors which then determine the scale of changes
[39]. Another possible explanation is that small-scale
correlation between soil pH and community structure
occurs particularly in chalk regions [14; this study] where
a qualitative difference in decomposition processes
may occur compared to acidic soils. This is because
decomposition activities are carried out by many diverse
taxonomic groups there but confined to a few taxa in
acidic soils [2].