Relationship between soil microbial communities and nutrient
parameters
In the present study, the most important variables explaining bacterial
community composition was TOC in invaded plots and SAL in uninvaded
plots (Table 2). It has been reported that soil nutrients provide ample
substrates to stimulate the growth of bacteria and serve as drivers of
bacterial diversity and abundance (Santonja et al., 2017; Yu et al.,
2019). The significantly increased soil bacterial abundance and
diversity following L.vulgare invasion can be possibly a result
of the TOC levels, which provides enriched substrates for the
proliferation of bacteria (Yu et al., 2019). Higher values of soil
salinity were observed in the invaded plots (Table 1), but showed a
significantly negative correlation with uninvaded plots (Table 2). By
altering the osmotic potential of soils, high salinity can lead to
alterations in microbial community structure with reduced microbial
biomass and can restrict the growth of heterotrophic bacteria (Kamble et
al., 2014; Xi et al., 2014). Among other variable examined, WC in plots
were most significantly and closely correlated with fungal community
structures (Table 2 ). Canini et al., (2019) has reported that
water content and pH has a strong effect on fungal community composition
and found a positive relationship between the fungal richness and the
vegetation cover. Similarly, invasion of Impatiens glanduliferahas been reported to effectively change soil characteristics
particularly soil moisture and soil pH in invaded areas (Ruckli et al.,
2014; Gaggini et al., 2018). Therefore, fungal communities can be
influenced by soil moisture and soil pH and thus can be viewed as an
indirect effect of the plant invasion.
Additionally, according to Canonical Correspondence analysis,
significant correlation were observed between soil physicochemical
properties and altitude, which indicates that sites with distinct soil
properties possess different microbial abundances and the plot-wise
distribution of both soil physicochemical properties and microbial
abundances are strongly influenced by temperature, K, pH, EC and Fe
(Fig.6). The present study, therefore, enhances our understanding of the
altitudinal patterns of variation in soil physicochemical properties and
the impact of these factors on belowground soil microbial communities to
drive plant invasions in the study region.