Patterns of diversity in soil microbial community along altitudinal gradient
In the present study, the highest species richness and diversity of bacterial and fungal communities were observed in the invaded plots at all the four sampling sites with highest values reaching at KU site (Fig.3). Yang et al., (2020) observed a similar pattern of species richness and diversity for soil bacterial communities invaded bySpartina alterniflora and reported a unique bacterial community composition with highest relative abundance associated with the invasive plant. The potential of plant invasion to shift the abundance and diversity of soil microbial communities has been demonstrated by few recent studies as well (Rodríguez-Caballero et al., 2017; Xiang et al., 2018). For instance, invasion of Alliaria petiolata  significantly increased fungal richness under field conditions with shifts in soil microbial community composition (Duchesneau et al., 2021). Similarly, a distinct microbial community structure was observed among the rhizospheres of invasive Mikania micrantha , (Yin et al., 2020). Therefore, our study provides more empirical evidence to generalize the fact that the rhizosphere of invasive plants generally contains a higher diversity of microbial communities than uninvaded plots. This could be possibly attributed to secretion of numerous root exudates and signalling molecules produced by the invasive plants (Lagos et al., 2015) as well as the mycorrhizal advantages, root predation shield benefits and increased attachment niches (Dawkins & Esiobu 2018). In terms of microbial community relative abundance, the results of NMDS using the Bray-Curtis similarity index revealed that different sites were clustered together and formed distinct groups along the altitudinal gradient (Fig.4). This further substantiates that bacterial and fungal communities significantly differ in relative abundance at the invaded and uninvaded plots (Yannarell et al., 2011).