Alpha (α) diversity
Irrespective of the plot type, significantly (p <0.05)
higher values of total observed OTUs and Chao1 estimator of bacterial
communities were obtained in the high-altitude sites as compared to the
low-altitude sites, though the pattern was inconsistent (Fig.3a, b and
Appendix S3: Table S3). The Shannon index followed similar pattern, as
observed above in case of observed OTUs in bacteria, reaching its peak
at KU site followed by decline at KD site (Fig. 3c and Appendix S3:
Table S3), however the Simpson index did not follow a monotonic trend
along the altitudinal gradient but differed significantly between the
plots and among the sites along the altitudinal gradient (Fig. 3d and
Appendix S3: Table S3).
The observed OTUs and Chao1 estimator in fungal communities also
followed a monotonic increase along the altitudinal gradient but dropped
sharply at KD site – the highest altitudinal site (Fig. 3e, f and
Appendix S3: Table S3). Overall, the alpha diversity of soil microbial
communities increased from KZ to KU and differed significantly (p<0.05) between the invaded and uninvaded plots (Appendix S3:
Table S3). The invaded plots at all sites showed higher diversity except
KD, where opposite trend was observed. On the other hand, both Shannon
and Simpson indices in fungal communities were significantly influenced
by both the plot and site type (Fig. 3g, h and Appendix S3: Table S3).
In particular, both indices were significantly higher in the invaded as
compared to the uninvaded plots except KD site.