Conclusion

The nestedness showed by the diatom community in this study was highly significant, even though it had quite a high proportion of idiosyncratic species, which was also noticed in earlier findings in diatoms. Idiosyncratic species were characterized with high numbers of cosmopolitan species, whereas the nested species were dominated by endemic species. Mantel and partial Mantel tests showed that the increase of community dissimilarity with increase in environmental dissimilarity and no relationship with geographical distance, which portraits the role of local environmental factors in determining the diatoms species patterns. PCA identify ionic parameters and nutrients as the major features which determine the characteristics of the sampling sites, hence the local water quality parameters are the major driver in deciding the diatoms species assemblages. We conclude that the landscape scales activities alter the stream local characters, which in turn decides the diatom community structure. It’s also important to carry out these kinds of studies across the biogeographic zone for a larger area, which might also give more insights about evolutionary patterns in community structure of diatoms.