Centaurea iberica invasion causes homogenization of diverse plant communities.

Among the key drivers of shift in global biodiversity and ecosystem change, plant invasion is ranked second after habitat fragmentation. Invasive plant species often cause reduction in native species richness, yet many aggressive invaders have not been well studied for such impacts. Hence, we investigated the impacts of invasive Centaurea iberica Spreng. (the Iberian knapweed or Iberian star-thistle) on species diversity in three regions of Kashmir Himalaya (North, Central and South Kashmir). Through intensive field surveys, we compared the species diversity of C. iberica invaded and uninvaded plots and found that the uninvaded plots are more diverse (H´ = 2.65 ± 0.287) than the invaded plots (H´ = 0.88 ± 0.266). Uninvaded plots on an average harbored 5.26 ± 1.23 more species per 1m2 than invaded plots. The higher value of species richness in the control plots revealed rather heterogeneous nature of the communities as against the more homogenous communities of invaded plots. At multivariate scale, the ordination (NMDS) and ANOSIM exhibited significant differences between invaded and uninvaded plots (R = 0.6752 and p < 0.0001). The implications of invasion induced decline in species diversity for ecosystem services and human wellbeing are discussed. [ABSTRACT FROM AUTHOR]