Stage-specific ploidy level variations in invasive species in comparison to rare endemics in Kashmir Himalaya

Abstract

Despite the recently recognized link between ploidy level and species invasiveness, disentangling ploidy variations throughout the various stages of invasion still is an open question. Therefore, our aim was to investigate the variations in the ploidy level of alien Kashmir Himalayan plant throughout different stages of invasion and to compare those variations with the ploidy levels of 112 rare endemics. Ploidy level data was derived from an extensive literature review and web-based sources. The equality of proportions test was used to assess the relationship between ploidy status and species invasiveness or rarity/endemicity. We used Pearson’s product-moment correlation coefficient to test the relationship between ploidy level and diversification among some of the most widespread alien plant families. Results showed a greater preponderance of polyploidy in invasive than in rare endemic species, which were mostly diploid. Regression analysis of 309 alien plant species showed that the proportion of polyploids increases with the stage of invasion, from stage II to stage V. Our results suggest a positive relationship between ploidy status and invasiveness. We emphasize the predictive value of these variations, as our model suggests that the 32 stage II alien polyploids seem more likely to become future invaders in Kashmir Himalaya than the 46 stage II diploids. Appropriate management strategies could be put in place early enough to prevent further damage from these potentially dangerous species.