Comparative analysis of growth and physiological traits between a natural hybrid Sphagneticola trilobata × calendulacea and its parental species
11 August 2015
Li, Ting; Huang, Li-Xin; Yi, Li; Hong, Lan; Shen, Hao; Ye, Wan-Hui; Wang, Zhang-MingBiological invasion is a global environmental issue. Hybridization is considered a stimulus for evolution of invasiveness. It is essential to evaluate invasive potential of new hybrids before management strategies are designed and implemented for them, especially, using performance-related traits. The comparison of growth and physiological traits between invasive species and their non-invasive congeners is an effective way to identify invasive traits and to predict the invasive potential of species. However, few studies have evaluated the invasive potential of new hybrids by comparative analysis of these traits. We examined the invasive potential of a recently confirmed natural hybrid between the invasive Sphagneticola trilobata, one of the 100 worst invasive species worldwide, and its indigenous congener S. calendulacea. We compared growth and physiological responses of the hybrid and its parental species to different light conditions (open, natural light; shade, 25% of natural light) by conducting a common garden experiment. We then used discriminant analysis to identify those growth and physiological traits that are most different between the invasive and the noninvasive species. We found that S. trilobata had a higher growth rate, photosynthetic capacity and resource use efficiency than S. calendulacea in both the open and the shade environments, and the hybrid was more similar to S. trilobata than to S. calendulacea in these traits. Discriminant analysis suggested that the hybrid more strongly resembled S. trilobata than S. calendulacea for a number of traits associated with performance, and that the hybrids had less invasive potential in the shade than in the open environment. These results indicate that the hybrid has a high invasive potential and could be an efficient invader in both open and shade environments.