Abstract: Alien invasive species usually have strong regeneration and colonization abilities. However, whether invasive species have advantages in terms of regeneration and colonization abilities over native species requires further exploration. In this study, the effects of fragment types (with and without apical tips) and lengths (5, 10 and 15 cm) on the regeneration and colonization abilities of the invasive Myriophyllum aquaticum and native M. spicatum in China were studied. Fragments of M. aquaticum and M. spicatum without apical tips had an advantage in branch formation, and their regeneration ability was stronger than that of fragments with apical tips. With longer initial fragments, the root length of M. aquaticum was longer and its colonization ability was stronger. This resulted in an increase in plant length, stem node number and biomass, with an increase in fragment length. However, the colonization ability of M. spicatum was not stronger with longer fragments. On the whole, native M. spicatum had stronger regeneration and colonization abilities than the invasive species M. aquaticum. However, M. aquaticum had a higher survival rate and plant length, enabling it to quickly occupy living spaces. Our results suggest that management needs to be strengthened for both M. aquaticum and M. spicatum to avoid biological invasion.

Key words: Myriophyllum aquaticum, M. spicatum, regeneration, colonization, fragments, biological invasion