Catalogus

Experiments on establishment of shoots, seed bank dynamics, seed germination and genetic analysis (AFLP) were conducted to establish whether L. natans disperse to new habitats within hydrologically linked water systems by means of vegetative shoots or by seeds. Shoots had high ability to establish by roots (52% in autumn shoots), but only when subjected to water depths <4 cm. Seeds of L. natans has a high germinate rate (mean of 51–60%), and the density of seeds in the seed bank ranged from 635 to 3354 m⁻² during a year. Analysis of the genetic diversity showed that samples could be differentiated to individuals with higher diversity between populations than within population. Low ability of shoots to establish if not subjected to low water depth, high germination rate of seeds, substantial seed bank and a high genetic diversity all indicate that most colonization events depend on sexual reproduction.