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Dispersal Abilities of Fragments of Introduced Exotic Submerged Macrophytes Are
Improved by Water Nutrients
Hong Zhu, Dong Xie*
(Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,
Nanjing 210037, People‚Äôs Republic of China; *[email protected])
The invasion of exotic species is considered to be a serious global phenomenon, resulting in
ecological, economic, and social systems consequences. Plant invaders can greatly diminish
the abundance or survival of native species and can completely alter the native ecosystem in
terrestrial and fresh water habitats. Identifying the factors associated with the success of
invasive species is helpful in predicting its invasion and controlling exotic species and to
elucidate the interaction between invasive and native species in ecosystems. However, our
understanding of the characteristics that contribute to invasion is still limited.
Compared with terrestrial plants, asexual reproduction is more frequent in aquatic plants. Stem
fragments are important for propagation and dispersal in some aquatic plants. Compared to
other means of asexual propagation, fragments have advantages in its easy production and
dispersal, long periods of survival and high colonization and regeneration abilities. The
dispersal of fragments plays an important role in invading and establishing a new habitat for
many invasive weeds. However, researches of fragment production and establishment in exotic
aquatic species are lacking.
This study tested the colonization (root production) and regeneration (shoot production)
abilities of five exotic submerged macrophytes in response different water nutrient gradients.
These abilities may ultimately influence the success of macrophyte dispersal in aquatic habitats.
Fragments of five common exotic submerged macrophytes were used in this experiment Elodea
nuttallii (Planch.) H. St. John, Cabomba caroliniana A. Gray, Cabomba furcate Schult. &
Schlult.f., Limnophila aquaticum (Willd.) Santapau, Rotala wallichii (Hook. f.) Koehne. After
8 weeks growth, most of the fragments survived, and there was no interactions between
nutrients gradients and species. Except for R. wallichii, the other four exotic species tended to
invest more biomass into the shoot growth in high water nutrients conditions. The colonization
abilities of these exotic species were also varied among species and nutrients gradients. The
differences in colonization and regeneration abilities among fragments of exotic species
indicate that these exotic submerged macrophytes differed much in their dispersal potential.
Our results provide evidence that water nutrients are important factors that drive the propagule
dispersal in aquatic habitats.
Key words: dispersal; plant invasions; submerged macrophytes; vegetative stem fragments