Strategies of reproduction, dispersion, and competition in river plants: A review

Abstract

The present paper reviews the literature on reproduction, survival, dispersion and competition in aquatic plants of mostly European rivers. The specificity of the strategies of colonization in aquatic plants in comparison with terrestrial plants is noted. The importance of the knowledge of these life history traits in the control of the harmful effects caused by aquatic plants and for ecosystem management is also considered. The difficulty of applying current ecological theories concerning adaptative strategies to aquatic plants is discussed, focusing on the great interest of studying the species traits of aquatic macrophytes for testing such theories and interpreting recolonization patterns of disturbed areas. Knowledge of strategies of reproduction, dispersion and competition among aquatic plants remains very fragmentary, particularly from a quantitative view-point, and further studies are required both for theoretical and practical applications. Nomenclature: The nomenclature follows Tutin et al. (1964) for most of the species.

Impact of riparian trees shade on aquatic plant abundance in conservation islands

“…Ceratophyllum demersum has a suitable morphology for light interception and longevity (GRIME 1979). These results suggest that C. demersum and M. spicatum are stress-tolerant, which are in line with other researches (FRANK 1975, SEGRETAIN 1996.…”

Conservation genetics of Ireland's sole population of the River water crowfoot (Ranunculus fluitans Lam.)

“…Likewise, they reported no difference in associated hydrophyte and helophyte species between R. fluitans and R. penicillatus. Previous studies have indicated that the high levels of vegetative reproduction observed in many populations of Ranunculus subgenus Batrachium species are associated with polyploidy and/or the formation of hybrids (Cook 1966;Holmes 1980;Dahlgren 1993;Barrat-Segretain 1996). Although hybrids between R. fluitans and R. penicillatus have been reported previously from the Six Mile Water (Hackney 1992), only a single potential case of hybridization was identified in the present study.…”

“…It was first identified in 1865 and has been recorded only in the same section of the river since then (Beesley 2006). R. fluitans is monoecious, and subaquatic pollination occurs as a result of the formation of an air bubble in the perianth (Arber 1920), although it has been suggested that vegetative reproduction may be more common (Zander and Wiegleb 1987;Cook 1990;Barrat-Segretain 1996). The species is occasionally found growing with R. penicillatus (Stream water crowfoot) and, although morphological differentiation between the two can be difficult, there are anecdotal reports of sterile hybrids between the species occurring in the sole Irish population (Hackney 1992).…”

“…Although hybrids between R. fluitans and R. penicillatus have been reported previously from the Six Mile Water (Hackney 1992), only a single potential case of hybridization was identified in the present study. As hybrids are sterile, and thus cannot contribute to successive generations (Barrat-Segretain 1996), these historical specimens may represent a transient episode of hybridization which is no longer ongoing to any great extent, given the current allopatric distributions of R. fluitans and R. penicillatus on the Six Mile Water. Nevertheless, the approximately 60%/40% assignment probability for the putative hybrid sample is close to that expected in a (sterile) F 1 individual.…”

The dispersal capacity of vegetative propagules of riparian fen species

“…The nature of vegetative propagules is diverse, but usually, any plant fragment that disperses and is capable of resprouting when it meets a favourable habitat after dispersal is considered to be a vegetative propagule (Barrat-Segretain, 1996). Vegetative propagules can be rhizomes, stolons, tubers, turions, simple stem or leaf fragments or even entire plants.…”