Spink A.J., Murphy K.J. Smith S.M. & Westlake D.F. (1993)

An experimental study on the effects of eutrophication on Ranunculus and Potamogeton.

Journal of Aquatic Plant Management 31, 113-117.


Water Crowfoot (Ranunculus penicillatus subsp. pseudofluitans (Syme) S.Webster) plants were grown in two artificial recirculating rivers, in one of which the phosphate concentration of the input was raised from 40 µgPl-1 to 200 µgPl-1. Fennel Pondweed (Potamogeton pectinatus L.) plants were planted as a competitor in association with 50% of the Ranunculus clumps. Chemical concentrations of the major elements in the water were measured weekly. Filamentous algae grew in profusion in the channel with added phosphate (0.77 T fresh weight), compared with an immeasurably low amount in the control channel. After 100 days the plants were removed, dried and weighed and the tissue concentrations of the major elements were measured. The Ranunculus shoots grew less in the eutrophic channel, and its roots grew less in the presence of Potamogeton. The Potamogeton showed a greater reduction in shoot and root biomass than the Ranunculus. Tissue phosphate concentrations were higher in both species in the eutrophic channel. The data suggested that P. pectinatus is a more competitive species (sensu Grime) than R. penicillatus.
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