Optimum water level for the ex situ and in situ conservation of endangered Korean aquatic plant Cicuta virosa L.

Abstract

Most endangered species are in a critical state of survival, and natural recovery in their native habitats is unlikely. Determining the optimum water level that affects the growth and survival of aquatic plants is crucial for their restoration. In the present study, we investigated the effects of different water levels on the growth of Korean endangered aquatic plant Cicuta virosa L. in two experimental environments: a greenhouse and a reservoir. The water level was adjusted to three conditions (−15 cm, 0 cm, and 15 cm) and 1- and 2-year-old plants were used. The plant height, root collar diameter, rhizome volume, and growth and survival rates were measured. In the greenhouse experiment, for 1-year-old plants, the best growth rate was observed at water levels of −15 ∼ 0 cm, but for 2-year-old plants, good growth rate was observed at water levels of 0 cm. The growth of rhizome volume was not affected by water level. In the on-site experiment at the reservoir, the different growth rates was not showed according to the water level, but the survival rate was good at −15 cm water level. However, the low survival rate (50 %) of C. virosa L. within the natural habitat remains a limitation of this study, and a strategy to increase survival rates when they are exposed to various natural threats is necessary.