Management of Nymphoides peltatum using water level fluctuations in freshwater lakes of Kashmir Himalaya

Lakes have an esthetic significance that is particularly important for attracting tourism. In this context, it is often preferable for lakes to have clear water, so many lake managers attempt to achieve clear lake water by various means. However, the lakes of Kashmir Himalaya are undergoing several complex ecological changes due to, for example, increasing tourism, overfishing, and intensive agriculture, which are making these lakes less clear. One such change is the vigorous growth and development of aquatic weeds in the shallow-water areas of Kashmir Himalayan lakes. We thus, investigated the response of Nymphoides peltatum, a rapidly multiplying clonal species, to water depth, in order to determine whether water depth can be used to control the spread of this proliferating macrophyte. Different traits of the given plant species, such as the mean number of ramets, were significantly higher (F = 55.412, p = 0.000) at depth zone D1 (0–100 cm) than at depth zones D2 (101–200 cm) and D3 (201–300 cm). In all of the lakes, mean spacer length—a tool for facilitating plant spread—was observed to be significantly higher (F = 45.890, p = 0.000) at lower water levels (0–100 cm). Also, the reproductive structures (flowers) of N. peltatum showed significant variation with depth (F = 51.909, p = 0.000) and with the lake examined (F = 9.909, p = 0.001). Thus, the results obtained during the present study indicate the importance of water depth in the management of N. peltatum in various Kashmir Himalayan lakes.