Implications for lake restoration
To restore a clear-water phase in shallow aquatic ecosystems, the re-establishment of a P. crispus population during the end of winter and early spring can help recover other submerged macrophytes, as the growth of P. crispus can suppress the growth of algae and keep the water clear, improving conditions for the establishment of other macrophytes (S. Hilt et al., 2018; Sabine Hilt et al., 2006). As shown here, however, it is important to take light availability and herbivory into consideration, as these can significantly affect successful establishment of P. crispus , particularly with ongoing climate change that may enhance herbivory on macrophytes (Elisabeth S. Bakker et al., 2016). Lowering water level could be a good measure to increase light availability and thus increase P. crispus growth. Other measures to prevent herbivory can also be applied, and may be especially needed during high light conditions. Furthermore, macrophytes with different thermal optima could be combined, as shown here where a temperature prevented growth of V. spinulosa . Since P. crispusdoes not tolerate high temperatures, it would die off during warmer conditions in summer, and it is thus essential to combine it with other macrophytes that germinate later and can handle warmer waters. If no other macrophytes establish during the senescence of P. crispusthe water may become dominated by phytoplankton and risks being shifted into a turbid state.