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.