Without intervention a reed bed will eventually dry out as each previous years reed growth decays and builds up thus raising the level of the reed bed above the water table. In the old days reed beds were cut to obtain reed for thatching and other uses, now the accepted way is to cut and burn sections on an annual basis at some time during the winter. This group of conservations are doing just that on a reed bed local to where I live.
Our indiginous Australians managed this huge continent by judicious annual burning for some 50,000 years. Many native plants require heat and/or smoke to germinate their seeds or having large underground swollen roots that regenerate quickly. We are still getting around to tapping in to their wisdom.