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In several areas, managers have switched their efforts from producing monotypic stands of a few species of waterfowl food plants to growing mixed stands with greater numbers of plant species that attract waterfowl and other marsh or aquatic birds. To meet these goals, some managers have directed their efforts toward thinning stands of the two bulrushes or intermixing bulrush stands with those of other food plants, especially shorter emergents and submersed species. Managers need to know the optimum size and interspersion of areas slated for increased plant diversity and how those areas will respond to current management techniques. Part of the effort to increase diversity of food resources stems from a lack of definitive proof of the digestibility and food value of the bulrush achenes to birds. This suggests the need for more complex food preference studies.

Several managers encouraged more research on the timing and intensity of prescribed burning. This practice opens dense stands and increases availability of achenes to wintering waterfowl, but the pre-burn periods when impoundments must be drained and dried may conflict with shrimp management. In areas subject to land subsidence and rises in sea level, it is vital that such burns do not damage rhizome systems and cause further losses of organic matter vital to marsh accretion. Some managers reported that regulations governing smoke management are making it increasingly difficult to conduct prescribed burns. Research to develop other means of thinning dense stands of the two bulrushes would be beneficial.

Most managers of coastal impoundments, where high-salinity water is usually available, reported few problems controlling undesirable freshwater plants by raising salinities. However, a few salt-tolerant plants (e.g., Scirpus californicus, Spartina cynosuroides, Typha angustifolia, and Zizaniopsis miliacea) still pose problems because they respond similarly to practices used to grow Scirpus robustus. Closure of these impoundments to the open sea for most of the year for management of this bulrush may negatively affect populations of certain marine fish. This problem is most serious where coastal marshes are disappearing because of subsidence and sea level increases. In other coastal areas the reverse can occur. For example, where freshwaters from diverted rivers push estuarine waters seaward it is difficult for managers to obtain waters of sufficient salinity. Some managers reported wetland damage or degradation from airboats and island construction. Research thus must be combined with conservation in many coastal areas.

Water pollution was not identified as a problem on most refuges or hunting areas. However, a few managers expressed a need for increased research on propagation techniques for the two bulrushes where the only available water is small amounts of highly saline irrigation return flows. Research there could involve the selection of highly salt-tolerant strains of the two bulrushes. Some managers speculated that valuable genetic diversity of these bulrushes has been lost after long periods of semidomestication through repeated seeding and harvest.

Managers with the ability to control bottom-substrate salinity and water supplies in inland wetlands were satisfied with current techniques used to propagate S. maritimus. In wetlands lacking water-control structures or where interstitial substrate salinities have slowly decreased, research is needed on methods to control the adventive Typha angustifolia. This species now dominates many moderately saline wetlands where S. maritimus once flourished. These wetlands would be good candidates for research to determine whether the combined effects of natural wetland disturbances such as grazing and burning could restore stands of this bulrush.

Acknowledgments

I thank E. J. Kantrud, who translated several French and German references, and D. L. Larson, G. E. Larson, J. T. Lokemoen, D. M. Mushet, and A. B. Sargeant, who reviewed the manuscript; M. C. Hager for editorial services; and S. Lauritzen for the layout.