Ecological effects of drawdown operations for the purpose of improving waterfowl habitat / Stanley W. Harris.
Material type:
TextSeries: Thesis ; (Ph.D.)Publication details: MN University of Minnesota, 1957.Description: 1 v. ; 28 cmOnline resources: Abstract: Within the past decade personnel interested in the management of waterfowl and muskrat (Ondatra zibethica) marshes have begun to question the validity of the absolutely stabilized water level as the best method of handling these wildlife areas (Hartman, 1949). In recent years various agencies and individuals have started to experiment with deliberately drying up shallow water areas as a means of enhancing habitat conditions for waterfowl and muskrats. The present study is an attempt to record and analyse the various effects on both plants and animals of an extensive program of water-level manipulations as carried out on the Mud Lake National Wildlife Refuge between 1949 and 1956. In this case the manipulation consisted of reducing water levels for one or more years -- termed a drawdown, and then restoring water levels --termed reflooding. An early investigation by Bourn and Cottam (1939)concluded that the lowering of water levels on tidal marshes of the east coast was detrimental to
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Within the past decade personnel interested in the management of waterfowl and muskrat (Ondatra zibethica) marshes have begun to question the validity of the absolutely stabilized water level as the best method of handling these wildlife areas (Hartman, 1949). In recent years various agencies and individuals have started to experiment with deliberately drying up shallow water areas as a means of enhancing habitat conditions for waterfowl and muskrats. The present study is an attempt to record and analyse the various effects on both plants and animals of an extensive program of water-level manipulations as carried out on the Mud Lake National Wildlife Refuge between 1949 and 1956. In this case the manipulation consisted of reducing water levels for one or more years -- termed a drawdown, and then restoring water levels --termed reflooding. An early investigation by Bourn and Cottam (1939)concluded that the lowering of water levels on tidal marshes of the east coast was detrimental to