I A 2. Bergo's Slough. Acreage: 33. 



Location: Worth County; Mason City 1:250,000; 5 miles E of Lake Mills; 

 reached via Rt. 105. 



Description: Bergo's Slough is a sedge marsh located in an old oxbow of Elk 

 Creek. It is surrounded on three sides by prominent ridges, which give an am- 

 phitheater effect. Dominant vegetation on the shallow flats of the marsh include 

 lake sedge (Care.x lacustris), tussock sedge (Carex tuckermanni), blue joint 

 grass, reed canary, manna grass, and associated wetland forms. In the deeper 

 portions (18 inches plus), dominants include bur reed, cattail, and scattered 

 beds of sweet flag and hardstem bulrush. It has an extremely rich avifauna, typi- 

 cal of midwestern marshes. 



References: Kaufman, G. W., and R. Ivens. 1965. The effects of a flood on 

 nesting Iowa marsh birds. Iowa Bird Life. 35:9-1 1; Martin, G. W. (ed). 1954. 

 Marsh and aquatic angiosperms of Iowa. State Univ. Iowa Studies Nat. Hist. 

 29(5): 1-92. 



Encroachments: An impoundment downstream raises winter water levels that 

 permit carp and muskrats to overwinter in the slough. This has resulted in 

 elimination of vegetation from the deeper portions of the slough, and a decline 

 of overwater nesting marsh birds breeding in Bergo's Slough. However, the 

 situation can be remedied by dropping water levels in the impoundment during 

 the winter. 



Ownership: State of Iowa, Public Shooting Area. 



Data source: DeVere E. Burt, TNC, 260 Ludlow Ave., Cincinnati, Ohio. 45220. 



Other knowledgeable persons: Dr. Milton W. Weller, Department of Wildlife 

 Biology, Iowa State University, Ames, la. 50010. 



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