CHANGES IN WILD RICE (ZIZANIA AQUATICA L.) COVERAGES IN POOL 8, 
UPPER MISSISSIPPI RIVER, 1989--1995

J. Therese Dukerschein,  Wisconsin Department of Natural Resources Long Term Resource
Monitoring Program (WDNR/LTRMP) Field Station, 575 Lester Avenue, Onalaska, Wisconsin
54650

In Wisconsin and Minnesota, wild rice stands are valuable, protected wetlands because they
provide food and cover for wildlife such as muskrats and water birds and highly nutritious grain
for humans.   Although wild rice has been harvested by native Americans for the past 300 to 500
years, on federal refuges such as the Upper Mississippi Fish and Wildlife Refuge in Pool 8,  no
harvesting for human consumption is permitted.  In 1989 and 1991-1996, the WDNR/ LTRMP
monitored wild rice along with other submersed, floating-leafed and emergent aquatic plants in
Pool 8, UMRS, through interpreted 1:15,000 color-infrared aerial photography along with
ground-truthing.  No wild rice (Zizania aquatica L.) was detected in Pool 8 by WDNR/LTRMP
staff  in the field or on aerial photos in 1989, a year of drought, or 1993, the year of the great
flood.  A 0.16-hectare (0.4-acre) patch of wild rice was delineated in the Blue Lake/Target Lake
backwater of Pool 8 in 1991, and a fringe too small to delineate on the photo was detected in the
field in 1992.  Acreage of wild rice increased to 148 hectares (365 acres) of pure or mixed stands
of wild rice in Pool 8 in 1994, and a mean density of 9.6 wild rice stems/m2 was calculated along
three 50-m transects containing wild rice in the Blue Lake/Target Lake area.  Also in 1994,
mature wild rice was observed in the field and delineated on the photos in Lawrence Lake.  Wild
rice continued to appear in Blue Lake, Target Lake, and Lawrence Lake in 1995 and 1996, 
totaling 233 hectares (577 acres) of pure or mixed stands in 1995, and preliminary data indicate
about 215 hectares (531 acres) of pure or mixed stands in 1996.  However, if only pure,
high-density stands of wild rice are considered (polygons with a classification of 724D under the
current LTRMP classification scheme), numbers of pure, high-density stands and areas decreased
from 124.5 hectares (23 polygons) in 1994 to 5.9 hectares (4 polygons) in 1995 and 10 polygons
in 1996 (no exact areas available for 1996).  Selected  water quality data and main channel river
stage data are presented with the wild rice coverages.

Key words: Zizania aquatica, wild rice, Mississippi River, aquatic vegetation, coverage

J. Therese Dukerschein
575 Lester Avenue
Onalaska, Wisconsin 54650
(608)783-6169, ext. 706, FAX (608)783-8058
e-mail:  Terry_Dukerschein@nbs.gov
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