DETECTING AND PROTECTING WILD RICE (ZIZANIA AQUATICA L.) IN THE UPPER 
MISSISSIPPI SYSTEM (UMRS) –1975, 1989-2001.

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

Wild rice (Zizania spp.), the sentinel plant of the deep marsh annual community, 
is an annual emergent that is protected throughout the Mississippi River Fish 
and Wildlife Refuge System for its food and cover value to wildlife.  To 
adequately protect a plant species, it must first be detected, and up until the 
mid-1990's, available data documenting wild rice stands on the upper Mississippi 
River System was localized, fragmented, or lacking.  Systemic CIR aerial 
photography mapped by LTRMP (1975, 1989, 2000) has detected polygons where wild 
rice is dominant in all Navigation Pools from 2—13, and in small patches in the 
Open River Reach and the Alton Reach of the Illinois River.  No wild rice has 
been detected in Pools 14-26 of the Mississippi River nor on any of the 
remaining portions mapped on the Illinois River (Brandon, Dresden, LaGrange, 
Lockport, and Marseilles Reaches).  Annual LTRMP field monitoring of aquatic 
vegetation employed a stratified random sampling (SRS) design in Pools 4, 8, 13, 
26 of the Mississippi River and the La Grange Reach of the Illinois River from 
1998-2002.  Additionally, SRS was done on a more limited basis in Pools 5, 7, 
12, and the Alton Reach of the Illinois River in 2002.This field method detected 
wild rice in Pools 4, 7, and 8 in areas that generally overlap distributions 
detected by CIR photography. However, stratified random sampling (Goose Island 
area in Pool 8, and some areas of Pool 4) and field observations (La Grange 
Reach, Illinois River) have also documented some patches of wild rice which so 
far have been undetected on maps derived from CIR photos.  UMRS coverages 
indicate wild rice typically grows in isolated backwaters, areas of contiguous 
backwaters that are relatively sheltered from prevailing winds, speedboat 
traffic, and strong currents, or sheltered sloughs near the confluences of 
tributaries.  Wild rice most consistently occurs in reaches where these types of 
deep marsh habitat are available or where managers artificially create these 
conditions with levies and pumps (Trempealeau Wildlife Refuge in Pool 6, and 
certain managed areas in Pool 13 and on the Illinois River).  Wild rice appears 
to cycle over time in a manner typical of an opportunistic, likely density-
dependent annual responding to hydrological and climactic events.  In Pool 8, 
coverages of wild rice in stands where it is the dominant plant appear to 
increase dramatically following unusually high or protracted spring flood events 
that occur early in the same growing season or following summer flood events 
that occurred the previous growing season.  Coverages in years immediately 
following these increases show substantial decreases, indicating a possible 
density effect.  Wild rice might nearly disappear for years and then 
"miraculously" reappear as it did in Pool 8 in 1994, which can present 
challenges to managing for this plant and its associated deep marsh annual 
habitat.   Management techniques used thus far on the UMRS to create or preserve 
deep marsh annual habitat include planting wild rice in promising areas, 
drawdowns, artificial levying and pumping, and resisting public pressure to 
increase boating accessibility to the relatively isolated areas where wild rice 
occurs.  

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