Long Term Resource Monitoring Program

Program Report

98-P011

1995 Annual Status Report

A Summary of Aquatic Vegetation Monitoring at

Fixed Transects in Pools 4, 8, 13, and 26 and

La Grange Pool of the Upper Mississippi River System

September 1998
The Environmental Management Technical Center issues LTRMP Program Reports

to provide Long Term Resource Monitoring Program partners

with programmatic documentation, procedures manuals, and annual status reports.

Environmental Management

Technical Center

CENTER DIRECTOR

Robert L. Delaney

APPLIED RIVER SCIENCE

 ACTINGDIRECTOR

Ken Lubinski

PROGRAM OPERATIONS

ACTING DIRECTOR

Linda Leake

REPORT EDITOR

Jerry Cox

Cover graphic by Mi Ae Lipe-Butterbrodt

Mention of trade names or commercial products does not constitute endorsement

or recommendation for use by the U.S. Geological Survey, U.S. Department of the Interior.

Printed on recycled paper 
1995 Annual Status Report

A Summary of Aquatic Vegetation Monitoring at

Fixed Transects in Pools 4, 8, 13, and 26 and 

La Grange Pool of the Upper Mississippi River System

by

 Sara Rogers

U.S. Geological Survey

Environmental Management Technical Center

575 Lester Avenue 

Onalaska, Wisconsin 54650

Heidi Langrehr and J. Therese Dukerschein

Wisconsin Department of Natural Resources

Onalaska Field Station

575 Lester Avenue

Onalaska, Wisconsin 54650

Jenny Winkelman

Minnesota Department of Natural Resources

1801 South Oak Street

Lake City, Minnesota 55041

John Nelson

Illinois Natural History Survey

Alton Field Station

4134 Alby Street

Alton, Illinois 62002

Theresa Blackburn

Iowa Department of Natural Resources

Mississippi River Monitoring Station

206 Rose Street

Bellevue, Iowa 52031

and 

Thad Cook

Illinois Natural History Survey

Havana Field Station

704 North Schrader Avenue

Havana, Illinois 62644

September 1998
Suggested citation:

Rogers, S., H. Langrehr, J. T. Dukerschein, J. Winkelman, J. Nelson, T. Blackburn, and T. Cook. 1998. 1995 annual status

report: A summary of aquatic vegetation monitoring at fixed transects in Pools 4, 8, 13, 26 and La Grange Pool of the Upper

Mississippi River System. U.S. Geological Survey, Environmental Management Technical Center, Onalaska, Wisconsin,

September 1998. LTRMP 98-P011. 24 pp. + Appendixes A–B

Additional copies of this report may be obtained from the National Technical Information Service, 5285 Port Royal Road,

Springfield, VA 22161 (1-800-553-6847 or 703-487-4650). Also available to registered users from the Defense Technical

Information Center, Attn: Help Desk, 8725 Kingman Road, Suite 0944, Fort Belvoir, VA 22060-6218 (1-800-225-3842 or

703-767-9050).
iii

Contents

Page

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction ........................................................................ 1

Study Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Methods ........................................................................... 6

Transect Sampling ................................................................ 6

Informal Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Environmental Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Statistical Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

All Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Pool 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Pool 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Pool 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Pool 26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

La Grange Pool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Appendix B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Tables

Table 1. Area and relative proportions of aquatic habitats (based on geomorphology) by navigation

pool for select reaches of the Upper Mississippi River System studied as part of the Long

Term Resource Monitoring Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Table 2. Frequency (%) of aquatic plant species found in Pools 4, 8, 13, and 26 of the Upper

Mississippi River and La Grange Pool (LG) of the Illinois River, 1995 . . . . . . . . . . . . . . . 10

Table 3. Frequency of vegetated sites of submersed species along transects in Pools 4, 8, 13, and 26 of

the Upper Mississippi River and La Grange Pool of the Illinois River during spring and

summer sampling, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
iv

Table 4. Maximum rooting depths (m) of submersed aquatic vegetation in Pools 4, 8, 13, and 26 of

the Upper Mississippi River and La Grange Pool of the Illinois River during spring and

summer transect sampling, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 5. Frequencies and relative frequencies of submersed aquatic plant species found along

transects in Pool 4 of the Upper Mississippi River during spring (May 22–June 13) and

summer (July 26–August 24) sampling periods, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 6. Seasonality of submersed aquatic plant species sampled along transects in backwaters of

Pool 4 of the Upper Mississippi River, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 7. Frequencies and relative frequencies of submersed aquatic plant species found along

transects in Pool 8 of the Upper Mississippi River during spring (May 15–June 7) and

summer (July 20–August 23) sampling periods, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Table 8. Seasonality of submersed aquatic plant species sampled along transects in backwaters of

Pool 8 of the Upper Mississippi River, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Table 9. Frequencies and relative frequencies of submersed aquatic plant species found along

transects in Pool 13 of the Upper Mississippi River during spring (May 19–June 15) and

summer (July 19–August 17) sampling periods, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Table 10. Seasonality of submersed aquatic plant species sampled along transects in backwaters of

Pool 13 of the Upper Mississippi River, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Table 11. Frequencies and relative frequencies of submersed aquatic plant species found along

transects in Pool 26 of the Upper Mississippi River during spring (June 7–13) and summer

(August 16–22) sampling periods, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Table 12. Seasonality of submersed aquatic plant species sampled along transects in backwaters of

Pool 26 of the Upper Mississippi River, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 13. Frequencies and relative frequencies of submersed aquatic plant species found along

transects in La Grange Pool of the Illinois River during spring (May 22–June 14) and

summer (August 8–September 12) sampling periods, 1995 . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 14. Seasonality of submersed aquatic plant species sampled along transects in backwaters of La

Grange Pool of the Illinois River, 1995 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figures

Figure 1. Location of Navigation Pools 4, 8, 13, and 26 and La Grange Pool in the Upper Mississippi

River System where aquatic vegetation was surveyed, Long Term Resource Monitoring

Program, 1995 ............................................................ 3

Figure 2. Backwater locations in Pool 4 (Upper Mississippi River) where transects were monitored for

aquatic vegetation, Long Term Resource Monitoring Program, 1995 .................. 4
v

Figure 3. Backwater locations in Pool 8 (Upper Mississippi River) where transects were monitored for

aquatic vegetation, Long Term Resource Monitoring Program, 1995 .................. 5

Figure 4. Backwater locations in Pool 13 (Upper Mississippi River) where transects were monitored

for aquatic vegetation, Long Term Resource Monitoring Program, 1995 ............... 5

Figure 5. Backwater locations in Pool 26 (Upper Mississippi River) where transects were monitored

for aquatic vegetation, Long Term Resource Monitoring Program, 1995 ............... 5

Figure 6. Backwater locations in La Grange Pool (Illinois River) where transects were monitored for

aquatic vegetation, Long Term Resource Monitoring Program, 1995 .................. 6

Figure 7. Daily water surface elevations (WSE) for select navigation pools of the Upper Mississippi

River System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
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Preface

The Long Term Resource Monitoring Program (LTRMP) was authorized under the Water Resources

Development Act of 1986 (Public Law 99-662) as an element of the U.S. Army Corps of Engineers'

Environmental Management Program. The LTRMP is being implemented by the Environmental Management

Technical Center (EMTC), a U.S. Geological Survey science center, in cooperation with the five Upper

Mississippi River System (UMRS) States of Illinois, Iowa, Minnesota, Missouri, and Wisconsin. The U.S.

Army Corps of Engineers provides guidance and has overall Program responsibility. The mode of operation

and respective roles of the agencies are outlined in a 1988 Memorandum of Agreement.

The UMRS encompasses the commercially navigable reaches of the Upper Mississippi River, as well as

the Illinois River and navigable portions of the Kaskaskia, Black, St. Croix, and Minnesota Rivers. Congress

has declared the UMRS to be both a nationally significant ecosystem and a nationally significant commercial

navigation system. The mission of the LTRMP is to provide decision makers and river managers with

information for maintaining the UMRS as a sustainable large river ecosystem given its multiple-use

character. The long-term goals of the Program are to understand the system, determine resource trends and

effects, develop management alternatives, manage information, and develop useful products.

 This report presents the results of aquatic vegetation transect surveys conducted in 1995 by field station

personnel under the direction of the EMTC. Selected areas in Pools 4, 8, 13, and 26 of the Upper Mississippi

River and La Grange Pool on the Illinois River were surveyed. This report satisfies, for 1995, Task 2.2.4.6,

Evaluate and Summarize Annual Present-day Results under Goal 2, Monitor Resource Change of the

Operating Plan (U.S. Fish and Wildlife Service 1993). The purpose of this report is to provide a summary

of data regarding the distribution and abundance of submersed aquatic vegetation collected from the field

stations for 1995. This report was developed with funding provided by the Long Term Resource Monitoring

Program. 
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1995 Annual Status Report

A Summary of Aquatic Vegetation Monitoring at

Fixed Transects in Pools 4, 8, 13, and 26 and

La Grange Pool of the Upper Mississippi River System

by

Sara Rogers, Heidi Langrehr, J. Therese Dukerschein, Jenny Winkelman,

John Nelson, Theresa Blackburn, and Thad Cook

Abstract

Distribution and frequency of aquatic vegetation in the Upper Mississippi River System are monitored as part

of the Long Term Resource Monitoring Program. This report summarizes results of sampling aquatic vegetation

along fixed transects in Navigation Pools 4, 8, 13, and 26 in the Upper Mississippi River and La Grange Pool

of the Illinois River in 1995. Pool 26 includes 12 miles of the Illinois River upstream of its confluence with the

Mississippi River; all of the backwaters surveyed in this river reach are on the lower Illinois River. Plants were

sampled using a modified rake technique along fixed transects. Data from additional qualitative surveys (or

informals) was used to augment species records in each pool. Twenty-three submersed and rooted floating-leaved

species were found in 1995. Pools 4 and 8 harbored the most species, including most of the large-leaved

pondweeds, and the number of species decreased in the pools to the south. Submersed aquatic vegetation was

most widespread in Pools 8 and 13 throughout the growing season (frequency of about 60%) and least in Pools

4 and 26 (30%). Sago pondweed (Potamogeton pectinatus) was the dominant species found along the length

of the river followed by coon’s tail (Ceratophyllum demersum). Curly pondweed (P. crispus), wild celery

(Vallisneria americana), and American lotus (Nelumbo lutea) were generally widespread in the upper three

pools, and their presence varied seasonally. The abundance of curly pondweed peaked during the spring, whereas

wild celery and American lotus were late-season strategists. Aquatic vegetation was generally rare in contiguous

areas of Pool 26 and La Grange Pool, and where vegetation was sampled (mostly isolated backwaters) fewer

species were found than in the three northern pools.

Introduction

Aquatic vegetation of the Upper Mississippi River System (UMRS) is monitored and trends in its status

are reported as part of the Long Term Resource Monitoring Program (LTRMP; U.S. Fish and Wildlife

Service 1993). This monitoring provides baseline information to which future observations can be compared.

In combination with water quality, fish, and invertebrate monitoring, the overall mission of the Program is

to provide scientifically sound and useful information for effective river management. The purpose of this

report is to document vegetation sampling at selected transects in 1995.

Historically, submersed aquatic vegetation (SAV) has played an important role in the UMRS ecosystem.

These plant communities provide food for migratory waterfowl (Korschgen et. al. 1988) and improvement

of water quality by stabilizing sediments, filtering out suspended materials, and taking up nutrients that can

otherwise support nuisance algal growth (Barko et al. 1991). Macrophytes also provide nursery areas for

young fish, serve as spawning habitat, and support invertebrate populations by providing structure and

surface area (Engel 1990).

We have been unable to understand or anticipate many changes in the distribution of SAV within the

UMRS, partly because few studies have adequately addressed the questions. Biologists have high interest

and concern for this important resource, however, especially in view of the drastic decline of SAV in the

Illinois River in the 1950s, of which only remnant populations survive (Talkington and Semonin 1991).

Concern for SAV in the Upper Mississippi River escalated in the mid- to late-1980s when widespread and

sudden declines in the abundance of wild celery (Vallisneria americana) were observed in Pools 5 to 19 (E.
2

Nelson and C. Cheap, U.S. Fish and Wildlife Service, Winona, Minnesota, unpublished data; C. Korschgen,

Northern Prairie Wildlife Research Center, Jamestown, South Dakota, unpublished data; J. Lyons, U.S. Fish

and Wildlife Service, McGregor, Iowa, personal communication; R. Anderson, Western Illinois University,

Macomb, personal communication; W. Thrune, U.S. Fish and Wildlife Service, La Crosse, Wisconsin,

personal communication).

Long-term monitoring can play a substantial role in increasing an understanding of trends in this resource

by addressing the following questions: 

(1) How temporally and spatially dynamic is SAV in the UMRS? 

(2) Are we observing short-term fluctuations in one or more species or is SAV becoming irreparably

lost?

(3) Based on patterns observed, what factors most likely contribute to the changes?

This report documents the results of sampling submersed and rooted floating-leaved vegetation along

transects at selected locations in 1995. It provides baseline information to evaluate changing conditions. The

1995 growing season was the fifth year that we conducted field surveys in designated LTRMP study reaches.

The objectives for monitoring aquatic vegetation in the UMRS are to

(1) document the distribution of SAV at selected locations of the UMRS,

(2) compare current distribution of SAV with past distribution, and

(3) identify environmental factors which may influence long- and short-term changes in the distribution

and abundance of SAV.

Fulfillment of these objectives requires focused research in addition to monitoring.

Study Areas

The LTRMP vegetation study area consists of five reaches within the UMRS, four on the Upper

Mississippi River and one on the Illinois River (Figure 1). Study areas are referred to herein by the navigation

pool designations according to the U.S. Army Corps of Engineers lock and dam system. The Upper

Mississippi River navigation pools studied were Pool 4 (Mississippi River mile [M] 752 to 797), Pool 8 (M

679 to 703), Pool 13 (M 523 to 557), Pool 26 (M 202 to 242), and La Grange Pool of the Illinois River

(Illinois River mile [I] 80 to 158). Pool 26 includes 12 miles of the lower Illinois River upstream of its

confluence (M 218.0) with the Mississippi River. River miles for the Upper Mississippi River are measured

from the confluence of the Mississippi and Ohio Rivers, and for the Illinois River from the confluence of the

Mississippi and Illinois Rivers. 

These study areas were chosen, in part, to reflect important differences in geomorphology, floodplain land

use, and water level management strategies that exist within the UMRS. Pools 4, 8, and 13 are

geomorphically complex with contiguous and isolated backwaters and numerous interconnected channels

(Table 1). A relatively large proportion of the aquatic area in these pools comprise backwaters and

impounded areas. The upper portions retain the most riverine character with braided channels, forested

islands, and relatively large water-level fluctuations (Peck and Smart 1986). In contrast, the lower portions

of these pools provide a shallow, more lacustrine environment. Pool 26 has a greater proportion of main

channel area. La Grange Pool has a high percentage of area in backwaters, but very little SAV has been

observed. Consequently, SAV sampling effort is less intensive in the two southern pools. 
3

Figure 1. Location of Navigation Pools 4, 8, 13, and 26 and La Grange Pool in the Upper

Mississippi River System where aquatic vegetation was surveyed, Long Term Resource

Monitoring Program, 1995. The Open River reach was not selected as a study site because

of the lack of habitat for submersed vegetation.

Table 1. Area and relative proportions of aquatic habitats (based on geomorphology) by navigation pool for select

reaches of the Upper Mississippi River System studied as part of the Long Term Resource Monitoring Program.a

Main Side

channel channel Backwater Lake Impounded Isolated

Location (ha) % (ha) % (ha) % (ha) % (ha) % (ha) % (ha) 

Area Area Area Area Area Area Total area

Pool 4 1,240 8 721 5 2,300 16 9,764 66 0 0 660 5 14,685 b

Pool 8 1,256 16 1,380 17 1,767 22 0 0 3,476 43 124 2 8,003

Pool 13 2,700 27 805 8 2,810 28 0 0 3,560 36 116 1 9,991

Pool 26 4,860 57 1,496 18 415 5 948 11 176 2 580 7 8,475 c

La Grange Pool 2,398 22 143 1 5,676 51 0 0 0 0 2,835 26 11,052 d

Data for Pools 4, 8, 13, and 26 were based on the sampling strata coverage. Data for La Grange Pool were based on the aquatic a

areas coverage.

Refers to Lake Pepin, a tributary delta lake. b

Refers to Swan Lake. c

La Grange Pool is located on the Illinois River. d
4

Figure 2. Backwater locations in Pool 4 (Upper Mississippi River) where transects were

monitored for aquatic vegetation, Long Term Resource Monitoring Program, 1995.

In Pool 4, we surveyed contiguous backwaters where transects were established in 1991 (Figure 2). We

also surveyed Upper Mud Lake, which was added in 1993. The transects were distributed in both the upper

and lower portions of the pool, but not in Lake Pepin. Upper pool locations included Dead Slough Lake,

Goose Lake, Upper Mud Lake, Mud Lake, and Catherine Pass (referred to as Bay City Flats in previous

reports; Appendix A). Lower pool locations (below Lake Pepin) included Robinson Lake, Peterson Lake,

Big Lake, and Rice Lake and Big Lake Bay, which are part of the Big Lake area. A Habitat Rehabilitation

Project (HREP), which involved dredging part of Big Lake Bay, was completed in spring, 1993.

In Pool 8, we surveyed five backwaters where transects were established in 1991 (Figure 3). Locations

included Target Lake, Lawrence Lake, a backwater area near Goose Island, Shady Maple, and the interior

of Horseshoe Island (Appendix A). We added a backwater near Stoddard, Wisconsin, in 1992, and two

backwaters, Blue Lake and the interior of Boomerang Island, in 1993. Horseshoe Island and Boomerang

Island are part of the Pool 8 Islands HREP. Most backwaters were in the lower two-thirds of the pool.

In Pool 13, we surveyed seven backwaters where transects were established in 1991 (Figure 4). Most of

the backwaters were in the middle and lower portions of the pool and included Brown's Lake, Savanna Bay,

Spring Lake, Pomme de Terre, Potter's Marsh, Johnson Creek, and Johnson Creek Levee (Appendix A).

Brown’s Lake and Potter’s Marsh are part of HREPs initiated in 1988 and 1994, respectively.

In Pool 26, we surveyed three backwaters where transects were established in 1991 (Figure 5). These

backwaters included the Calhoun Point area—consisting of several backwater lakes, sloughs, and ephemeral

ponds—and Swan and Stump Lakes (Appendix A). We also surveyed Fuller Lake, added in 1992. The reach

known as Pool 26 includes portions of both the Mississippi and lower Illinois Rivers. All backwater locations

sampled for vegetation were in the lower 12 miles of the Illinois River. Most transects were in isolated

backwaters that are intensively managed as moist soil units (to mimic preimpoundment conditions). Swan
5

Figure 4. Backwater locations in Pool 13 (Upper

Mississippi River) where transects were monitored

for aquatic vegetation, Long Term Resource

Monitoring Program, 1995.

Figure 3. Backwater locations in Pool 8 (Upper

Mississippi River) where transects were

monitored for aquatic vegetation, Long Term

Resource Monitoring Program, 1995.

Figure 5. Backwater locations in Pool 26 (Upper Mississippi River) where transects were

monitored for aquatic vegetation, Long Term Resource Monitoring Program, 1995.

Lake is a large shallow area contiguous with the Illinois River and, although it is not managed as a moist soil

unit, low water levels in the summer often limit access.
6

Figure 6. Backwater locations in La Grange Pool (Illinois River) where transects were

monitored for aquatic vegetation, Long Term Resource Monitoring Program, 1995.

In La Grange Pool, we have surveyed three backwaters since 1991 and the Grape Island area since 1992

(Figure 6; Appendix A). Bulrush Pond in Banner Marsh State Fish and Wildlife Area, Point Lake, and Spring

Lake are separated from the main stem of the Illinois River by levees. Water levels in the main river

influence the Grape Island area and Point Lake, but not Spring Lake and Banner Marsh, which are behind

larger drainage-district levees. 

Methods

Transect Sampling

Transects were positioned perpendicular to shorelines at regular intervals, from 50 to 200 m apart

depending on the size of the area. Transects typically traversed an entire backwater. Sampling was performed

twice in most locations during the growing season to observe seasonal changes. Spring sampling began on

May 15 and ended June 15. The summer sampling period ran from July 19 to September 12 (Appendix A).

In spring of 1995, sampling was discontinued in Spring Lake (La Grange Pool); however, substantial changes

in SAV were observed and sampling was resumed late in the year to document these changes.

Sampling along the transects was conducted at regularly spaced intervals or sites. Sites were surveyed

every 15 m in Pools 8, 13, and 26 and La Grange Pool, but every 30 m in Pool 4 because of the large size of

some backwaters. The sampling method was modified from a technique used by Jessen and Lound (1962).

At each site along a transect, a sampling area about 2 m in diameter was divided into thirds. Plants on the

bottom were sampled once within each third by lowering a long-handled thatching rake and twisting it to
7

snag samples. The thatching rake had a 38 cm (15-inch) head with 20, 12.7-cm-long (5-inch) teeth and

sampled an area of approximately 0.1 m . The submersed species on the rake were identified and recorded. 2

After all three twists were made, each species retrieved was assigned a rating of from 1 to 4, based on the

number of times it appeared on the rake. A rating of 4 was assigned only if a species completely covered the

rake teeth on all three twists. 

If rooted floating-leaved species were present, they were assigned a rating of 1 to 4 based on the amount

of vegetative cover visible in the entire 2-m sampling area (1 = 1–25% cover, 2 = 26–50% cover, 3 = 51–75%

cover, and 4 = 76–100% cover). Rooted floating-leaved species were not included in analysis of relative

frequency. Nonrooted floating species (e.g., Lemnaceae) were recorded if they exceeded 5% of the surface

area, but were excluded from analysis.

Fassett (1957), Voss (1972, 1985) and Gleason and Cronquist (1991) were the primary keys used for plant

identification. Scientific nomenclature and common names are based on those found in the U.S. Department

of Agriculture PLANTS Database on the Internet (http://plants.usda.gov/plants/). Leafy pondweed

(Potamogeton foliosus) and small pondweed (P. pusillus) were collectively referred to as “small and leafy

pondweeds.” They were not distinguished from each other during field sampling and were combined for

analysis. Chara (Chara spp.), a macroalga, was analyzed together with the vascular plants. 

An example of each species found during monitoring was saved as a voucher specimen. Voucher

specimens were pressed, dried, mounted, labeled, and stored at each field station. Rare species and unusual

specimens were saved for reference and sent to outside experts for verification. A list of submersed and

floating-leaved species found during LTRMP monitoring since 1991 appears in Appendix B. 

Informal Surveys

To gain perspective on the distribution and composition of SAV in habitats other than transect locations,

we qualitatively surveyed many portions within each study pool. When vegetation was observed, we recorded

species composition, relative abundance, approximate bed size, water depth, substrate type, and location

information. Informal surveys have not been conducted in Pool 26 since 1992 when extensive surveys

revealed that SAV was generally scarce.

Environmental Factors

Water depth was recorded at each site. The maximum rooting depth was calculated by averaging the

deepest 10% of sites with SAV. Depths were not adjusted for water surface elevations, which fluctuate

because of water level management and natural events. A qualitative sediment assessment based on visual

and tactile characteristics was recorded for each transect, but was excluded from analysis.

Daily water surface elevations were measured by the U.S. Army Corps of Engineers (Figure 7). Most

backwaters with transects were in the middle to lower sections of the pools, therefore, select mid-pool gage

readings were used to produce stage hydrographs for Pool 4 (Wabasha, Minnesota; M760.4), Pool 8 (La

Crosse, Wisconsin; M696.8), Pool 26 (Grafton, Illinois; M218.0), and La Grange Pool (Beardstown, Illinois;

I88.0). Because Pool 13 had no mid-pool gage recorded for 1995, comparative data for that pool were not

available. Mid-pool gages are preferred because most transects are located in that part of the pool and data

from other locations, such as tailwaters, have more extreme fluctuations and are less accurate. Similar stage
Month

Water surface elevation (feet above mean sea level)

Pool 4 (Wabasha gage, M 760.4)

Pool 8 (La Crosse gage, M 696.8)

Pool 26 (Grafton gage, M 218.0)

La Grange Pool (Beardstown gage, I 88.0)

J F M A M J J A S O N D

J F M A M J J A S O N D

J F M A M J J A S O N D

J F M A M J J A S O N D

8

Figure 7. Daily water surface elevations (WSE) for

select mid-pool gages within selected navigation pools

of the Upper Mississippi River System. Solid line shows

1995 stage hydrograph. Dotted line indicates mean

annual stage hydrograph and shaded area shows

minimum and maximum WSEs for the period of record

from 1950–1995. (Mississippi River mile [M]; Illinois

River mile [I]; USACE data). Mid-pool gage data are not

available for Pool 13.

hydrograph patterns are observed along the length of a pool and depend ultimately on discharge, which

determines the method of pool level control.
9

Statistical Analysis

The frequency of a species is defined as

f = j / i i n

where 

 j = number of sample sites containing species i on at least one of the three rake twists, i

 n = total number of sample sites.

Relative frequency of a species is defined as

rf = e /Ef i i

where

e = number of rake twists in which species i was present, i

Ef = sum of the total number of times present for each species.

Frequency and relative frequency are expressed as percent. Records of rooted floating-leaved vegetation

were omitted from the relative frequency calculations.

Chi-square tests were used to test for significant seasonal differences in the number of vegetated sites in

each pool. To test for significant change in a species frequency between sampling periods, a value for Z was

calculated for each species in each backwater location using the following formula:

Z = p - p /pq[(1/n )+(1/n )] 12 1 2

where

p = (j + j )/(n + n ); 12 1 2

q = 1-p;

p = j /n ; 1 1 1

p = j /n ; 2 2 2

n and n = number of sampling sites, spring and summer, respectively; 1 2

j and j = number of times species j was found during the spring and summer sampling periods, 1 2

respectively.

Results and Discussion

All Pools

We found 20 species of submersed plants and 3 of rooted floating-leaved plants in 1995 (Table 2). Of

these, 16 submersed species were found along transects, and the remainder during informal surveys. The

number of species found declined as we moved in a southerly direction. Pool 4 was the most species rich

(22 species, 19 of which were submersed) and Pool 26 the most depauperate (8 species, 7 of which were

submersed). La Grange Pool of the Illinois River hosted 10 species, a relatively low number. As Peck and

Smart (1986) noted, most species were found above Pool 14.
10

Table 2. Frequency (%) of aquatic plant species found in Pools 4, 8, 13, and 26 of the Upper Mississippi River and

La Grange Pool (LG) of the Illinois River, 1995.

Spring Summer

Species 4 8 13 26 LG 4 8 13 26 LG

Submersed species

bladderwort, common IS 0.4 – – – – 1.6 – – –

(Utricularia macrorhiza)

a b

buttercup, longbeak IS – – – – – – – – –

(Ranunculus longirostris)

chara IS – – – – – – <0.1 –

(Chara spp.)

+c

coon’s tail 1.5 34.5 12.3 – 25.7 4.0 47.8 21.9 2.1 44.6

(Ceratophyllum demersum)

pondweed, alpine IS – – – – – – – – –

(Potamogeton alpinus)

pondweed, curly 10.9 15.0 10.0 0.2 14.3 1.0 5.0 4.7 – –

(P. crispus)

pondweed, flatstem 0.1 0.7 0.5 – – – 0.6 2.0 – –

(P. zosteriformis)

pondweed, horned 0.2 0.1 – – IS 0.1 – 0.1 – –

(Zannichellia palustris)

pondweed, longleaf – 0.4 2.8 0.9 2.9 0.5 1.1 4.6 4.2 13.8

(P. nodosus)

pondweed, ribbonleaf IS – – – – – – – – –

(P. epihydrus)

pondweed, Richardson’s IS – – – – – – – – –

(P. richardsonii)

pondweed, sago 19.9 19.8 52.2 22.5 7.1 5.0 25.4 44.3 11.0 9.2

(P. pectinatus)

pondweeds, small and leafy – 11.0 0.1 – 2.9 0.5 9.8 – 4.2 9.2

(P. pusillus, P. foliosus)

water stargrass – – 12.5 – – 0.6 0.5 19.3 2.1 –

(Heteranthera dubia)

watermilfoil, Eurasian 1.6 13.2 8.1 – 14.3 2.2 11.6 7.4 – 16.9

(Myriophyllum spicatum)

watermilfoil, shortspike 0.1 IS – – – – – – – –

(M. sibiricum)

waternymph, nodding – – 0.7 – – 0.4 4.8 2.8 – –

(Najas flexilis)

waternymph, southern – – – – – – – 2.1 6.3 –

(N. guadalupensis)

waterweed, Canadian 0.4 4.2 6.5 – – 1.3 5.2 7.7 –

(Elodea canadensis)

+

wild celery – – 5.1 – – 8.8 0.1 13.2 – –

(Vallisneria americana)

Number of submersed species 8 10 11 3 6 11 12 13 6 7

(transects)

Rooted floating-leaved species

American lotus 0.1 0.2 7.4 – – 2.8 11.4 31.1 11.9

(Nelumbo lutea)

+
Table 2. Continued.

Spring Summer

Species 4 8 13 26 LG 4 8 13 26 LG

11

pondlily, yellow – 3.1 – – – 0.1 3.8 – – –

(Nuphar lutea)

waterlily, American white 7.7 23.2 IS – – 9.1 35.6 – – –

(Nymphaea odorata)

Number of rooted 2 3 1 0 0 3 3 1 1 1

floating-leaved species

(transects)

Total number of species per 22 17 16 8 10

poold

IS indicates that a species was recorded during informal surveys but not during transect sampling. a

The symbol “–” indicates the species was not found. b

The symbol “+” indicates a species was found in an area that was sampled only once during the field season. c

Includes data from spring and summer transects as well as informal surveys. d

Sago pondweed (Potamogeton pectinatus), coon’s tail (Ceratophyllum demersum), and curly pondweed

(P. crispus) were the most cosmopolitan species, present in all pools and in the greatest proportion of sites

(Table 2). Longleaf pondweed (P. nodosus), small and leafy pondweeds, and American lotus (Nelumbo lutea)

were also widely distributed. Eurasian watermilfoil (Myriophyllum spicatum) was found in all the study sites

except Pool 26. Less common species were also less widely distributed. common bladderwort (Utricularia

macrorhiza), longbeak buttercup (Ranunculus longirostris), short spike watermilfoil (M. sibiricum), and

yellow pondlily (Nuphar lutea) were found in one or both of the two northern pools (Pools 4 and 8). Southern

waternymph (Najas guadalupensis) was found only in the southern reach (Pools 13 and 26). The range of

nodding waternymph (N. flexilis) was wider and, like American white waterlily (Nymphaea odorata),

spanned Pools 4, 8, and 13. In general, curly pondweed growth peaked in the spring and subsequently

declined. Other species, such as southern and nodding waternymph, water stargrass (Heteranthera dubia),

wild celery, and American lotus increased in frequency later in the season.

In most pools (4, 8, 26, and La Grange), the percent of sites with SAV changed significantly between

sampling periods, but the direction of change varied among pools (Table 3). Whether vegetation increased

or declined could usually be attributed to the regional phenology of the most dominant species. For example,

in Pools 4 and 26, the general drop in the percent of submersed vegetated sites reflected a summer decline

in sago pondweed. Conversely, in Pool 8 and La Grange Pool, sago pondweed and coon’s tail expanded

during the summer, thereby increasing the percent of submersed vegetated sites.
12

Table 3. Frequency of vegetated sites of submersed species along transects in Pools 4, 8, 13, and 26 of the Upper

Mississippi River and La Grange Pool of the Illinois River during spring and summer sampling, 1995.

Pool Spring (%) Summer (%) Significance n n a

 4 30.0 1,073 18.1 1,014 * P < 0.001 b

 8 57.1 1,291 62.2 1,250 * P < 0.009 

13 61.5 1,018 63.4 1,111 P < 0.382 

26 23.8 426 10.7 429 * P < 0.001 

La Grange 34.3 70 47.7 65 c * P < 0.113 

Probability value is based on Chi-square test where  = 0.05 a

The symbol “*” indicates significant change. b

Spring Lake was excluded from calculations. c

The maximum rooting depth of SAV decreased from north to south in the upper three study pools (Pools

4, 8, and 13; Table 4). In general, SAV was recorded at greater depths in the spring than in the summer. This

trend reflects the effects of seasonal precipitation which typically swells water surface elevations (WSE) in

the springtime (Figure 7). Also, mid-summer WSEs were higher than the annual mean in the northern three

pools.

Table 4. Maximum rooting depths (m) of submersed aquatic vegetation in Pools 4, 8, 13, and 26 of the Upper Mississippi

River and La Grange Pool of the Illinois River during spring and summer transect sampling, 1995.a

Pool Spring Summer n n

 4 1.9 ± 0.03 32 1.4 ± 0.05 19

 8 1.7 ± 0.01 74 1.3 ± 0.01 78

 13 1.6 ± 0.01 63 1.0 ± 0.01 70

 26 4.1 ± 0.00 10 0.5 ± 0.02 5 b

La Grange 2.7 ± 0.09 3 2.5 ± 0.12 3 b, c

Maximum rooting depth was calculated by averaging the deepest 10% of sites with SAV. a

Water levels exceeded flood stage during spring (Figure 7). b

Spring Lake was excluded from calculations. c

In the lower two pools (Pool 26 and La Grange Pool), spring flooding in the Illinois River resulted in

record WSEs. Subsequently, maximum rooting depths in the spring were inflated. The deepest (4.1 m, spring)

and most shallow (0.5 m, summer) maximum rooting depths were observed in Pool 26 illustrating the

extreme conditions to which SAV is exposed. Intensive water-level control in backwaters managed as moist

soil units makes it difficult to compare Pool 26 with the other LTRMP study reaches. The maximum rooting

depth of SAV in the La Grange Pool was also high but more consistent, a result of spring flooding and later

an artifact of a water level management strategy aimed at improving fish production in isolated areas.

Pool 4 

Of the 13 submersed species found along transects in Pool 4, 8 were recorded in the spring and 11 in the

summer (Table 5). Most species found were rare, present in fewer than 2% of the sites. Flatstem pondweed

(P. zosteriformis) and short spike watermilfoil were found only during spring sampling. Small and leafy

pondweeds, longleaf pondweed, water stargrass, nodding waternymph, and wild celery were sampled only

during the summer.
13

During spring sampling, curly and sago pondweeds were the most widespread; however, they were present

in 20% or fewer of the sites surveyed (Table 5). These two species collectively contributed to more than 90%

of the relative frequencies during the spring effort. During summer sampling, no species exceeded a

frequency of 10%. Wild celery displaced sago pondweed as the dominant species (relative frequency of 44%)

and curly pondweed virtually disappeared. Coon’s tail, sago pondweed, and Eurasian watermilfoil together

made up almost 42% of the remaining SAV community, even though they were each found in 5% or fewer

of the sites.

Table 5. Frequencies and relative frequencies of submersed aquatic plant species found along transects in Pool 4 of

the Upper Mississippi River during spring (May 22–June 13) and summer (July 26–August 24) sampling periods, 1995.

Frequencies (%) Relative frequencies (%)

Species n = 1073 n = 1014 Spring Summer 

Spring Summer

coon’s tail 1.5 4.0 3.1 14.1

(Ceratophyllum demersum)

pondweed, curly 10.9 1.0 31.5 3.3

(Potamogeton crispus)

pondweed, flatstem 0.1 0 0.2 0

(P. zosteriformis)

pondweed, horned 0.2 0.1 0.3 0.5

(Zannichellia palustris)

pondweed, longleaf 0 0.5 0 1.7

(P. nodosus)

pondweed, sago 19.9 5.0 60.5 18.5

(P. pectinatus)

pondweeds, small and leafy 0 0.5 0 1.4

(P. pusillus, P. foliosus)

water stargrass 0 0.6 0 1.7

(Heteranthera dubia)

watermilfoil, Eurasian 1.6 2.2 3.6 8.8

(Myriophyllum spicatum)

watermilfoil, short spike 0.1 0 0.2 0

(M. sibiricum)

waternymph, nodding 0 0.4 0 1.7

(Najas flexilis)

waterweed, Canadian 0.4 1.3 0.6 4.1

(Elodea canadensis)

wild celery 0 8.8 0 44.2

(Vallisneria americana)

Percent of vegetated sites 30 18.1 a

From Table 3. a

In 1995, more species were found in Pool 4 than in the other study sites and grew in water up to 1.9 m

deep (Tables 2 and 4); however, the overall presence of vegetation was low (30% and 18%, spring and

summer respectively; Table 5). Upstream of Lake Pepin, SAV was sparse and composed almost singularly

of sago pondweed; whereas, many more species were found in backwaters downstream of Lake Pepin (Table

6). Lake Pepin is a 22-mile long tributary delta lake in the middle of Pool 4 that was created by vast amounts

of sand deposited at the confluence of the Chippewa River.
14

Seasonal differences were observed for particular species and locations—upper versus lower Pool 4

(Table 6). Sago and curly pondweeds matured and died in some locations between sampling periods. Sago

pondweed declined in all upper pool backwaters, but remained almost unchanged in the lower pool. Wild

celery, coon’s tail, and Canadian waterweed (Elodea canadensis) increased in a number of lower pool

locations between spring and summer sampling. No significant changes were observed in any backwaters

for flatstem, small and leafy, and longleaf pondweeds, horned pondweed (Zannichellia palustris), water

stargrass, Eurasian and short spike watermilfoil, and nodding waternymph. This may, in part, be because of

their low frequency. Submersed aquatic vegetation was most dynamic in Robinson Lake, where two species

declined and three species expanded between sampling periods.

Table 6. Seasonality of submersed aquatic plant species sampled along transects in backwaters of Pool 4 of the Upper

Mississippi River, 1995.

Species sampling periods sampling periods sampling periods

Decreased between No change between Increased between

spring and summer spring and summer spring and summer a a

coon’s tail Big Lake Robinson Lake 

(Ceratophyllum demersum) Big Lake Bay

Lower Peterson Lake

Peterson Lake

Rice Lake

Upper Mud Lakeb

pondweed, curly Big Lake Bay Big Lake

(Potamogeton crispus) Robinson Lake Lower Peterson Lake

Rice Lake

Peterson Lake

pondweed, flatstem Big Lake

(P. zosteriformis)

pondweed, horned Big Lake Bay

(Zannichellia palustris) Peterson Lake

pondweed, longleaf Big Lake

(P. nodosus) Rice Lake

Robinson Lake

pondweed, sago Catherine Pass Big Lake

(P. pectinatus) Dead Slough Lake Big Lake Bay 

b

b

Goose Lake Lower Peterson Lake b

Mud Lake Peterson Lake b

Robinson Lake Rice Lake

Upper Mud Lakeb

pondweeds, small and leafy Peterson Lake 

(P. pusillus, P. foliosus) Rice Lake

Robinson Lake

water stargrass Big Lake 

(Heteranthera dubia) Lower Peterson Lake

Peterson Lake

Robinson Lake

watermilfoil, Eurasian Big Lake Bay

(Myriophyllum spicatum) Big Lake 

Lower Peterson Lake

Rice Lake 

Robinson Lake 
Table 6. Continued.

Species sampling periods sampling periods sampling periods

Decreased between No change between Increased between

spring and summer spring and summer spring and summer a a

15

watermilfoil, short spike Robinson Lake

(M. sibiricum)

waternymph, nodding Peterson Lake 

(Najas flexilis) Robinson Lake

waterweed, Canadian Big Lake Robinson Lake

(Elodea canadensis) Rice Lake 

wild celery Rice Lake Big Lake

(Vallisneria americana) Lower Peterson Lake

Peterson Lake

Robinson Lake 

Changes in a species frequency were significant at P < 0.05. a

Upper Pool 4 locations. b

Pool 8

Of the 13 submersed species found along transects in Pool 8, ten were recorded in the spring and twelve

were found in the summer (Table 7). Horned pondweed was found only during spring sampling, whereas

water stargrass, nodding waternymph, and wild celery were recorded only during summer.

Table 7. Frequencies and relative frequencies of submersed aquatic plant species found along transects in Pool 8 of

the Upper Mississippi River during spring (May 15–June 7) and summer (July 20–August 23) sampling periods, 1995.

Frequencies (%) Relative frequencies (%)

Species n = 1291 n = 1250 Spring Summer 

Spring Summer 

bladderwort, common 0.4 1.6 0.2 1.0

(Utricularia macrorhiza)

coon’s tail 34.5 47.8 38.7 51.6

(Ceratophyllum demersum)

pondweed, curly 15.0 5.0 12.9 3.4

(Potamogeton crispus)

pondweed, flatstem 0.7 0.6 0.6 0.4

(P. zosteriformis)

pondweed, horned 0.1 0 <0.1 0

(Zannichellia palustris)

pondweed, longleaf 0.4 1.1 0.4 0.8

(P. nodosus)

pondweed, sago 19.8 25.4 17.9 18.4

(P. pectinatus)

pondweeds, small and leafy 11.0 9.8 11.0 7.3

(P. pusillus, P. foliosus)

water stargrass 0 0.5 0 0.3

(Heteranthera dubia)

watermilfoil, Eurasian 13.2 11.6 13.8 8.3

(Myriophyllum spicatum)
Table 7. Continued.

Frequencies (%) Relative frequencies (%)

Species n = 1291 n = 1250 Spring Summer 

Spring Summer 

16

waternymph, nodding 0 4.8 0 4.0

(Najas flexilis)

waterweed, Canadian 4.2 5.2 4.5 4.5

(Elodea canadensis)

wild celery 0 0.1 0 <0.1

(Vallisneria americana)

Percent of vegetated sites 57.1 62.2 a

From Table 3. a

Coon’s tail was the most frequently recorded submersed species during spring (35%) and summer (48%)

sampling periods. Coon’s tail and sago pondweed dominated the submersed community in both sampling

periods combining for greater than 55% of the relative frequencies. Water stargrass and wild celery were

rarely found in Pool 8 transect locations (<1%). The percent of submersed vegetated sites increased from

57% (spring) to 62% (summer). 

Seasonal differences were recorded in seven of eight backwaters surveyed in Pool 8 in 1995 (Table 8).

Sago pondweed and curly pondweed were widespread, present in all eight backwater locations. Coon’s tail,

sago pondweed, and nodding waternymph increased in at least three backwaters. Conversely, curly pondweed

declined in four of the eight locations. No seasonal differences were recorded for flatstem, longleaf, and

horned pondweeds, water stargrass, Canadian waterweed, and wild celery. Blue Lake was the most dynamic

location, where two species declined and four species increased.

Table 8. Seasonality of submersed aquatic plant species sampled along transects in backwaters of Pool 8 of the Upper

Mississippi River, 1995.

Species sampling period sampling period sampling periods

Decreased between No change between Increased between

spring and summer spring and summer spring and summer a a

bladderwort, common Lawrence Lake Blue Lake

(Utricularia macrorhiza) Target Lake

coon’s tail Horseshoe Island Blue Lake

(Ceratophyllum demersum) Shady Maple Goose Island

Stoddard, Wisconsin Lawrence Lake

Target Lake

pondweed, curly Blue Lake Goose Island

(Potamogeton crispus) Boomerang Island Horseshoe Island

Lawrence Lake Shady Maple

Stoddard, Wisconsin Target Lake

pondweed, flatstem Goose Island

(P. zosteriformis) Horseshoe Island

Lawrence Lake

pondweed, horned Horseshoe Island

(Zannichellia palustris)
Table 8. Continued.

Species sampling period sampling period sampling periods

Decreased between No change between Increased between

spring and summer spring and summer spring and summer a a

17

pondweed, longleaf Goose Island

(P. nodosus) Lawrence Lake

Shady Maple

Target Lake

pondweed, sago Boomerang Island Goose Island Blue Lake

(P. pectinatus) Horseshoe Island Shady Maple

Lawrence Lake Target Lake

Stoddard, Wisconsin

pondweeds, small and leafy Blue Lake Goose Island

(P. pusillus, P. foliosus) Lawrence Lake

Shady Maple

Stoddard, Wisconsin

Target Lake

water stargrass Boomerang Island

(Heteranthera dubia) Goose Island

Lawrence Lake

Shady Maple

Target Lake

watermilfoil, Eurasian Lawrence Lake Boomerang Island Goose Island

(Myriophyllum spicatum) Horseshoe Island

Shady Maple

Target Lake

waternymph, nodding Goose Island Blue Lake

(Najas flexilis) Horseshoe Island Lawrence Lake

Target Lake

waterweed, Canadian Blue Lake

(Elodea canadensis) Goose Island

Lawrence Lake

Stoddard, Wisconsin

Target Lake

wild celery Lawrence Lake

(Vallisneria americana)

Changes in a species frequency were significant at P < 0.05. a

Pool 13

Of the 14 submersed species found along transects in Pool 13 in 1995, 11 were found during the spring

sampling period and 13 in the summer (Table 9). Small and leafy pondweeds were found only during the

spring sampling, whereas chara (Chara spp.), horned pondweed, and southern waternymph were found only

during the summer sampling.
18

Table 9. Frequencies and relative frequencies of submersed aquatic plant species found along transects in Pool 13 of

the Upper Mississippi River during spring (May 19–June 15) and summer (July 19–August 17) sampling periods, 1995.

Frequencies (%) Relative frequencies (%)

Species n = 1,018 n = 1,111 Spring Summer 

Spring Summer 

chara 0 <0.1 0 0.1

(Chara spp.)

coon’s tail 12.3 21.9 10.8 16.2

(Ceratophyllum demersum)

pondweed, curly 10.0 4.7 6.1 2.2

(Potamogeton crispus)

pondweed, flatstem 0.5 2.0 0.2 1.1

(P. zosteriformis)

pondweed, horned 0 0.1 0 0.1

(Zannichellia palustris)

pondweed, longleaf 2.8 4.6 1.7 3.1

(P. nodosus)

pondweed, sago 52.2 44.3 51.4 34.8

(P. pectinatus)

pondweeds, small and leafy 0.1 0 <0.1 0

(P. pusillus, P. foliosus)

water stargrass 12.5 19.3 9.9 15.0

(Heteranthera dubia)

watermilfoil, Eurasian 8.1 7.4 9.3 6.7

(Myriophyllum spicatum)

waternymph, nodding 0.7 2.8 0.5 2.3

(Najas flexilis)

waternymph, southern 0 2.1 0 1.5

(N. guadalupensis)

waterweed, Canadian 6.5 7.7 6.2 7.1

(Elodea canadensis)

wild celery 5.1 13.2 3.9 9.8

(Vallisneria americana)

Percent of vegetated sites 61.5 63.4 a

From Table 3. a

More than 60% of the sites surveyed were vegetated throughout the growing season (Table 9). Sago

pondweed was the most abundant species found during both sampling periods (52% and 44% in the spring

and summer, respectively) followed by coon’s tail and water stargrass. Coon’s tail and water stargrass

became more widespread as the growing season advanced, so that by summer their combined relative

frequency (31%) neared that of sago pondweed (35%). Wild celery frequency increased between sampling

periods (from 5% to 13%), becoming the fourth most important species in Pool 13 by the summer (relative

frequency of 10%).

Seasonal differences were observed in most species in at least some of the backwaters surveyed (Table

10). Curly and sago pondweeds showed localized declines. However, the latter also increased in other

backwaters. Coon’s tail, water stargrass, wild celery, flatstem and longleaf pondweeds, and nodding and

southern waternymph increased in at least one location. The only species whose frequencies did not change

significantly in any of the locations were Eurasian watermilfoil and Canadian waterweed. Most late season

growth was observed in Pomme de Terre, Johnson Creek, and Spring Lake, where three species increased

in each location. 
19

Table 10. Seasonality of submersed aquatic plant species sampled along transects in backwaters of Pool 13 of the

Upper Mississippi River, 1995.

Species sampling period sampling period sampling period

Decreased between No change between Increased between

spring and summer spring and summer spring and summer a a

chara Johnson Creek

(Chara spp.)

coon’s tail Johnson Creek Brown’s Lake

(Ceratophyllum demersum) Johnson Creek Levee Savanna Bay

Pomme de Terre Spring Lake

Potter’s Marsh

pondweed, curly Johnson Creek Brown's Lake

(Potamogeton crispus) Spring Lake Johnson Creek Levee

Pomme de Terre

Potter's Marsh

 Savanna Bay

pondweed, flatstem Brown's Lake Johnson Creek

(P. zosteriformis) Johnson Creek Levee

Savanna Bay

Spring Lake

pondweed, horned Savanna Bay

(Zannichellia palustris)

pondweed, longleaf Brown's Lake Spring Lake

(P. nodosus) Johnson Creek

Johnson Creek Levee

Pomme de Terre

Savanna Bay

pondweed, sago Johnson Creek Levee Johnson Creek Brown’s Lake

(P. pectinatus) Potter's Marsh Savanna Bay Pomme de Terre

Spring Lake

pondweeds, small and leafy Johnson Creek

(P. pusillus, P. foliosus)

water stargrass Johnson Creek Johnson Creek Levee

(Heteranthera dubia) Savanna Bay Pomme de Terre

Spring Lake Potter’s Marsh

watermilfoil, Eurasian Johnson Creek

(Myriophyllum spicatum) Johnson Creek Levee

Pomme de Terre

Potter's Marsh

Spring Lake

waternymph, nodding Brown's Lake Spring Lake

(Najas flexilis) Johnson Creek

Johnson Creek Levee

Pomme de Terre

Savanna Bay

waternymph, southern Johnson Creek Levee Johnson Creek

(N. guadalupensis) Potter’s Marsh

Spring Lake
Table 10. Continued.

Species sampling period sampling period sampling period

Decreased between No change between Increased between

spring and summer spring and summer spring and summer a a

20

waterweed, Canadian Johnson Creek

(Elodea canadensis) Johnson Creek Levee

Pomme de Terre

Savannah Bay

Spring Lake

wild celery Johnson Creek Levee Johnson Creek

(Vallisneria americana) Potter's Marsh Pomme de Terre

Savanna Bay

Spring Lake

Changes in a species frequency were significant at P < 0.05. a

Pool 26

Of the seven submersed species found along transects in Pool 26 in 1995, three were found during the

spring sampling and six were surveyed in the summer (Table 11). Curly pondweed was found only in the

spring, whereas coon’s tail, small and leafy pondweeds, water stargrass, and southern waternymph were

found only during summer sampling. The frequency of submersed vegetated sites in Pool 26 was halved

despite the appearance of additional species.

Table 11. Frequencies and relative frequencies of submersed aquatic plant species found along transects in Pool 26

of the Upper Mississippi River during spring (June 7–13) and summer (August 16–22) sampling periods, 1995.

Frequencies (%) Relative frequencies (%)

Species n = 426 n = 429 Spring Summer 

Spring Summer 

coon’s tail 0 2.1 0 4.4

(Ceratophyllum demersum)

pondweed, curly 0.2 0 1.0 0

(Potamogeton crispus)

pondweed, longleaf 0.9 4.2 4.0 9.2

(P. nodosus)

pondweed, sago 22.5 11.0 95.0 38.6

(P. pectinatus)

pondweeds, small and leafy 0 4.2 0 13.0

(P. pusillus, P. foliosus)

water stargrass 0 2.1 0 7.3

(Heteranthera dubia)

waternymph, southern 0 6.3 0 27.5

(Najas guadalupensis)

Percent of vegetated sites 23.8 10.7

Sago pondweed dominated the plant community and was the only species whose frequency exceeded 10%

during the entire season (Table 11). Sago pondweed declined between sampling periods in Swan Lake where

it was the only species found (Table 12). In Stump Lake, vegetation changed seasonally. By summer, the

presence of small and leafy pondweeds, longleaf pondweed, and southern waternymph expanded. In the
21

southern portion of Stump Lake, American lotus was observed as the dominant species by summer and was

seen covering much of the water surface.

Table 12. Seasonality of submersed aquatic plant species sampled along transects in backwaters of Pool 26 of the

Upper Mississippi River, 1995.

Species sampling periods sampling periods sampling periods

Decreased between No change between Increased between 

spring and summer spring and summer spring and summer a a

coon’s tail Stump Lake

(Ceratophyllum demersum)

pondweed, curly Calhoun Point

(Potamogeton crispus)

pondweed, longleaf Stump Lake

(P. nodosus)

pondweed, sago Swan Lake Stump Lake

(P. pectinatus)

pondweeds, small and leafy Stump Lake

(P. pusillus, P. foliosus)

water stargrass Stump Lake

(Heteranthera dubia)

waternymph, southern Stump Lake

 (Najas guadalupensis)

Changes in a species frequency were significant at P < 0.05. a

Overall, the percent of submersed vegetated sites was very low (Table 11). Calhoun Point had a single

sample of curly pondweed and Fuller Lake was devoid of SAV. The lack of vegetation in this river reach was

probably influenced by spring flooding, shown by water levels that exceeded flood stage and rooting depths

that exceeded 4 m (Figure 7; Table 4).

La Grange Pool

Of the eight submersed species found along transects in the La Grange Pool in 1995, six were found

during the spring sampling and five were sampled in the summer (Table 13). In Spring Lake, surveyed only

late in the season, six species were found including the only 1995 records for chara and Canadian waterweed.

In the spring, coon’s tail was the most widespread plant (26%) followed by curly pondweed (14%) and

Eurasian watermilfoil (14%), and together they accounted for almost 90% of the relative frequencies.

Eurasian watermilfoil and curly pondweed were present at the same number of sites; however, the former

was encountered more frequently at each site, accounting for its higher relative frequency values. During the

summer sampling, the presence of coon’s tail expanded to 45% and continued to dominate the plant

community. Eurasian watermilfoil remained the second most common species, but curly pondweed

disappeared. Longleaf pondweed expanded over the growing season reaching a relative frequency of 15%.
22

Table 13. Frequencies and relative frequencies of submersed aquatic plant species found along transects in La Grange

Pool of the Illinois River during spring (May 22–June 14) and summer (August 8–September 12) sampling periods, 1995.a

Frequencies (%) Relative frequencies (%)

Species n = 70 n = 65 n =146 Spring Summer Spring Lake

Spring Summer Spring Lakea

a

chara – – 6.8 – – 13.4

(Chara spp.)

b

coon’s tail 25.7 44.6 11.6 46.9 50.7 17.4

(Ceratophyllum demersum)

pondweed, curly 14.3 0 0.7 12.5 0 0.6

(Potamogeton crispus)

pondweed, longleaf 2.9 13.8 – 3.1 15.0 –

(P. nodosus)

pondweed, sago 7.1 9.2 0.7 5.2 7.8 0.6

(P. pectinatus)

pondweeds, small and leafy 2.9 9.2 – 3.1 8.6 –

(P. pusillus, P. foliosus)

watermilfoil, Eurasian 14.3 16.9 31.5 29.2 17.9 61.6

(Myriophyllum spicatum)

waterweed, Canadian – – 4.8 – – 6.4

(Elodea canadensis)

Percent of vegetated 34.3 47.7 43.8

sitesc

Spring Lake sites were monitored during summer only and were calculated separately. a

The symbol “–” indicates the species was not found. b

From Table 3. c

Few seasonal differences were observed in 1995 (Table 14). Only curly and longleaf pondweeds declined

and expanded, respectively, in Banner Marsh. The only contiguous area where transects were located, Grape

Island, was devoid of plants. Vegetation in the Grape Island area and Point Lake were probably impacted by

spring flooding (Figure 7).

Table 14. Seasonality of submersed aquatic plant species sampled along transects in backwaters of La Grange Pool

of the Illinois River, 1995.

Species sampling periods sampling periods sampling periods

Decreased between No change between Increased between 

spring and summer spring and summer spring and summer a a

coon’s tail Banner Marsh

(Ceratophyllum demersum) Point Lake

pondweed, curly Banner Marsh

(Potamogeton crispus)

pondweed, longleaf Banner Marsh

(P. nodosus)

pondweed, sago Banner Marsh

(P. pectinatus)

pondweeds, small and leafy Banner Marsh

(P. pusillus, P. foliosus)

watermilfoil, Eurasian Banner Marsh

(Myriophyllum spicatum)

Changes in a species frequency were significant at P < 0.05. a
23

Spring Lake could not be compared to other locations because it was surveyed only once in 1995.

Following the 1994 growing season we decided to cease transect sampling in Spring Lake, but important

changes occurred. As in previous years, Eurasian watermilfoil grew profusely in the spring creating a large

homogenous bed with low diversity in the plant community. In the middle of the growing season, Eurasian

watermilfoil suddenly died back and transect sampling was reinstated. Subsequently, five additional species

were found (Table 13). Inspection of Eurasian watermilfoil tissue later revealed that the milfoil weevil

(Euhrychiopsis lecontei) was present in Spring Lake during the 1995 growing season (Wayne Henderson,

Fisheries Biologist, Illinois Department of Natural Resources, personal communication).

Acknowledgments

The authors gratefully acknowledge M. Coulombe-Moore, W. Popp, L. Carnal, P. Lockhart, M. Mangrich,

G. Hoyle, and R. Cosgriff for their valuable assistance and support. We also thank LTRMP field station staff

at the participating agencies: Illinois Natural History Survey, Alton and La Grange; Iowa Department of

Natural Resources, Bellevue; Minnesota Department of Natural Resources, Lake City; and Wisconsin

Department of Natural Resources, Onalaska.

References

Barko, J. W., D. Gunnison, and S. R. Carpenter. 1991. Sediment interactions with submersed macrophyte

growth and community dynamics. Aquatic Botany 41:41–65.

Engel, S. 1990. Ecosystem responses to growth and control of submerged macrophytes: A literature review.

Technical Bulletin 170. Wisconsin Department of Natural Resources, Madison. 22 pp.

Fassett, N.C. 1957. A manual of aquatic plants. University of Wisconsin Press, Madison. 405 pp.

Gleason, H.A., and A. Cronquist. 1991. A manual of vascular plants of northeastern United States and

adjacent Canada. 2nd edition. The New York Botanical Garden, Bronx. 910 pp.

Jessen, R., and R. Lound. 1962. An evaluation of survey techniques for submerged aquatic plants. Game

Investigational Report 6. Minnesota Department of Conservation, St. Paul. 10 pp.

Korschgen, C. E., L. S. George, and W. L. Green. 1988. Feeding ecology of canvasbacks staging on Pool 7

of the Upper Mississippi River. Pages 237–249 in M. W. Weller, editor. Waterfowl in winter. University

of Minnesota Press, Minneapolis.

Peck, J. H., and M. M. Smart. 1986. An assessment of the aquatic and wetland vegetation of the Upper

Mississippi River. Hydrobiologia 136:57–76.

Talkington, L. M., and R. G. Semonin. 1991. The Illinois River: working for our state. Miscellaneous

Publication 128. Illinois State Water Survey, Champaign. 51 pp.

U.S. Fish and Wildlife Service. 1993. Operating Plan for the Upper Mississippi River System Long Term

Resource Monitoring Program. Environmental Management Technical Center, Onalaska, Wisconsin,

Revised September 1993. EMTC 91-P002R. 179 pp. (NTIS #PB94-160199)
24

Voss, E. G. 1972. Michigan Flora, Part I, Gymnosperms and Monocots. Cranbrook Institute of Science,

Bloomfield Hills, Michigan. 488 pp.

Voss, E. G. 1985. Michigan Flora, Part II, Dicots. Regents of the University of Michigan, Ann Arbor. 724 pp.
A-1

Appendix A

Locations, Number of Transects and Sites, Sampling Dates, and Distances Between

Sites Surveyed in Pools 4, 8, 13, and 26 of the Upper Mississippi River and La Grange

Pool of the Illinois River During the 1995 Sampling Season

Location spring:summer spring summer spring summer sites (m)

Number of Number of Number of Sampling Sampling Distance 

transects sites sites dates dates between 

Pool 4

Upper Mud Lake 4:4 36 41 6/13 8/24 30

(M791.5)a

Mud Lake 3:3 61 68 6/12 8/18 30

(M791.3)

Dead Slough Lake 9:9 162 135 6/7–8 8/15–16 30

(M789.2, M788.5,

 M788.0)

Goose Lake 3:3 31 28 6/8–9 8/15 30

(M788.G)b

Catherine Pass 3:3 85 80 6/9 8/16–17 30

(Bay City Flats; 

 M787.0)c

Robinson Lake 9:9 230 227 5/25–26, 8/1–4, 7 30

(M758.R) 30–31 b

Big Lake Bay 3:3 54 43 5/31; 6/5 8/8 30

(M758.5)

Rice Lake 3:3 36 34 5/31 8/7, 14 30

(M758.0)

Big Lake 5:5 171 158 6/5–6 8/9–11, 14 30

(M757.5)

Peterson Lake 6:6 77 72 5/22–23 7/26–27 30

(M754.8, M754.5)

Lower Peterson Lake 4:4 130 128 5/23–25 7/28, 31 30

(M753.5)

Total Pool 4 52:52 1073 1014 15 20

Pool 8

Blue Lake 3:3 124 118 5/31 8/14, 16 15

(M697.0)

Target Lake 11:11 291 298 5/15, 7/20, 25, 15

(M696.0) 17, 22 26–28

Goose Island 5:5 118 113 5/23 8/8 15

(M692.0)
Location spring:summer spring summer spring summer sites (m)

Number of Number of Number of Sampling Sampling Distance 

transects sites sites dates dates between 

A-2

Lawrence Lake 10:10 422 386 5/30; 8/17–18, 15

(M691.0) 6/1, 5–7 21–23 

Shady Maple 3:3 102 104 5/26 8/9 15

(M690.0)

Horseshoe Island 5:5 82 80 5/25 8/4 15

(Pool 8 Islands HREP;

 M687.0)d

Boomerang Island 4:4 104 104 5/24 8/1 15

(Pool 8 Islands HREP;

 M686.0)d

Stoddard, Wisconsin 4:4 48 47 5/16 8/3 15

(M684.0)

Total Pool 8 45:45 1291 1250 14 17

Pool 13

Brown's Lake 20:20 367 458 6/5–7, 12 8/2–4, 15

(M545.1, M544.5) 8–9, 11

Savanna Bay 12:12 137 138 5/26, 30 7/26–27 15

(M541.5, M540.5,

 M539.5)

Spring Lake 12:12 175 173 5/31, 7/28, 31; 15

(M534.8, M533.6, 6/1 8/1

 M532.0 )

Pomme de Terre 5:5 75 71 5/19 7/19 15

(M526.0)

Potter's Marsh 6:6 87 94 6/15 8/17 15

(M524.0)

Johnson Creek Levee 4:4 117 107 6/13–14 8/14–16 15

(M523.5) 

Johnson Creek 2:2 60 70 5/22, 25 7/20–21 15

(M523.0)

Total Pool 13 61:61 1018 1111 14 18

Pool 26

Calhoun Point 11:9 82 86 6/7 8/16, 18 15

(I003.0)e

Swan Lake 5:5 149 159 6/7 8/17 15

(I005.5)

Stump Lake 8:8 166 155 6/13 8/22 15

(I010.0)
Location spring:summer spring summer spring summer sites (m)

Number of Number of Number of Sampling Sampling Distance 

transects sites sites dates dates between 

A-3

Fuller Lake 2:2 29 29 6/13 8/18 15

(I011.5)

Total Pool 26 26:24 426 429 2 5

La Grange Pool

Grape Island 3:3 21 15 6/13 8/10 15

(I086.4)

Point Lake 6:6 25 26 6/14 8/8–9 15

(I100.0)

Spring Lake 0:5 not sampled 146 not sampled 9/8, 11–12 15

(I135.5)

Banner Marsh 2:2 24 24 5/22–23 8/8 15

(Bulrush Pond; I140.0)c

Total La Grange 11:16 70 211 4 7

Pool

Mississippi River miles, measured from the confluence of the Mississippi and Ohio Rivers. a

“G” and “R” to distinguish this lake from another lake with the same river mile. b

Locally recognized alternate name. c

Part of the Pool 8 Islands, Habitat Rehabilitation and Enhancement Project. d

Pool 26 is located at the confluence of the Illinois and Mississippi Rivers and the portions named here extend up the Illinois e

River, are managed by the Illinois Department of Natural Resources, and are designated by Illinois River miles. Illinois River

miles are measured form the confluence of the Illinois and Mississippi Rivers.
A-4

This page has been intentionally left blank.
B-1

Appendix B

List of Submersed and Floating-leaved Aquatic Species Present atTransect Sites in

Pools 4, 8, 13, and 26 of the Upper Mississippi River and La Grange Pool of the Illinois

River During Monitoring for the Long Term Resource Monitoring Program, 1991–1995a

Family Scientific name Common name

Azollaceae (Salviniaceae) Azolla spp. watervelvet, mosquitofern b

Ceratophyllaceae Ceratophyllum demersum L. coon's tail, coontail

Characeae Chara spp. chara

Characeae Nitella spp. nitella

Haloragaceae Myriophyllum sibiricum Komarov northern watermilfoil,

shortspike watermilfoil

Haloragaceae Myriophyllum spicatum L. Eurasian watermilfoil,

spike watermilfoil 

Hydrocharitaceae Elodea canadensis Michx. Canadian waterweed

Hydrocharitaceae Vallisneria americana Michx. wild celery, American eelgrass

Lemnaceae Lemna minor L. lesser duckweed, small duckweed, b

common duckweed

Lemnaceae Lemna trisulca L. star duckweed b

Lemnaceae Spirodela polyrhiza (L.) Schleid. greater duckweed, big duckweed, b

common duckweed

Lemnaceae Wolffia braziliensis Weddell Brazillian watermeal b, c

Lemnaceae Wolffia columbiana Karst. Columbian watermeal b

Lentibulariaceae Utricularia macrorhiza Le Conte common bladderwort

(Utricularia vulgaris L.)

Najadaceae Najas flexilis (Willd.) Rostk. & Schmidt bushy pondweed, slender naiad, 

nodding waternymph

Najadaceae Najas gracillima (A. Braun ex Engelm.) Magnus slender waternymph 

Najadaceae Najas guadalupensis (Spreng.) Magnus southern waternymph d

Nymphaeaceae Nelumbo lutea Willd. American lotus

Nymphaeaceae Nuphar lutea (L.) Sm yellow pondlily

Nymphaeaceae Nymphaea odorata Ait. American white waterlily

Onagraceae Ludwigia decurrens Walt. wingleaf primrosewillow b

Pontederiaceae Heteranthera dubia (Jacq.) MacM. water stargrass,

(Zosterella dubia [Jacq.] Small) grassleaf mudplantain

Potamogetonaceae Potamogeton alpinus Balbis alpine pondweed, red pondweed e

Potamogetonaceae Potamogeton crispus L. curly pondweed, 

curlyleaf pondweed
Family Scientific name Common name

B-2

Potamogetonaceae Potamogeton epihydrus Raf. ribbonleaf pondweed

Potamogetonaceae Potamogeton foliosus Raf. leafy pondweed

Potamogetonaceae Potamogeton illinoisensis Morong. Illinois pondweed e

Potamogetonaceae Potamogeton nodosus Poir river pondweed, American

pondweed, longleaf pondweed

Potamogetonaceae Potamogeton pectinatus L sago pondweed

Potamogetonaceae Potamogeton pusillus L. small pondweed, slender pondweed

Potamogetonaceae Potamogeton richardsonii (Benn.) Rydb. Richardson’s pondweed

Potamogetonaceae Potamogeton zosteriformis Fern. flatstem pondweed

Ranunculaceae Ranunculus flabellaris Raf. yellow water buttercup

Ranunculaceae Ranunculus longirostris Godr. longbeak buttercup, white f

watercrowfoot

Zannichelliaceae Zannichellia palustris L. horned pondweed

Scientific nomenclature and common names follow the U.S. Department of Agriculture PLANTS Database on the Internet a

(http://plants.usda.gov/plants/). Common names most often used by Upper Mississippi River managers are also included.

Species excluded from analysis. b

Gleason and Cronquist (1991) treat this as two separate species: Wolffia papulifera C. Thompson and Wolffia punctata Griseb. c

Verified for Pool 13 by Dr. E. Cawley, Loras College, Iowa. d

Verified by Dr. C.B. Hellquist, North Adams State College, Massachusetts. e

Ranunculus longirostris and R. trichophyllus were combined (Voss 1985). f
REPORT DOCUMENTATION PAGE Form Approved

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

September 1998

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

1995 annual status report: A summary of aquatic vegetation monitoring at fixed transects in Pools 4, 8, 13, and 26 and La

Grange Pool of the Upper Mississippi River System

6. AUTHOR(S)

Sara Rogers , Heidi Langrehr , J. Therese Dukershein , Jenny Winkelman , John Nelson , Theresa Blackburn , and Thad 1 2 2 34 5

Cook6

7. PERFORMING ORGANIZATION NAME AND ADDRESS 8. PERFORMING ORGANIZATION

U.S. Geological Survey, Environmental Management Technical Center, 575 Lester Avenue, Onalaska, Wisconsin 54650. 1

Wisconsin Department of Natural Resources, 575 Lester Avenue, Onalaska, Wisconsin 54650. 2

Minnesota Department of Natural Resources, 1801 South Oak Street, Lake City, Minnesota 55041. 3

Illinois Natural History Survey, 4134 Alby Street, Alton, Illinois 62002. 4

Iowa Department of Natural Resources, 206 Rose Street, Bellevue, Iowa 52031. 5

Illinois Natural History Survey, 704 North Schrader Avenue, Havana, Illinois. 6

 REPORT NUMBER

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

U.S. Geological Survey 

Environmental Management Technical Center 98-P011

575 Lester Avenue

Onalaska, Wisconsin 54650

 AGENCY REPORT NUMBER

11. SUPPLEMENTARY NOTES

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Release unlimited. Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 

(1-800-553-6847 or 703-487-4650)

13. ABSTRACT (Maximum 200 words)

Distribution and frequency of aquatic vegetation in the Upper Mississippi River System are monitored as part of the Long Term Resource Monitoring Program. This

report summarizes results of sampling aquatic vegetation along fixed transects in Navigation Pools 4, 8, 13, and 26 in the Upper Mississippi River and La Grange Pool of

the Illinois River in 1995. Pool 26 includes 12 miles of the Illinois River upstream of its confluence with the Mississippi River; all of the backwaters surveyed in this river

reach are on the lower Illinois River. Plants were sampled using a modified rake technique along fixed transects. Data from additional qualitative surveys (or informals)

was used to augment species records in each pool. Twenty-three submersed and rooted floating-leaved species were found in 1995. Pools 4 and 8 harbored the most

species, including most of the large-leaved pondweeds, and the number of species decreased in the pools to the south. Submersed aquatic vegetation was most

widespread in Pools 8 and 13 throughout the growing season (frequency of about 60%) and least in Pools 4 and 26 (30%). Sago pondweed (Potamogeton pectinatus)

was the dominant species found along the length of the river followed by coon’s tail (Ceratophyllum demersum). Curly pondweed (P. crispus), wild celery (Vallisneria

americana), and American lotus (Nelumbo lutea) were generally widespread in the upper three pools, and their presence varied seasonally. The abundance of curly

pondweed peaked during the spring, whereas wild celery and American lotus were later season strategists. Aquatic vegetation was generally rare in contiguous areas of

Pool 26 and La Grange Pool, and where vegetation was sampled (mostly isolated backwaters) fewer species were found than in the three northern pools.

14. SUBJECT TERMS 15. NUMBER OF PAGES

1995 annual report, Illinois River, La Grange Pool, LTRMP, Mississippi River, submersed aquatic vegetation, aquatic plant 24 pp. + Appendixes A–B

monitoring 

16. PRICE CODE

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT

 OF REPORT OF THIS PAGE OF ABSTRACT

Unclassified Unclassified Unclassified
The Long Term Resource Monitoring Program (LTRMP) for the Upper Mississippi

River System was authorized under the Water Resources Development Act of 1986 as 

an element of the Environmental Management Program. The mission of the LTRMP

is to provide river managers with information for maintaining the Upper Mississippi 

River System as a sustainable large river ecosystem given its multiple-use character.

The LTRMP is a cooperative effort by the U.S. Geological Survey, the U.S. Army Corps

of Engineers, and the States of Illinois, Iowa, Minnesota, Missouri, and Wisconsin.