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Pool 8 Transect Data Summary

Introduction

Vegetation data has been collected by the Onalaska Field Station at fixed transect sites from 1992 to 2000 following standardized Long Term Resource Monitoring procedures (manual 95-P002-3). Eight backwaters (six contiguous and two isolated) were chosen for sampling. Blue Lake, Target Lake, a backwater near Goose Island, Lawrence Lake, Shady Maple, inside Horseshoe Island, inside Boomerang Island, and a backwater near Stoddard, Wisconsin were the areas sampled.

Transects were placed perpendicular to the shoreline at 50 to 200 meter intervals (depending on the size of the backwater). They began and ended at either the shore or an emergent bed. Sites were sampled at 15 meter intervals each transect. At each site, a long handled threshing rake was used to collect the aquatic plants. A 2 meter circle was visualized and three rake grabs were made within each third of the circle. The rake was lowered to the sediment, twisted 180 degrees and lifted out of the water. All plants on the rake head were identified to species. Sampling was conducted twice during the growing season: May 15th to June 15th and July 15th to August 30th. Although transect sampling was discontinued in 2000, selected transects ( Target Lake, Goose Island, Lawerence Lake, Shady Maple, Horseshoe Island, and Boomerang Island) were sampled in August 2001 to provide additional information about a drawdown that occurred in Pool 8 that year. Photos were taken of the drawdown.

Data was summarized by individual backwater for each species recorded. All summaries were calculated from the July/August sampling period data. The summary includes species frequencies tables and maps of the location of each species. Some areas of Target Lake, Goose Island and Lawerence Lake sampled in previous years were not sampled in August 2001. Therefore, frequencies for these backwaters were recalculated for all years based on the areas that were sampled in August 2001 and were appended to the original tables. Data is also summarized by lifeform: submersed (underwater) and rooted floating leaf vegetation.

To create the maps, Universal Transverse Mercator (UTM) coordinates were collected for the first site along each transect using a Global Positioning System unit. The UTM coordinates for all other sites along the transect were assigned by adding 15 meters for each site. Therefore, the points are a representation not the actual location of the sites.

Species that were recorded in Pool 8, Upper Mississippi River System during transect sampling include:

Leafy pondweed and small pondweed were not identified to species in the field, but rather combined together. One or both species may have been present. For more information and photos of these plants, see the United States Department of Agriculture's PLANTS Database. Please use the scientific name in your search because plants can have several common names. Chara is a macroalgae and is not included in the PLANTS Database.

Observations

Chara was first recorded in 1998 and longbeak buttercup in 1999 in Lawrence Lake. Lawrence Lake was the only backwater where longbeak buttercup was found while chara was also found in Target Lake and Goose Island in 1999.

The only record of southern waternymph was in 1992 in Lawrence Lake.

Species which increased in frequency more than 30% from 1992 to 2000 included:

• coontail in Target Lake, Goose Island, and Lawrence Lake
• Canadian waterweed in Goose Island, Lawrence Lake, and Stoddard
• water stargrass in Shady Maple and Boomerang Island
• Eurasian watermilfoil in Lawrence Lake and Shady Maple
• curly pondweed in the Stoddard backwater
• leafy and/or small pondweed in Blue Lake
• flatstem pondweed in Goose Island
• submersed vegetation in Goose Island, Shady Maple, and Boomerang Island

Species which decreased in frequency more than 30% from 1992 to 2000 included:

• Eurasian watermilfoil inside Horseshoe Island
• white water-lily in the Stoddard backwater
• sago pondweed in Target Lake

Disclaimer

These summaries have been generated by the Wisconsin Department of Natural Resources under contract with the Department of the Interior and the Upper Midwest Environmental Sciences Center (UMESC). Data (1992-1999) used to produce the summaries has undergone the LTRMP standard QA/QC procedures. Data from 2000 is still undergoing the process and is therefore in draft form. Although these summaries have been processed successfully on a computer system at the UMESC, no warranty, expressed or implied, is made regarding the accuracy or utility of the summaries for general or scientific purposes, nor shall the act of distribution constitute any such warranty. However, error correction is a continuing process, and the UMESC routinely makes changes to data as errors are discovered. The release date for the summary data is October 19, 2000 and should be mentioned in all references to the summaries. Methods, purposes, and conditions can vary dramatically among data-collecting efforts and these summaries should not be combined with other datasets from the UMESC or other sources unless the user fully understands the procedures and purposes used to create each set of data and can verify that data are comparable across sources.

For more information, contact Heidi Langrehr, Wisconsin Department of Natural Resources:
heidi_langrehr@usgs.gov