Aquatic Vegetation Monitoring

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By Upper Midwest Environmental Sciences Center December 15, 2023

The Mississippi River is of global importance to persons and to the wildlife that live on and migrate along the river corridor. Data collected and processed by the Long-Term Resource Monitoring (LTRM) element of the Upper Mississippi River Restoration (UMRR) Program serves to help us understand, restore, and protect this remarkable ecosystem. The LTRM has collected aquatic and floodplain vegetation data for over 25 years, making it one of the largest and longest running aquatic vegetation data sets in the world. With these data, scientists can assess river health status, document trends, and develop models to forecast future conditions. This is especially important for understanding river health and guiding restoration strategies. The LTRM data set is used in numerous ways to help researchers and managers understand how the Upper Mississippi River is changing over time.

A shallow lake with lots of plants emerging from the water — Shallow lakes such as this can support thousands of waterbirds during autumn migration, especially when managed as high-quality duck habitat.

Shallow lake management enhanced habitat and attracted waterbirds during fall migration

Principal Investigator – Dr. Danelle Larson

Shallow lakes are a key resource for waterfowl species, so protecting and restoring these areas is of great importance to managing their populations. This study evaluated the effectiveness of management practices on shallow lakes and their influence on waterbird populations that depend on them. Researchers found that lake management actions increased the abundance of submerged aquatic vegetation and wild rice, which was positively corelated with the waterbird community abundance.

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Photographs of five types of aquatic plant community types: lotus, submersed, diverse, arrowhead, and wild celery. — Five types of aquatic plant community types found in the Upper Mississippi River.

Overview of Aquatic Vegetation Community Types in the Mississippi River

Principal Investigator – Dr. Danelle Larson

Aquatic vegetation provides numerous ecosystem services, including food for wildlife, water clarification, fisheries habitat, and natural beauty. This project evaluated the vegetation community types in the Mississippi River. By comparing vegetation abundance data to environmental factors, scientists were able to predict the type of vegetation that might be expected in segments of the river system. These predictions will benefit restoration efforts in stretches of river where those vegetation types are scarce.

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Aquatic plant raking on the Mississippi River from a boat — We use aquatic plant rakes to determine the species and abundance of underwater plants.

Constraints of Aquatic Vegetation & Restoration Potential of Aquatic Vegetation

Principal Investigator – Dr. Danelle Larson and Dr. John Delaney

Aquatic vegetation is a foundational element of life in aquatic systems, providing food and habitat for several species, and aquatic vegetation restoration is a high priority for Mississippi River managers. Understanding why plants grow in certain places, but not others is important for successful restoration efforts. This study evaluated the constraints on aquatic vegetation growth by using computer models to understand where different types of plants are found in the Mississippi River. The scientists created an interactive web tool to map the plants along the river, classify areas where vegetation is vulnerable to loss, and locations having the greatest restoration potential.

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A plant rake holding up an excessive amount of filamentous algae. — An excessive amount of filamentous algae in the Upper Mississippi River is aesthetically unpleasing and a nuisance for wildlife and boaters.

Identifying Ecosystem States of the Upper Mississippi River

Principal Investigator – Dr. Danelle Larson and Dr. Wako Bungula (University of Wisconsin - La Crosse)

Ecosystem states are bundles of biological and physical characteristics that occur regularly in a habitat. They are used to help understand ecosystems and to communicate which state conditions are desirable or unhealthy. Scientists hypothesized that there are several different ecosystem states in the Mississippi river, with one of them being the best for waterfowl, and therefore a desirable goal for restoration projects. To identify the different ecosystem states, scientists used abstract mathematical tools. This project is groundbreaking as it is the first ecological study to use this type of mathematics.

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photograph showing aquatic plants that are underwater, floating on top of water, and emerging out of water — The Mississippi River supports a diversity of aquatic plant types, such as those pictured under water, floating on the water’s surface, and those emerging out of water. All these plants also play diverse roles in providing habitat to wildlife and purifying the river water.

25 Years of Change in Aquatic Plants in the Upper Mississippi River

Principal Investigator – Dr. Danelle Larson

The Upper Mississippi River, along with a few other rivers worldwide, has experienced a remarkable increase in aquatic vegetation over the last 25 years. Using complex community modeling, scientists are determing where, what species, and why, aquatic vegetation increases were observed in the Mississippi River. This information can help us understand the natural recovery of aquatic plants, and how we can help restore plants in areas that need human intervention.