DNR Projects
Lake Julia Stewardship Project continues with $10,000 DNR grant to study aquatic plants
Posted July 8, 2003
Think all plants in lakes are weeds?
"That would be like calling an oak tree or a maple tree a weed," says ecological researcher Dean Premo. "We were all raised to think that any plant growing in a lake was a weed, but nothing could be further from the truth. Lake plants create the foundation for the aquatic ecosystem in exactly the same way plants on land create the base for a terrestrial ecosystem."
Aquatic Vegetation
Aquatic vegetation, like the emergent pickerelweed pictured in the foreground, provides excellent cover for a wide variety of small fish. The fry that seek protection in this habitat eventually grow bigger and are then sought by fisherman, like the one pictured here in the background on Lake Julia. This summer Premo and other ecologists will study the aquatic vegetation in Lake Julia just south of Rhinelander to assess the overall quality of the underwater plant communities. The study is being made possible by a $10,000 lake management
grant the Lake Julia Lake Association and Nicolet College received from the Wisconsin Department of Natural Resources. The study also constitutes the second phase of the Lake Julia Stewardship Project, a long-term effort to assess and maintain the environmental health of numerous aspects of the Lake Julia ecosystem.
"Lake Julia is a true gem of the Northwoods," says Harry Helwig, president of the Lake Julia Lake Association. "The goal of the stewardship project is to keep it that way and the aquatic vegetation study is just another effort to take a close look at a very important part of the lake ecosystem." Last summer a DNR grant funded a wetlands study that found each of the 20 wetlands looked at were functioning as they should by filtering run-off water before it enters the lake and providing valuable wildlife habitat. During the wetlands study researchers conducted an informal survey of the underwater plant life.
Their initial thoughts were that the aquatic vegetation looked to be in pretty good shape. They also did not see any evidence of problematic exotic plants such as purple loosestrife or Eurasian milfoil, the bane of many lakes because they can quickly drive out native species. The formal survey this summer will provide more detailed and definitive results on exactly what plants are growing in the 238-acre lake, where they are located, their overall health, and also identify any threats to plant communities.
"It's so much easier and cheaper to keep an ecosystem healthy than it is to try to restore one that has problems," says Premo, Ph.D., president of White Water Associates, Amasa, Mich., which will be conducting the study. "The project this summer will go a long way in keeping Lake Julia healthy."
So why are plants so essential to a healthy aquatic ecosystem?
One of the most important roles, Premo says, is the protective cover they provide for small fish and other species. "Without this cover, the small fish would be very vulnerable to predation by larger fish," he says. "It essentially gives small fish a place to hide so they can eventually grow to become large fish." Obviously, many small fish do get eaten by larger fish. Other creatures such as
loons, eagles, osprey, herons and otter also depend of small fish as a source of food. In order to maintain this base population of small fish, 
aquatic plant communities need to be healthy.
Another important role is that plants, through photosynthesis, also give off dissolved oxygen, which fish and other aquatic species need to breathe. This is especially important in northern climates where lakes freeze over in the winter, thus eliminating any wave action which also adds dissolved oxygen to lakes.
Many insects, such as dragonflies, also depend on aquatic plants to complete their life cycles. These mosquito-devouring predators spend the early, nymph portions of their lives underwater. In order to become full-fledged dragonflies, grown nymphs need to climb a plant that is sticking out of the water in order to change into adult dragonflies.
Aquatic plants also serve as a direct food source for many other species such as ducks, geese, and muskrats.
"All of these creatures contribute to create very rich and diverse natural communities that really define the Northwoods," Premo says. "And they all depend on healthy communities of aquatic plants."
Greatest Threat
The greatest threat comes when too many nutrients enter a lake, most commonly from failing septic systems or from lawn fertilizer run-off. This sends plants into hyper-growth drive. What typically happens is that a few species of plants will boom especially well, choking the lake and driving out other plants. This can greatly reduce the number of different plant species in a lake from a healthy 20 to 25 to just a handful. "That loss of diversity can have a strong negative impact on a lake," Premo says.
Premo and his colleagues at White Water will be working closely with science students and staff at Nicolet College's Rhinelander campus, which sits along the eastern shore of Lake Julia, and lake association members to conduct the aquatic vegetation study.
The lake association plans on applying for additional DNR grants in the future to look at other environmental factors that are important to keeping the lake habitat healthy. The grants are made available through DNR's Lake Management Planning Grant Program, which is funded entirely from a portion of the state excise tax on motorboat gasoline. For more information about grant program, including how to apply for a grant, contact Jennifer Wudi, DNR lake management coordinator, at (715) 365-8937.