Monitoring and management is key
Michigan is the land of 11,000 lakes. Indeed, our state is nearly overflowing with lakes, and as Michiganders we should be proud of this and at every possible opportunity remind Minnesotans that Michigan has more lakes. This wealth of freshwater is an invaluable resource both from a human and a natural perspective. Lakes are wonderful places to live, boat, fish, and play. They become cherished and important places where people spend their lives and learn to appreciate nature. Lakes become peoples’ homes, and residents take pride in them. At the same time, lakes are homes to all sorts of fish, birds, frogs, and insects, which rely on the ecosystems for protection, reproduction, and food.
Yet with great resources comes great responsibility. A common phrase you will hear from a freshwater scientist is that “Michiganders are loving their lakes to death.” With so many human activities on lakes, and with so much development along lakeshores, lakes are far from the pristine locations we may imagine when gazing at a photograph of a loon swimming at sunset. The lake in that idyllic photo may be overgrown with invasive plants, it may be full of algae, or there might be so many seawalls along the shoreline that the loon can’t even find a place to lay her eggs. For lakes to continue to thrive, humans need to recognize their own impact and wisely manage lakes to support human activities and ecosystem functions.
Invasive aquatic plants
Consider the management of aquatic plants, one of the dominant lake management problems for Michigan lake riparians. Rooted aquatic plants are a natural and essential part of a lake, just as grasses, shrubs and trees are a natural part of the land. However, sometimes a lake is invaded by an aquatic plant species that is not native to the region. Some of these exotic invasives, like Eurasian milfoil and starry stonewort (a macroalgae), can be extremely disruptive to the lake’s ecosystem and recreational activities. These invasive plants can “take over” a lake by crowding out beneficial native species, and they can negatively affect fish populations and human recreation.
Lakes with extensive invasive plant coverage are not enjoyable for boating or swimming, as they get tangled in motors and legs. Studies have shown that invasive plants in lakes can reduce property values by about 13%.1,2 Starry stonewort forms a thick mat that makes a barrier on the bottom of the lake, preventing or reducing fishes’ ability to create spawning nests. Fish are forced to go to suboptimal locations to spawn, diminishing their reproductive effectiveness and opening predation opportunities on themselves or their eggs/young.3
An ounce of prevention
Many lake communities use herbicide treatments to control the quantity of invasive plants on their lake, yet these are not simple management decisions to make, as treatments are costly and often need to be repeated annually since the roots of the plants are not affected. The use of herbicides is often contentious and can turn neighbors against each other. Mechanical harvesting is costly as well. The process is slow and labor intensive, and as some plants spread by fragmentation, harvesting can make an infestation of invasive plants worse in the long term.
The best management technique for dealing with invasive plants is to never get infested in the first place. This is where monitoring comes in, and a concept called Early Detection and Rapid Response. Lakes need to be monitored for exotic invasive plants so that they can be identified when their populations are still very small, and then most quickly and cheaply eliminated with targeted removal. Often, invasive plants first show up at a lake’s public boat ramp after they are transferred from another body of water. Watching public access points for these plants could have huge benefits in the long run.
Preventing the spread of invasive plants could save lake residents hundreds of thousands of dollars in herbicide costs. Volunteer monitors are key to this process. Continually monitoring and treating the invasive plants as they first pop up is time consuming and requires persistence and dedication, but it can keep the invasive populations at low, manageable levels. The alternative is to wait until the invasives expand to cover large areas of the lake, after which control will be very expensive.
As seen in the prior example, the first step to good lake management is good lake monitoring. Monitoring gives an understanding of lake ecosystem dynamics and information that guides people to make sound lake-management decisions.4 Monitoring a lake can involve considering its temperature (throughout the water column) and tracking color, transparency, dissolved oxygen levels, nutrient levels, plants, fish, and habitat both in the water and along the lakeshore. Every lake is unique. It is subject to different factors, both human-induced, like lakeshore development and upland pollution, and natural factors, like water sourcing, geology, and riparian habitat.
Lake management resources
The Cooperative Lakes Monitoring Program (CLMP) is a statewide monitoring program that has been operational since 1974. HRWC has helped run it since 2004 as a part of a core team of university, government, and nonprofit scientists. The CLMP relies on the efforts of volunteers, most of whom are lakeshore property owners or residents. Program leaders provide equipment and training, and volunteers conduct the needed monitoring on their lake throughout the late spring and summer.
Volunteers can “opt in” to monitor an entire ecosystem, or select certain ecological parameters to measure such as water transparency, phosphorus, chlorophyll, dissolved oxygen and temperature, lakeshore habitat, and aquatic invasive plants. Some volunteers even elect to conduct full aquatic plant surveys. It’s the volunteers’ choice, and the job can be as simple as taking measurements a couple of times a month from May through September, or a highly intensive survey taking tens of hours during the summer season.
If you live on or have regular access to a lake that you worry is being “loved to death,” consider volunteering your time to be a CLMP lake monitor and give back to the lake that you love so much! It needs your help. The more information that you can collect on your lake, the more informed your community’s lake management decisions will be and thus the more effective.
As you volunteer, you will learn other ways to be a good lake steward, such as the impact of fertilizers on lake water quality and the value of a natural shoreline to all the lake’s inhabitants. You will gain confidence in and understanding of lake science, and learn how to share your new-found knowledge with your neighbors. So, what are you waiting for? Sign up to be a lake monitoring volunteer now!
- Liao, F.H.; Wilhelm, F.M.; Solomon, M. The Effects of Ambient Water Quality and Eurasian Watermilfoil on Lakefront Property Values in the Coeur d’Alene Area of Northern Idaho, USA. Sustainability 2016, 8, 44. https://doi.org/10.3390/su8010044
- Horsch, Eric & Lewis, David. (2009). The Effects of Aquatic Invasive Species on Property Values: Evidence from a Quasi-Experiment. Land Economics. 85. 391-409.
- Pullman, G.D, and Crawford, G. 2010. A Decade of Starry Stonewort in Michigan. Lakeline. https://www.nalms.org/wp-content/ uploads/2018/09/30-2-9.pdf
- USGS, https://www.usgs.gov/centers/upper-midwest-water-science-center/science/lake-monitoring-and-research
This blog post was originally published March 1st in the Huron River Report, Spring 2022.