If you’re outside the orbit of the Center for Limnology, you might not have heard of TLS. In the Northwoods, though, it’s an established, and popular, part of the landscape. And yet, many on campus don’t know that UW–Madison operates a field station conducting long-term research on Wisconsin’s lakes far from the shores most students are familiar with.
“There’s nothing like TLS.” -Tom Ewing, Vilas County Lakes and Rivers Association
Founded one hundred years ago, the Center for Limnology’s Trout Lake Station (TLS) sits on the south shore of Trout Lake in Vilas County, giving its researchers access to 2500 lakes within a 50-kilometer radius. TLS is part of a large ecosystem of tribal partners, state agencies, community organizations, and non-profits stewarding our Northwoods lakes.
In addition to beautiful grounds, access to recreation on a clear lake, and charming cabins, TLS is home to a large main laboratory, office space, and a library for its full-time staff members and visiting researchers. Researchers from all over the world take advantage of the facility and its world-renowned resources.
The field station operates year-round and supports environmental and limnological research, training, and outreach in the Northwoods of Wisconsin. The station’s population ebbs and flows with the season. There are a number of year-round staff members and researchers who live in the area, as well as housing for visiting researchers and students. Every summer, the warm weather allows undergraduate and graduate students from UW–Madison to conduct their research and assist on existing projects.
Much of that research happens in partnership with state agencies and local organizations. “It’s always been a natural fit for Wisconsin DNR to partner with TLS and vice versa,” said Greg Sass, Fisheries Research Supervisor at the Wisconsin Department of Natural Resources (DNR).
Sass received his master’s, doctoral, and postdoctoral degrees from the Center for Limnology and conducted all of his graduate research at TLS. Now, with the DNR, he works with TLS to take advantage of “the mutual strengths of the Center for Limnology and Trout Lake Station” on projects like the reintroduction of native cisco into Crystal and Sparkling lakes, which are currently dominated by invasive rainbow smelt.
According to Sass, TLS’ affiliation with UW–Madison is critical. UW–Madison’s good reputation and status as a “flagship university in Wisconsin” means the station attracts some of the “brightest students” and researchers. The university also provides the station with necessary infrastructure, which benefits the broader community as the DNR and TLS trade equipment regularly. Ultimately, he said, “it would be difficult to independently thrive.”
Trout Lake station is one of few sites in the world where limnology began more than one hundred years ago. In 1981, researchers at UW-Madison established consistent long-term monitoring. One of these projects, the North Temperate Lakes Long-Term Ecological Research (NTL-LTER), measures lake characteristics and dynamics in seven northern Wisconsin and four southern Wisconsin lakes and their surrounding landscapes.
NTL-LTER’s numbers speak for themselves: 7,000+ sampling events over 45 years of continuous data collection, 14,000+ measurements of phosphorus concentrations, and 989,151 fish sampled as of 2024. In fact, including 2025, the number may be very close to one million. This data feeds into the Global Lake Ecological Observatory Network, allowing TLS to collaborate with global partners to understand, predict, and communicate the role and response of lakes in a changing global environment. UW–Madison’s reach outside the four southern lakes into Wisconsin’s Northwoods through TLS has reverberations far beyond the state.
TLS’s work in the Northwoods extends beyond long-term monitoring and into the communities that surround these lakes. Katie Hein, a community-engaged research scientist at TLS, describes herself as a “Wisconsin Idea limnologist.” Hein is invested in interfacing with communities and bringing them into conversation with science, since lakes are a big part of our culture in Wisconsin. Her research projects, some of which involve aquatic plant or invasive species management, habitat loss on lakeshores, and climate adaptation, rely on community engagement as most of the lakes in the area are used frequently by both tourists and locals.
Even with her existing community engagement, Hein describes it as “still aspirational.” Listening to communities and their concerns and finding ways to work with them is an ongoing project, one that can always be improved upon. One popular way TLS engages is by hosting a monthly Science on Tap event at Rocky Reef Brewery, which, along with TLS’ annual open house, communicates to community members and tourists what projects TLS is working on and how they impact them.
The station also has an Artist in Residence program, which brings together artists and scientists to explore the relationships between people, northern lakes, and landscapes in a changing world. Jim Arnold, an underwater photographer and former Artist in Residence, explained that “their love of the lakes and my love of the lakes is different, but both come together.” He’s motivated by sharing this love as he wants to “show people that there’s more than they think out there” through underwater photography.
TLS often operates as a hub of a larger network built through diverse partnerships. Beyond the departments within DNR, TLS partners with the North Lakeland Discovery Center, Vilas County Lakes and Rivers Association, and various other organizations. These collaborations address pressing environmental challenges impacting the Northwoods lakes. Invasive species, changing precipitation patterns, warming effects, and phenological shifts create a variety of unpredictable effects on lakes.
Despite these challenges, lake restoration and conservation efforts in the Northwoods have seen a number of successes, such as the reduction of Rusty Crayfish in Sparkling Lake. A project that spanned years, removing the invasive Rusty Crayfish was critically important for lake health, as they aggressively displace native species and destroy aquatic plant beds that serve as nurseries for native fish.
When asked about next phases for collaboration with TLS, Abby Vogt from the North Lakeland Discover Center echoed everyone I interviewed to say she’d “love the partnership to continue.” Trout Lake Station has worked to protect and restore the Northwoods lakes for the last hundred years, and the continued strength of its partnerships will shape how those lakes are stewarded in the century ahead.
By: Laleh Ahmad