Ensuring the Vitality of Our Wetlands

Nearly 15,000 years ago, glaciers moving across Illinois buried McHenry County in ice. As they retreated, these ice forms left a lasting impact on the landscape and the ecology of the area. One of the places where their artistry is most apparent is at the District’s 345-acre Elizabeth Lake Nature Preserve and Varga Archaeological Site, where the glaciers scraped and shaped what the Illinois Nature Areas Inventory now identifies as the highest quality lake ecosystem remaining in McHenry County and one of the highest quality in Illinois. 

While nature was responsible for creating natural areas like Elizabeth Lake, human intervention is often necessary to ensure the continued health and vitality of our most critical ecosystems. Nowhere is this need more evident than in wetland communities, where even subtle disturbances can upset the balance of these delicate, but essential, systems. This is why, in 2018, the District began intensive management work at the site with support from the McHenry County Conservation Foundation.

When an invasive plant species takes root in a wetland, it can quickly grow out of control and displace native populations. Additionally, given the remote and sensitive nature of wetlands it is often impossible to access and manage these invasives without the use of specialty equipment. At Elizabeth Lake, purple loosestrife and Phragmites are two of the most aggressive invaders and have the potential to transform these vibrant wetlands into dense monocultures were little to no native plant or animal species thrive.

Over the past two years, Foundation support has made it possible for District staff to manage more than 60 acres of the site. This work includes removing buckthorn and hiring a contractor with access to the appropriate equipment to apply herbicide to purple loosestrife and Phragmites. The Distict was also able to purchase a necessary mulching attachment for one of their tractors and use it to cut invasive brush, which opens up the area and gives native plants the opportunity to reestablish themselves.  

Wetlands like those at Elizabeth Lake are an essential component of our watershed. After every heavy rainfall, they store and slowly release water that might otherwise flood the Fox River. They also play the role of our watershed’s kidneys by filtering out pollutants from our water supply.  Wetlands are also home to some of the greatest biological diversity on our planet. At least 20 state threatened or endangered species have been recorded at Elizabeth Lake, including black terns and Blanding’s turtles. It was also one of the first District sites to see the return of nesting sandhill cranes.

This restoration project will continue at Elizabeth Lake through the end of 2021, but site maintenance is an ongoing effort. Positive intervention is essential to ensuring healthy wildlife populations and the overall wellbeing of our environment.