Habitat Restoration

The Forest Preserve District of DuPage works to foster ecological conditions that sustain and preserve native plant and animal communities in the county’s prairies, wetlands and woodlands. District staff and volunteers work to remove invasive and exotic vegetation, propagate native plant species and, in some cases, reintroduce native wildlife and plants in order to maintain the biodiversity of some of the county’s high-quality open spaces.

View a recent presentation on Woodland Management Efforts in DuPage County which shows current ecological issues and solutions for habitat restoration.

What methods are used in the program?

The District’s course of action depends greatly upon the specific goals of the site. Ecologists may use prescription burns at a prairie to give native grasses and forbs the advantage over nonnative, fire-intolerant species. They may remove brush at a woodland or savanna where European buckthorn or other highly invasive species dominate the understory. Other methods include:

  • Planting native trees, shrubs, grasses and wildflowers to restore the plant diversity that once existed
  • Reintroducing native wildlife species that are rare to the region
  • Returning native shoreline vegetation to help prevent streambank erosion
  • Educating the public about the function and importance of natural communities

Woody Plant Removal

The Forest Preserve District of DuPage County often removes aggressive native and nonnative shrub and tree species that are taking over high-quality woodlands, savannas and prairies. Selective clearing and brush mowing work has shown that native plants and also populations of birds and butterflies can recover once the weedy vegetation is removed.

Selective Clearing
Invasive shrubs, such as European buckthorn and honeysuckle, produce dense clumps of leaves that sprout earlier in the spring and drop later in the fall than those of native plants. Their impenetrable vegetation keeps sun and water from reaching the ferns, wildflowers, and oak and hickory seedlings that grow below. As a result, the variety of plants and animals that live there declines.

Selective clearing is typically done in woodlands and savannas and involves crews cutting down individually selected invasive trees and shrubs and burn the resulting brush piles on site. They then carefully apply herbicides to the cut stumps so the plants cannot grow back. Work is done during winter to protect any dormant plants below the soil. The sparse vegetation at this time of year also lowers any risk of fire hazards from the brush piles.

Brush Mowing
The Forest Preserve District of DuPage County often removes aggressive native and nonnative shrub species that are taking over high-quality prairies.

Invasive shrubs, such as gray dogwood and European buckthorn, shade sub-loving prairie plants and make the area less desirable to birds that nest in grassland habitats.

Brush mowing involves cutting shorter woody growth down using a heavy-duty mower. This work is typically done in fall, winter and spring to minimize impacts to native plants and wildlife.

Aquatic Plant Management

Aquatic vegetative communities form healthy conditions for many pond and lake ecosystems. Various plant communities in the water and at the water’s edge are important for water quality, water oxygen levels, habitat for many aquatic organisms, and as a food source for many pond and lake inhabitants. Aquatic plants can act as a natural filter for excess water runoff, thereby reducing sedimentation and erosion along shorelines. Aquatic plants also absorb excess nutrients, primarily nitrogen and phosphorus, which helps control unwanted algae blooms. Healthy native aquatic plant communities are instrumental in preventing exotic, invasive and nuisance plants such as Eurasian watermilfoil (Myriophyllum spicatum), curly-leaf pondweed (Potamogeton crispus), water hyacinth (Eichhornia crassipes) and phragmites (Phragmites australis).

Aquatic Plant Management

Invasive aquatic plants such as the ones listed above can cause problems in lake and pond environments. Populations of invasive species often dominate native plants for space and nutrient resources. In order to protect native aquatic plants and prevent the spread of invasive aquatic plants, various techniques are employed.

•Biological controls
•Physical techniques such as drawdown or bottom plant barrier
•Mechanical plant removal
•Manual plant removal
•Chemical controls

Physical and mechanical mechanisms can include cutting with specialized tools, unique heavy machinery to pull and pulverize, and hand-pulling plants. These methods are often labor intensive and are less efficient.

Physical techniques, such as water drawdowns, can only be used if an existing water control structure is present. Plant barriers are somewhat successful, but invasive plants tend to be more resilient to these mechanisms than native plants, and this technique has the potential to assist in the proliferation of aquatic invasive plant life while tamping down native plants.

Biological controls can also be effective, but much of the research concerning these methods suggests that these options create an “all or nothing” result. Biological controls, such as grass carp, tend to prefer many native plants over invasive species, thereby creating more favorable conditions for the spread of undesired plants.

Chemical controls are typically the most effective control mechanism in terms of immediate results. Chemicals are required when aquatic plants reach levels that hinder ecological and recreational function of a water body or if “spot” treatments are needed. If proper long-term planning and strategies are utilized, chemical treatments can often be the best method to provide short-term controls and as a bridge to larger scale changes within the watershed. Due to the dynamic nature of managing invasive, exotic and nuisance aquatic plants, EPA-registered chemicals may be used by District ecology staff. Some chemicals may or may not be accompanied by various water-use restrictions for a period of time. Appropriate signage is posted prior to application of chemicals at a site.

Although many techniques for aquatic plant management are listed here, it is important to note that there is no “silver bullet,” and the best management strategy may vary from location to location. Much of the success of aquatic plant management depends on what nuisance species needs to be controlled, how prevalent those species are, and what, if any, native or desirable species are present.

Each management plan is subject to change over time because as strategies and techniques are employed, these actions create dynamic situations that may require different management strategies and techniques in the future. 

Why do we care?

Typically, desirable recreation opportunities such as fishing occur on many water bodies. As an angler, the first place to fish is near aquatic plant beds. Aquatic plants provide important niche habitats, including areas for reproduction, foraging and refuge for a host of aquatic organisms including invertebrates and other aquatic wildlife. Aquatic plants are often responsible for the presence and/or absence of aquatic/semi-aquatic creatures. Because aquatic plants provide the base for all of the creatures necessary for healthy ecological function as well as recreational and aesthetic value, it is imperative to make every effort to keep these aquatic plant communities diverse and healthy. 

Prescription Burns

Prescription burns are carefully set fires that trained Forest Preserve District employees use in late fall and early spring to remove invasive plants and improve conditions for native species.

Why use fire?

  • It turns dried plants into ash, which allows nutrients locked inside the plants to quickly reenter the soil and fertilize new growth in the spring.
  • It prevents dead grasses and leaves from piling up. Too much accumulated plant “litter” can lower the temperature of the soil, which makes it harder for seeds and sprouts to develop.
  • It kills or stunts nonnative shrubs such as buckthorn and honeysuckle. These plants have only been in the area for a century or two and can’t bounce back after fires as easily as native species, which have developed deeper roots or thicker bark.

Why are they called “prescription” burns?
The “prescription” is a set of directives. At the Forest Preserve District, each burn site has two.

The first outlines the site’s overall management plan. Ecologists use observations and data to determine what’s growing at a site and which tools — fire, mowing, brush cutting, herbicides, etc. — can improve the density and variety of native species. Ecologists may decide to use fire in different situations.


  • If they’ve cut invasive buckthorn and honeysuckle but they’re seeing new sprouts, which fire can knock back
  • If they’ve applied herbicides to invasive plants and burning the dead vegetation will expose the soil and allow the dormant invasive seeds to germinate for a second more exhaustive treatment prior to putting in native seed
  • If there’s a mix of native and invasive grasses and burning will clear the entire site and allow them to better target and eliminate invasives as they sprout in the spring

The second prescription is a safety plan for the morning of that dictates whether or not the burn is a go.

  • What’s the humidity? Is there rain in the forecast? Moisture on the plants will make it difficult to burn.
  • What’s the wind speed and direction? If there’s a busy road east of the site, the Forest Preserve District can’t burn if winds are out of the west.
  • Which equipment and how many employees are available? Forest Preserve District burn managers consider at-site conditions to determine minimum requirements.
  • Where’s the site on the District’s priority list?
Required: Because of a grant or formal agreement 
High:First-time site with a lot of accumulated dry vegetation 
 Previously treated area with a lot of nonnative resprouts 
 Site that needs clearing for future seeding or targeted herbicide application 
 High-quality area that hasn’t been burned in three or more years 
Medium: High- or good-quality area that hasn’t been burned in three to five years 
Low:Area that can benefit from a burn but isn’t as critical as others 

What about wildlife?
Naturally occurring fires were part of the landscape long before humans arrived. For centuries after that, Native Americans used fire to control flies and mosquitoes and to remove ground cover to make hunting and traveling easier. As a result, wildlife has learned how to avoid the slow-burning fires, which leave behind soils barely warm to the touch. Still, if an area has a rare species, such a Blanding’s turtles, the Forest Preserve District will avoid using fire during the spring breeding season as an added precaution.

What happens before the prescription burn season?
After selecting sites and outlining the prescriptions, the Forest Preserve District applies for burning permits from the Illinois Environmental Protection Agency and, if needed, local fire departments. It also mails postcards to people who live within 1,000 feet of each burn unit. (Depending on the size, a forest preserve can have more than one burn unit.) Residents with health conditions that smoke can aggravate can request calls the morning of the burn.

Who helps with prescription burns?
Only District employees who meet National Wildfire Coordinating Group standards can work on a prescription burn.

What happens on the morning of a burn?

  • The Forest Preserve District reviews site prescriptions and determines which, if any, it can burn that day. If a burn is a go, the District notifies local fire and police departments and the DuPage County sheriff’s office. 
  • The District also calls nearby residents who received postcards and requested calls.

What happens during a burn?
  • Employees post signs at entrances and along trails to ensure visitors remain at safe distances.
  • Employees follow strict protocols on lighting, controlling and monitoring each fire. 
  • The Forest Preserve District remains in touch with fire and police departments.
  • Crews remain on-site after the fire burns out to look for flare ups. At prairies and wetlands they may stay for an hour; in woodlands they may need to remain for several.

Click here to watch a prescription burn video.


What are some of the Forest Preserve District’s current projects?

Regardless of the season, the Forest Preserve District engages in a variety of restoration projects. For a list of current conservation-related projects, visit Plans and Projects.

Why improve our natural habitats?

In the early 1800s, DuPage County was a land of open prairies, wetlands and woodlands. These areas teemed with wildlife and attracted explorers and settlers alike. As the land became more populated, settlers began to farm the rich black soil — a result of centuries of prairie development and timber logging. Farmers overturned the land and extinguished the natural fires that were so important to native prairie, wetland and woodland ecology. The landscape began to change.

Today, exotic species, drainage modifications and habitat fragmentation have taken their toll on native plants and animals. The effects of these changes need to be reversed in order to ensure a biologically diverse area for future DuPage County residents.

Winter Brush Removal

As the ground freezes and plants go dormant in the winter, District restoration workday volunteers, site stewards and crews start to conduct selective removal of invasive and exotic brush. Invasive shrubs, such as European buckthorn and honeysuckle, produce dense clumps of leaves that sprout earlier in the spring and drop later in the fall than those of native plants. Their impenetrable canopy keeps sun and water from reaching the wildflowers and oak seedlings that grow below.

Brush also steals water and nutrients from native plants. As a result, the variety and health of plant and animal communities that live there declines.

Selective removal work is typically done in woodlands and involves crews cutting down selected invasive trees and shrubs and burning the resulting brush piles on site. Herbicide is carefully applied to the cut stumps so the plants cannot grow back. Work is done during the cold months to protect any dormant plants from damage.

Removal of invasive brush and reintroduction of native plants has noticeably improved populations of butterflies and birds.

Click here to see a gallery of before and after photos documenting the value of a cleared landscape.

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