Natural Areas Management

Ecosystem Management

“Ecosystem management” is a term used to describe natural resource practices that incorporate managing all organisms within an ecosystem rather than focusing on an individual species. By carefully managing entire ecosystems, the Huron-Clinton Metroparks play an important role in maintaining and restoring Michigan’s natural habitats for vegetation, wildlife, and people.

Many natural areas within the Metroparks have been degraded as a result of large-scale changes such as intensive land use, fire suppression, and the introduction of exotic species. These ecosystems require active management by humans to restore their ecological health and to ensure their sustainability into the future.

In order to manage its natural areas, the Metroparks collect information on plants, animals, and other natural features from ecosystems throughout the 13 Metroparks. Natural areas are then prioritized based on ecological quality, restoration feasibility, and other factors. Depending on specific management goals, a number of strategies including invasive species removal, prescribed burning, and reintroducing native plants may then be used as part of the restoration process. Although much of the hard work is done at the beginning of restoration, ecosystem management is an ongoing process that often takes years or even decades to be successful.

Invasive Species Control

An invasive species is an organism that does not naturally occur in a specific area and whose introduction causes ecological or economic harm. Invasive species can be plants, animals, or other organisms, and are usually introduced to an area by humans, either intentionally or unintentionally. Invasive species are one of the greatest threats to the biodiversity and ecological health of the Metroparks’ natural areas. In fact, invasive species are the second-leading cause of global species extinction, behind habitat destruction.

Invasive species are not inherently “bad” species, but because they do not have natural predators in their new environment, they are often able to spread rapidly and outcompete native species for precious resources such as sunlight and water. For example, invasive shrubs like buckthorn and autumn olive can create very dense stands that shade out all other plants. Other invasive species are able to alter soil nutrients, produce natural herbicides, change water chemistry, or prey on native organisms, making their habitat less suitable for native plants and wildlife.

Some invasive plants can be mechanically controlled by physical removal, by either pulling, cutting, or mowing. Many species require repeated mechanical control to completely kill the plant. Invasive shrubs that colonize an old field can be controlled by periodic mowing with a brush hog. The most effective control for garlic mustard, an invasive woodland forb, is hand pulling during spring and early summer. Prescribed burning also acts as mechanical control by removing the aboveground portions of a plant.

Herbicides can be used to control invasive plants that do not respond well to mechanical removal, or they can be used in combination with mechanical control methods. Localized applications involve applying a small amount of herbicide to a specific part of the plant. One type of localized application, cut stump treatment, is frequently used for controlling invasive shrubs such as buckthorn, honeysuckle, and autumn olive. Foliar applications with a backpack or boom sprayer are more appropriate for controlling large or dense patches of invasive vegetation, such as extensive stands of oriental bittersweet, spotted knapweed, or Phragmites. Chemical control is always implemented in such a way as to minimize potential impacts to native species and human health.

Below are a few of the invasive species that occur in the Metroparks’ natural areas:

Land Plants

• Autumn Olive
• Black Swallowwort
• Common Buckthorn
• Common Privet
• Dame’s Rocket
• Garlic Mustard
• Glossy Buckthorn
• Japanese Barberry
• Japanese Knotweed
• Multiflora Rose
• Narrow-leaved Cattail
• Norway Maple
• Oriental Bittersweet
• Phragmites
• Purple Loosestrife
• Reed Canary Grass
• Spotted Knapweed

Land Animals

• Emerald Ash Borer
• Mute Swan

Aquatic Plants

• Curly-leaf Pondweed
• Elodea
• Eurasian Milfoil
• Starry Stonewort

Aquatic Animals

• Eurasian Ruffe
• Round Goby
• Spiny Water Flea
• Quagga Mussel
• Zebra Mussel

For detailed information on identification and control of invasive plants in our area, visit the Midwest Invasive Plants Network: http://mipn.org/

Prescribed Burning

Fire is often thought of as a destructive force, but periodic burning is critical for restoring and maintaining fire-dependent ecosystems such as prairies, oak savannas, dry-mesic forests, and some wetlands. Historically, fire was one of the greatest shaping forces of the southeast Michigan landscape, and many plants, animals, and ecosystems have become dependent on periodic fire for their survival. In the past, fires were ignited periodically by Native Americans and lightning strikes, but today, prairies and other fire-dependent ecosystems throughout the Metroparks are burned by professionals in a safe and controlled way as part of an overall ecological management plan.

In many ecosystems, fire promotes the growth of native plants that have special adaptations such as deep roots and thick bark, which help them survive periodic fires. For example, prairie grasses such as big bluestem have roots up to ten feet deep, which allow them to resprout vigorously after a burn. Black oak, a keystone species in many oak savannas, has bark up to three inches thick at the base, which prevents fire from damaging sensitive vascular tissue. In addition to stimulating growth and reproduction, prescribed fire also helps control invasive species that are not adapted to frequent burning, including spotted knapweed and most exotic shrubs.

Successful prescribed burning requires careful planning and preparation. Prescribed burns can be conducted in spring, summer, or fall, depending on management objectives. The burn season determines which plants will be benefited and controlled by the burn, and also the potential impacts to wildlife. For example, late fall or early spring burns benefit native grasses, while late summer burns tend to control woody species and favor native wildflowers.

Proper weather conditions, particularly humidity, temperature, wind speed, and wind direction are also required for a burn to be successful. Above all, safety is the top priority for a prescribed burn. Local fire departments and law enforcement agencies are always notified before a prescribed burn takes place.

Native Species Establishment

Re-establishing native plant species is a critical part of ecosystem management and restoration in many cases. It is particularly important for restoring areas that have been severely degraded and have little or no native vegetation remaining.

Native plants can be introduced by hand-planting small plants (plugs), scattering seeds by hand, or by using a seed drill towed behind a tractor. For all restoration projects, the Metroparks seeks to use plant material originating from Michigan. Using local plant material helps preserve the genetic integrity of plant species specifically adapted to Michigan’s soils and climate.

The Metroparks has established more than 50 acres of native prairie vegetation on old fields where prairies likely existed historically. Prior to planting, the site is often prepared by removing existing vegetation and roughening the soil surface to ensure good seed contact. In areas where some prairie vegetation already exists, new species are interseeded through the existing vegetation. After the plants have established for one or two growing seasons, prescribed fire is used periodically to help native species persist and to discourage invasive species from taking hold.

Native plants are also used to improve water quality near streams, rivers, and in rain gardens. Many native plants have deep root systems that help to slow stormwater runoff, stabilize eroding banks, and filter out excess nutrients. Plants selected for these projects have extensive root systems and are tolerant of saturated soils or periodic flooding.