Resource Management

Sherburne National Wildlife Refuge


The mission of the National Wildlife Refuge System is to oversee a system of lands "for the conservation, management and, where appropriate, restoration of fish, wildlife and plant resources..." When Sherburne National Wildlife Refuge was established in 1965, the landscape had been significantly altered and the fish, wildlife and plant resources in the area had gone through great changes as a result.

Management of the refuge's resources has been extensive over the last several decades. Some tools of the trade:

  • Prescribed fire
  • Conservation grazing
  • Integrated pest management
  • Timber thinning
  • Native plant seedings
  • Water level manipulation

At Sherburne, resources are managed within three primary ecosystems: oak savanna, wetlands and big woods. Annual planning by refuge staff establishes management goals and dictates which tools will be used throughout the year.

Oak Savanna

Historically, this was the predominant upland habitat on the refuge, comprising approximately 95% of those acres. By the time the refuge was established, only 4.3% of the upland acres were still considered oak savanna. Thousands of acres had been lost to agriculture, timber cutting, homesteading and fire suppression. The refuge's ultimate goal is to return these areas to "pre-settlement" state as much as we can, with a focus on restoring oak savanna.

Restoring oak savanna is a complex and extensive undertaking that requires the use of many management tools. Oak savanna is a plant community created and maintained by wildfires and grazing by large herbivores, such as bison or elk. Today the refuge uses prescribed fire and conservation grazing to help mimic those natural disturbances. Burning and grazing encourage the growth of native wildflowers and grasses, while reducing competition from non-native grasses and encroaching woody vegetation. Additionally, prescribed fire opens up the canopy in heavily wooded areas to recreate oak savanna. Thousands of acres of native grass and wildflower seedings have been conducted on old agricultural fields and removed conifer plantations and in the understory of restored oak savanna. As well, the mechanical removal of trees has reopened the canopy in savannas that had transitioned into oak forests.

To date, a few thousand acres of oak savanna have been restored at Sherburne. The restoration and management of this important habitat is ongoing.

Wetlands

When the refuge was established, the area was heavily ditched and 130 wetland basins had been drained, with many more affected to some extent. The creation of an impoundment system has enabled the current relative cover of wetland acres to regain close to what it was prior to European settlement.

On the refuge, restored wetlands, commonly referred to as impoundments or pools, as well as natural lakes and wetlands provide homes for many species of wildlife including waterfowl, wading birds, shorebirds, mammals, frogs, turtles and salamanders. Wetlands are scattered throughout the other two refuge habitats, oak savanna and big woods, in their low lying areas. Sherburne has 22 restored wetlands where the water level can be manipulated using water control structures. Not all of the impoundments are kept at the same depth; water management by controlled fluctuations creates a variety of habitats to provide for a diversity of wildlife requirements. 

Big Woods

Sometimes referred to as a maple-basswood forest, it is dominated by these two tree species and is present near the refuge's northern boundary. The understory is comprised of shade tolerant herbaceous (leafy) plants, a sparse shrub layer and a subcanopy of iron woods and sugar maple. Other species present include red oak, green ash and elm.

It is home to animals including deer, black bears, squirrels and many songbirds. This unique plant community is managed by excluding prescribed fire to preserve native trees and retain downed timber and snags. These standing dead trees and downed logs are used by wildlife for roosting, loafing, nesting, hunting, feeding and food storage.

Trapping Occurs on this Refuge

Trapping is a wildlife management tool used on some national wildlife refuges. Trapping may be used to protect endangered and threatened species or migratory birds or to control certain wildlife populations. The U.S. Fish and Wildlife Service also views trapping as a legitimate recreational and economic activity when there are harvestable surpluses of fur-bearing mammals. Outside of Alaska, refuges that permit trapping as a recreational activity may require trappers to obtain a refuge special use permit. Signs are posted on refuges where trapping occurs. Contact the refuge manager for specific regulations. For more information: FWS Trapping.

Sherburne National Wildlife Refuge occasionally traps near water control structures for management purposes.