Dale Bumpers White River National Wildlife Refuge

Moist Soil Management

Since its establishment as a National Wildlife Refuge in 1935, much of the habitat management that occurs on Dale Bumpers White River National Wildlife Refuge (NWR) has focused primarily on waterfowl. Since the 1950's, several wetland units have been developed on the refuge that allow for an annual drawdown and flooding up to benefit wintering waterfowl. Wetland/waterfowl managers often refer to managing a "moist-soil unit" for wintering waterfowl. This means that the water level in the wetland will be lowered during the spring and summer to encourage the growth of early successional grasses and weeds (e.g. "moist-soil grasses") that provide seeds to be utilized as food for wintering waterfowl when the impoundment is flooded during the fall and winter. These impoundments are also heavily utilized by shorebirds and wading birds.

To maximize the amount of desirable plants in these impoundments, it is necessary to disk them on a rotational basis (usually every three to four years) in order to set back plant succession. Oftentimes, millet or other agricultural grain crops highly desirable to wintering waterfowl may be planted in those years that a disking is needed in the moist-soil rotation. Currently, most of the moist-soil managed by the refuge occurs on approximately 120 acres at the Demonstration Area, 200 acres at Dry Lake, and 130 acres at the Turner Tract. Management actions, such as herbicide spraying for undesirable broadleaf weeds and flushing with water several times during the summer, are implemented in order to maximize the presence of desirable plants such as sedges, sprangletop, barnyard grass, and smartweed, and to minimize the presence of non-desirable plants such as cocklebur and coffeeweed. By using these different management techniques, land managers can keep moist soil units in an early successional stage where the plants produce a lot of seeds that are beneficial to waterfowl.
 

Cropland Management

Areas of the refuge that are outside of the river floodplain and suitable for farming are often planted with agricultural crops to be left unharvested for wintering waterfowl.  There are approximately 145 acres of precision-leveled fields on the Farm Unit of Dale Bumpers White River NWR that are used to grow various grain crops for wildlife. Today, these crops are grown exclusively by refuge staff. Historically, a cooperative farming program was utilized on the Farm Unit. Under this program, a local farmer commercially farmed refuge land on a 25 percent crop share basis. This crop share approach required the farmer to leave 25 percent of the acreage planted in unharvested crop. The 25 percent served as the farmer's rent for the 75 percent harvested for himself. Typically, corn, milo and/or rice were left unharvested as the refuge share. These cropland areas serve as a sanctuary and feeding area for resident wildlife such as black bear, deer, turkey, and non-resident wildlife such as waterfowl.
 

Forest Management

Approximately 150,000 acres (94%) of the Dale Bumpers White River NWR is forested habitat. The majority of this habitat is a bottomland hardwood forest that can be characterized as a “swamp forest” because of frequent flooding. Tree species diversity is relatively high in most bottomland forests, but slightly less so in a swamp forest. The forest is composed primarily of water tolerant species such as: overcup and nuttall oaks, bitter and sweet pecans, sugarberry, ash, elms, cypress, sycamore, persimmon, and others. Although not the predominant habitat on the refuge, there are some high ridges along the river escarpment with the Grand Prairie that contain tree species characteristic of an upland hardwood forest.  

The refuge manages for a healthy forest habitat that is intended to benefit the most diverse suite of wildlife species possible including waterfowl, black bear, and neotropical songbirds. This is accomplished through the implementation of both passive and active forest management. Passive forest management involves no human-induced disturbances such as timber harvests or salvage cuts. In the absence of natural disturbances such as tornados, excessive flooding, or wind-thrown trees, the forest produced by this method usually has an overstory with a closed canopy and an open, almost park-like condition underneath. Eventually, this closed-canopy forest will undergo some natural disturbances where tree-fall gaps of differing ages and sizes will occur to provide for regeneration of the overstory as well as a more robust midstory and understory. Although the forest created by passive management is beneficial to many wildlife species, there are also many wildlife species (some of conservation concern) that require the type of forest created by frequent disturbances resulting from active forest management. Active forest management involves the selective harvest or logging of timber through the use of a “variable retention thinning” approach. This is accomplished by removing trees less desirable for wildlife habitat, while placing an emphasis on keeping a high species and size class diversity within the stand and retaining trees with specific wildlife benefits (i.e. cavity trees, food production, etc.). This type of thinning creates numerous variable sized gaps in the overstory, allowing sunlight to reach the forest floor and encouraging vegetative growth. The resultant forest exhibits a complex assemblage of older age class trees in the overstory, a robust midstory, and a regenerating or actively growing understory. Understory and midstory growth is beneficial to a variety of wildlife during some stage of their annual life cycle. For example, white-tailed deer feed on understory growth during times of the year when hard mast is limited, and many other mammal and bird species depend on this growth to provide food and cover. To provide the best habitat possible for the widest array of wildlife species, both passive and active management strategies are necessary.
 

Invasive Species Control

Beavers
Beavers (Castor canadensis), like people, modify their environment to make it suitable for them. With their agility in the water, they prefer to move by swimming rather than walking overland. To create areas for swimming, feeding, and building lodges or houses, they frequently build dams across streams to flood suitable areas. Beavers are herbivores, feeding primarily on the inner bark of trees. They often cut trees down for food and/or for dam building material. A consequence of their flooding land is the change in the availability of that land for use by other wildlife. Forested areas rapidly change to an open water pond that provide food and cover for tree-dwelling wildlife. Dry habitats such as upland areas see a great increase in habitat and wildlife diversity with a few beaver ponds along steep banked creeks. Bottomland habitats often have abundant wetland areas without additional conversion of forests to ponds.

Wetland managers carefully manipulate water levels at different seasons to nurture habitat during the growing season, and flood during the winter season for migratory waterfowl. Beavers prefer high water levels year-round and clog up water control structures to get their way, much to the consternation of land managers. Thus, the refuge reduces the beaver population in problem areas to limit conversion of live forest habitat to ponds and reduce management efforts to fluctuate water levels.
 

Feral Hogs
Feral hogs (Sus scrofa) have been present in small numbers on the refuge for a long time. However, since 2009, hog populations on the refuge have greatly increased. This was first noticed on southern parts of the refuge. Since 2012, feral hog numbers have increased on portions of the refuge not known to have a hog population prior to 2009.

Feral hogs are destructive invaders who outcompete native wildlife species for food resources and depredate nests of ground nesting birds. Their feeding behavior consists of rooting for food on the ground, and this causes extensive damage to natural habitats and man-made structures like levees. Their tendency to root and wallow in wet areas can also have negative impacts on water quality and can impair tree regeneration. Additionally, feral hogs may carry diseases that are communicable to humans and other domestic and wild animals. In 2013, a USDA Wildlife Disease Biologist took blood samples from twenty feral hogs on the refuge and four tested positive for pseudorabies, six were positive for swine brucellosis, and four were positive for toxoplasmosis. 

Although the refuge conducts control activities and encourage hunters to harvest feral hogs, these animals have extremely high reproductive rates. Females reach sexual maturity as early as six months and can have two litters per year of approximately ten piglets each. This, combined with the fact that feral hogs are not very susceptible to natural predation, make hog populations extremely hard to control. Despite hogs being prolific breeders, prior to 2009, it was thought that the annual floods from the White River would never allow feral hogs to become well established on the refuge. However, as we are seeing now, this may not be the case.