Tennessee National Wildlife Refuge
Southeast Region
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Natural Habitat Protection

Credit: Clayton Ferrell, USFWS

Credit: Clayton Ferrell, USFWS

In addition to the managed habitat addressed above there are several naturally occurring habitats (or at least habitats not actively managed by the refuge) that are extremely important to many species of wetland wildlife. The primary role the refuge plays associated with these habitats is protection.

Most of these habitats are outside the main levees of Duck River and Busseltown Dewatering Areas and are influenced by TVA’s Kentucky Lake operation schedule. Under the current water control schedule the drawdown of Kentucky Lake from summer pool (359 MSL) toward winter pool starts around July 5 and steadily drops to winter pool (354 MSL) by December 1. By mid to late August the level typically drops approximately two feet. At this level water is completely off the willow-buttonbush zone, allowing woody plants and herbaceous perennials an opportunity to “breath” and seedlings to germinate. Annual plants, such as yellow nutsedge, germinate in areas where the sunlight is sufficient. Shorebirds and early migrating blue-winged teal readily utilize the newly exposed mudflats that are free of dense woody vegetation. The water level continues to drop throughout the fall, exposing vast areas of mudflats. Normally, during the fall the only habitat available to shorebirds on the refuge are the flats associated with Kentucky Lake. Annual grasses and sedges carpet these flats providing browse for geese and some species of ducks. This habitat is critical for early migrating geese that start arriving in late September because it is typically the only habitat available at this time of the year, since crop harvest has not yet been initiated. Throughout the fall and winter tens of thousands of green-winged teal, wigeon, and gadwall forage on these flats. During winter and early spring flood events many of the mallards, black ducks, and wood ducks will vacate the managed habitats in the bottoms to utilize the newly flooded moist-soil, willow-buttonbush, and bottomland hardwood habitats along the shoreline of the reservoir. Over 55% of the duck use and 48% of the goose use on the refuge is found to occur in the reservoir as opposed to the more intensively managed impoundments. The water schedule reverses on April 1 and the reservoir is allowed to quickly rise to summer pool by May 1. The willow-buttonbush zone is again flooded providing excellent wood duck brood habitat, as well as habitat for many other species of birds, reptiles, amphibians, and mammals. This habitat is also essential for spawning and fry survival for many species of fish.

 

Click to see "The Value of Transient Mud", an article published by the Wildlife Society in the Spring 2011 edition of The Wildlife Professional.

 

Submersed and free-floating aquatic plant communities are found in scattered locations within the impoundments and on the reservoir throughout the refuge where conditions are favorable. These plant communities consist of both native and exotic species, including Eurasian watermilfoil ( Myriophyllum spicatum), spinyleaf naiad ( Najas minor), southern naiad ( N. guadalupensis), coontail ( Ceratophyllum demersum), and duckweeds ( Lemna spp.). Waterfowl commonly utilize these habitats especially during the early fall. The refuge does not specifically manage for or against the aquatic plant species listed above.

Canvasback - A Species of Diving Duck. Credit: USFWS

Canvasback - A Species of Diving Duck. Credit: USFWS

Diving ducks and mergansers utilize the open deep water habitats that primarily occur on Kentucky Lake. The Big Sandy Unit holds a greater number and diversity of these species than the other two units combined. Diving ducks and mergansers make up approximately 20% of the ducks on this unit. The only means of management that the refuge does in these habitats is protection from disturbance and unintentional take with commercial fishing nets. During the early 1990's the refuge documented a problem with diving ducks getting entangled in commercial fishing gear within high use areas of the Big Sandy Unit. The refuge staff worked with TWRA to change commercial fishing regulations for the refuge during the wintering period. Since this regulation has been in place there have not been any further kills documented on the refuge. The refuge has also closed some of the highest use areas to boats to reduce disturbance.

Bottomland hardwood stands on the refuge are primarily limited to small isolated blocks within the Duck River and Busseltown Dewatering Areas and low lying areas along the shore of Kentucky Lake, especially along the Duck River and Cub Creek. Many of these stands have resulted from natural succession of abandoned agricultural and moist-soil areas. Tree species composition consists mostly of light seeded species, such as black willow ( Salix nigra), sweetgum ( Liquidambar styraciflua), silver maple ( Acer saccharinum), and green ash ( Fraxinus pennsylvanica). There are very few stands that contain a good composition of hard mast producing trees. Only a few areas that were abandoned have been planted to oaks. Within some more remote areas of the refuge loss of quality bottomland hardwoods have resulted from beaver activities. Currently, there are no active forest management activities planned within any bottomland hardwood stands.

 

Last updated: February 13, 2014