 |
 |
Browns Park National Wildlife Refuge |
Managing Habitat for Wildlife
Historically, waterfowl were given management priority; however, today refuge management is focused on maintaining a variety of native habitats and wildlife, with emphasis on migratory birds, threatened and endangered species, and species of special concern.
Thanks to current management techniques, Refuge habitats support a rich diversity of wildlife species including 68 mammals, 15 species of reptiles and amphibians, and at least 223 species of birds.
Riparian Habitat
Wetland Habitat
Grassland Areas
Upland Habitat
Habitat Management Tools
The riparian habitat along the Green River and Beaver Creek at Browns Park NWR is made up of cottonwoods, buffaloberry, willows, and many other plants that are restricted to flood plains or areas of permanent underground water supplies. These plants are dependent on water for their survival. Similarly, many species of wildlife depend on riparian plants to fulfill their life needs. Thousands of migrating songbirds like the Lazuli bunting and Wilson's warbler rely on riparian habitat for refueling when traveling further north to their breeding grounds. Other songbirds such as the black-chinned hummingbird and Bullock's oriole stop to nest. Bald eagles, several hawk species, great blue herons, moose, and river otter also raise their young in the riparian area.
Water development has caused the Refuge riparian habitats to change over time.
Beaver Creek, although affected by water use upstream, still remains a prime
example of riparian habitat in the high desert region.
Like Beaver Creek, the riparian area along the Green River has also been affected
by upstream water use at the Flaming Gorge Dam. Before construction of the dam,
the Green River's water levels responded solely to the uncertainties of
nature. Flooding usually occurred in the spring, tapering off to reduced flows
in summer. Natural marshlands bordered the river, and spring flooding was the
primary source of water. After construction of the dam in 1962, people began
to control the river flows. Human control has resulted in a decrease in spring
floods and a reduction in the amount of sediment carried by the river. This
results in the gradual deepening of the river channel, further reducing the
likelihood of flooding, making it difficult for tree and willow roots to reach
water, and inhibiting the germination of new seedlings. Field research has confirmed
that cottonwood forests are aging and not being replaced. Instead, nonnative
species such as perennial pepperweed and saltcedar are overtaking this habitat.
The dam's effect on the river and riparian habitat is very complex and may be compounded by factors other than flooding, such as decreased water temperature, climate change, and increased pressure from animals feeding on the plants. Research is ongoing to help determine how to increase the production of new cottonwoods and willows in the riparian areas. (back to top)
The seven wetlands at Browns Park NWR provide essential foraging and resting grounds for migratory waterfowl during their spring and fall migrations. Species dependant upon the wetlands includes the American bittern, northern harrier, and white-faced ibis. The refuge and the adjacent State of Utah's waterfowl management area contain the only significant wetland habitat for miles around because seasonal flooding no longer naturally floods meadows along the Green River. Therefore, Refuge staff pumps water from the Green River, as well as diverts water from Beaver and Vermillion Creeks, onto the seven wetland units totaling approximately 1,245 acres. (back to top)
Nearly 1,900 acres of the Refuge are covered by grassland plants such as the alkali sacaton, inland saltgrass, western wheatgrass, and Great Basin wildrye. These plants provide nesting cover for waterfowl, northern harrier and songbirds such as the savannah sparrow. The grasslands also provide cover for small mammals like the montane vole and crucial winter range for elk and deer. Over time, vegetation in the grasslands becomes heavily matted and nesting habitat is lost. Therefore, refuge staff uses prescribed fire to remove matted vegetation which restores the grassland habitat. Refuge grasslands can be found primarily along Beaver Creek and the Green River. (back to top)
Semidesert shrubland dominates the upland habitat. Approximately 7,930 acres of semidesert shrubland exists on the Refuge. The dominant plant species are big sagebrush, greasewood, Indian ricegrass, and the non-native, invasive cheatgrass. Refuge species that rely on the semidesert shrubland for breeding include sage grouse, Brewer's sparrow, loggerhead shrike, Ord's kangaroo rat, and sagebrush vole. The shrubland also provides winter range for mule deer and, to a lesser extent, pronghorn. The upland habitat also consists of about 1,083 acres of Pinyon-Juniper ecotone as well as interspersed areas of exposed rock along the southern boundary of the refuge. Many species depend on this arid environment away from the river including such species as the gray flycatcher, black-throated gray warbler, pinyon jay, and several species of bats. (back to top)
In their continuing efforts to enhance Refuge habitats, Refuge staff also use other management tools such as prescribed burning, native plant seeding, hunting, and control of invasive weeds. Invasive plant species such as perennial pepperweed, cheatgrass, salt cedar, and Canada thistle have become established, greatly reducing the value of the habitat available to wildlife on the Refuge. Biological, mechanical, and chemical controls are used to manage these invasive plants. (back to top)
