Short-grass Field Conservation

Cows are used as a grasslands management tool/Photo Courtesy of Dr. Madeline Kalbach

Grassland management is a major activity at Julia Butler Hansen Refuge. Cattle grazing, mowing, and seeding are used to maintain about 700 acres in short, actively growing, nutritious grasses and clover that provide high-quality forage for Columbian white-tailed deer, Canada geese, and cackling geese.

Grasslands occupy 2,384 acres on the Julia Butler Hansen Refuge. Grasslands are not native habitats of the refuges; rather, they were created when dikes were constructed and former marsh and swamp habitat was cleared and drained for agriculture. The grasslands are dominated by introduced varieties of grasses that were originally planted for livestock forage. Species include tall fescue, reed canarygrass, orchardgrass, velvetgrass, meadow foxtail, ryegrass, and bentgrasses. Other plants that are common in the grasslands include red and white clover, creeping buttercup, field horsetail, curly dock, and common rush (tussock).

Both the Mainland and Tenasillahe Island pastures have been extensively managed since the early seventies through grazing on the island, and both grazing and haying the mainland. The focus of the pasture management program is to provide high-quality feeding sites for the Columbian white-tailed deer (CWTD). Goose pasture is a secondary consideration and one that has become an issue now that depredation problems are becoming more of a concern.

While the grasslands are managed primarily to benefit Columbian white-tailed deer and geese, other wildlife also utilize them. Townsend’s voles flourish in the grass, and their presence attracts predators such as northern harriers, white-tailed kites, great horned owls, barn owls, coyotes, long-tailed weasels, and garter snakes. Other species that utilize the grasslands include Wilson’s snipe, western meadowlark, American kestrel, tree swallow, barn swallow, purple martin, Virginia rail, yellowthroat, and American wigeon.

Learn more about how the Refuge manages pastures for CWTD… 

Pastures managed for CWTD are generally 2-3 feet higher in elevation than surrounding wetlands, have a much higher component of grasses than wetlands, and have somewhat better drainage. The condition of many pastures is poor because they have drainage/flooding problems and have been invaded by noxious weeds such as Canada thistle, tansy ragwort, and reed canarygrass. These undesirable plants have reduced the amount and quality of available deer forage. The loss of clover as a component of the pastures is also an important indicators of the degraded health of these sites.

Common rush, also called tussock, is found in many of the mainland and island pastures. It generally indicates a wetter zone with drainage problems. As with many diked wetlands, control of this plant is difficult. Wintering goose use on pasture lands is likely reduced by the extensive invasions of this plant. Some pasture renovation, including disking, seeding and replanting has been done in recent years on the mainland, but only in selected sites and not on a consistent basis.

Reed canarygrass is an exotic invasive grass from Eurasia. It is well established in wetter sites throughout much of North America. On the refuge, it is extremely abundant. It covers over 70 percent of the refuge grasslands, mostly in sunny, undisturbed, low-lying, wet sites. While it is somewhat palatable to the deer when it is short, it grows so fast that it out-competes the native grasses, brush, and trees. Chemicals commonly used for invasive plant control include Roundup, Vantage and Low-Vol Ester (2,4-D product).

Find out how the Refuge employs a 4-legged tool... 

Grazing and Haying 

Haying and grazing are two methods used to control exotic plant species and provide short grass growth in pastures that are managed for Columbian white-tailed (CWTD) deer habitat on the Mainland and Tenasillahe Island Units.

Management tools include high intensity short duration grazing, mowing, and haying, as well as other restoration strategies, such as herbicide applications, disking and seeding. The primary objective of using haying and grazing is to manage vegetation to maintain or increase itsvalue to wildlife at minimal cost to the government.

Haying and grazing occurs on approximately 850 acres of pastures. Local permittees graze and hay introduced reed canarygrass, native grasses, tame pasture grasses, sedges (Carex spp.) and rushes (Juncus spp., Eleocharis spp.) on refuge pastures. The haying program is rather minimal at this time and involves only 24 total acres all on the Mainland Unit. This refuge pasture management program using private individuals is conducted under a cooperative land management agreement (CLMA), which is established between the Refuge and the individual livestock operators (cooperator). The CLMA is an in-kind program, which means that both parties receive mutual benefits from the land without any funds being transferred. In this case, the cooperator receives grazing and haying privileges, and the US Fish and Wildlife Service receives habitat enhancement actions conducted primarily for the benefit of the CWTD and Canada geese at the Refuge.

Grasses and forbs are the primary food sources for the CWTD on the refuge. Browse is also used, but the deer prefer to feed in fields where the vegetation had been kept short by cattle grazing and mechanical cutting. The new actively growing plants are more succulent and digestible than mature plants, and deer naturally seek out the most nutritious food forages. The short grass pastures complement the marsh habitat on and around the refuge in providing forage and resting habitat for migrating and wintering Canada geese. Many off-refuge pastures are gradually being converted to other uses that exclude goose use. Refuge pastures also provide foraging habitat for ducks, raptors and elk. Grazing and haying are desirable means of maintaining this type of habitat because the climate is too wet for prescribe burning and repeated mowing of the pastures is beyond the capability of the refuge.


Grazing and haying have been successfully used as a tool to manage pastures for the benefit of wildlife since the inception of the refuge in 1972. Mowing is another management method used to control exotic plant species and provide short grass growth in pastures that are managed for the CWTD. As opposed to haying and grazing, mowing is generally conducted by refuge employees with the mowed vegetation chopped up and left on the field to decompose. Fields are mowed to a height of 4-6 inches at least twice per year, in July and then again from September through October. An early mowing in May is desirable if fields are dry enough. Mowing is planned for those fields that are not appropriate for grazing or haying activities such as those pastures with limited access and areas directly adjacent to visitor viewing facilities.

Discover additional conservation efforts employed... 

Herbicide Applications 

Canada thistle (Cirsium arvense), bull thistle (Circisum vulgare), tansy ragwort (Senecio jacobaea), tussock (Juncus spp.) and blackberry (Rubus spp.) are controlled with herbicide to maintain pastures for wildlife. These plants, if left uncontrolled, eventually make pastures unusable to wintering geese and Columbian white-tailed deer (CWTD). Tansy is listed as a noxious weed by both the state and county, and Canada thistle is listed as a state noxious weed. Low densities and random distribution of tansy and Canada thistle render biological control impractical. Treatment sites are diked pastures on the Mainland and Tenasillahe Island units. 

Ditches and channels within the treatment areas are sensitive areas and are avoided so that no herbicide enters the water. Waters bearing anadramous fish have buffer zones alongside either side within which no treatment with herbicide will occur unless applied using a wicking device. Herbicide applications do not occur during periods of gusty winds or when wind is in excess of 15 miles per hour. Although CWTD inhabit the area, there is no conflict since spraying is very limited, target plants are not major dietary plants of the deer, and this product is considered to be relatively nontoxic to ruminants. 

Pasture Rehabilitation 

As pastures age, they generally become more decadent with high percentages of weedy and invasive species that are less palatable to Columbian white-tailed deer (CWTD) and Canada geese. Even with a grazing, haying and mowing program, pastures occasionally need to be rehabilitated through intensive efforts of plowing, disking and reseeding. Pastures that are grazed seem to require less rehabilitation while mowed pastures require more frequent rehab work. Pasture rehabilitation is rotated so no more than one or two fields are done in any one year. There is no set schedule for pasture rehabilitation with many fields going 10 years or more before they are rehabbed. Field plowing and disking is generally done in the summer to help kill off dense reed canary grass stands while replanting is done in the early fall when there is increased soil moisture. Fields are replanted with various grasses and clover that are beneficial to target wildlife including orchard grass, timothy, perennial rye, annual rye, white clover, red clover and birdsfoot trefoil.