Grazing

Grazing is a desirable management practice under the right conditions and objectives. In general, grazing at the right time and amount can cause undesirable plants to decrease and preferred plants to increase. The purpose for grazing wetlands is not for livestock production or revenue, but rather to economically manage the type and abundance of plants in WPAs.

Grazing is a natural event associated with healthy grasslands and wetlands. It plays an important role in keeping grasslands in an early successional stage and sustains the nutrient cycle used by other wildlife. For example, a recent study of invertebrate (Davis and Bidwell, 2008, Wetlands, 28(3), pp 793-805) was conducted in Rainwater Basin wetlands. They found higher species richness and diversity of aquatic invertebrate in seasonal wetlands that were grazed than in those burned, hayed, disked, or left undisturbed.

The grazing strategy used on WPAs differs between wetlands and uplands. To address each habitat type, temporary electric fences are built by the grazing cooperator to keep the livestock in the specific area being managed. A portion of the fee collected from grazing is used to control weeds, maintain fences and tree control. The balance is sent to the national office for use in refuge revenue sharing.

Grazing Wetlands

The majority of lands grazed each year are wetlands. Wetland grazing has been shown to provide desirable plant response. With the right timing and amount of grazing pressure, plants such as reed canarygrass, river bullrush, and cattails can be severely injured. The extensive root systems are literally shredded by the cows' hooves as they move through the wetland. Species such as smartweed, burreed, barnyard grass, spikerush, and other desirable plants can flourish after the undesirable species have been injured or killed. If plant regrowth is limited, the wetland will provide open water during spring and fall migration.

Objectives for grazing wetlands are nearly opposite of the objectives for grazing uplands. In the uplands we are trying to maintain perennial plant communities and the amount of "rest" these plants receive is critical. In the wetland, our objective is to convert from a late-successional to an early-successional plant community. The objective of grazing heavy stands of reed canarygrass, river bullrush, and cattails is to graze it for as long and intense as possible. We select and work with livestock owners to get the optimum amount of grazing. If the area we wish to graze is too large for the owner's herd, we reduce the size of the pasture to increase grazing pressure. Owners with too small of herd to impact a significant amount of area are not permitted to graze.

The average stocking rate is 1.5 AUMs/acre with some units as high as 6.0 AUMs/acre. An AUM equals the amount of forage a 1100 pound animal consumes in a 30-day period. Upland stocking rates average 0.75 AUMs/acre. Wetlands without dense stands of reed canarygrass, river bulrush, or cattail concern are generally grazed at much lighter rates to encourage desire plants to produce seed and to provide an aquatic invertebrate substrate.

Currently we have a waiting list of livestock owners who wish to graze WPAs. When areas come open for grazing, they are contacted in the order they were listed. Owners selected to graze are charged a grazing fee and issued a permit. The grazing fee reflects the state average rate, with discounts given for installing temporary fences, hauling water, and doing land management practices on the property. If livestock owners (lessees) follow the terms of the permit, pay their fees, remove temporary fences and other materials, we give them first chance to graze in future years. The intent of this arrangement is to establish good lessees who understand and support grazing management for the benefit of waterfowl production.

Cross fencing through wetlands is a problem and in most situations we allow the cooperator to fence the wetland as a whole grazing unit. On those situations, larger herds are usually needed to get the desired effect. Depending on how many cattle are available for the size of the wetland being grazed, results can vary from the extreme of bare dirt to the other extreme of livestock trails and small pockets or openings. In general, the greater the intensity of grazing, the more dramatic the shift in plant communities and the greater the length of time until management is needed again.

The decision of what areas to graze again the following year depends on the response of the plant community. Many factors affect plant response. They include how well the root system is established, the intensity of grazing, soil moisture, and the amount of rainfall received before, during, and after the grazing season.

Wetlands are known to support highly productive plant communities. Those grazed down to bare dirt can regrow dense stands of vegetation (more than 6 feet tall) in the same season. For that reason, we try to work out a wetland grazing scheme that provides optimum spring migratory habitat seven out of 10 years.

A definition for "optimum migratory habitat" is hard to pin down; it varies with bird species. Pintails favor one water depth and vegetative composition and structure, while white-fronts another, snow geese another, and shorebirds as a group, still another. We strive for habitat which has abundant wetland plant seed, aquatic invertebrate substrate, and at least 50% open water when flooded one foot deep.

The drought years, beginning in 2002, provided significant "proof" of the value of wetlands for grazing. While neighboring private bromegrass pastures withered and quit producing, wetland plants continued to provide forage. One cooperator stated that in 2002, his private 80-acre pasture (100% smooth bromegrass) could not handle the eight cows he had stocked, while the 80-acre wetland on the WPA handled four times as many. In 2006, eighty eight forage samples were taken of wetland plants being grazed. The results showed the nutritional value to be extremely good.

In 2009 intense grazing was done on a small 25 acre wetland to determine the affect that could be achieved is grazing intensity has very high. A large herd was used that was capable of removing all the vegetation in eight days or less. The results of intense grazing can be seen at this link.

Grazing Upland Grasses (top)

Upland grazing is done to encourage warm season grasses. Warm season grasses are noted for having stronger stems that remain erect during winter storms. Cool season grasses collapse after the first winter storm, forming a mat layer of little protection to resident birds and animals. Livestock, grazing in early spring, clip the cool season grasses such as smooth brome and Kentucky bluegrass. The shorter cool-season grass allows more sunlight to reach the newly growing warm-season plants, promoting for their faster growth. Stocking rates on uplands is about 0.75 AUMs/acre.

The amount of time an area is grazed is a critical to effective management. Areas dominated by undesirable grasses are grazed longer so each plant is clipped more than once. Plants frequently clipped are required to use up nutrients in their root system to regenerate new foliage, resulting in a weaker plant. Areas dominated by preferred grasses are grazed just long enough for each plant to be clipped once. Then, the area is allowed to rest from grazing. It is during the period of rest that grasses respond to grazing. The single clipping causes the plant to respond by building a larger root system. The larger root system allows the plant to capture more soil moisture and nutrients; resulting in a healthier plant.

Grazing as a Management Tool (top)

Grazing as a management tool, requires us to use an outside resource (privately owned livestock) to accomplish our objects. Therefore, one-on-one relationships have to be developed with each cooperator. Each one has unique circumstances: some need early grazing, some season long, some have access to many cattle, and some have just a few. But all of them have a limit to what they are willing to subject their livestock to. Some cooperators are willing to leave cows on a cattail-chocked marsh. Others get anxious by mid-June and want to move the cows. Our approach is to work with each one individually to get close to our objective and still stay within their "comfort zone" needed to stay in business.

Fencing is a real concern associated with livestock grazing. Few permanent fences exist on our properties, so we rely on low cost electric fences, which the cooperator builds, maintains, and removes at the end of the grazing season. Adjacent landowners, have very low tolerance of free-roaming livestock. Most escapes occur while deer and livestock are getting used to a fence being where one wasn’t before. Cooperators who cannot keep their animals fenced are asked to remove them from our property. Our long term plan is to build a permanent perimeter fence around our property so livestock that escape a grazed unit are still contained on our property. Currently, one to two WPAs are fenced each year.

Water and/or the lack of it causes problems as well. If plans are made to graze a wetland and halfway through the summer a large rain floods the wetland, an alternative plan is needed. That usually includes short term rotational grazing on the uplands until the wetland dries enough to put the cows back in the wetland. Having a second wetland area to move the cows into is also a backup plan.

Livestock water is absent on many areas during July, August and September. For small numbers of cattle, trucking water is a possibility. Hauling water for more than about 30 cows, however, becomes a problem for most cooperators.

Grazing complexes, with one cooperator grazing two or three WPAs, are slowly being developed. This gives more flexibility on what to graze and hay. When each cooperator has lease or use of one WPA, we cannot develop a grazing plan that will insure some grazing each year. A good cooperator can’t deal economically with this uncertainty, so we would quickly lose the good ones. Grazing complexes allows us to graze one wetland hard for multiple years and then rest for several. The cooperator's livestock is rotated through the complex as habitat conditions warrant.

Cooperators who graze are charged a fee. The fee is based on the average statewide rate with deduction given for such factors as building fence, providing water, and grazing poorer vegetation. The money received is divided into two funds: a portion goes toward refuge revenue sharing and the balance is used for other management needs on the property.

Last updated: October 15, 2009