Wetlands – Functions and Values

Edward “Shawn” DeKeyser, Animal and Range Sciences Department, NDSU

 




Table of Contents

 

  Wildlife Habitat

  Forage and Livestock Production

  Forage Quality

  Water Quality

 




The Central Grasslands Research Extension Center (CGREC) is located in the heart of the Prairie Pothole Region (PPR), an area famous for millions of depressional wetlands. The PPR spans North America from central Alberta to central Iowa, with the highest density of wetlands occurring along the Missouri Coteau physiographic region in which the Center lies.


The Missouri Coteau is known for its diversity in farming and ranching products which include crops such as wheat, corn, canola, and sunflowers. The wetlands of the Missouri Coteau vary in size, shape, and functional abilities. The natural functions performed by the wetlands of this area have been assigned values that are important to the ecology, sociology, and economy (tourism, hunting, birding, etc.) of North Dakota.


The ability of a wetland within the PPR to perform any one or more functions depends on several factors. The size, shape, time of year, placement on the landscape, and amount of degradation all are important factors in a wetland’s ability to provide a certain function. For example, smaller wetlands are important in the spring for pair bonding and egg development in several waterfowl species. Larger wetlands are important for brood raising during the summer months. Even larger wetlands are important in the fall as staging areas for these waterfowl as they migrate south for the winter months.

 


Wildlife Habitat


The most publicly recognized function that wetlands of the PPR provide is valuable food and cover for wildlife species. These wetlands are especially important for waterfowl production in that they provide breeding, brooding, fledging, and staging sites. Because of this habitat the PPR produces almost 50% of North America’s waterfowl on a yearly basis (Kirby et al. 2002a). Many species of mammals, reptiles, amphibians, and non-waterfowl birds also depend, either partially or entirely, on these wetlands for food and cover.

 


Forage and Livestock Production


Wetlands not only supply nutritious forage for wildlife, but this forage can be beneficial to livestock as well (Kirby et al. 2002a). The region is especially important in the state’s forage and livestock production. In 2002, the Missouri Coteau produced nearly half of North Dakota’s hay: about 1.5 million tons of alfalfa hay (46 percent) and about 873,000 tons of other hay (47 percent). The region has about 42 percent of the state’s cattle inventory and about 31 percent of the state’s sheep inventory. In 2003 several counties in the region ranked in the top ten in the state for livestock production. The 2003 ND Ag. Statistics, show McHenry County ranked third for total number of cattle and third for the number of beef cattle. Kidder ranked fourth in all cattle production, fifth in beef and seventh for the number of sheep. Emmons ranked second in dairy cattle, sixth in all cattle and eighth in beef cattle production. Stutsman ranked ninth in all cattle and fourth in dairy. McIntosh ranked fifth in the number of milk cows.

 


Forage Quality


Nutritional value of the forage provided by wetlands can vary depending on the type of plant community, which is determined by the brackishness and permanence of water. Smaller, fresh water wetlands, provide some of the highest quality forage of any prairie pothole wetland. Also, nutritional value varies considerably depending on the time of the growing season. Most wetland plant species are most nutritious in the spring and early summer, where crude protein levels and digestibility drop rapidly by mid- to late summer.

 


Water Quality


Another important function provided by wetlands is the maintenance of water quality. The soils and plant species associated with wetlands purify water moving through the ecosystem. Nutrients such as phosphorus and nitrogen, heavy metals, suspended solids, and pesticides all can be removed from the water and eventually incorporated into the wetland soil.


These PPR wetlands not only purify water moving through them, but also aid in recharging ground water supplies. Wetlands act as temporary holding basins for water that will either evaporate back into the atmosphere or infiltrate into the soil. The infiltrating water supplies downslope wetlands, springs, and regional shallow aquifers.


Another function PPR wetlands provide is flood attenuation (Kirby et al. 2002b). Every wetland has width, length, and depth, giving it the ability to hold a volume of water. The degree to which wetlands can provide flood protection depends on the size of individual wetlands, the number of wetlands within a region, and the placement of the wetlands upon the landscape. This function of wetlands is highly debated both politically and socially– the main issue being if draining wetlands contributes to the severity of floods. Finally, the values assigned by the public to functions performed by PPR wetlands vary drastically. Society can value these functions either economically, ecologically, socially, or not at all. No matter what values are assigned by man to wetlands within the PPR, the fact remains that there are several natural functions provided by these unique systems whether man is there or not. It is important to evaluate these aspects when making management decisions.

 


  
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