OutdoorNebraska

12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 GUIDE TO NEBRASKA'S WETLANDS Wetland Classifi cation N umerous classifi cation systems have been developed for wetlands. The one most used today is the Cowardin system (Cowardin et al. 1979). This is a hierarchical system that classifi es wetlands according to system, plant community and substrate, water regime, water chemistry, and numerous special modifi ers such as the presence of dikes, drainage, and excavations. In many cases, portions of the same wetland can be classifi ed differently. Systems — The three wetland systems that occur in Nebraska are palustrine, lacustrine and riverine. Palustrine systems include marshes, wet meadows and the edges of lakes and streams. Lacustrine systems are lakes, usually deeper than 6.6 feet. Riverine systems are rivers and streams that fl ow in a defi ned channel. Water Regime — Water regime describes the duration and timing of inundation or saturation in a wetland. In Nebraska, most palustrine wetlands are of the temporarily, seasonally, or semipermanently fl ooded water regimes. Temporarily fl ooded wetlands are fl ooded for brief periods, often only a few weeks, during the growing season. Seasonally fl ooded wetlands have water present for extended periods during the growing season, but tend to dry up by the end of the season in most years. Semipermanently fl ooded wetlands have water in most years and only occasionally dry up. Wetland Inventories and Maps M any different techniques have been used to inventory the past and current number and acreage of wetlands and track the conversion or loss of wetlands in Nebraska. Because of this, the numbers derived statewide or within a complex not always are in agreement, and care needs to be taken when interpreting these numbers. Nevertheless, these numbers are useful in examining the major, long-term trends in wetland numbers and acreage. The most complete wetland inventory for Nebraska was conducted by the National Wetlands Inventory of the U.S. Fish and Wildlife Service. The inventory produced maps that depict wetlands using the Cowardin classifi cation system (Cowardin et al. 1979). They are an excellent tool for inventorying and locating wetlands, but they are not delineation maps. Much of the state was mapped using aerial photographs taken in the early 1980s, so some inaccuracies are present in the mapping due to changes that have happened since then. The Rainwater Basin and Central Platte River areas were updated in 2011, and a large portion of the Sandhills is being updated. Digital maps are available for much of the state and can be accessed at fws.gov/wetlands. Wetlands are found in every county, and many are associated with streams, such as this fringe and seepage wetland along Spring Creek in Lancaster County. ETHAN FREESE, PLATTE BASIN TIMELAPSE Wetlands Are Everywhere Even if a wetland is not within one of the complexes in this guide, it does not mean it is unimportant or does not provide benefits. Wetlands are in every Nebraska county, especially along Nebraska's many streams and rivers, and are important components of the ecosystem. Wetlands also are associated with many of the state's constructed farm ponds and reservoirs.

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