OTTER CREEK MARSH will always offer a never ending challenge to wildlife biologists and managers. The trick is to work with natural weather related cycles and conditions to make the best of available opportunities to enhance certain wetland vegetation or cut back or curtail vegetation when they can.

Some years will see normal rains and good water flows. At other times, floods will greatly impede options, and of course, drought years may see the waters of this marsh go dry. In either case, the ability of DNR staff to implement vegetation management plans must remain flexible.

“Otter Creek is a man-made wetland complex that was built for the purpose of providing migrating waterfowl critical habitat during spring and fall migrations,” says Rodney Ellingson, Natural Resource biologist with Iowa DNR wildlife bureau. “The job of management is to provide the highest quality habitat to migrating species that is possible. Habitat manipulation boils down to making food for wildlife at the times they need it most.”

The design of the area has a number of levies that act like stepping stones and hold water at slightly different heights. Between these pools are control structures to hold or release water. DNR staff takes water off as needed and refills pool areas at other times. Water absence or abundance is a tool to help control desired vegetation growth cycles.

Water draw downs are one tool in the tool box after a migration peak has passed. Removing stop logs in water control structures will allow pool waters to drain away, exposing soils to make mudflats.

These conditions are ideal for shorebirds. Seeds already in the soil may now germinate and grow to create new annual plant growth and their seeds (food) for waterfowl in the coming fall migration.

Desired plants include smartweed, millets, and Rice Cutgrass. These vegetation types also support invertebrate habitat. Invertebrates are consumed by waterfowl later in the year.

Summer months will have staff spending time at control of hybrid cattail, river bulrush and reed canary grass. Removing as much of these plant species as possible is the goal. Replacing these with annuals that make seed is a tool box trick.

Sometimes the offending vegetation, if access allows equipment to be used, can be mowed, hayed, or by disking. Spraying herbicides both from the ground or more efficiently by aerial methods (helicopter) may be utilized. The herbicide is a glyphosate formulated and labeled for use over and around water.

After the summer season is winding down, and before the fall migration begins, stop logs at control points will allow water to refill the pool segments. The ideal circumstances is to have enough open water available for the early Teal hunting season on or about Sept. 1.

While pool vegetation is actively growing, those plants also consume water. This is just normal. Later in the fall, as vegetation begins to go dormant, water filling the pools becomes easier since not as much is lost to evaporation. The goal is to have each pool of water be at an optimum level by the time the second waterfowl season opens.

The more food types that management can allow to happen or make happen means more food for waterfowl during the fall. Feeding birds of all sizes, game or non game, is the intent.

Hunters provide the financial support for management through license sales, habitat stamp sales, and the cooperative efforts of each state’s share of federal Migratory Bird Stamp sales. There is additional support to each state from the excise tax on firearms and ammunition.

Reptiles and amphibian wildlife are another goal of wetland management. Some water retention is required for these species to overwinter. Many shorebirds use wetlands for feeding and migration stopovers, and those big charismatic birds of Trumpeter Swans and Sandhill Cranes benefit from habitats at Otter Creek Marsh and nearby vicinity.

Deer use wetland extensively. Fur bearing animals are also big time wetland users. These include otters, raccoons, mink, and muskrats.

If they can find food sources in wetlands, they will exploit all opportunities, and there are lots of small species of mammals like mice and voles finding food and cover to live in at wetlands. A huge variety of songbird species use wetland habitats as they migrate each spring and fall.

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The MANN WETLAND area located south of Albion is a wetland complex. It is owned by Marshall County and managed by the conservation board staff.

It is getting the first of several management mowings at this time. Mowing new prairie seedlings is essential to allow light to penetrate to newly emerging plants.

In 2023, a huge variety of native prairie grasses and forbs were winter frost seeded. Those seeds worked their way onto the soil surface over winter.

Germination happened the following spring of 2024. Mowings were conducted in 2024 to assist those plants getting sunlight.

During 2025, several mowings will be undertaken to let the new plants get the best boost possible. Mowings also cut off any tall weeds or unwanted grasses to remove the shade they created. Another reason to mow is to prevent unwanted plants from developing seeds.

Just like the Otter Creek Marsh management schemes, the Mann Wetland area needs vegetation management to encourage native prairie plant types. Mowing also prevents woody vegetation from gaining footholds where trees are not desired.

Time will allow the desired prairie species to maximize their influence on this landscape.

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If you want to see an upland prairie doing its natural grassland thing, do visit the Marietta Sand Prairie. It is located west of Albion about three miles away on Knapp Avenue.

That area began as the original 17-acre acquisition in 1987. In the early 2000s, the Howard Conrad farm was acquired to add to the prairie lands. A special wetland called a fen was part of this acquisition.

Native prairie seeds were winter frost seeded over a snow covered landscape. Those seedings were successful. As the prairie established itself, periodic controlled fire management was a tool in the tool box of conservation board staff.

A rotating portion of the Sand Prairie may get burned each year so that over a three to four year time frame, fire will be used on all segments. The process of fire management will then be repeated. Fire used wisely is a good thing.

To learn more about prairies, do come to the program on July 21 at the Conservation Center. This early notice will let you mark your calendar so that one month from now you will not miss it. Jim Kessler, a retired Iowa Valley Community College professor, will present on the topic of Why

Native Prairie Plantings Matter to all Life. Register for this free program by calling 641-752-5490 before July 16.

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For your Dad joke of the day: What side of wild turkey has the most feathers? Answer — the outside.

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Garry Brandenburg is the retired director of the Marshall County Conservation Board. He is a graduate of Iowa State University with a BS degree in Fish & Wildlife Biology.

Contact him at:

P.O. Box 96

Albion, IA 50005