When Wetlands Aren’t Wet

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Published on: Aug. 2, 2008

Last revision: Dec. 8, 2010

of millet, giant cut grass, sedges and rushes on Monopoly Marsh, providing more nesting and feeding areas for songbirds, shorebirds and herons. The improved plant diversity has even drawn least bitterns to the marsh.

“The drawdown promotes seed germination, and it helps the water become cleaner and clearer,” Wood said.

Suspended sediment becomes soil after a drawdown, and stays down even after water levels rise again. Freshly germinated marsh plants bloom quickly in the new soil and generate an abundance of seeds. These provide a feast for all swamp creatures, including invertebrates, which in turn become nutritious food for waterfowl.

Wood, who constantly tracks species diversity on Monopoly Marsh, noticed that American featherfoil showed up in the marsh following Monopoly’s drawdown in 2000. Featherfoil favors clear, cool water in swamps and marshes. Conditions must be right at Monopoly, for the dainty swamp plant’s numbers have been increasing for the past three years.

Bottoming Out

Flooded timber in October can make for a hunter’s delight in November. Hunting flooded timber is not a common opportunity in Missouri, but it can be habit-forming when you see the waterfowl banking through the trees toward well-placed decoys.

Waterfowl hunters have good memories of hunting the flooded timber of Duck Creek Conservation Area’s pools 2 and 3 and Mingo’s Pool 8, but the hunting is no longer as good as it was. During what were considered the “golden years” of the ’60s, ’70s and ’80s, heavy pin and willow oak acorn crops made for fabulous mallard hunting in the green tree reservoirs.

What attracts ducks to flooded timber are the small acorns produced by pin and willow oaks. They are the right size for ducks to swallow and are loaded with carbohydrates and fat, allowing waterfowl to replenish their energy stores during their southward migration.

To attract and hold ducks, and to increase hunting opportunities, these areas usually were flooded in mid-October. This was earlier than they would flood naturally, but early flooding ensured that these wetlands would be in optimal condition for ducks and hunters.

The strategy seemed to work well. The areas drew in lots of ducks, and waterfowlers had great hunting. In the 1990s, however, the larger oaks on the wetter sites began declining. Many large pin oaks died while others were unhealthy and produced few acorns.

Mike Anderson, a Conservation Department forester and an avid waterfowl hunter, said the problem arose because repetitive early flooding stressed the oaks and made them

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