The swollen Missouri River that promises to be a prolonged headache for small towns and farmers along its path is likely to be a boon for several protected and endangered species living in or near its basin, biologists say.
The piping plovers and interior least terns that lay eggs on the river's sandbars are likely to find more room to do so once the river recedes. The pallid sturgeon, a fish also classified as endangered, is likely to benefit from increased nutrients and organic matter carried and deposited by the high water, which mimics the Missouri's flow before it was dammed starting some 60 years ago, said Greg Pavelka, a U.S. Army Corps of Engineers wildlife biologist at Yankton, S.D.
It could leave behind a more natural habitat than the area's native species have seen in decades.
"The former function of the river is being restored in this one-year event," Pavelka said. "In the short term, it could be detrimental, but in the long term it could be very beneficial."
Flood concerns are high along the Missouri as massive amounts of water are released far upstream from dams along the river's length. Last month's heavy rains in the Northern Plains prompted corps to let water out faster, and heavy snowpack in the Rocky Mountains still must make its way down the river. Authorities are re-enforcing levees and evacuating some low-lying areas near the river from the South Dakota capital of Pierre to the Iowa-Missouri border, where crews dropped massive sandbags Monday to after several small breaches along earthen flood walls.
Wildlife near the river is coping with disruption, too.
A stretch of the river between Fort Peck, Mont., and Sioux City, Iowa, is designated as critical habitat for the plover and least tern, whose sand-colored eggs are tougher for predators to spot on sandbars. Yet most of that habitat is either under water or will be soon, said Kelly Crane, a corps biologist in Omaha, Neb.
Some piping plovers have been spotted building their nests on gravel boat ramp parking lots near the Garrison Dam, about 75 miles upstream of Bismarck. No nests have been detected this spring for the least tern.
The corps, which manages dams and reservoirs along the 2,341-mile river, has spent $40 million since 2004 building habitat for birds in the upper portion of the river because the reservoir system restricts the natural creation of sandbars, said Crane, who manages the corps' sandbar restoration project.
Crane said the sandbar work won't be wasted. The deep water and high river flows should deposit more sediment on the sandbars and expand them.
"We should come out of this with an increased amount of habitat on top of sandbars we've already created," she said.
Pavelka, manager of the corps' plover and tern monitoring program, said the birds rebounded after similar conditions in 1997.
"Both species go through boom-and-bust cycles and they have adapted to the Missouri River," he said. "They can have a bad year then come back and be productive."
Bald eagles are one species that might do worse during flooding, as the waters spread the fish and make it more difficult for the eagles to forage for food, Pavelka said.
The pallid sturgeon is among the many species of native fish expected to eventually do well after the flooding, said Tim Welker, a fish biologist with the corps in Yankton. The corps actually canceled a pair of "spring pulses" that were planned to raise water levels in the lower Missouri this year because the water already is high. The pulses are meant to replicate the natural spring rises of the river.
"High flows were a component of the natural Missouri River under which pallids and other native fish species evolved," he said.
But in the short term, sport fishermen are finding things tough along the river.
Dan Miller, owner of Carl's Bait Shop in Fort Pierre, S.D., said his business is suffering because boats aren't allowed on the river and fisherman have a tough time casting a line from shore. He fears the high water will hurt fishing for years.
"I'm no biologist, but I believe the walleye spawn has just been swept away," he said. He recalls high water in 1997 that "took us a dozen years to get it back in balance."
"We had just recovered and were getting cleanable panfish but now that's out," Miller said.