Flood Effects Are A Mixed Bag For Wildlife
Unusually wet weather has been a bane to some animals and a boon to others.
Those are the broad outlines of reports from Missouri Department of Conservation biologists around the state. They say the effects of heavy rains, swollen rivers and bank-full lakes are a mixed bag for fish and wildlife. They also report that conservation areas (CAs) took a hit, and hunting opportunities will be curtailed at some areas as a result.
Missouri’s average annual precipitation ranges from approximately 35 inches in the state’s northwest corner to about 48 inches in southeastern Missouri. As of Aug. 31, St. Joseph had recorded a fairly normal 26 inches of precipitation, according to the Missouri Agricultural Weather Database. However, Knox County in northeastern Missouri recorded nearly 42 inches of precipitation during that period, and Cape Girardeau County got 48 inches, its full annual allotment in the first two-thirds of the year.
Equally important for wildlife is the way this year’s rain has fallen. In Knox County, 19.5 inches (47 percent) of the precipitation that fell from January through August came in 10 cloudbursts of 1 inch or more. The biggest deluges occurred June 24 through 26 (6.44 inches) and July 24 and 25 (4.83 inches). Eight to 10 inches of rain fell on southeast Missouri in less than 24 hours in March and was followed by more torrential rains a week later.
Resource Scientists Tom Dailey and Beth Cole monitor quail, pheasant and wild turkey populations in Missouri. They say these three species and other ground-nesting wildlife are strongly affected by unusually wet weather.
“The most dramatic effect is drowning of nests and young animals,” said Dailey. “We certainly have seen the potential for that this year, but wet weather has other, more subtle effects – especially when coupled with below-normal temperatures.”
Dailey said young birds remain vulnerable to chilling for several weeks after hatching. Until then their feathers are not fully developed to shed rain and provide insulation.
Quail, turkeys and pheasants whose early nest attempts fail often try again. However, the continuation of wet weather throughout the summer made subsequent nest attempts less productive than normal. Dailey said this fact is borne out by early results of turkey brood surveys conducted from June through August.
“Data from August are still coming in,” Dailey said, “but it doesn’t look good so far. I think it is likely that turkey production will be disappointing again this year.”
He said last year’s turkey production was the second-worst on record, largely due to a freak freeze that occurred after hens had started laying eggs. This year’s limiting factors were flooding and rain.
“The worst year for turkey brood production was 1961,” said Dailey. “We recorded an average brood size of .8 poults per hen that year. Last year we recorded 1 poult per hen. It looks like this year will be at or below 1 poult per hen this year.”
Every coin has two sides, and rainy weather is not without advantages for wildlife. Dailey noted that wet conditions caused extensive delays in haying activity, and this gave young animals from deer to quail a longer-than-normal window of opportunity to grow large enough to escape the danger posed by mowers. Also, weeds and grass are common in fields where row crops failed, possibly supplying food and cover for wildlife.
Birds were not the only wildlife that suffered. Flood conditions persisted for months along the Mississippi River Valley in southeast Missouri, hitting deer with a double whammy. Rising water drowned fawns and pushed adult deer out of low-lying areas, crowding them together in limited upland habitat. The displaced deer suffered disproportionately from conflicts with resident deer and collisions with cars.
In one month, Conservation Agent Kyle Booth saw 16 deer in Pemiscot County that died of drowning, vehicle strikes or injuries crossing fences. He also reported seeing a video of 172 deer stranded on a small portion of levee and a group of turkeys huddled on a patch of dry ground within a few yards of a coyote The predator, apparently gorged to capacity on wildlife fleeing flood waters, was not bothering the turkeys.
Besides those immediate effects, flooding also destroyed much of the vegetative cover needed by deer and turkeys in low-lying areas, and substantially reduced this year’s crop of acorns and other staple foods. On the other hand, all the rain has led to an abundance of soft mast and hard mast in areas that were not flooded.
When 8 inches of rain fell on southeastern Missouri in less than 24 hours in March, followed by more torrential rains a week later, the Conservation Department was forced to close 11 areas during Missouri’s spring youth turkey hunting season. Those areas were open during the regular spring turkey season, but hunters in the Mississippi River flood plain will find worse hunting overall this fall as a result of flooding. The effects will be erratic, with very little game in low areas and more than usual in upland refuges.
The managed deer hunt at Clarence Cannon National Wildlife Refuge in Pike County has been cancelled. The refuge, along with much of the surrounding land, is one big mud flat, with little chance that much vegetation will grow before fall. The situation was similar at B.K. Leach CA in Lincoln County, and persistent flooding at Ted Shanks CA in Pike County killed an undetermined number of trees planted to replace mature trees that died when the Great Flood of 1993 covered the area.
Damage persisted into September, as torrential rains from the remnants of Hurricane Gustav caused rising rivers to re-flood hunting areas whose levees were breached by earlier crests.
Managed deer and waterfowl hunts still will take place on most public areas, but conditions are likely to be less than ideal at many. Duck habitat and hunting are likely to be severely affected. Flooding prevented planting and cultivation of crops on many public wetland areas. Water levels also prevented growth of native weeds, which normally produce food for waterfowl on land not planted with corn or other crops. Without food to eat, migrating waterfowl will be less likely to linger on these areas.
Wetland areas on the western side of the state avoided these woes, but these, ironically, may have limited capacity to flood wetland pools due to dry weather. Montrose CA in Henry County is one such area. In mid-August Montrose Lake was about 6 feet low and falling fast. Rain from Hurricane Gustav helped, but the area needs more rain for maximum waterfowl habitat.
Flooding caused extensive damage to recreational facilities, also. Soulard Access on the Fabius River in Marion County was closed for some time due to downed trees on the entrance road. Workers are still trying to determine whether flood waters washed away the concrete boat ramp at Fenway Landing Access on the Mississippi River in Lewis County or simply smothered it under tons of boulders, gravel, sand and mud. The area’s concrete privy washed away, and like many flood-damaged CAs, Soulard Access might not reopen until next year.
If all that is discouraging, consider fisheries biologists’ perspective on this year’s floods. They say the strongest year classes of bass, bluegill, crappie and a whole array of non-game fish occurred in 1993. They say this year’s floods likely will produce a similar effect. Floods also deliver a bounty of foods and nutrients needed by the plants and animals that fish eat.
“During this spring’s fish sampling, one of our biologists commented that there were already a lot of juvenile catfish out there from last year,” said Fisheries Management Biologist Travis Moore. “The flood waters of ’08 would have exposed them to a tremendous amount of food, helping their growth. Although we have not sampled them lately, I’m sure they are little footballs.”
Flooded vegetation is spawning structure for fish, and such spawning habitat was abundant in large reservoirs around the state this year. The water level in lakes managed by the U.S. Army Corps of Engineers rose dramatically this spring, covering thousands of acres where vegetation had grown in recent dry years.
High water can be a mixed blessing, too, however. If lake levels fall after fish lay eggs, their offspring can be stranded. But this year’s wet summer has kept water in large areas that normally would be dry. Concrete information about the effect of spring floods on fish populations won’t emerge until fisheries biologists begin fall sampling, but they are guardedly optimistic about the long-term effects on fishing
The scouring action of floods creates deep holes and increase the diversity of habitat types available for fish’s different life stages. Those same areas benefit turtles, frogs, fur-bearing mammals, migratory birds, fresh-water mussels and other wildlife.
Sometimes you can have too much of a good thing, however. Heavy rainfall in late July filled up Mark Twain Lake so fast that the Corps of Engineers was forced to release water into the lower Salt River in Ralls County at a rate of 58,000 cubic feet per second. For comparison, that is about as much water as the Missouri River’s normal flow at that time of year. The normally placid river became a raging torrent unsafe for boating, and the river was closed to traffic. Fisheries biologists are waiting to learn how the unprecedented event might have affected the lower river’s thriving smallmouth bass population.
Although heavy rains disrupt human activities, biologists say that periodic floods are part of dynamic ecological processes. Short-term dislocations can be distressing to people who love plants, animals and wild places, but floods play an important role in maintaining healthy biological systems.