‘It was just too dry.’ Summer drought’s impact on fish, wildlife can be dramatic

DULUTH — The first clue that the drought of 2021 was getting serious was when the big paper birch tree in our front yard started shedding yellow leaves. In June. The second hint came when the July blueberries around our campsite on Rainy Lake were shriveled, like miniature raisins, too dry and tiny to eat. […]

‘It was just too dry.’ Summer drought’s impact on fish, wildlife can be dramatic

DULUTH — The first clue that the drought of 2021 was getting serious was when the big paper birch tree in our front yard started shedding yellow leaves. In June.

The second hint came when the July blueberries around our campsite on Rainy Lake were shriveled, like miniature raisins, too dry and tiny to eat.

The third sign came in mid-August when the Lester River simply stopped flowing into Lake Superior.

Then it hit home: Northern Minnesota’s drought of 2021 is bad, the worst so far this century, and in some areas approaching 1976 as the worst on record.

While there are signs the long-term dry-weather pattern may be changing, it will take weeks of above-normal rainfall — and a winter of normal snowfall — just to catch up. Meanwhile, the drought’s impacts on outdoor recreation and on fish, wildlife, forests and nature have been profound. And some of those impacts will last well into the future, even after the rains return.

Bears are scrambling for food and may have fewer cubs this winter. Fish are stranded in pools along rivers that no longer flow, some unable to make fall spawning runs. Boat landings on some lakes and rivers have been rendered unusable because the water level is so low. Campfires, a staple of summer life, are banned across the region. Both the Boundary Waters Canoe Area Wilderness and Quetico Provincial Park are closed; too many fires burning make them unsafe for canoe travel. The BWCAW hasn’t closed like this since 1976.

Across Minnesota as a whole, the 2021 drought has inched into the top 10. But in the far north, the situation is much dryer.

In far northern Minnesota, the summer rainfall deficits at mid-August were the worst ever. Both Koochiching and Lake of the Woods counties had their lowest rainfall amounts on record, according to the Lake of the Woods Control Board.

International Falls has had the driest summer on record, according to data from the National Weather Service — just 3.8 inches of rain as of Aug. 24, when nearly 10 inches would be normal. Virtually all of northern Minnesota is at least 4 to 6 inches short of normal rainfall this summer, considered a moderate or severe drought. But some areas in the north, including Duluth, have been 6 to 8 inches short, approaching an extreme drought. And there have been some areas with 8- to 12-inch deficits, the worst classification at “exceptional” drought.

“Most places have seen only half or even less of their average rainfall thus far this summer,” said Joshua Sandstrom, a meteorologist with the National Weather Service in Duluth. “And that is a pretty significant deficit.”

FISH OUT OF WATER

Perhaps hardest-hit in the Northland are fish in streams, especially trout, many of which are now hanging on in disconnected pools in streams that had little or no flow for weeks on end.

The North Shore’s Knife River, for example, is usually running at a low but steady 70 cubic feet per second in mid-August. This year, it was flowing at just 2.6 feet per second, less than 5 percent of its usual flow at that time of year. The St. Louis River was flowing at just 10 percent of its normal August water, not good for its walleye and smallmouth bass.

“That’s a pretty stark reality for a fish trying to make it in those rivers. They lost 90 or 95 (percent) or more of their habitat,” said Deserae Hendrickson, Duluth-area fisheries manager for the Minnesota Department of Natural Resources. “For many of our trout streams, they’re just pools of water separated by rifles that aren’t flowing. There might be some sub-surface water flowing in some of them, but not much.”

Brook trout like this one may be among the hardest hit by the drought of 2021, with many of their streams seeing vastly reduced flows or no flow at all. Many stream trout may not be able to get to their normal fall spawning areas. And more may perish if shallow streams freeze to the bottom this winter. (Sam Cook / Forum News Service file)

While some southern Minnesota trout streams and even Wisconsin’s Brule River have cold-water springs providing a constant flow, northern Minnesota’s streams are mostly dependent on rainfall. The fish can hang on as long as they have some water that’s cool enough to hold oxygen, which makes tree cover critical to keep the streams shaded.

But with so many hot days this summer (2021 so far is the hottest summer on record in Duluth), it’s likely many fish have perished. It’s most serious for brown and brook trout, which spawn in the fall, Hendrickson noted. Not only will individual fish perish but many won’t be able to reach their spawning beds to propagate another generation.

“They’re not going to get there this year unless some serious rainfall comes fast,” Hendrickson added. “It was just too dry.”

The situation is so dire that the DNR called off many of its usual fish population surveys for fear they might stress the remaining fish too much. And now winter freeze-out becomes a bigger threat.

“There will be pockets of fish that survive the drought this summer. But, especially if this continues into fall and winter, I’m worried about a big winter-kill problem,” Hendrickson said, noting shallow streams can freeze hard to the bottom, leaving no water for fish to survive. “This drought is going to have a long-term impact on fish populations wherever that happens.”

Most Northland lakes are deep enough to avoid major drought issues with fish finding refuge in deeper, well-oxygenated pools. But with water levels down a couple feet or more, that leaves less water in shallow lakes. Combined with heavy snow cover on the ice this winter, that could lead to winter kill with fish deprived of oxygen, Hendrickson noted.

UNBEARABLE BERRY SHORTAGE

“The most noticeable difference this year for me was the almost complete absence of blueberries. The rock ridges where berries typically grow just looked scorched starting in June,” said Thomas Gable, a wildlife biologist studying wolves in Voyageurs National Park. Now “these ridges just look like they have been slowly baked in a drying oven.”

For the second straight year, bears have been in trouble with people all summer, pushed to scrounge for food wherever they can find it — at cabins, campgrounds and dumpster sites — because their normal berry and nut crop is almost nonexistent in many areas. The first problem actually hit in late May, said Tom Rusch, Tower-area wildlife manager for the Minnesota Department of Natural Resources. That’s when a hard freeze hit many areas, nipping many plants that never recovered. Since then, plants that survived the freeze never got enough rainfall to produce much fruit.

Now, some bears aren’t just hungry but downright unhealthy. Bears mate in early summer but have a biological phenomenon called delayed implantation. Sows that aren’t getting enough food now won’t get pregnant, producing no cubs over the winter, no new generation of bears in 2022.

Severe drought this summer has sent many bears looking for food and getting into trouble, like this one in Duluth. But the lack of wild food may have longer-term impacts as well. Sows in poor health will produce fewer or no cubs over winter, meaning fewer bears in the woods next year and for years to come. In some areas this may be the second straight year of poor reproduction.(Clint Austin / Forum News Service files)

The lack of natural food in the woods, for the second straight summer, should mean another high success year for bear hunters who use food for bait to lure bears into range. But that also can be a problem. When too many hungry sows are shot — studies show sows are more vulnerable during low-food years — then the population can see longer-term declines. Hunting is by far the leading cause of bear mortality in Minnesota.

Mast crops, such as corns and other wild nuts, also are way down this year, forcing bears (and deer and other animals) to find new food sources. In some cases, bears will migrate many miles to find better food.

“The acorn crop is pretty bad. Maybe 10 percent of a good year. In some areas, there aren’t any at all,” said Beau Liddell, DNR wildlife manager in Little Falls, Minn.

The one exception is where bears can find corn, which is now grown farther north into bear country than ever before. Corn makes a great, high-calorie food for bears, but it also gets them in trouble with farmers, and may even be encouraging bears to migrate south this time of year, spurring higher bear mortality on roadways, Liddell noted.

NO BERRIES TO WOLF DOWN

Gable, whose research was the first to show how much wolves depend on berries in the Voyageurs region, said some of the big canines usually spend several weeks each summer eating mostly blueberries.

But not this year.

“This is a pretty big change because typically wolves are spending a substantial portion of this July-to-August period foraging for berries,” Gable said. “It’s possible the lack of berries could provide stress on wolf pups, which are usually consuming quite a few berries. But whether this will have any impact on pup survival is unknown.”

MUTED FALL COLORS, TREES DYING

Experts say severe drought will likely mute this autumn’s color show across parts of northern Minnesota forests. The leaves of many trees may skip the bright-color phase, turn brown and shrivel up. Some aspen, birch and balm of Gilead already have done that, starting their fall shutdown more than six weeks earlier than normal, part of the tree’s defense mechanism against dehydration.

Val Cervenka, forest health specialist for the Minnesota DNR’s Division of Forestry, said most trees will survive the initial shock of drought. But that shock makes them vulnerable to other problems.

Many leaves around the region, like these seen Tuesday, Aug. 24, 2021, have already turned colors because of stress caused by the drought.(Steve Kuchera / Forum News Service)

“Some impacts, beyond a dull fall color season in most of the state, won’t be realized for a few years,” Cervenka said. “But this kind of drought can weaken young trees and increase the stress on trees already stressed, and they will become vulnerable to insects and disease.”

That’s already happening to oak trees in many areas. Stressed by drought, the oaks are falling prey to the two-lined chestnut beetle, a native wood-boring insect related to emerald ash borer. Oaks can usually withstand the beetle, but during the drought “the beetles can bring down a tree in a matter of a few years,” Cervenka said.

If the drought lasts into 2022, some trees will simply die from lack of water, Cervenka noted.

FEWER FROGS, NO MUSHROOMS

Naturalist Larry Weber of Wrenshall, Minn., noticed that small woodland ponds dried up fast this year. And that led to fewer frogs and other amphibians in the woods, especially where they couldn’t get to larger bodies of water.

“I think some of the frogs did suffer,” Weber said.

Now, Weber is noticing that something is missing on his usual August walks.

“The August woods at this time is usually full of mushrooms. On a recent walk, I saw none,” he said.

FEWER WATERFOWL PRODUCED, MAY SEE MORE

While most animals can simply move on to find water to drink, animals that nest and live in water have had a tough season.

“There are some species, like western grebes, when we only have a few hundred total, that if they lose a nesting year and just move on, that may be it for them in Minnesota,” Liddell said. “When a species is already scarce, maybe one severe drought can be the last straw.”

Biologists are predicting greatly diminished summer waterfowl production with so many wetlands simply dried up and waterfowl broods much smaller. Some ducks may have given up on nesting altogether, instead flying longer distances north to find summer water to save themselves.

Ironically, with the prairie nesting areas so dry, waterfowl hunters may see more western birds flying south through Minnesota where large lakes always have some water. That happened in 1988, Liddell noted, a bad year for duck production but a pretty good year for duck hunters.

NOT ALL BAD

While droughts reduce duck numbers in the short run, a dry year can be a good thing in the longer-term, rejuvenating small wetlands so they can produce more ducks and grebes and geese in the future.

“The upside is that periodic drying of wetlands is beneficial in providing oxygen to promote decay of vegetation and sediment and thus releasing nutrients making them available for use by plants and animals,” said Greg Kessler, Wisconsin DNR wildlife manager in Brule. “This process makes these wetlands more productive for plants and animals in the future. This is a natural and desirable process, but not always easy to accept in the short term.”

TURKEYS, GROUSE DOING JUST FINE

Just about everyone who spent a lot of time in the woods this summer is reporting seeing lots of wild turkeys — more and bigger broods — as a warm, dry summer made for perfect weather for poults (chicks) to survive. The same holds for ruffed grouse. The dry weather was conducive for grasshoppers, Kessler noted, which young upland birds love to eat to get big fast.

NEAT HOW NATURE ADAPTS

Bill Berg, a retired Minnesota DNR wildlife biologist who spent much of his career in the Grand Rapids area, said the 1976 drought — the worst in northern Minnesota that anyone alive can remember — hit hard in the fall, with such dry conditions and so many wildfires that the DNR postponed the firearms deer season until Thanksgiving week to keep hunters from starting accidental fires.

Berg was part of a team that, when they weren’t out fighting wildfires, surveyed the impacts of drought on beavers, flying over beaver dams that had entirely dried up. The DNR canceled the 1976-77 beaver trapping season for fear the population might be in danger due to the utter lack of beaver ponds.

But Berg said nature has a way of coping and that, as much of a crisis as it might be for a beaver to lose its pond and its lodge, they somehow persevered. So did most other critters.

“We’d see otter tracks and beaver tracks going for miles out from those dry ponds. It’s amazing how far they would go to find some water they could use,” Berg said. “I’m sure the predators had a feast, the wolves and coyotes, getting those beaver out of water where they are vulnerable. But, you know, we did surveys the next year and the (beaver) population really hadn’t changed much at all because of the drought. Those beaver managed to find water somewhere. It’s pretty neat how nature adapts.”