Great Salt Lake brine flies are in crisis mode. What does it mean for birds?

As Great Salt Lake continues to shrink to unprecedented levels, a key component of its landscape and food chain is missing.

The lake is known for billions of thick, black clusters of brine flies, which pupate in its salt water and then gather in thick mats to breed on the shore. The masses of insects occasionally bother swimmers, but the insects are harmless to humans. Basically, they provide a nutrient-rich feast for millions of migratory birds. This year, however, the swarms of flies have disappeared. And something is wrong with the few bugs that remain.

Scientists say it’s a sign that the lake’s ecological end is here.

“We no longer have clouds of flies around our ankles,” said biology professor Bonnie Baxter, who directs Westminster College’s Great Salt Lake Institute to a group of lake researchers and experts late last month. “Flies are not well. They are small. They are behaving strangely. “

Brine flies and brine shrimp are the most unique and charismatic endemic creatures of salt lakes. Each year they attract more than 10 million migratory coastal and water birds to Great Salt Lake, from phalaropes to ducks, from seagulls to avocets. Now, the flies’ food web has all but disappeared and things aren’t going well for the shrimp either.

“It’s not like we have a thousand different food chains,” Baxter said in an interview. “There are two with these two keystone species.”

And all the indicators point to food chains collapsing, Baxter said.

A crisis situation

He recently contacted one of the nation’s top salt fly researchers, biologist David Herbst, to conduct a field survey of the lake and help Westminster College develop a program to better monitor flies. Herbst is affiliated with the University of California Sierra Nevada Aquatic Research Laboratory.

He conducted research on saline lakes throughout the Great Basin, contributing to some of the first studies that shed light on the impending disaster that Mono Lake faced in the 1970s.

[Read more: Five things to know about Mono Lake — and how it compares to the Great Salt Lake]

“Even if he’s in a crisis situation,” Herbst said in an interview about his visit to Great Salt Lake, “it’s really that good people are starting to pay attention.”

Biologist David Herbst, left, Westminster College student Cora Rasmuson, and Great Salt Lake Institute coordinator Carly Biedul conduct field research on brine fly populations on October 25, 2022.

Brine flies are facing stressors from multiple fronts, Herbst explained. Flies need a bedrock to attach themselves underwater as they transform from pupae to adults. At Mono Lake they stick to the tuff. At Great Salt Lake, they use rock structures formed from bacterial mats called microbialites.

But many of the lake’s microbialites emerged, killing the microorganisms that form them along with food for the flies. And the structures that remain underwater are still too close to the surface, causing the action of the waves to release the young insects. On their trip last month in search of the once generous salty flies, Baxter and Herbst found only half a dozen adults.

“I would expect to see a much greater abundance of adult flies and pupae” in the lake at this time of year, Herbst said, adding that his impression of the ecosystem is “that it has suffered great losses.”

(Photo courtesy of Westminster College) Scientists and students search for brine flies in a microbialite field exposed at Great Salt Lake on October 25, 2022. Microbialites support brine flies, which in turn feed millions of migratory birds each year at Great Salt Lake Salt Lake, but that food web is collapsing due to low water levels and increased salinity.

The lake has lost so much water – and concentrated so much of its salts – that even insects have a hard time regulating blood salinity levels. This leads to smaller adults, which lay fewer eggs.

“In conclusion, from my observations,” Herbst said, “… they seem to survive but not thrive.”

‘We have reached that point. We are seeing impacts. ‘

The Utah Division of Wildlife has a lot of data on Great Salt Lake Brine Shrimp because it has a viable shrimp harvesting industry that pays for research. But much less is known about salt lake flies, admitted John Luft, program director of DWR’s Great Salt Lake Ecosystem.

“It’s not something we actively harvest like we did brine shrimp,” said Luft, “as commercial fisheries are the main source of income and funding for our program.”

In his regular field survey across the lake, however, Luft said one thing is obvious: “We have seen a significant decrease in brine fly populations.”

(Francisco Kjolseth | The Salt Lake Tribune) A close-up view reveals the bacterial composition of the rock structures found along the banks of the Great Salt Lake known as microbialites, stained with brine larvae in 2015.

This is concerning because while many birds depend on lake brine shrimp for survival, including 5 million eared grebes, many more flocks rely on flies. The common golden eye dives down the water column and devours any pupae attached to the microbialitic structures. Phalaropes collect insects that float to the surface. The seagulls cross the beaches, their mouths open wide and insinuate themselves into the throng of adults that cover the coast.

And with all those flies gone, it’s clear the birds will starve.

“I don’t know if I want everyone to think that once we get over this cliff there will be no recovery,” said Luft, “but I think we have reached that point. We are seeing impacts.”

But the collapse wasn’t sudden or surprising – scientists like Luft and Baxter warned it long before the lake hit its current all-time low.

“First is the [loss of] habitat, and we have noticed this for years due to lack of water, ”Luft said. “Then the next thing was the loss of microbialites. The next thing would be the brine. We are seeing it. I too have seen the number of birds decrease. “

The brine shrimp are the last harbinger of the ecological disappearance of the lake. And while commercial shrimp fishermen are seeing an average harvest this season, Luft said the resource may not make it another year unless something changes.

“Adults are now struggling” for high salinity, Luft said. “They are not producing.”

Is Great Salt Lake Unrecoverable?

Utah lawmakers have made great strides in recent years to help the endangered lake. During the last general session, they set aside $ 40 million to improve habitat and ensure more water for Great Salt Lake, which would be 11 feet higher were it not for human consumption of water according to research sponsored by the state. Last month, House Speaker Brad Wilson announced that two water districts would send 30,000 acre feet into the lake by the end of the year.

In the end, it’s a drop in the bucket: Great Salt Lake needs about 2 million acre feet to reach a sustainable level.

But all the political discussions about the lake and efforts to ensure its survival signal a major change of tone, Luft noted.

“A decade ago, when I complained that people had to pay attention to this,” he said, “they would blow me away.”

(Scott Sommerdorf | The Salt Lake Tribune) Cup-collected brine shrimp are suspended above Great Salt Lake walking tour participants as they wade into the shallow lake waters examining shrimp in 2012.

Herbst’s experience has shown that even when salt lake systems shrink to catastrophic levels, they can recover. She pointed to Lake Owens in California, which was drained into unhealthy dust when the city of Los Angeles diverted its tributaries.

Although often referred to as a warning by Great Salt Lake advocates, and sometimes referred to as a “dead lake,” Herbst noted that this is not the case: brine flies and birds survived on the fringes of Owens Lake, thanks to seepage and sources. And when Los Angeles began rehabilitating the environmental disaster, flooding it with water again, the shrimp, insects and birds returned.

[Read more: Struggling salty lakes can bounce back. Just add water.]

“The message of hope is that we can restore these places, we can restore these places,” Herbst said. “I’m not a lost cause.”

But some proponents of the lake worry about what may be lost as the lake resurrects. Lynn de Freitas, executive director of FRIENDS of Great Salt Lake, likened him to neglecting his own health until he suffers a heart attack.

(Francisco Kjolseth | The Salt Lake Tribune) The Great Salt Lake Marina near Saltair is rendered unusable for all boats as ongoing drought conditions continue to drop lake levels on Tuesday, October 18, 2022.

“Denial is easy,” de Freitas said. “But the result is tragic”.

He expressed exasperation at the lake’s mining industries seeking approval to extend the canals and draw more water from the lake, even though it appears to be a hemorrhage. And if Utah’s policymakers and water users can find a way to resurrect the lake, it now faces serious consequences, including endangered species lists and toxic dust storms.

“To what extent have you lost a lot of important muscle tissue in your heart because you waited,” said de Freitas, “because you didn’t pay attention to the signs that were informing you that something was wrong?”

Baxter, who studies the microorganisms that form the basis of the lake’s ecology, said laboratory studies show that microbialites can bounce as long as they are not “too long” without water, which means that flies and shrimp could also bounce. bounce.

“This assumes we can get water to the lake in a short period of time,” Baxter said. “I’m optimistic, but moving the water into the lake isn’t something scientists can do.”

This article is published via The Great Salt Lake Collaborative: A Solutions Journalism Initiative, a partnership of news, education, and media organizations that aims to educate readers about Great Salt Lake.


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