Migratory birds depend on this salt lake – but it is dying

Loch Abart is a rare and vital habitat for palaropes and avocets among other waders. As the salt water recedes, its salinity increases and the invertebrates that the birds eat cannot survive. It is one of many lakes in the USA that has had much of the water it feeds extracted. Photo: Tim Giraudier

The water level in Oregon’s remote, brackish Lake Abert dropped to unusually low levels in July 2013. As it did, the salt concentrations became too high even for the few species adapted to its salty waters. Six tiny brine shrimp and alkali flies died en masse. By September, so much water had been lost that the salts formed into a glistening white crust of triangular crystals.

Shorebirds reached 350,000 in July – a density higher than even found at the Great Salt Lake – but after the lake dried up and remained empty the following summer, bird numbers dropped by 90%.

In 2014, 2015, 2021 and 2022, the lake remained largely dry, and bird numbers declined. Last winter, an unusually wet season managed to replenish some of the lake’s water, but scientists warn that the overall trend is still declining and that the factors that dried up the lake are still there.

Most people have never heard of Loch Abert, but it is a vital stopover point for migratory birds that have adapted to live on saline inland waters. In the last ten years, however, it has dried up five times, prompting recriminations between conservationists and local farmers, who use water from the lake’s tributaries to irrigate their land.

Finally, in 2022, the two groups decided to work together, following in the footsteps of numerous conservation cooperative groups that have helped various stakeholders across Western North America find common ground on topics such as fire and species conservation.

Now, the partnership faces a new stress test: the fact that the climate-changing American west doesn’t have enough water to go around.

Terminal lakes or sinks such as Abert form at the lowest point of closed basins, which have no surface outlet. In the American west, there are only a few large and permanent terminal lakes, including Abert, the Great Salt Lake, Mono Lake and the Salton Sea.

These closed basin water systems are unusual because “you only get that one shot of water – what you see is what you have”, says Colleen Withers, a seventh-generation farmer in the basin.

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Most of the water that flows into Abert comes through the Chewaucan River. As it carries snowmelt across the valley’s steppe in the spring, farmers divert the river into canals and it floods grazing marshes where their cattle live during the winter and give birth to their young in the spring.

These irrigation systems date back to the early 1900s, but diversions have increased over time. If all the water abstraction rights on the Chewaucan were now fully used, they would exceed the flow of the river. Climate change has also increased evaporation from the river and lake.

This is of concern to conservationists and scientists because of its implications for shorebirds such as Wilson’s falcon and American avocets that have adapted over time to live around saline lakes, learning to feed in ways that minimize their -salt intake and develop specialized glands above their eyes to excrete. salt.

The abundant invertebrates attract them to salt lakes – since there are no other fish or birds to eat the flies and shrimp, they are abundant and “just dead easy to eat”, in the words of Theo Dreher, president of Lakes Oregon . Association. While at Abert, the birds cry and double their body weight before their arduous flight south – all the way to Argentina, in the case of the paleope.

However, when such lakes lose water and their salinity increases, the invertebrates cannot survive and there is not enough food for the needs of the birds. They are so specialized that they cannot live anywhere else, and since around 10% of the total population of these shorebirds pass through Abert, the lake’s decline could have a huge impact on the species.

“They’re on a razor’s edge in terms of their physiological ability to survive — they’re so dependent on these shallow saline lakes,” says Ron Larson, a retired scientist and member of the Oregon Lakes Association.

“We don’t want to get into a situation where the population gets so low that they can’t recover.”

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Farmers and landowners have formed the Chewaucan Watershed Collaborative, so they, too, can join the debate about the lake’s decline. The farmers emphasize the need to consider the Abert watershed as a whole.

For example, areas of the Fremont-Winema national forest, through which the Chewaucan River flows, burned in the 2021 fire due to long-term drought conditions. “Abert is at the end of the system, and the whole system is affected,” says Tess Baker, a fourth-generation farmer in the basin.

Baker, Withers, Dreher and their spouses met in May 2022 to discuss collaboration. “We found from those initial meetings that it was easy to talk,” says Dreher.

They enlisted the support of Oregon Consensus, an institution that sponsors complex conflict resolution, and spent the summer bringing together environmental groups, government agencies and local tribes to form the Partnership for Lake Abert and the Chewaucan.

After the group members identified their points of disagreement, they realized that they lacked sufficient facts, so they commissioned six months of research gathering scientific data, traditional tribal ecological knowledge, and the experiences of the farmers.

One of the main differences relates to the farmers’ water diversion. Ranchers argue that their flood irrigation mimics the way the marshes functioned before the land was settled and drained in the late 1800s.

They say the marshes have a huge biodiversity of grasses – more than 50 species – and attract birds such as sandhill cranes, geese and black-necked stilts. “There’s a symbiotic relationship between wildlife and ranching,” says Keith Baker, Tess’s husband.

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Conservation organizations and the Oregon state department of fish and wildlife supported the development of that flood irrigation in the 1980s. But Dreher disputes the claim that the practice mimics the natural hydrology of the marshes, and says that such water use should be reconsidered now that the impact of increased heat and water scarcity in the west is now more visible.

“At the time, it looked like there was enough water to go around the lake and this type of irrigation,” he says. “And the thing is, that’s not the case anymore.”

Conservationists and other scientists agree that Abert’s unique ecological function should be prioritized over marsh ecosystems found elsewhere. “All the birds are important, and they all have their needs,” says Ryan Carle, scientific director of Oikonos Ecosystem Knowledge.

But for some shorebirds, he says, Loch Abert is “the only habitat that provides what they need. Whereas if you have flood-irrigated habitat in the basin for ducks, it’s important, but there are other habitats that ducks use as well.”

Wilson Wewa, of the Warm Springs Paiute Tribe, believes ranchers have a responsibility to use less water. “The water is infinite and the spell is overused [Abert],” he says. “The land has a voice too, and the lakes too, and no one is listening to them.”

Elsewhere, two main solutions have been used to conserve lakes. In California, lawmakers invoking the public trust doctrine — which states that states have a responsibility to protect water bodies within their borders in the public interest — mandated a minimum water level for Mono Lake. In September 2023, environmental groups in Utah announced such a lawsuit for the Great Salt Lake.

Another option is to set minimum flow requirements, which would require a specified amount of Chewaucan flow to reach Abert.

So far, the members of the partnership say that they do not have a specific goal, but that they hope that the collaborative process will lead to a solution. “We want water in Abert,” says Keith Baker, “because it means the whole system is happy.”