Science

This ultra-rare plant that only grows on Adak is getting new attention

The federal government has announced a review of the status of the tiny Aleutian shield fern, which barely survives between the rocks and hard places of Adak Island and is the only plant in Alaska on the endangered species list.

Because of its remote habitat on Adak's Mount Reed, the fern also is generally free of threats from human activity, though animals introduced by humans — caribou and Norway rats — are two of its biggest challenges. The fern itself has resisted cultivation efforts.

Adak is about 1,200 miles southwest of Anchorage and part of the sprawling Alaska Maritime National Wildlife Refuge, which puts the U.S. Fish and Wildlife Service in charge of safeguarding its ecosystem. The fern was listed as endangered in 1988 and is exceedingly rare — the 142 clumps growing in the moist, rocky recesses of Mount Reed are the only sites where the plant has been found.

The plant is small, growing to just about 6 inches long, with delicate leaves fanned out from a stem that is brown at the base.

"It's a beautiful little fern," said Sandra Talbot, a U.S. Geological Survey geneticist and one of only a handful of people who have actually seen the plant in its Adak habitat.

Years of attempts to find it elsewhere have been fruitless, as have attempts in laboratories and greenhouses to cultivate it and spread it elsewhere.

The Fish and Wildlife Service review is in accordance with the Endangered Species Act and is designed to try to collect any additional information about the plant's status and future prospects. Comments are being accepted through Sept. 12. Such reviews are generally done every five years, though the last one was launched in 2005.

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There has not been much news about the fern to report in the last 12 years.

The Aleutian shield fern was first documented in 1932 by a botanist who found it on Atka. Despite scientists' many searches, the fern has not been seen there since — or on any Aleutian islands other than Adak, and nowhere on Adak other than Mount Reed.

The 142 known clumps on that rugged mountain are spaced out in four groups at elevations of about 1,100 feet and above.

The initial Adak discovery was in 1975. In the 1980s, Steve Talbot, a Fish and Wildlife Service botanist and Sandra Talbot's husband, began periodic searches for more, and he found the second Adak group in 1988. Sandra joined in the project later, and she and her husband found the rest of the known Aleutian shield ferns.

That last discovery was in 1999, made when they got lost in the fog, a disorienting few moments, Sandra Talbot said.

"It was a weird experience to think you know where you are," she said.

They wound up at a near-vertical spot, much more precarious than the other places where they went on the rugged mountain, and came upon what is now the fourth clump of Aleutian shield ferns.

As with any endangered species, the Aleutian shield fern faces some threats to its continued existence.

The main threat is the product of a quirk of history associated with Adak's military past. The isolated island was, for decades, a Cold War-era U.S. Navy air station housing thousands of personnel and family members, and, before that, a World War II military station. In the 1950s, federal officials put a herd of caribou on the island, intending it as a source of meat for military personnel in that outpost. The caribou multiplied and now roam the island, grazing on plants and walking over trails traced through the tundra by their ancestors.

Refuge managers have long worried that they might munch or trample the Aleutian shield fern. Hunts are strongly encouraged as a way to keep the population in check, but few hunters can afford the steep price of travel to Adak.

Finding out how much of a threat the free-ranging caribou pose was the point of a 2011 project that placed time-lapse and motion-sensor cameras on Mount Reed. The project captured some images of caribou tracks near the ferns — plus some images of caribou themselves, including a few close-up face shots of startled-looking animals. It also captured an unnerving image: the tail of a Norway rat zipping by the rare ferns. Rats are invasive in Alaska and have devastated ecosystems in the Aleutians and on islands around the world, so their proximity to the Aleutian shield ferns is potentially worrisome.

"Rats are the ultimate generalists and will eat pretty much anything, and even the steepest terrain presents no obstacles at all," Lisa Spitler, the Adak-based Fish and Wildlife Service technician who conducted the project, said in her 2012 report on it.

Another potential threat is rock slides or some other form of site disturbance, always a possibility in the Aleutians, a region notorious for its frequent earthquakes and volcanic eruptions. If all Aleutian shield ferns are indeed on Mount Reed, they are all vulnerable to catastrophe, Fish and Wildlife Service biologists have warned.

What does not seem to be much of a threat is human disturbance.

Even for the 330 or so hardy souls who now dwell on Adak, the nation's westernmost municipality, Mount Reed is out of the way. It is not accessible from the island's road system, and is off-limits to walkabouts because it sits above the town's water supply, said Adak City Manager Layton Lockett.

He has never seen the ferns "in person," and doubts that many people other than scientists have gone to the Mount Reed sites in the past, he said in an email. The area is a bit too treacherous for casual visits, anyway, he said.

"It might be a different situation if they were in an area that was not so high in elevation," he said in the email. "However maybe that's what helps with their survival."

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Jeff Williams, assistant manager of the Alaska National Wildlife Refuge, concurs.

"We're not really worried about people trampling on it," said Williams, a biologist who is among the select group of Aleutian shield fern experts. The habitat is very tricky, he said: "It's the place you don't want to go as humans."

Could Aleutian shield ferns be growing somewhere else? Williams believes that is likely.

"We just haven't found them," he said.

The fern's rarefied habitat might exist on 17 islands besides Adak, according to a study by scientists from Texas State University and the USGS. The study, published in 2012 in the Journal of Wildlife Management, identified about 189 square miles of "highly suitable and moderately suitable habitat" scattered over Adak and the other 17 islands. Among the places that hold such habitat are very obscure islands like Gareloi and Igitkin, according to the study.

Could Aleutian shield ferns be cultivated in a greenhouse and planted somewhere, possibly at any of those locations? That is doubtful, according to experience to date.

Attempts have been made at the University of Alaska Fairbanks, the National Arboretum in Washington, D.C., and Kew Gardens in the United Kingdom. The UAF project went the furthest, but after two years all specimens died, according to an Aleutian shield fern management plan issued by the Fish and Wildlife Service in 2007.

One thing that might change is the fern's species classification,

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It is known to be related to a fern, Polystichum lachenense, that grows in the Himalayas and some other high-altitude spots in eastern Asia. Whether that is actually the same thing as the Aleutian shield fern is the subject of an unresolved decades-long debate.

In the past, the paucity of specimens hindered genetic testing, but work continues. They might turn out to be the same species, though separated by vast distances, Talbot said.

If that is the case, it could have implications for the fern's endangered status.

No matter how the genetics information turns out, however, the Aleutian shield fern will always be ultra-rare for Alaska — and special to Talbot.

"I like the idea of things that are rare," she said. "It's awesome when you see it."

The Aleutian Islands in general, with their mysteries, oddities and wild weather, are special to her, and they appeal to her as a scientist.

"Every island is different," she said.

She has spent a lot of time in recent years, for example, trying to understand the new ecosystem at Kasatochi, an Aleutian island transformed by ash-dumping volcanic explosions in 2008.

The Aleutians' lush, treeless greenery and isolated beaches also appeal to her as an artist, the avocation she pursues outside of her USGS hours.

"The Aleutians always have a mystique," she said.

Yereth Rosen

Yereth Rosen was a reporter for Alaska Dispatch News.

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