A lush knee-high jungle grows in the Arctic, but warming is changing Earth’s mini-greenhouse

TOOLIK LAKE, Alaska (AP) — With no tall trees reaching to the sky, Alaska’s North Slope tundra can look desolate — especially to outsiders from the Lower 48 who are used to in-your-face greenery.

But up close, “the tundra’s kind of like the jungle,” said Adam Bloom, a Florida Atlantic University plant biology student. Except this lush Arctic jungle tops out at about 10 inches (25 centimeters).

Together with Jake Francis, a professor at the university, Bloom walked through the spongy soil that was frozen solid a few weeks earlier. They towered over the knee-high dwarf birch trees. Showy rhododendrons didn’t reach the backs of their shoes as they walk in the North Slope, a vast and sparsely populated treeless area stretching from the Brooks mountain range to the Arctic Ocean.

For centuries, Arctic cold has kept plant life small, a sort of dollhouse of Earth’s miniatures. The extreme environment has long given researchers a unique perspective on what makes plants grow, insight that would be hard to obtain elsewhere. Now it offers them one of the world’s most useful windows on how climate change affects plant life, with the Arctic warming four times faster than the rest of Earth, especially in the winter. For example, researchers at the Toolik Field Station, 200 miles (320 kilometers) north of the Arctic Circle, are studying whether plants facing these harsh conditions evolve to compete or cooperate with one another.

Studies show that the colder and further north in the Arctic, the smaller the plant life. There are several reasons, but the main one is that life is rough in the winter. Anything that protrudes above the shallow, insulating snow cover is more prone to being damaged by the cold and wind or eaten by wildlife, said plant ecologist Anne Bjorkman of the University of Gothenburg in Sweden.

Plus the frozen permafrost doesn’t allow roots to grow too deep, she said.

Earth’s miniatures are growing

But the cold is weakening and the miniatures are stretching. This part of Alaska is about 4.8 degrees (2.7 degrees Celsius) warmer than it was 40 years ago mostly because of the burning of coal, oil and gas.

“Plants that are already there are growing taller,” Bjorkman said, adding that they’re likely to grow even taller in the future.

And they are getting greener. Some of the long-term studies here are “trying to understand what controls how much plants grow, what controls how green it is,” and how all that is changing, said Columbia University ecologist Duncan Menge.

Meanwhile, taller plants that previously couldn’t survive the cold are moving in, Bjorkman said.

This process, called shrubification, can accelerate warming because of how the plants trap heat, said University of Colorado plant ecologist Sarah Elmendorf. Canopies of the taller, darker shrubs stick out of the snow and absorb more energy from the sun than the blanket of white snow, which reflects heat back.

“It’s certainly a major fingerprint of change that we can see,” she said.

Darker tundra absorbing more radiation is “one of the main reasons for what we call arctic amplification, which causes climate change to accelerate” especially in the Arctic, Menge said.

The shrubs also trap more snow. That snow warms the ground below and allows microbes during the winter to release more of the heat-trapping gas methane, Elmendorf said. The added greenery from the taller plants and shrubs could compensate somewhat by absorbing more carbon dioxide, she said.

Expanding stands of willows seem to be providing more shade to streams and changing the ecology of fish, insects and birds, according to Chris Neill and Linda Deegan of the Woodwell Climate Research Center. They are conducting a multiyear study to see if an ecosystem adapts and even genetically evolves to handle the stress of climate change. If that is happening, it offers hope for the survival of some of the most fragile Arctic ecosystems, Deegan said.

Using a magnifying lens to appreciate tiny plants

During a foray around Toolik Lake, Francis carried a knuckle-sized magnifying lens around his neck like a locket, using it to reveal the wonder of the tiny flora at his feet.

“Tiny changes in a tiny jungle make a big difference,” said Francis, an Arctic newcomer.

Big trees in Francis’ home base of Florida are showy and amaze people because they’re so easy to see, he said. But here on the spongy tussocks — clumps of plants that jut upward, making walking an ankle-turning adventure — Francis said, “we have three or four different species of flowering plants growing. We have mosses. We have liverworts and it’s the same thing. Layers growing on top of plants on top of plants on top of plants. But it’s not yelling at us.”

“You have to get down there and stop and look,” Francis said. “You could walk right past it and not even see it. And so this is what to me is cool.”

What helps survival, competition or cooperation?

These plants are competing for sun, nutrients, water and especially pollination in this harsh environment of limited but intense sunlight. Francis and his students are examining if it’s more cooperative than the long assumed life-or-death competition. Francis’ team focuses on a specific parasitic plant — the Arctic lousewort — that they think is getting a bad rap. The Arctic lousewort taps into the roots of nearby plants to suck out nutrients.

Sure, it’s a vampire, siphoning resources from its neighbors. But doctoral student Jonathan Carcache theorizes that the lousewort is helping its neighbors as much as stealing from them. That’s because its dramatic shaft of purple flowers catches the attention of the not-so-plentiful bumblebees here “like a billboard that advertises pollination,” he said. And once that sought-after bee arrives, everyone gets pollinated.

To test their theory, Carcache and Bloom play bee. It’s a painstaking, difficult task that they split between them. Bloom uses tweezers to remove a plant’s male parts, and back at the lab he uses a mechanical device to shake out the pollen. It takes several hours each night to produce less than a teaspoon full of microscopic pollen grains.

Then Carcache finishes the job, belly-first on the ground and trying not to crush any of the plants they have come to study. Wearing a net over his head and nitrile gloves to protect him from swarming mosquitoes, he takes a paintbrush to dip grains of pollen on just the right female parts of neighboring heather blossoms.

By doing the bees’ job, Carcache and Bloom hope to figure out whether the plants around the parasite are pollinated more than those further away. If so, there’s a fair trade taking place, rather than one plant simply taking advantage of others.

Amid the stresses of the Arctic, scientists are rethinking the idea that all life is a cutthroat competition with winners and losers. It might be more about mutualism, with plant species cooperating so that everybody survives, like the lousewort and its neighbors, Francis said.

“It would be wonderful if humans were the same way,” Francis said.

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