Jumping slugs: the tiny sticky acrobats of the Northwestern forests

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The Pacific Northwest is home to a group of rare species you’ve probably never heard of. Their name alone can horrify or delight you: jumping slugs.

Environmentalists and the federal government are clashing over a species whose populations appear to be declining and its habitat on Washington’s Olympic Peninsula.

It’s not a salmon or a spotted owl or even a salamander.

It’s a slug, and it jumps, sort of.

Unless you’re a malacologist, as shellfish experts are called, it’s unlikely you’ve seen or even heard of this half-inch-long creature: Burrington’s Jumping Slug.

The inhabitant of fallen maple and alder leaves can only be found from Vancouver Island to the Oregon Coast Range.

Although his fans say the tiny mollusk has a certain charisma up close, it is camouflaged and stealthy enough to evade detection by the occasional intruder in its mossy rainforest habitat.

Most slugs are known to glide slowly and gooey across the ground, but at least half a dozen species in Washington, Oregon, and Idaho are called jumping slugs for their habit of twisting and collapsing. like a fish out of water. Biologists believe it is a defense mechanism.

Slugs don’t take much air, but they can fall off a branch or leaf they’re on and break free from their own trail of mud to throw a hungry predator out of the scent.

“Yeah, they’re jumping,” said biologist Michael Lucid of Selkirk Wildlife Science in Sandpoint, Idaho. “But they don’t jump like you might imagine.”

“Yeah,” retired Olympia biologist Bill Leonard hesitantly said. “More like a somersault or something like a jump.”

Above, a dromedary jumping slug, a close relative of the Burrington, struggles on Vancouver Island.

“It’s kind of a tight corkscrew and winding and unwinding that makes them rush or fall,” Leonard said.

He saw his first jumping slug on the Olympic Peninsula in 1982.

“I was working watching the spotted owls up there and saw these crazy slugs,” Leonard said.

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Like spotted owls, jumping slugs are considered a kind of indicator species of Northwestern forests.

Jumping slugs are sometimes called half-slugs: they are halfway between snails and slugs, wearing a sort of half-shell inside a bump on their back.

Slugs are snails whose ancestors got rid of all or most of their shells at some point in their evolution.

If you’ve ever thought about slugs, there’s a good chance you think of them as slimy pests that can make gardening an exercise in frustration. Shellfish experts say garden and crop destroyers are almost exclusively European species that hitchhiked across the Atlantic.

There are at least six species of jumping slugs in the Pacific Northwest.

“They are full residents of our Northwestern forests,” Leonard said. “They don’t happen anywhere else in the world.”


Caption: A Burrington jumping slug, with its multicolored hump concealing a partial shell, at Rialto Beach in Olympic National Park in 2001

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The Burrington’s Jumping Slug glides through the rain forests of the Oregon coast to Vancouver Island, where biologist Kristiina Ovaska studies a variety of small creatures. (“All things gooey and scaly,” she said.)

Others go bird watching. Ovaska will watch for the slugs.

“You have to look very carefully, like one leaf at a time, and you can find them on the forest floor,” she said.

Burrington’s Jumping Slug may never be a Northwest icon like salmon or orcas, but Ovaska says if you get close enough, she has a certain charisma.

It has a multicolored bump like a dazzled little backpack. His eyes are at the end of pretty little eye stems.

“We have droppers and jumping slugs, and we have these really cool native species in our forest that most people know very little about,” Ovaska said.

Jumping slugs might not have a lot of fans, but they do have some ardent fans.

In England, there is even an Ugly Animal Preservation Society that advocates for the jumping slugs of the North West, among other eccentric species.

“A slug, with a bump on her back, and she can jump, where’s her Disney movie?” asks for a company video. “We have the Hunchback of Notre-Dame. Where are the dromedary jumping slug and the princess? “

(In a contest to choose the Ugly Animal Preservation Society’s mascot, voters chose the blobfish over the Dromedary jumping slug, a close relative of the Burrington.)

Environmentalists plan to sue the federal government to prevent the extinction of the Burrington.

In November, the Center for Biological Diversity gave the US Fish and Wildlife Service the 60-day notice required for its intention to sue the agency for failing to grant endangered protection to four species: the Burrington’s Jumping Slug. , the southern California rubber boa, the Florida Black Creek crayfish, and a Utah fish called the Virgin River Spinedace.

The center also said it would sue the agency for delaying protection of six other species, including the hairy-necked tiger beetle from Siuslaw in Oregon and Washington.

The Fish and Wildlife Service found the Jumping Slug to be in trouble across much of its range, particularly along the Hood Canal, Willapa Bay and Vancouver Island.

When their habitat is cleared, slugs cannot soar or jump fast enough to find a place that is moist and shady enough to live.


Caption: A Burrington's jumping slug clings to a log on Vancouver Island.

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“Burrington Jumping slug will continue to decline in levels of resilience, redundancy and performance over the next 20 to 50 years,” the agency concluded.

Still, the agency said the species had “moderate” resilience and did not warrant further measures to protect its habitat, prompting the lawsuit.

“We need to do a better job of protecting our forests and protecting old growth forests,” said Noah Greenwald of the Center for Biological Diversity, the group that sues to protect the slug as an endangered species.


Caption: It is known that more mollusks, mainly land snails, have become extinct in modern times than any other type of animal.

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As far as scientists have been able to document, more mollusks have become extinct in modern times than any other type of animal. The few people who study these little-known animals think they deserve more respect, especially given all the work they do for us.

“Decomposition is not as sexy as pollination,” Lucid said. “But it’s still a super essential ecosystem service.”

“Imagine a world without decomposers,” he said. “Imagine the leaf litter that would accumulate on the forest floor and all the fuel that would fuel these already worsening fires. So the group of species is really important to humans.

Almost 20 years ago, the US Forest Service declared the Burrington’s Jumping Slug dependent on old growth forests. Lucid says it can thrive in younger forests as well, as long as loggers leave microhabitats with shade and woody debris, slugs can stay cool – and as long as our changing climate doesn’t dry places out. wet where the slug calls its home.

“It’s definitely sensitive to warming temperatures,” Greenwald said.

“The ecosystems we all depend on and which are made up of species are starting to crumble across the world,” he said. “Burrington’s Jumping Slug might seem like a small species, but it’s one of those caught up in it. “

Extinction and our collapsing climate are ongoing tragedies, but there is also a jumping slug comedy.

While some experts say jumping slugs don’t really jump, Tim Pearce, the curator of molluscs at the Carnegie Museum of Natural History in Pittsburgh, says they can jump higher than the Empire State Building.

This is because the Empire State Building cannot jump.

“I once told my friend that I was going to the Olympics to see the jumping slugs,” Pearce said. “And she said, ‘I didn’t even know it was an Olympic event.'”


Caption: A Burrington jumping slug on Vancouver Island

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People who study these neglected little creatures seem to develop a real fondness for them.

In Idaho, Michael Lucid and his wife, biologist Lacy Robinson, named a species of jumping slug they discovered in 2018 after their young daughter, Skade. They had named it after the Norse goddess of winter, mountains, skiing and bow hunting. The Skade Jumping-slug, according to their research, lives in the colder nooks and crannies of Idaho’s Coeur d’Alene Mountains and can be particularly sensitive to climate change.

“These are species that need the cold, they need to be wet, and anyone who lived in the Northwest last summer knows that is about to change,” Lucid said.

Ovaska said another rare mollusk, the blue-gray tailed dropper, appeared to have disappeared from the site she is studying on Vancouver Island after the drought and extreme heat this summer.

Now Lucid and Robinson are hoping to find another new species of mollusk named after Skade’s little brother.

“Fair is fair,” Lucid said. “We’re going to be in trouble someday if we don’t find another one for him.”

Lucid says he wants to make sure the jumping slugs are still around when his kids grow up.

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