Melting Glaciers and the Animals that Follow

Researchers taking soil samples to extract micro-arthropods (springtails and mites)(Source: Hågvar et al.).

Last week, GlacierHub reported on a study that followed the types of plants that colonize new areas exposed by glacier retreat. But what about animals that colonize de-glaciated regions? A recent study from a team of Norwegian ecologists led by Sigmund Hågvar explores 200 years of arthropod succession in a Norwegian glacier foreland, home to what the researchers described as “biological oases.” Arthropods are a phylum of invertebrates with hard outer shells and segmented legs, which includes insects, spiders, and many marine species like shrimp, lobsters, crabs, and even barnacles.

Headlines of melting glaciers and their implications aren’t new to anyone. “Melting glaciers all over the world are strong proof for global warming,” lead researcher Hågvar told GlacierHub. “If glaciers disappear, rivers which delivered water to people may dry up.” But for scientists like Hågvar, what’s left behind is ecologically fascinating. His team published their findings in a book titled “Glacier Evolution in a Changing World.”

“A melting glacier leaves large areas of barren ground, which is available for the colonization of plants and animals. How fast is this colonization, who are the pioneers, and how are plant and animal colonization connected? The sequence of organisms with time is called a succession, and in this case a primary succession because it starts on bare ground with no species present,” Hågvar explained.

Mauro Gobbi, research entomologist at the MUSE-Science Museum in Italy and a specialist on the ecology of alpine glacier forelands, shared similar sentiments. “The study of environmental changes occurring after the retreat of glaciers are giving us an extraordinary experimental opportunity to measure in space and time the temporal evolution of biotic communities, and how they are colonizing pristine areas,” he told GlacierHub.

Hågvar and colleagues Mikael Ohlson and Daniel Flø conducted their study close to the Hardangerjøkulen glacier in central southern Norway. Star Wars fans may recall how this glacier was the filming location for the iconic ice planet of Hoth, as GlacierHub reported earlier this year. Hardangerjøkulen has been receding for about 250 years since the end of the Little Ice Age, but “the melting rate has been especially high during the last two decades,” according to the study. Due to the rapid melting rate and good data on the glacier’s position, glacier forelands offer unique opportunities to study primary succession.

In general, previous studies dealt with plant succession, with few focusing on the animal’s story. However, this study is unusual because it provides an integrated account about animal succession near a melting glacier in Norway and how it is in accordance with findings in other parts of the world.

Which animals colonize retreated glaciers?

Researchers working at this 8-year old pond near the glacier, studying midge larvae (Source: Hågvar et al.).

Along the frigid slopes of the Hardangerjøkulen glacier foreland, few creatures call the treeless alpine region home save for an array of beetles (Coleoptera), spiders (Aranea), springtails (Collembola) and mites (Acari). These hearty, cold-tolerant arthropods utilize a wide variety of life strategies to survive in this harsh environment. Among these fighters is a “super-pioneer,” the biofilm-eating springtail. These animals closely follow the newly de-glaciated melting ice edge and are among the first organisms to colonize the barren ground, surviving on invisible diatom algae that attach to each other and the surface of the ground to form a biofilm. With the ice edge moving faster and faster each year, these organisms are put to the test to keep up.

Each species follows a distinctive successional pathway depending on the species, topography and moisture content of the physical environment. In this study, the researchers were able to distinguish the soil-living micro-arthropods and the surface-living macro-arthropods between a dry and moist succession. Among the first colonizers of the bare ground were large predatory beetles and spiders. But this is a bit odd. “According to common ecological theory, it is impossible to start an ecosystem with predators. A food web must start with plants, then herbivores, and finally predators,” Hågvar states.

The answer to the puzzle: a combination of long-distance aerial transport of prey unable to survive in the conditions as well as midge larvae colonizing in nearby ponds. The presence of these food sources allows for the predatory species to colonize much earlier than ecological theory may anticipate.

But what about the others?

With limited plant species or none available, how do so many of these observed species survive? In answering this question, the team analyzed the gut contents of these creatures and found three food sources that feed the arthropods: 1) biofilm with diatom algae, 2) tiny pioneer mosses, and 3) ancient carbon released from the glacier.

This figure demonstrates the food web of both dry and wet succession. The three colored frames represent the three sources of food supporting the colonizers (Source: Hågvar et al.).

Of these three, it is the third option that was the most “surprising” to the researchers. “We wondered whether ancient carbon was released also by our glacier, and if so, whether it could be used as a nutrient source for pioneer arthropods… We concluded that ancient organic material released by the glacier was assimilated by chironomid larvae [mosquito-looking flies], and transported further to aquatic and terrestrial predators,” the study noted.

But what was the source of the ancient carbon stored in the glacier? The likely source appears to be long-transported aerosols, including via heavily glaciated watershed. When predatory beetles, spiders, and harvestmen eat the adult versions of carbon-eating midge larvae, the predators would “achieve a radiocarbon age up to 1000 years,” according to Hågvar.

Looking Ahead

Despite widespread negative impacts of melting glaciers, the rise of “biological oases” present opportunities for scientists to explore the dynamics behind primary succession, a subject not easy to study. The resilience and persistence of the animals that survive in these harsh environmental conditions are remarkable. But cold-adapted species that enjoy sticking close to the ice edge may not be able to keep up if the rate of glacial retreat gets much higher, Gobbi told GlacierHub. “As the rate of glacial retreat is predicted to accelerate in the near future, recently de-glaciated areas will increase, therefore monitoring the uphill shift of the cold-adapted species chasing the glacier is one of the most important challenges for ecologists and conservationists. All of these cold-adapted species are in danger of extinction,” he said.

Besides the arthropods, other animals that rely on glacier forelands are humans. For instance, glacier meltwater supports a wide range of socioeconomic activities, including activities of the tourist industry, pastoralists, and hydrologists. Ultimately, “naturalistic components, social values, local perceptions and cultural beliefs are closely intertwined with the existence of glaciers in the regions, therefore it is mandatory to invest on research projects aimed at monitoring the changes of these habitats in relation to the ongoing glaciers disappearing,”states Gobbi.

As glaciers melt worldwide, it will be interesting to see what communities some of the planet’s toughest plants and animals build and the opportunities these communities present to scientists. Such organisms exemplify the tenacity of life. Even in the harshest circumstances, and despite the threat of climate change and its unknown effects, life still finds ways to survive.

Hardangerjøkulen: The Real-Life Hoth is Disappearing

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An image from the set of the Empire Strikes Back (Source: Brickset/Flickr).

Any Star Wars fan will recognize the remote ice planet Hoth, the location of some of the most iconic scenes from Episode V: The Empire Strikes Back, including the attack on the Rebel Alliance’s Echo Base by Imperial Walkers and Han Solo’s daring rescue of Luke Skywalker after his tauntaun was attacked by a wampa. Not many people, however, would know that those legendary scenes were filmed on a Norwegian ice cap called Hardangerjøkulen.

When the movie was filmed in 1980, the crew had to cope with subzero temperatures and freezing winds. However, nearly forty years later, the real-life Hoth is disappearing. According to a recent paper by Henning Akesson et al., published in The Cryosphere, the ice cap is extremely sensitive to small changes in temperature, and therefore vulnerable to climate change as global temperatures continue to increase.

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An edge of the Hardangerjøkulen ice cap (Source: Ingolf/Flickr).

Akesson explains in an article for ScienceDirect that due to increasing temperatures, it is feasible that Hardangerjøkulen could fully melt by 2100 if the trends continue. Once it melts, he and his team maintain that the ice cap will never return.

As the authors of the study explain, Hardangerjøkulen is located in southern Norway and measured 73 square kilometers as of 2012. It is generally flat in the interior and has several steeper glaciers along the edge of the ice cap that drain the plateau. Two of these glaciers, Midtdalsbreen and Rembesdalsskaka, have retreated 150 meters and 1386 meters respectively since 1982. Akesson et al. base their study of Hardangerjøkulen on modeling, as opposed to measurements or observations.

The team used a numerical ice flow model to produce a plausible ice cap history of Hardangerjøkulen thousands of years before the Little Ice Age. Using a modelled history of the ice cap, they examined the sensitivity to different parameters. They found that it is “exceptionally sensitive” to changes in temperature. These changes in temperature impact the ice cap’s surface mass balance, which is the gain and loss of ice from a glacier system.

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A sunny view near the summit of Hardangerjøkulen (Source: Martin Talbot/Flickr).

The possible disappearance of Hardangerjøkulen has many implications, including impacting Norway’s tourism and hydropower industries. 99 percent of all power production in Norway comes from hydropower, which depends on glaciers’ water storage and seasonal water flow. Glaciers help contribute to water reservoirs used for the hydropower, and Norway itself contains nearly half of the reservoir capacity in Europe.

The ice cap is also a popular destination for hiking and glacier walking, as well as for Star Wars fans hoping to visit the location of Hoth scenes.

Local residents have remarked on noticeable differences in Hardangerjøkulen. Grete Hovelsrud, a senior researcher at the Nordland Research Institute and vice-president of the Norwegian Scientific Academy for Polar Research, told GlacierHub that the potential loss of Hardangerjøkulen is “very sad.” She added, “It is such a beautiful place. I skied across it last spring, and it really feels like being on top of the world.”

Glacier Retreat Ushers in Arachnids

Harvestmen— a spider-like arachnid— are among the first creatures to inhabit land in the wake of glacier retreat, according to a recent study by Sigmund Hågvar and Daniel Flø in the Norwegian Journal of Entomology. The land where glaciers have recently melted is an ideal habitat for creepy-crawlies including spiders, beetles, and other invertebrates. Perhaps surprisingly, these predators are often the first species found on this new land, before herbivores and even plants, although classical theories in ecology state that it should be the other way around.

The authors suggest that this reversal is made possible by the availability of two types of prey: insects that fly in from neighboring areas or are carried in by the wind, and midges that hatch in the carbon-rich puddles formed by meltwater from the retreating glaciers.

Mitopus morio (Photo:Source: Parent Géry)
Mitopus morio (Photo:Parent Géry)

Although Hågvar and Flø mention other species in their article, the study focuses on Mitopus morio, a common spider-like creature in the arachnid family called a harvestman (Opiliones). In America, harvestmen are commonly known as daddy-longlegs. These creatures are both predators and scavengers, since they consume living and dead invertebrates. Having a relatively short life cycle of only one year, young harvestmen hatch during snowmelt in spring and die as mature adults in the fall. Due to their habit of living on newly uncovered land, harvestmen are considered pioneer invertebrates.

Harvestmen are found across Norway, but Hågvar and Flø focused on the ones living in areas of glacier retreat, specifically at the Midtdalsbreen Glacier near the mountain village Finse. This glacier drains the eastern portion of the Hardangerjøkulen (Hardanger Ice Cap).

Hardangerjøkulen Glacier (Photo: Source: de:Benutzer:GerdM)
Hardangerjøkulen Glacier (Photo: de:Benutzer:GerdM)

The study was conducted in different areas— on land that was uncovered 205 years ago and on more recently uncovered terrain. Hågvar and Flø found that harvestmen greatly outnumbered spiders except at the oldest site, and also outnumbered the total number of carabid beetles located at three of the sites (areas uncovered 40, 160 and 205 years ago). In the land that has been uncovered for three years, harvestmen follow the glacier retreat, living alongside the glacier’s edge.
The creatures live on barren ground, meaning there doesn’t need to be any vegetation for them to thrive. The lack of vegetation allows them to move freely, and the empty land is better heated by the sun— an important benefit for these cold-blooded organisms. The study found that the harvestmen thrive best during warm and dry years. Because of the quick establishment of life on what is considered inhospitable land, harvestmen serve as a reminder that nature is remarkable and surprising.

Mitopus morio (Photo: Photo: Ed Nieuwenhuys.)
Mitopus morio (Photo: Ed Nieuwenhuys.)

When glaciers appeared in a galaxy far, far away

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Star Wars fans gather (in Imperial Snowtrooper costumes) in Finse, Norway in 2010 for the 30th anniversary of the filming of the Empire Strikes Back. (source:

Rabid Star Wars and glaciologists share at least one thing in common. They both know about the Hardangerjøkulen Glacier in Norway, where scenes set snow planet of Hoth were shot for The Empire Strikes Back.

The possibility of returning to Hoth in the new Star Wars movie has been circulating the Internet rumor mill for a few months now, and even in the age of blue screen and CGI effects, there’s something to be said about shooting on location, on a glacier itself, as the first of the series’ sequels did in 1979.

Norway’s claim to fame dates to March of that year when crews shooting The Empire Strikes Back were based in the town of Finse during the filming of scenes set on the frozen planet Hoth. The nearby Hardangerjøkulen Glacier was used near the beginning of the film during the battle scene between Luke Skywalker’s Rebel Alliance and Darth Vader’s Imperial forces.

The film crew for the Empire Strikes Back prepares to film a scene with Harrison Ford  in Norway. (film still from documentary "Empire of Dreams - The Story of the Star Wars Trilogy)
The film crew for the Empire Strikes Back prepares to film a scene with Harrison Ford in Norway. (film still from documentary “Empire of Dreams – The Story of the Star Wars Trilogy’)

Filming during Norwegian wintertime wasn’t the easiest. When the worst winter storm in 50 years hit the area, it trapped the production crew in their hotel in Finse. Not to lose any time, they shot a scene of Luke Skywalker escaping from an ice monster’s cave by sending actor Mark Hamill out the hotel door into the cold, while the cameras and crew remained warmly inside.

The village of Finse is so remote that no public roads connect it to the rest of Norway, only a railway. The glacier itself is located in a national park and tourists must travel there not only with special permission, but also a guide that can help them avoid dangerous crevasses.

There is a small group of superfans who make the trek out to whatever Earth-related locations stood in for the galaxy far, far away.

Brandon Alinger, who has visited several other Star Wars filming sites, recently made the trip up to Finse, but not before stopping in London to chat with Empire Strikes Back location manager Phillip Kohler.

“We went up [on these trails] when we were on the recce (film slang for reconnaissance trip), on snow cats,” Brandon recalls Kohler telling him. “We told the driver in front, ‘If you don’t know the way, don’t leave the route, don’t let the guys tell you they want to go to the left’, because it looks safe! So what do they do? We see the snow-cat turn left, turn right, and it suddenly stopped. And the director got out and went straight down on his right leg. We said, ‘told ya, it’s all crevasses.’”

Star Wars tourism sometimes brings fans to the ends of the earth (in this case Fense, Norway) to visit filming locations. (source:
Star Wars tourism sometimes brings fans to the ends of the earth (in this case Fense, Norway) to visit filming locations. (source:

The Hardangerjøkulen Glacier isn’t the only Star Wars location difficult for tourists to visit. Production crews have used Tunisa multiple times as the setting for Luke Skywalker’s desert homeworld Tatooine. Recently shifting Saharan sands threaten to cover old filming sets, and the Arab Spring uprisings have scared tourists away.

Those looking to travel to Hoth without leaving their front door can find plenty of glacier-inspired Star Wars work. Artist James W. Rook, for example, imagined what it might be like if melting ice revealed a long-missing prop, in this case a crashed rebel snowspeeder. The elements from the Norwegian glacier and surrounding area are even incorporated into Angry Birds Star Wars.

As long as Star Wars exists, in some form or another, so will Norway’s glaciers.