Glacier Retreat Unveils Truth of ‘Predator First Paradox’

A recent paper published in Molecular Ecology studies ecological evolution in areas exposed by glacial retreat, shedding light on the “predator first paradox,” a phrase used by ecologists to describe the predator-dominated primary succession in glacier forelands. The authors found that predator anthropods such as spiders and beetles can show up as pioneering dwellers on newly exposed land, even before plants colonize the area. The predator first phenomenon shakes up the traditional understanding of a bottom-up ecological pyramid in which plants serve as the basis of the food chain that feeds the predators. Less was known about the prey that sustains these predators in the early stages of succession. By examining the stomachs of insect predators, the researchers determined that spiders and beetles can survive without vegetation on the prey species of local food webs as well as some flying insects.

View from the separating ridge of two of the valleys investigated by the researchers. Gaisbergtal lies to the left and Rotmoostal to the right (Source: Daniela Sint).

Daniela Sint, the paper’s lead author from the University of Innsbruck in Austria, told GlacierHub, “We could show that the amount of local production and the importance to sustain the arthropod predators on those sites was underestimated over many years.” This conclusion is at odds with previous studies that found that flies from other areas, instead of local mites, are the primary food source of the spiders and beetles.

To understand how ecological evolution starts on bare land, the authors selected several glacial forelands in three valleys in the Tyrol region of Austria, namely Gaisbergtal, Rotmoostal and Langtal, which have recently undergone glacial retreat. All three areas have a glacier above them and lie close to each other, with similar climatic conditions. The researchers found that the three glacier toes had retreated 1.5 to 2 kilometers each since 1850, placing these forelands in the early stages of the ecological progress.

Sint and her colleagues pictured as they approach the study sites located close to the edge of the glaciers (Source: Daniela Sint).

Using self-made pitfall traps, the authors collected samples of spiders and beetles from exposed areas to study how the anthropods feed themselves. The paper notes that the authors went so far as to turn over the stones to catch spider and beetle species missed by traps.

“It’s the first time that so many different prey types were molecularly checked for,” Sint explained to GlacierHub. Sint and her team examined the gut of nearly 2,000 spiders and beetles and conducted a DNA analysis on a total of twenty species.

Through the “autopsy” of these captured spiders and beetles, and a DNA detection of prey within their guts, the researchers found only 30 percent of gut content was made up of flies from other places. The rest of the anthropods’ diet comprises mites and other prey found locally.

The researcher’s data shows that the spiders and beetles have dietary preferences toward mites (not flies), regardless of the differences between the sites. Meanwhile, as time passes, the prey options for spiders and beetles increases, providing more food for the predators. Gradually, this positive interaction empowers the substantial development of the food chain and ecological community.

Some dry ground beetles trapped by the pitfall set by the researchers (Source: Daniela Sint).

Although the researchers identified different food sources for the spiders and beetles, resolving important questions about the prey of predators, Sint also discussed with GlacierHub her team’s plans for future research. “We still were not able to cover the whole food web on the study sites. For example, we found out that springtails are very important food for the predators, but we still don’t know what the food for the springtails themselves is,” she said. “There are several options as they might feed on locally produced algae or fungi, but it could also be that ancient carbon and nitrogen released from the melting ice might play a role.” A follow-up study at the University of Innsbruck is currently focused on this question.

Sint says she will continue to research glacier areas, as “glacier retreat is the factor initiating the whole process of primary succession.” When the glacier melts, land that has been covered by ice for thousands of years is “released” and colonization by microorganisms, plants and animals starts immediately.

Sint further described her concerns about global warming-driven glacial retreat worldwide, saying, “This does not only have the local effect of additional land becoming ice-free and being thus available as new habitat exposed to primary succession, but it also has strong influences on numerous other aspects. Many of them will only become obvious once a specific glacier is gone.”

Glaciers and the Rise of Nazism

Poster from the 1938 Luis Trenker film, “The Mountain Calls” (Source: Prisma).

Glaciers and the mountains that convey them have come to symbolize purity— one which has been marred by glacial retreat. We long to return to a state in which glaciers aren’t retreating as a result of anthropogenic climate change, where the condition of the world aligns more closely with our belief in what it should be again. But, historically, glaciers and the mountains that convey them have also symbolized other, more insidious forms of purity.

In a recent article in German Studies Review, Wilfried Wilms outlines the ways in which a flurry of German films and novels in the 1930s recast the glacier-rich Alps and region of South Tyrol as traditional German living space. Wilms focuses on works produced between 1931 and 1936, a time when German nationalist discourse was on the rise and support of a greater pan-German alliance between Germany and mountainous Austria was gaining widespread currency in the lead-up to the Nazi takeover of 1933 and annexation of Austria by Germany in 1938. By locating German speakers within alpine settings and showcasing their natural affinity to mountain climbing and glacier landscapes, filmmakers and novelists contributed to a discourse that sought to integrate the greater Germanic world by establishing a common set of uniquely German traits.

The jagged Dolomite range (Source: Kordi Vahle/Creative Commons).

In an interview with GlacierHub, Wilms described the roots of the notion of mountain and glacial purity in relation to both German racial and environmental ideals. “There is the discourse on elevation in Nietzsche’s ‘Zarathustra on rising above the lowlands; ennobling the Self in its struggle with the mountains; the purity of snow and firn [an intermediate stage between snow and glacier ice], and its disconnectedness to the (soiled) realms below. After the defeat in World War I, the mountains become a place of individual, cultural and national renewal— a proving ground, a training ground for the youth and its future for Germany,” he said. Unlike “All Quiet on the Western Front,” which portrayed the horrors and banality of the first World War, German films after 1931 valorized war in ways that fed into the nation’s growing territorial ambitions.

The Langenferner Glacier in South Tyrol (Source: Noclador/Creative Commons).

Historically, the mountainous region of Tyrol had been home to a mostly German-speaking, Austrian population— that is, before Italian irredentists got in the way. With the Axis defeat at the close of the first World War, South Tyrol was formally ceded to Italy in the 1919 Treaty of Saint-Germain. Over the next decade, Mussolini instituted a series of Italianization programs in an effort to reduce the Germanic cultural sway in the region. These programs were well known to the public in Weimar Germany, and Wilms argues that a crisis emerged for Germans: as ideas of pan-Germanism were taking hold, their German-speaking brethren were being pushed out of their homeland, a place that was felt through its Alpine features to be distinctively German. A spate of cinematic and literary portrayals of the Alpine War, fought between Austrian and Italian troops in Tyrol during World War I, became a means through which the German population was mobilized and militarized in the lead-up to the second World War.

According to Noah Isenberg, a professor of culture and media at The New School, certain technical innovations also changed the way films were watched in Germany during this period. “In the early 1930s, thanks largely to the advent of sound (which came quite late to Germany), films tended to take advantage of recorded dialogue and elaborate musical scores. Berlin was known for its majestic picture palaces, with more than a thousand seats and ornate interiors, but in Germany’s smaller cities, audiences watched the films in mid-sized theaters, less grand in appearance and with more limited seating,” he said in an interview with GlacierHub. The stage was set for irredentist films to have a maximal impact on German society. 

The Illimani Glacier as seen from the Bolivian city of La Paz (Source: Globus-Film).

One work that Wilms analyzes in detail in his article is Luis Trenker’s 1931 film, “Berge in Flammen” (Mountains in Flames). Trenker was a native of South Tyrol, as well as an Alpine War hero, mountaineer, novelist, actor and director. “Berge in Flammen” opens with a visual ode to the Tyrolean Alps. One can easily imagine how a German audience would have been transfixed by the spectacle: the camera first muses over billowing clouds, then transitions to a frontal shot of a looming mountain before following dense waves of fog as they drift through the spaces between stark stone cliffs. Even in 1930s black and white, the landscapes are mesmerizing.

Enter the film’s hero, played by Trenker himself, a confident rope in hand as he leads the way up a precipitous rock face, undaunted by the thousand-foot drop that outlines his figure. As he climbs further up the impossible height, the camera focuses in on his muscled legs and steady hands. The Austrian reaches a small platform where he pauses to pull up his climbing companion’s rope. His climbing partner, an Italian, then begins his own ascent, but he quickly loses his grip and careens down the rock face. The camera pans quickly to Trenker’s hands as they grip the rope that separates his friend from certain death. Then the camera pans again, this time to a close-up of Trenker’s determined face as he grits his teeth, holding fast to the rope as he selflessly risks his own life to save his companion.

A still taken from another Trenker film, “The Mountain Calls” (Source: Ernst Baumann).

As Wilms persuasively argues, scenes like these come to place German speakers firmly within an environment dominated by mountains and glaciers, places in which Italians are decidedly not at home. “Berge in Flammen” is filled with stunning shots of the snow-laden Alps, their glaciers appearing voluptuous and pure. Austrian glacial fortresses are bombarded by Italian shells, and explosions of smoke and snow crash across the mountaintops, but in having to enact this destruction, the Italians further reveal their unbelonging. Where the Italians work against the mountains, the Austrians work with them.

A typical scene in which Trenker negotiates with the elements (Source: Ernst Baumann).

According to Wilms, films from “Berge in Flammen” onward differ from the climbing epics of Arnold Fanck, Trenker’s mentor and the progenitor of the German “Mountain Film” genre. While Fanck’s films were centered on the struggle between man and mountain, Trenker’s films found their antagonists in exogenous non-Germans attempting to live in German-speaking lands. “Trenker juxtaposes topophilic depictions of place – in his case, his homeland of South Tyrol – with almost xenophobic depictions of dubious intruders, generally city people, tourists, and business men. These topophilic attachments lend themselves to national or nationalistic extensions,” Wilms said.

The return of South Tyrol to German control was a priority for Hitler in “Mein Kampf,” and a collection of important writers also propagated this view. Some of the titles from the period are telling: novels with names like “Comrades of the Mountains” (1932), “Heroes of the Mountains” (1935), “The Fortress in the Glacier” (1935), and “War Diary of a Mountain Climber” (1936) populate the German literary scene of the 1930s. German speakers are portrayed within this corpus as the native, original inhabitants of these mountain realms. Tyrol’s mountains are portrayed as eternal in the way that the German bloodstream is felt to be eternal.

An English-language poster for the 1932 Luis Trenker film (Source: Universal).

Glaciers, we know, are not eternal. But it is important to pause and reflect on the nature of our discourse about glaciers and how our ideals of purity can be turned in horrifying directions. According to Andrew Denning, a professor of German history at the University of Kansas, Germany’s race-based nationalism emerged through notions of the poetic grandeur of nature itself.

“Romantic artists and thinkers laid the groundwork for the shift in the perception of the mountains in the late 18th and early 19th century from fearsome to awe-inspiring,” Denning said. “Romantics celebrated the spirituality of nature and saw in ancient, imposing mountain landscapes the physical manifestation of their critique of Enlightened hubris. Simultaneously, Romantics spoke of mystical, spiritual communities defined by common history and culture, laying the foundation for the rise of cultural forms of nationalism over the course of the nineteenth century.” Our own U.S. national parksspaces of exclusion in their own waywere born of that same Romantic spirit, after all.