The probably highest insect trap in Switzerland

Researchers from the WSL Institute for Snow and Avalanche Research (SLF) and the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) are investigating the impact of climate change on insect biodiversity. As part of a larger project, they have set up an insect trap on the Weissfluhjoch in Davos, which they will be emptying every week. With photo series.

13 July, 8.45 a.m.: The summit station of the Parsenn Funicular in Davos is enveloped in clouds. Visibility is barely 50 metres. Three heavily laden individuals with crammed backpacks make their way downhill towards the Weissfluhjoch test site. SLF biologist Anne Kempel also has two long wooden posts tucked under her arm, her colleague Mathieu Cretton from WSL is carrying an insect trap, and Mauro Vareni, who is doing his civilian service, is holding a digging bar, a pointed steel rod used to make holes in the ground.

The three are heading off to set up an insect trap at a location where researchers collect snow data every day in the winter. At 2,536 metres above sea level, it is probably the highest such trap in Switzerland, and certainly the highest installed as part of the INSECT-RBA project, in which WSL is working withAgroscope, the Research Institute of Organic Agriculture (FiBL), info fauna (CSCF) and the Swiss Ornithological Institute to collect information oninsect diversity and abundance at 42 sites. In Davos, Anne Kempel and her team from the SLF are supporting this work by emptying the trap once a week for seven weeks, always on the same day. This saves their WSL colleagues from having to make the long journey from Birmensdorf.

13 July, around 9 a.m.: The three researchers have reached the test site. Visibility is slowly improving. Kempel points to some raised ground. "If I were you, I'd put the trap up there," she says to Cretton. This proves to be good intuition on her part. Scientists already studied insect biodiversity across Switzerland between 2000 and 2007, and WSL and its partners are now replicating this work in 2023 to 2025, at the same locations.

On the elevated ground, the researchers come across a plastic pipe in the ground. "Part of the old trap from 2007 is still here!" says Kempel, delighted that they can use the very same spot. And so the trio set to work, driving posts into the ground, attaching a yellow plastic funnel, and building a roof over the pipe in the ground.

Most scenic location of the project

It is the only trap in the project that has not yet been installed. "Because of the harsh climate and later snowmelt at this elevation, we started operating this trap four weeks later than at the other sites," explains Kurt Bollmann, Head of WSL's Conservation Biology research group, who is responsible for the project. The researchers will also completely dismantle the trap on the Weissfluhjoch every autumn, whereas the other frames will mostly be left in place over the winter.

13 July, around 10 a.m.: Just under an hour later, the work is complete. The trap is in place; all that's needed now are the insects. By now the cloud has cleared. Cretton lets his eyes wander down the valley and over the mountains: "This is definitely our most scenic location."

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Setting off from the SLF early in the morning (from left to right: Mauro Vareni, Anne Kempel, Mathieu Cretton) (Photo: Jochen Bettzieche/SLF)
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Walking down from the Parsenn Funicular summit station in poor visibility… (Photo: Jochen Bettzieche/SLF)
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…to the Weissfluhjoch test site. (Photo: Jochen Bettzieche/SLF)
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SLF biologist Anne Kempel resurrects an old insect trap from 2007. (Photo: Jochen Bettzieche/SLF)
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She then hammers in four small posts and installs... (Photo: Jochen Bettzieche/SLF)
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Another larger trap next to it requires heavy tools... (Photo: Jochen Bettzieche/SLF)
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…and a cordless screwdriver. (Photo: Jochen Bettzieche/SLF)
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Cretton and Kempel attach the catch funnel. (Photo: Jochen Bettzieche/SLF)
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…and tie it in place. (Photo: Jochen Bettzieche/SLF)
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Cretton fetches water for the traps from a nearby stream. (Photo: Jochen Bettzieche/SLF)
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Time to head back to the SLF. (Photo: Jochen Bettzieche/SLF)

More facts, to be able to properly arrange support measures

It is also a location that should contribute important results. Overall, the researchers predict that the number of species and the quantity of insects recorded for the INSECT-RBA project will have remained more or less stable. "However, at the high-altitude Weissfluhjoch site, I expect an increase in both quantity and biodiversity, due to climate change," says Bollmann. He wants to gather more facts about how the insect world in Switzerland is changing in order to be able to properly arrange support measures. "We're not assuming a general insect die-off, but rather a reorganisation of insect communities with clear winners and losers," he explains.

13 July, 10.15 a.m.: On the Weissfluhjoch, Kempel, Cretton and Vareni pack up their kit and take one last look at their trap, before shouldering their backpacks and making their way to the middle station to return to the SLF.





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