Rainforest ecosystems play an important role in the balance of life on Earth. They absorb carbon from the environment, protecting the ozone layer. They contribute to the formation of clouds and are home to the most diverse animal and plant species on the planet. Rainforests harbor millions of plants, animals, insects, and microorganisms that haven’t even been discovered yet. More than a quarter of the natural medicines used by people every day have been discovered in rainforests. Some believe that the possibility of finding cures for some of the most devastating diseases lies hidden in rainforests.

However, all rainforests on the planet are under threat of destruction from influences such as deforestation for legal and illegal logging, agriculture, urbanization, and climate change. Biologists say that so far, deforestation has led to the extinction of thousands of species. Protecting and rehabilitating rainforests has become vital. While we know a great deal about rainforests, they still hold a lot of mystery for us, making it hard to understand what exactly we need to protect. “If we want people to protect nature, we need to tell them what we are actually protecting,” says Steffen Kirchgeorg, a PhD student at the Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL).

For his research, Steffen is developing autonomous robotic systems, like drones, to study tree canopies. His goal is to collect data that will provide the framework for the implementation of conservation models for rainforests. The data Steffen is trying to collect is environmental DNA (eDNA). In a rainforest environment, eDNA could be feces, mucus, shed skin, or hair. By collecting and identifying eDNA, biologists can better understand what species are present in certain areas. It could even lead to the discovery of new species. The challenge is devising a way to safely collect samples in a vast, inaccessible environment such as a rainforest canopy.

Steffen designed a special probe that can be attached to a drone to collect eDNA. The drone can access the treetops without putting people at risk or damaging the environment. The first step was to make a probe and winch system that could be adapted to a common drone. To ensure the probe was sturdy enough to collect eDNA, Steffen reinforced the fleece fibers of the probe with fiberglass. This allows eDNA to adhere to the probe when it brushes against vegetation. The winch had to be designed in a way that would allow the drone to remain at a safe distance and avoid entanglement.

Besides the standard cameras on the drone, Steffen had to install special sensors to help the device avoid branches within the dense tree canopy. The sensors also aligned with the winch to further prevent any chance of the drone or probe getting tangled in the canopy, which could destroy the device, data, or natural vegetation. When the probe is done collecting samples, it is retrieved by the drone to protect the samples from contamination. Navigational markers within the drone’s computer log where each sample is collected from.

Steffen’s drone system was a semi-finalist in the XPRIZE Rainforest, a 5-year-long competition that funds research for rainforest projects. As part of the competition, Steffen and his team demonstrated the eDNA-collecting drone in a rainforest in Southeastern Asia. Steffen also published an article about the project in ACS Publications titled eProbe: Sampling of Environmental DNA within Tree Canopies with Drones. In the article, Steffen states, “The effectiveness of this method was demonstrated during the XPRIZE Rainforest Semi-Finals as 10 eDNA samples were collected from the rainforest canopy, and a total of 152 molecular operational taxonomic units (MOTUs) were identified using eDNA metabarcoding.”

The eDNA collected by the drone identified a range of creatures. For example, the eDNA revealed the presence of long-tailed macaques, ants, spiders, and gall midge flies among the rainforest canopy. Though the drone did not collect any evidence of previously unknown species, there is always a chance that with continued use, such a discovery could be possible. As technology continues to evolve, innovations like Steffen Kirchgeorg’s drone system represent a promising way to protect our planet’s most precious ecosystems. By using advanced tools to collect and study eDNA, we gain a deeper understanding of biodiversity and the urgent need for conservation. With continued research and support, we may be able to unlock even more secrets hidden in the rainforest, preserving them for future generations.

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