Drones Are Set to Revolutionize Biodiversity Research by Providing Close-Up, High-Resolution Imaging and Data Collection Capabilities

To have a healthy ecosystem, we need biodiversity, as it supports all life on Earth, including humans. Without a variety of microorganisms, plants, and animals, we simply can't have a balanced environment.

To maintain a healthy ecosystem, we need biodiversity, as it supports all life on Earth, including humans. Without a variety of microorganisms, plants, and animals, we simply can't have a balanced environment.

Biodiversity provides ecosystem services such as clean air, freshwater, and flood management, which are crucial to human well-being. It also supports food security, helps in carbon sequestration, detoxifies and decomposes waste, enhances resilience in organisms, and helps regulate disease. The genes in plants and animals are even used to develop medicines and pharmaceuticals.

So, it's clear that we need a better understanding of biodiversity. A powerful tool to study biodiversity in forests and tree canopies is the analysis of environmental DNA (eDNA). However, collecting the samples of eDNA isn't easy in such high and complex environments.

Traditionally, labor-intensive approaches like tree rolling or surface swabbing have been used to achieve the task. Relying on satellite imagery or using cranes to study regions not only required significant efforts to reach sufficient coverage but also lacked precision.

But not anymore. Drones are all set to transform the situation by providing close-up, high-resolution imaging and data collection capabilities.

A new study proposed using unmanned aerial vehicles (UAVs) to explore biodiversity in treetops, specifically in remote and inaccessible areas. This means drones will perform the job safely without requiring people to go to hard-to-reach areas like tropical rainforests to collect genetic material from treetops while helping us get a deeper understanding of biodiversity.

Gathering eDNA Using Drones

eDNA is found in biological substances such as mucus, feces, and dead skin cells and has been used to examine biodiversity for several decades now. Used to catalog and monitor biodiversity, the DNA traces help researchers determine which species are present in a particular area.

Early last year, scientists from ETH Zurich research institute used this technique to find out just which species use forest canopy to build their homes.

To build this special drone that has the ability to gather samples on tree branches on its own, researchers at ETH Zurich along with those from the Swiss Federal Research Institute WSL partnered with the company SPYGEN.

The aircraft was installed with adhesive strips on the bottom of it. The UAV was gently brought down on branches and once generic material was transferred from branches to these adhesives, it was then analyzed.

But ranches vary in their thickness and elasticity. And having the aircraft approach a branch and remain stable to take samples successfully proved to be a big challenge for the researchers.

“Landing on branches requires complex control.”

– Stefano Mintchev, Professor of Environmental Robotics at ETH Zurich and WSL at the time

So, the team fitted the drone with a force-sensing cage, which allowed the aircraft to measure the flexibility of the branch and use that to move. The device was then tested on seven tree species, and the samples were found to contain DNA from 21 distinct groups of organisms, including birds, insects, and mammals.

While this is an easier, faster, and safer alternative to sending biologists high up into the treetops, even this method isn't completely risk-free.

When using the drone, there is a risk of not only damaging the tree but also the drone itself in case there's an unintentional hard collision. Then, there's the limitation of gathering samples only from branches on which the drone lands. So, while the results have been “encouraging,” the drone had to improve.

An Improved System to Study Biodiversity

Now, scientists from ETH Zurich have created a novel, custom-designed robotic system. This new approach for UAVs to collect eDNA within tree canopies uses a surface swabbing technique.

Led by Steffen Kirchgeorg, a robotics PhD student at ETH Zurich, the study developed a sampling system with a flat fabric probe. The piece of fleece cloth is actually cut into a circle, much like how a coffee filter is shaped, and attached with fiberglass strips to provide structure.

The probe is moved down on a tether from a lifting gear mounted on the quadcopter's underside. This way, the drone is kept out of the vegetation.

The drone was also equipped with a sensor that prevents the tether of the probe from tangling on branches. The researchers programmed the system to shift position automatically when detecting an impact.

The way it works is that the UAV hovers safely above the treetops. The probe is then lowered through the foliage where it brushes against leaves and branches. And once eDNA has been gathered, the probe can be removed for its content to be subsequently analyzed.

The experiment was performed in a rainforest in Southeast Asia, where the drone was remotely controlled by Kirchgeorg and colleagues through a live feed from its onboard camera. The drone was flown out of the line of sight to collect ten samples from the forest canopy.

The effectiveness of the new approach was demonstrated during the XPRIZE Rainforest Semi-Finals, where the team revealed they found the eDNA of 152 different species from these