The drone revolution. What does it mean for aerial biodiversity?

Unoccupied aerial vehicles (aka drones) were invented in the early 20th century with military uses in mind, but were not used en masse until the Vietnam War. Today, while they continue to be used in conflict zones, drones have many other applications. Indeed, recognition of their versatility and low-carbon footprints (though not zero-carbon) drives the drone revolution. By that, I mean the current explosion in manufacturers, models and applications, such that the drone industry is an economic juggernaut. And with uses like parcel delivery, security, traffic surveillance and air taxis (yes, in the near future you might be picked up by a drone instead of a Lyft driver—check this out!), growing fastest in cities, the drone revolution is an urban-ecology phenomenon.

So, a big concern in our lab is what this booming industry means for aerial biodiversity. And note, we are talking about a realm (the atmosphere) whose biodiversity is poorly studied, let alone conserved. On one hand, drones present conservation benefits. Researchers use them to study terrestrial and aquatic ecosystems and species, including in very challenging terrain (like sea cliffs). On the other, drones are novel human-made objects that flying animals could collide with, and their lights and noise are stimuli that could adversely affect wildlife.

Thus far, there have been perhaps a few dozen tests of how drones affect wildlife. And they have yielded valuable information, with negative impacts common (but variable depending on focal species, locales and more). But these studies have left at least one research gap: nearly all of them tested impacts on animals that were on the ground or in the water. Which is problematic considering that most drone-wildlife encounters occur in the air.

We are investigating the ecological impacts of drones on aerial species. This builds on work by my former student in Singapore, where bat activity declined in 77 % of drone flights. But with drone enthusiasts in Singapore crowding the very few places where they can fly their drones each evening, we could not run a controlled experiment there. Fortunately, that is possible in NYC, where we performed a pilot study, using a before-after-control-impact (BACI) design. Using acoustic monitoring, we measured the effect of experimental drone flights on bat activity. This study showed that the research idea is feasible and—while we are still analysing the complex data—uncovered preliminary evidence of negative impacts.

Now, the plan is to introduce an urban gradient to test the hypothesis that animals in urban skies are less sensitive to drones because they are used to all the noise and light of the city. We also want to measure impacts on birds and insects (which could be killed by drone strikes).

But we are not just focused on negative impacts. We are also curious about whether drone surfaces are passively picking up environmental DNA (eDNA), which all kinds of organisms shed and leave behind in their habitats (not just aerial ones). If drones do collect eDNA, then drone technology might be adaptable to monitoring and describing the species that live in the air. This pilot study is also nearly done—we amplified and sequenced eDNA collected from the surfaces of our drones and are now running the bioinformatics that will reveal what we found.

So, watch this space!


The pilot bat-impact study was funded by the PSC CUNY Enhanced Research Grant, while the eDNA sequencing was funded by Queens College’s Research Enhancement Grant. And the infrastructural support of Prof John Dennehy and his awesome team (special shout out to Prof Monica Trujillo and Dr Sherin Kannoly) made the molecular work possible. Same for John’s invaluable expertise and advice, augmented by the assistance of Prof Elizabeth Clare, a true eDNA pioneer.