How drones and AI could help stem the spread of a plant invading Quebec parks

Next time you're in one of Quebec's provincialparks, take a look around. Notice anything that shouldn't be there?

You likely wouldn't, as a pesky invasive plant wreaking havoc on local biodiversity, called the common reed, holds true to its name.

The alien grass,Phragmites australis subsp. australis, can be spotted across much of the province and the country, spreading throughmarshes and in ditches along highways.

Tall with a woody stem and clusters of flowers that start purple and turn wheat-coloured, the common reed can also be found in seven of Quebec's 23 provincialparks for now.

"The common reed is a really aggressive, invasive species, and when it arrives, it takes almost all the biodiversity," said Antoine Caron-Guay, a researcher at Montreal'sInstitut de recherche en biologie vgtale (IRBV).

Inles-de-Boucherville provincial park,located on a chain of islands onthe St. Lawrence River between Montreal and the South Shore, large areas have been colonized by the plant, becoming giant reed beds that deprive the park's animals of food and habitat.

"There's a lot of interesting species here, and the common reed is like a threat to [them all]," said Caron-Guay.

Quebec's highest concentration of common reed is found in the park, according to Caron-Guay. So the researcherhas begun experimenting with drones and artificial intelligence to map the plant's relentless spread in hopes of nipping it in the bud so to speak.

How the technology works

Before you can stop the spread of an invasive species, you need to know where it can already be found.

While the mature common reedcolonies are pretty easy to spot, as the reedscan grow more than five metres tall,Caron-Guayis trying to identify the plants whilethey'restill very young, to stop them from getting a foothold.

To conduct his field research throughout May and September of 2022, heusedtwo large drones to take a multitude of high-resolution aerial photos, flying them through the air tomapthe area below in detail.

He took these photos back to a lab and fedthem into an AI program that he trained to look for common reed plants from above.

Once the AI knows what it's looking for, it can analyze new photos in minutes or even seconds. Caron-Guay says his program, for which preliminary results show about 90 per centaccuracy, can be used tospeed up the work of park conservation officers.

Sophie Tessier, co-ordinator of the conservation and education service for the les-de-Boucherville park, agrees.

"If you had someone really go [out in]the field with a pen and paper, maybe taking pictures, maybe taking some samples, that would be a really long project without the drone," she said.

"But now, with technology, you could have lots of data and just maybe one person doing the work of, let's say, 10 botanists in the field.But that doesn't mean that technology will take over all the human aspects of it."

Common reed removal can take years

That's because humans still need to validate the findings of the AIand even once you know where the plants are, you still need to get rid of them.

Caron-Guay says the smaller the plant, the easier it is to clear.

"You have to put local herbicidewith a sponge, and it won't affect the environment around," he said. "But when you have a big colony, it is much harder."

Ripping out mature plants is difficult, as common reed can reproduce easily from a small piece of stem or rhizome left behind, meaning the earth around the plants must also be removed and replaced with uncontaminated soil.

As the plant hates shade, Caron-Guaysaid it can also be eradicated by covering it witha large tarpwhich deprives it of sun and suffocates it, but this process can take years.

Tessier says the park is using the tarp method, and it takes daily effortto make sure nothing is growing back.

Future of AI for other invasive species

Caron-Guay is now testing to see if the AI program can still give accurate results with lower quality photos shot by smaller, more consumer-sized drones,which are cheaper anddon't requirea drone pilot certificate to operate.

That would make this type of research more accessible to other researchers and possibly expedite conservation efforts.

The reduction of invasive species by 50 per cent by 2030 was a key goal agreed uponat the UN biodiversity summit, known as COP15, held in Montreal in December.

tienne Lalibert, Caron-Guay's supervisor and a professor in plant ecology at Universit de Montral, says that Quebec's provincial parksareessentially open-airresearch labs where scientists can test out projects likeCaron-Guay'sand see the real-world impacts they have on conservation efforts.

Lalibert is already overseeing some other researchers who are also using drones for different aspects of biodiversity research. He believes this technology could have applications for other invasive species, too.

"I'm thinking, for example, in particular thewater chestnut, which is an aquatic plant that is taking over rivers and lakes," he said.

"It's actually quite difficult, obviously, to find it because it moves around with the current, and so I think this technology is sort of the first steps."

Lalibert said you could also likely use the same technology to map the impacts of pests like the emerald ash borer,an invasive beetle, by identifying damaged ash trees.

As for the future of the les-de-Boucherville park and the fight against the common reed, Caron-Guay is looking forward to the day when he can witness the fruits of his labour.

"It could be a small impact.I won't change the world, but I hope that someday, likein a few years,I could come here and see that there's a place where there's no common reed," he said.

Seeing the return of theleast bittern, an endangered bird speciesaffected by the loss of its natural habitat to the common reed, would also be a testament to his efforts.

"To see that this species could return to the les-de-Bouchervilleparkwould be truly magical. It would be seeing that my work has served a purpose."