One sniff at a time, an energetic Labrador retriever named Dia is changing the way we combat invasive species in New York State Parks.

Along with her handler Joshua Beese, this invasives-fighting team from the nonprofit New York-New Jersey Trail Conference is on the hunt for Scotch broom, a threat to the native ecosystems in Bear Mountain and Harriman state parks in the Lower Hudson Valley.

Dia uses her powerful sense of smell to help find small and sparsely distributed invasive species that might be missed by human searchers. Since November 2018, her incredible nose has been specially trained to sniff out the invasive plant Scotch broom.

Scotch broom (Cytisus scoparius)is one of the most destructive invasives on the Pacific Coast, where it has had costly implications for agricultural industries. When it began showing up in New York’s parks, land managers became concerned. Scotch broom forms dense clusters that can displace native plant species and reduce biodiversity that is essential for a healthy ecosystem.

The Lower Hudson Partnership for Regional Invasive Species Management (LHPRISM), which works to minimize the harm caused by invasives, ranks Scotch broom as a tier 2 priority invasive species. That means it is present in such low numbers in the Lower Hudson Valley that with proper action it could be completely eradicated from the area before the population becomes established.

The New York State Parks Invasive Species Strike Team and the Trail Conference’s Invasives Strike Force (ISF) Crew of AmeriCorps members, volunteers, and interns have collaborated over the past several years in a bid to eradicate Scotch broom in the region. The ISF Crew has been finding and removing Scotch broom in state parks since 2014, when 37 separate populations were recorded at Bear Mountain and Harriman.

While a few locations no longer have any plants, other locations are harder to manage. It becomes challenging to find the few remaining individuals among all the other vegetation, which means this destructive plant could still propagate. That’s where Dia comes in!

“Dia first comes into the field with her nose up, smelling what’s in the air, working to detect the Scotch broom scent,” explains handler Beese. “She’s using what are called scent cones; she works her way into a cone and uses that cone to help her narrow down the source.”

Once in a cone, she will search until she gets to the source and put her nose to the ground to sniff out smaller plants that may be tiny and low to the ground. She alerts Beese that she’s found the species by standing or sitting. “The most important thing is that she’s committed to an area where she’s detected the plant until I come and reward her,” Beese says. “Then we can mark it and remove it.”

Dia’s reward: Her ball on a rope with a game of tug and fetch. See Dia in action by following her on Instagram @diasavestheforest.

Utilizing their exceptional sense of smell, dogs have been commonly used for search and rescue, as well as weapons and narcotics detection. These tracking and detection skills are now being used to protect our wild spaces. In 2010, the journal Invasive Plant Science and Management published a study that concluded trained dogs could smell and detect twice the number of invasive plants that humans could observe with their eyes.

Although other groups have used dogs for short projects to detect of invasive species, the Trail Conference’s Conservation Dog Program is the first permanent program of its kind in the Northeast.

This is Dia’s first season in the field; she has already been on more than 20 surveying trips. In several instances, the Trail Conference’s Invasives Strike Force Crew had been to a site and completely removed every plant they were able to find—and then Dia found a few more.

Dia came to the Trail Conference from a farm in Wisconsin that breeds dogs for hunting competitions. She was selected for the program by Beese, an experienced search and rescue dog handler, who is assisted by volunteer Arden Blumenthal. He has trained Dia with the mentorship of Aimee Hurt from Working Dogs for Conservation in Montana, an organization that has been working with dogs on conservation projects for more than 20 years.

In a metropolitan region highly prone to invasive infestations, early detection when populations are small is a key component of successful invasive species management. Not only does Dia make search-and-destroy efforts more thorough within infestations, she is also able to find stray plants outside the known boundaries where people had focused their searches. Dia helps make sure the area is really cleared to reduce the potential for reinfestation or further spread. With better search efficiency, it should be possible to declare New York State parks Scotch broom-free in the near future. 

Up next for Dia is slender false brome (Brachypodium sylvaticum), an invasive grass that can outcompete existing vegetation, including threatened and endangered species, and harm wildlife populations by altering food sources. Slender false brome has recently been found in Letchworth State Park, and this location will serve as a training ground for Dia.

***UPDATE: Dia and her team recently went to Letchworth State Park, where they did find the invasive slender false brome in areas where surveyors had missed it.

Conservation dogs can learn to detect up to three new species each year, meaning Dia’s incredible talents will continue to develop. “In three or four years,” Beese says, “we’ll be pushing forward the science on what can be done with invasive species detection using dogs.”

Post by Linda Rohleder, Director of Land Stewardship, New York – New Jersey Trail Conference and Coordinator, Lower Hudson Partnership for Regional Invasive Species Management (PRISM)