It is already known that dogs can use their highly developed sense of smell to search out drugs, explosives and disaster survivors. Now, some are being trained to find a different kind of threat - plant species that can harm the environment.

New York officials have identified an invasive plant species starting to spread in several of the state's major parks. The plant is a yellow-flowered bush called Scotch broom. Scotch broom is widespread in areas of America's Pacific Northwest. But it is still fairly new to New York. Officials are seeking to stop the plant's growth before it becomes widespread.

Handler Joshua Beese plays with Dia, a Labrador retriever, while they work to find Scotch broom, an invasive species, in Harriman State Park in Tuxedo, N.Y., Tuesday, Aug. 6, 2019. (AP Photo/Seth Wenig)

The plant spreads quickly, grows thick and can crowd out native plants. The growth of invasive species can also close off areas to wildlife.

One not-for-profit group is using the dogs to help fight Scotch broom and other invasive species. The New York-New Jersey Trail Conference launched its Conservation Dogs program in 2018. The program coordinates the training of dogs to find invasive species. It receives money from donations as well as New York's Department of Environment Conservation.

After the dogs identify the species, people then attempt to remove the plants before they become a wider problem.

A 2010 study reported high success rates of dogs using their noses to search out invasive species. The study found that trained dogs could smell and find two times more invasive plants than humans could observe with their eyes.

Joshua Beese is a dog handler with the Trail Conference group. He has worked with a Labrador retriever called Dia to hunt for Scotch broom in New York state parks.

"If we had to find all these plants ourselves, combing the grass for every tiny plant, it would take so much longer. And we'd still miss a lot," Beese told The Associated Press. Dia was able to lead him to hundreds of small Scotch broom plants largely hidden by other growth. Beese has trained Dia and other dogs to find other invasive species too.

Another not-for-profit organization working on the problem is Working Dogs for Conservation. It is based in Bozeman, Montana. It seeks to train dogs "to protect wildlife and wild places," including invasive species work. The group has trained dogs in several states including Montana, Iowa, Colorado and Hawaii.

The organization's director, Pete Coppolillo, said, "We've trained over 200 dog and handler teams to help in global wildlife trafficking, and now we're doing a lot of invasive species work."

Coppolillo added that human teams had tried for years to find and remove a destructive plant in one area of Montana without much success. But after a border collie and golden retriever from Working Dogs for Conservation were brought in to help, the species nearly disappeared within a few years.

Dogs are especially effective at this work because they can smell plants hidden among other species. People often need to see flowers on the plants to make an identification.

"That's a game-changer," Coppolillo said. "Each plant can set up to 15,000 seeds a year, and seeds can live seven years in the soil. Dogs find plants before they flower and reproduce."

The Associated Press reported on this story. Bryan Lynn adapted the report for Learning English, with additional information from the New York-New Jersey Trail Conference. Ashley Thompson was the editor.

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