Invasive plants, weeds are causing problems at a New York park. The solution: Hungry goats.

Goats truly are the Greatest of All Time, this time for munching on weeds and invasive plant species at Riverside Park in Manhattan to protect the area's native vegetation.

On Wednesday, 20 goats from Green Goats Farm in Rhinebeck, New York were dropped off at Riverside Park and started chowing down immediately. Only four goats will stay there – Skittles, Elenor, Big G and Cheech, said Alison Ettinger-DeLong, communications and development coordinator for Riverside Park Conservancy.

The goats will likely stay in the park until August or early September.

She said their presence in the area is an environmentally-friendly way to remove invasive species, which have been an issue for "a really long time." One of the most dire areas in the park is a steep slope in the 400-acre park, she said.

"It's very hard for human hands to get in there and remove invasive species," Ettinger-DeLong said. "(Goats) eat pretty much anything and they can get right in there. They can traverse this really steep slope."

Goats can eat porcelain berry, English ivy, mugwort, multiflora rose and poison ivy, she said.

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It's the third year the goats have visited the park to help out as part of Manhattan's "Goatham" program. They'll be in a small, dense area that covers a couple of blocks. It has hilly terrain, despite many people thinking Manhattan is a flat area.

Goats can consume 25% of their own body weight in the in vegetation in one day, she said.

What is an invasive species and why is it bad?

Invasive species are amphibians, plants, insects, fish, fungi, bacteria and seeds or eggs that are not native to an ecosystem and cause harm, according to the National Wildlife Federation.

An invasive species does not have to come from another country, the organization said.

These species cause harm by destroying or replacing native food sources, providing little to no food value for wildlife and even replacing diverse ecosystems. They can also carry disease and prevent native species from reproducing.

That's where the goats of "Goatham" come in. They'll be plenty comfortable too, said the conservancy.

There's a tent area for them to take cover if need be, and Riverside Park Conservancy staff will work with about 70 volunteers to herd the goats back to their shelter every night, Ettinger-DeLong said.

They are also monitored early in the morning, throughout the day and at night, and there are professional horticulture and veterinarian staff members on standby to make sure they're safe.

The goats not only help the park, but draw a lot of attention to the area and the conservancy's projects, she said.

"Anything that can draw people into the park, get them involved, and get them caring about their green spaces is incredibly important."

Saleen Martin is a reporter on USA TODAY's NOW team. She is from Norfolk, Virginia – the 757 – and loves all things horror, witches, Christmas, and food. Follow her on Twitter at @Saleen_Martin or email her at sdmartin@usatoday.com.

This article originally appeared on USA TODAY: NYC park in Manhattan welcomes goats to kill weeds, invasive species