DADE CITY, Fla. — The Southwest Florida Water Management District continued its work to stop the spread of old world climbing fern in Tampa Bay this week. 

“We have to try and find it early, when it’s small, and try and keep it at a maintenance level so it doesn’t get really bad,” said SWFWMD Vegetation Management Section Manager Brian Nelson.

On Wednesday, that effort was focused in an area of the Green Swamp Wilderness Preserve’s west tract. Vegetation Management Specialist Mike Busacca worked to cut back vines of the fern that had covered a small tree.

“Now, since I made a cut, all this stuff will die up here,” Busacca said, gesturing to the ferns on top of the tree. He then sprayed the base with herbicide. 

SWFWMD keeps track of new infestations through ground and aerial surveys. Busacca said about 700 of these small infestations had been identified in this tract of the swamp since November 2015.

Nelson said a significant amount of old world climbing fern was recently found for the first time in water management district-owned lands in the Starkey Wilderness Preserve and Cypress Creek Preserve. In the Green Swamp’s Tully Plantation area, there are two areas where it’s been detected extensively.

Old world climbing fern isn’t new to Florida. The invasive species was first detected in Martin County in the 1960s. Since then, it has overrun areas of South Florida and the Everglades.

The fern grows over existing vegetation, creating canopies as it climbs up trees. There are no predators or diseases to help keep it in check. Nelson said the fern is known for its monotypic infestations.

“That’s where you take a diverse habitat, like you see around here, you have a lot of different species that the wildlife depend on for food and habitat and stuff like that. And they replace it with just one species,” Nelson said.

According to Nelson, it also makes especially good kindling. That can make getting wild fires under control more difficult.

“The climbing fern acts as a chimney, so the wild fire goes right to the canopy,” Nelson said.

Controlling planned burns used to maintain other areas could also be a challenge if the fern spreads into wetlands.

“Those areas don’t normally burn because there’s not enough fuel for them,” said Nelson. “When you bring flammable old world climbing fern in there, all of a sudden, it brings fire into those non-fire adapted communities.”

Nelson said SWFWMD is also working with the state agriculture department to figure out what bio controls can be used to control the fern.