Southwest Florida’s landscape is graced by numerous native plant species. From towering longleaf pine trees with their prickly pinecones bobbing in the breeze, to the leatherleaf ferns that blanket the marshy bald cypress forest floors, there is so much more to these native ecosystems than meets the eye.
Experts and residents say they are aware of troubling trends impacting these native plant ecosystems, which they say can be attributed to exotic invasive plants taking root in Southwest Florida.
Chad Roy, a park ranger supervisor for Lee County Parks and Recreation since 2017, says this hits home for him.
“I do kind of take it as a personal thing, especially when I see the amount of plants that are out there that are negatively affecting our habitat,” Roy said.
Roy explains that some of the negative impacts include the displacement of indigenous plant species from their native locations, the destruction and elimination of resources these species rely on, and ecosystem disruption.
Dr. John Griffis is Florida Gulf Coast University’s chair for horticulture education and research. He’s also a professor in ecology and environmental studies, and he agrees with the exotic and invasive plant effects. He says when an exotic plant harms surrounding habitats, it is considered invasive.
Griffis says he sees many people confuse the terms “exotic” and “invasive,” likely unaware of the critical distinction between the two. He says correcting this is the first step a person can take in understanding the true impact invasive plants can have on native species.
Griffis explains exotic plants are those that are not native to an environment in which they live. He says while some plants can be both exotic and invasive, just because a plant is exotic does not necessarily mean it’s invasive.
Citrus, for example
“Many exotic plants are not invasive at all,” said Griffis. “A good example is the citrus tree, which is certainly not native, but doesn’t tend to invade and if not carefully managed and fertilized and watered, most citrus trees are dead in two to three years here.”
Roy added that with more than 4,700 native and exotic plant species in Florida alone, managing invasive plant populations can be challenging.
“We have, in the past, made mistakes, where we’ve brought in plants for different reasons,” said Roy.
Roy references the Brazilian pepper tree (Schinus terebinthifolius) as an example—a now invasive plant in Florida that people introduced for ornamental purposes in the mid-1800s.
“It’s everywhere you look,” Roy said.
Roy said other invasive plants, like the Brazilian pepper tree, harm native plant populations in many ways. He highlighted the worst result.
“They basically displace the native populations, and it creates what we call monoculture,” Roy said.
Roy said monoculture describes conditions where environments have only one species of plant growing, reducing the biodiversity of surrounding native plants. This allows that species to grow unimpeded, making it invasive.
Roy added that the increasing trend of monoculture in once sprawling and diverse habitats holds severe implications for remaining native plants. He pointed to the Australian Pine (Casuarina equisetifolia) as another prime example of an invasive plant making way for monoculture to take over.
According to the Florida Fish and Wildlife Conservation Commission (FWC), the Australian Pine was introduced to Florida in the 1890s to form windbreaks around canals, agricultural fields, roads, and houses.
“It basically takes over and it chokes out all the sunlight, preventing a lot of small herbaceous plants (leafy plants with no woody stems) from coming up underneath,” Roy said.
Roy notes that the effects do not stop there as invasive plants also impact native wildlife species. He says the gopher tortoise (Gopherus polyphemus), a keystone species native to Florida which many other wildlife populations depend on for their ubiquitous burrows, has felt the brunt of the punch.
“If they don’t have herbaceous plants to forage on down on the forest floor, they can’t survive,” Roy said.
It's personal
Avalee Lane, a 19-year-old Lee County resident originally from Chattanooga, Tenn., says this is personal for her, highlighting her love and appreciation for nature and all of its intrinsic residents, both plant and animal.
“It’s definitely a negative feeling,” Lane said. “It definitely shouldn’t be happening.”
Lane says she wants to see more native plant species to provide sustainable food and shelter for native wildlife.
Dennis Giardina, a biologist who has worked in the invasive plant management section of the FWC since 2007, also wants to see more native plant life. In addition to planting more native plants, he mentions another avenue he says his department is currently utilizing to preserve the remaining native plant populations. He calls this “integrated pest management.”
Giardina says this involves scientists going to the native ranges of different invasive species and collecting insects from the plant. The scientists then bring the insects back to a laboratory, where they examine them. What they are looking for is the potential that the insects evolved with these plants in their native environments, and, for that reason, the insects cannot survive without them.
If these characteristics are present, the scientists create a colony of these insects and release them into the impacted areas.
He says a current example is the Brazilian pepper tree thrip (Pseudophilothrips ichini), an insect that exclusively feeds on Brazilian pepper tree and helps to tame the plant’s population. According to the U.S. Department of Agriculture, the process of releasing the thrips throughout 567 sites in Florida began and progressed between May 2019 and December 2021.
Brazilian pepper tree thrips feed on Brazilian pepper tree leaves.
“There’s literally no impact to the greater ecosystem other than their suppression of the group of plant species that they were identified as being specialists of,” Giardina said.
He also says his team also uses herbicides for more concentrated outbreaks.
Roy says another way Southwest Florida, particularly Lee County, continues to make great strides in preserving native plant populations is through the Conservation 20/20 program, which voters approved in 1996.
According to Roy, the program involves purchasing county lands to protect and preserve them for future generations. As of now, the program has acquired and manages over 31,000 acres of conservation land.
“We kind of look at it as 20/20 vision, to be able to not make the mistakes that other people have made throughout the state with over population and urbanization in an effort to try and conserve what’s left of our preserve and our natural areas in Lee County,” Roy said.
Get smart
Dr. Mike Knight, a district biologist with the Florida Forest Service who oversees invasive vegetation control in two state forests, says while these methods are extremely helpful, more can be done. He says he wants ordinary people to know that they can also make a difference to preserve native plants. This starts with educating the public, mainly seasonal residents and tourists.
“These groups of people, because they’re coming from other parts of the country, they don’t necessarily understand the Florida environments,” Knight said.
Knight suggests specific educational campaigns targeting neighborhood associations and viewers of local media.
Roy says he agrees with this notion, adding he feels these programs would foster a more unified understanding regarding which plants are invasive, and which are not, and the dangers associated with their occurrences. This, he says, is his secret for a brighter and more diverse future here in Southwest Florida.
“It’s one of those things that there’s only so much that one person can do, and I got to keep it in the back of my mind that it’s a group effort from everybody,” Roy said. “And if everybody understands and is more educated, I think it would make ultimately a better place for all of us.”
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