Exotic Plants Affecting Florida’s Ecosystem

Exotic plants continue to adversely affect Florida’s native biodiversity and plant communities. As exotics displace native plants, ecologies change and may leave endangered and other animal species without food.

“Exotic plants are a problem statewide,” said Beth Jackson, environmental program supervisor for Orange County’s Environmental Protection Division.

Despite the knowledge about the risks of invasive exotic plants, retailers continue to sell the plants; homeowners then place them in their gardens; and Orange County and other stewards of public and natural lands remain vigilant as they fight the non-native species and educate people about the risks.

“There are native alternatives that will give people the same feel in their yard [as exotics],” Jackson said.
About 25,000 non-native species are present in Florida and account for more than one-third of all plants in the state.

A 2009 City of Orlando, Municipal Forest Resource Analysis by the Center for Urban Forest Research and the U.S. Department of Agriculture Forest Service found that invasive exotics constituted about 7 percent of Orlando’s street trees. The city will waive its tree-removal permit fees for invasive, exotic species. Residents cannot plant new exotics to replace trees they remove.

Many of the exotic plants were introduced by accident, before people knew the risks, Jackson explained. For instance, someone is thought to have seeded the Everglades from an airplane with melaleuca, a genus of plants in the myrtle family, hoping to drain the Everglades. The air potato was brought from Africa as a potential food source. However, the yams do not grow in Florida. Neither exotic has natural enemies, and, as a result, they have reproduced rapidly.

“A lot of exotics escaped from people’s backyards,” said Jackie Rolly, a board member at Oakland Nature Preserve. “People want to keep planting them, and the nursery industry supports them.”

Rolly said many people who moved to Florida from other areas like to plant vegetation native to their home region, because it is familiar to them. Other people want to create a tropical ambiance, even though Central Florida is subtropical.

Orange County tries to limit growth of exotics by using herbicides. According to Jackson, the invasive species are so pervasive that the county cannot eradicate them. It also conducts workshops to educate people about the risks and how to manage the invaders.

Among the suggestions the county recommends is for homeowners to learn which plants are native and exotic, and then inspect the yard for exotics and remove them. The plants should be thrown away with the household trash to avoid them growing or spreading elsewhere. Homeowners should plant only native varieties.

People also can participate in events to remove exotics from public lands. For example, the county and Oakland Nature Preserve often holds volunteer events to remove the potatoes growing on the preserve’s air potato plants, since that is a successful method of controlling the air potato. If left to grow, the air potato will shade natural plants and eventually kill them.

In South Florida, the U.S. Army Corps of Engineers, South Florida Water Management District, U.S. Department of Agriculture’s Agricultural Research Service, and several other partners have begun construction on a $16.7 million science facility that will raise insects to help control invasive plant species, including melaleuca, Lygodium and Brazilian pepper.

Rolly explained that when people import plants, they do not bring the species’ natural enemies, which keep the plant under control in their native country. The exotic then out-competes Florida’s native plants. Native animals, unfamiliar with the exotics, will not eat them.

“One plant can devastate an ecosystem,” Rolly said. “Exotics are starting to be a serious problem.”

For more information about Florida invasive species, visit www.fleppc.org/list/list.htm on the Web.