Native Ferns: Edging Out the Competition

The Tropical Garden, Fall 2015

By Jennifer PossleyDuring the past decade, Fairchild has worked with Miami-Dade County to increase our conservation collections of endangered native ferns. Today, we have well over a dozen species of threatened and endangered native ferns in our care. We use these plants primarily for wild reintroductions, spore production for long-term storage and display plantings at the Garden.

Another unanticipated use of our collection has been to provide material for testing biological control agents that might be used to suppress the spread of Old World climbing fern (Lygodium microphyllum)—one of the most damaging invasive plants that Florida has ever seen.

Scientists responsible for developing biological control agents for Old World climbing fern are housed at the U.S. Department of Agriculture/Agricultural Research Center’s Invasive Plant Research Laboratory in Fort Lauderdale. Staffers there travel to an invasive plant’s area of origin (in this case, Asia, Africa and Australia), identify insects that eat the weed in question and bring those insects back to the Fort Lauderdale lab for testing. The tests involve years in quarantine, during which the insects are presented with closely related plants to determine whether they might choose to eat other species, if given no other option. In the case of Old

World climbing fern, the USDA must test its biocontrol agents on native ferns to rule out any off-target damage.

Rare ferns, as you might guess, are extremely hard to come by, because they are not available for sale and cannot be collected from the wild. But Fairchild has made our collections available to the USDA in order to further this important research.

To date, the USDA has released three months and one mite that have passed through screening. Testing continues on two more insects: another moth and a sawfly. If these insects refuse to eat any Florida native ferns, then they, too, may be released to help curb the spread of Old World climbing fern in Florida. In a very real way, Fairchild’s endangered native ferns are taking an active role in preserving the rapidly disappearing habitat they so desperately need.