Author: Stephanie Koontz
In conservation sometimes rare plants and animals need a little boost in numbers to help populations in the wild rebound or remain stable. For plants, this is typically done by directly sowing seeds or by collecting seeds or stems from plants in the wild, growing them up in a greenhouse, and then re-planting them into their natural habitat. These translocations can be to new sites, where the habitat is right, or to existing populations in the wild. The Plant Ecology Program at Archbold Biological Station has successfully conducted three translocations of one of the rarest mints on our planet, Garrett’s Mint (Dicerandra christmanii), found only in Highlands County, Florida. “Through these efforts, we hope to keep this unique little mint around for generations to enjoy”, exclaims Program Director Eric Menges.
Garrett’s Mint is listed by the US Fish and Wildlife Service as federally endangered, and only protected on a single property that is part of the Lake Wales Ridge National Wildlife Refuge. Due to its limited distribution, its status and recovery have received a lot of attention. Scientists from Archbold have partnered with the US Fish and Wildlife Service to design and implement a recovery strategy using translocations. “Our program first experimented with translocating Garrett’s Mint in 2010 to a site where the mint was known to occur,” explains Menges. “We worked with the Rare Plant Conservation Program at Bok Tower Gardens to grow the plants from cuttings and seeds collected in the wild. Starting with 200 plants and 4,000 seeds, next thing we knew, there were 1,546 plants five years later. Many of these recruited as seeds from the soil seed bank, which tells us these translocated plants are successfully producing their own seeds for the next generation. And lots of them!” With such success, the Plant Ecology Program moved forward with another translocation, this time to a new property where the habitat was right, but Garrett’s Mint was not known to occur.
On a hot day in September 2012, scientists from the Plant Ecology Program again set out to transplant 216 Garrett’s Mints to a new site, a property protected for conservation. “We had high hopes for this site, given how well our previous translocation had gone,” explains Lexi Siegle, a research assistant in the Plant Ecology Program. “Then, barely three years in, the site was managed with a prescribed fire, which killed 70% of our plants. Although we know the plant lives in fire-prone scrub habitats, we were concerned that maybe not enough time had passed for a seed bank to build up for recovery from fire.” Prescribed fires are a natural disturbance in Florida scrub, reducing thick oak and palmetto vegetation, and opening habitat for other plant species to grow. Garrett Mint adults are known to be killed by fire, but seeds stored in a soil seed bank germinate following fire events, quickly aiding population recovery. “All we could do was wait and see,” remarked Siegle.
Archbold scientists would not have to wait for long. They returned to the site six months after the fire and were delighted to find ~250 new seedlings emerging from the ashes. “Not only did we find seedlings less than a year after the fire, but the following year we found more than 700 seedlings!” exclaimed Siegle. “This told us this little mint is able to build up a seed bank faster than we expected and that translocations are a reliable tool for recovery efforts.” Archbold scientists continue to return to the site annually to check on progress, and most recently counted over 1,300 individuals.
Armed with the success of two previous translocations, the Plant Ecology Program continued their recovery efforts this spring with a third translocation. The goal this time was to compare how sown seeds and plants responded in unburned and recently burned habitats. “Part of the site we chose for this translocation burned earlier this year as part of habitat restoration efforts,” explains Siegle. This time, 200 plants and 6,000 seeds were transplanted, some into unburned scrub and the rest into recently burned scrub, to determine which population would be more successful immediately and in the long-run. “Now we wait,” says Siegle “and hope this recent translocation follows suit of those before it.”