Author: Lexi Siegle
This summer, biologists with the Plant Ecology Program at Archbold Biological Station were on a mission: to bolster a newly discovered population of a rare mint plant called Scrub Balm (Dicerandra frutescens). The property where the new population was found is near Lake Placid and managed by the Florida Fish and Wildlife Commission. It was recently surveyed for rare plants. When the previously undocumented population of Scrub Balm was found, biologists were excited about the discovery since only a dozen populations of this rare plant were already known. There were, however, very few plants in the newly discovered population, meaning it was vulnerable to extirpation. Thus began a plan to augment the population.
Augmentations are when plants or seeds are added to existing populations of wild plants. One way to augment a population is to plant seeds directly into the ground and wait for them to grow. However, this method can take a while before one starts to see results. . Another way to accomplish the same goal is by taking stem cuttings. This is possible for many plants, where stem cuttings taken from healthy plants and placed in water encourages root growth from the stem. By using stem cuttings from the same population, unique local genetic combinations are conserved, improving the chances of a successful augmentation. With more plants in a population, there are more flowers to attract pollinators, which could mean more seeds produced, and overall a higher chance of “recruitment”, or seeds germinating, in the next year.
Stem cuttings of Scrub Balm from this population were collected in 2018 by a conservation biologist from Bok Tower Gardens, specifically for population augmentation. Biologists at Bok Tower Gardens have grown hundreds of native and rare plants for out-planting over the years in collaboration with many conservation organizations, including Archbold. It took a year for the stem cuttings to develop a healthy enough root system to support a healthy plant, and in July 2019 they were ready to be transplanted back home.
That summer morning, Archbold biologists planted approximately sixty of these endangered plants. “The work is hard and hot, but overall worth it to see this rare plant population increase,” said research assistant Lexi Siegle-Bates. “We navigated to previously identified ‘gaps’, which are open, sandy areas with plenty of light and little competition from neighboring plants. At each gap, we dug anywhere between five and seven holes about six inches deep into the sand and one foot apart in a circle around the gap. After covering the roots with sand and watering them, we repeated the process until all sixty plants were in the ground.”
“We tripled the number of plants found in this area in one morning of work”, commented intern Megan Verner-Crist. In addition to increasing the number of plants within this population, the population now extends across a sandy fire lane into two different management units. “This is like an insurance policy for the Scrub Balm,” explains research assistant Stephanie Koontz, “if something happens to the population on one side of the fire lane, we can collect stems from the plants on the other side again.” These plants will mature and flower next year and hopefully, new seedlings will germinate shortly after.
Highlands County has some of the highest numbers of rare and endangered plants in Florida. However, due to habitat loss, there is very little remaining suitable habitat for rare plants, and finding out where rare plants have grown in the past, or their ‘historic range’ is difficult. As Koontz explains, “This is why finding wild populations of rare plants is exciting for biologists. It is helpful to know where rare plants are growing naturally so we have an idea of what kind of habitats are good for introducing or augmenting new populations of plants. Finding suitable habitat within the historic range can be a guessing game. Therefore, when we find intact wild populations, this assures us that this habitat should be appropriate to support this rare plant.”
Lexi Siegle-Bates concluded, “Even though finding a new population of rare plants in the wild does not happen every day, it can happen. Some populations of rare plants go undetected because most people do not recognize the rare species. You may even have rare plants in your backyard! Learning to identify rare plants can be a fun pastime—we have over forty species in Highlands County alone.” Using phone apps, such as iNaturalist, can be a great tool for helping anyone interested in learning to identify plants. It can be useful for citizen scientists to gather data and information on where to look for new populations of rare plants on public lands. Biologists can always use help from enthusiastic naturalists to keep wild populations of endangered plants healthy for future generations to enjoy.