By Dr. Brian Sidoti, Director of The Kampong
Florida is home to a diverse range of flora, including 16 native bromeliad species and two natural hybrids. These unique plants, which are part of the Pineapple family (Bromeliaceae), play a critical role in their ecosystems. From the iconic Spanish moss (Tillandsia usneoides) to the pseudo-carnivorous powdery strap airplant (Catopsis berteroniana), Florida’s native bromeliads grow in tree canopies where they provide homes and food for many animals while also enriching the state’s plant diversity.
Partnering with colleagues from other botanical gardens, colleges, and local high schools, NTBG has been investigating the biology and life history of these fascinating plants to better understand their ecological significance and the threats they face.
Plants and pups
One of Florida’s most remarkable bromeliads is the giant airplant (Tillandsia utriculata). As Florida’s largest native bromeliad, the giant airplant can reach up to two meters. This keystone species provides essential habitat and resources for various organisms within its micro-ecosystem. By capturing small pools of water among overlapping leaf bases, giant airplants act like an aquarium with dragonfly larvae, and tadpoles. Overlapping dead leaves at the base of the plant become a natural terrarium where ants, cockroaches, and scorpions live. These microorganisms and invertebrates boost biodiversity and increase nutrient availability for the plant itself and animals that live within. It takes 15-20 years for giant airplants to reach reproductive maturity. They can produce more than 25,000 seeds in a massive, one-time only reproductive event.
Another long-lived native bromeliad is the cardinal airplant (Tillandsia fasciculata) which also takes a considerable amount of time to reach reproductive maturity and shares a similar distribution with the giant airplant. This species, however, is much smaller, typically growing about 70 cm in height. Another key difference between the two is that the cardinal airplant can reproduce both sexually via pollination and asexually as “pups” that form clones at the base of the plant.
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Florida’s remarkable bromeliads are threatened by habitat destruction, illegal collecting, and invasive species. As land development and urbanization claim more bromeliad habitat, their numbers continue to decline. Additionally, many of these beautiful plants are highly coveted and are being illegally poached from the wild by collectors and hobbyists.
The greatest threat imperiling Florida’s larger native bromeliads is an invasive weevil that was inadvertently introduced through the horticulture trade in the 1980s. This weevil (Metamasius callizona) has caused a significant decline in native bromeliad populations by feeding on leaves and stems, often killing the plants before they can reproduce.
Research indicates that the giant airplant is more severely affected by the weevil than the cardinal airplant which may be able to survive an attack by producing pups. The spread of this weevil has been devastating and continues to pose a significant threat in Florida.
Hoping to mitigate these threats, our research team, in collaboration with local high schools, is considering several key questions of population, reproduction, growth, nutrients, and microbial communities that will help us better understand and protect bromeliads.
In order to learn more about bromeliad population structures and dynamics, we are studying how various environmental factors influence the distribution, demographics, and health of bromeliad populations over time. We are also examining the proportion of resources invested in reproduction and the success rates of these efforts.
Additionally, we are quantifying how bromeliads grow and use nutrients that are crucial to their health. Our research includes an examination of the microbial communities associated with bromeliads and determining how they significantly impact health and growth.
Harnessing the skills and strengths of our diverse team, our research employs a combination of direct observation, laboratory and field studies, and mathematical, statistical, and simulation modeling. For this research, both the Kenan Lab and the facilities at the International Center for Tropical Botany at The Kampong have been invaluable.
Two Miami-Dade High School students measuring air plants at The Kampong. Photo by Rodrigo Gaya.
Scientific findings
Among our preliminary findings, we have learned that because Tillandsia seeds are dispersed by wind, their success in finding suitable habitats depends largely on wind patterns. We found this to be true for the giant airplant at both Fairchild Tropical Botanic Garden in Miami and Myakka River State Park in Sarasota.
Our studies also included measuring different aspects of bromeliad growth and reproduction, as well as vegetative vs. reproductive mass. We compared the mass of the leaves and stems (vegetative parts) to the mass of the flowers and seeds (reproductive parts) in two bromeliads — the giant airplant and the cardinal airplant — to understand how they use their resources.
We used math and computer models to predict how giant airplant populations will change over time. We found that to keep the population stable for 100 years when the invasive weevil is around, 13-20% of the seeds need to sprout and grow. Our research shows that the presence of the weevil appears to reduce plant reproduction size which may adversely affect plant populations.
In recent seed studies, we discovered that giant airplants produce more seeds than previously thought, while the size of each seed stays about the same. This suggests that giant airplants might produce more seeds each time it reproduces, which could affect its survival and growth in Florida, especially with the threat of weevil infestations.
By studying the growth stages and chemical processes that affect giant airplants, we better understand the need to protect bromeliads when they are most susceptible to weevil attack.
Collaborative conservation
At NTBG, we are committed to including local high school, undergraduate, and graduate students in our research through summer internships, hands-on data collection, and interdisciplinary scientific explorations. Students at each level have conducted research at the intersection of botany, evolutionary biology, ecology, conservation, and mathematical modeling. Through these activities, students have honed their skills for data collection, analysis, and presentation.
Our collaboration with students has not only helped us gather important data, but is also inspiring the next generation of scientists. Furthermore, students are learning from each other. To cite one example, through our bromeliad research, undergraduates from Colorado College trained Florida high school students on protocols for measuring bromeliad growth and development.
Science educators are also benefiting. We’ve had professors offer professional development workshops to Florida’s high school teachers, helping develop teacher skills by working with bromeliads. Undergraduates have coauthored publications with professional scientists and much more cross-pollination will happen in upcoming inter-institutional, interdisciplinary bromeliad research projects.
Brian Sidoti (left) and collaborators install a weather station in a Tillandsia host tree at Myakka River State Park near Sarasota, Florida. Photo by Brad Oberle.
By researching Florida’s native bromeliads, particularly the giant airplant, we are gaining valuable insights to the crucial role these plants play in their ecosystems. Understanding their biology and life history, as well as the threats they face, is key to their conservation.
Studying and protecting these plants need not be limited to scientists and students. Each of us can play a positive role by joining a local native plant society, volunteering, spreading awareness of the remarkable plants around us, and supporting NTBG’s future research initiatives.
Through a combination of curiosity and respect for nature, collaborative research, and life-long education, we can help protect keystone species and ensure their survival for future generations.
[1] Partners include Colorado College; Rhodes College; New York Botanical Garden; University of Connecticut; Eastern Kentucky University; and several Miami-Dade high schools.
