Thursday, June 18, 2020
The next time you visit our botanical garden, consider this: You’re only seeing half the operation. Out of the public view and away from the magnificent display gardens, the Conservation Department works tirelessly to save plants. Sometimes, it is not enough to bury a seed in soil and walk away, thinking we’ve saved the genetics of an at-risk species. And yet, that’s one misperception we in plant conservation encounter. Today, we lift the veil off the mysterious work of conservation specialists, how we prioritize species for conservation, the challenges we run into, our wilderness treks (the fun stuff), and the meticulous data collection that follows (the less fun stuff).
We start with the numbers. There are an estimated 390,900 plant species worldwide, begging the question: Which deserve priority for conservation? We start by targeting the ones not sufficiently represented in botanical gardens around the world. When a plant appears in a botanical garden’s collection, you see, that institution has committed to safeguarding it. If a plant appears in few — or no — collections, its protected population is too small to conserve it successfully. Contrary to popular assumption, not every plant we target is threatened. Some are, but the plants we seek may be well-represented in the wild (for now) but not protected for the long-term.
So, we head into the wild. We carefully survey our collection area to determine how much seed we can collect without damaging the resiliency of the next generation. Then, we gather the seeds for propagation, taking note of the environmental factors that affect the plant’s growth. This is not as easy as one would think, as many of these plants are ephemeral and offer a short window to study before they disappear or go out of reproductivity.
We don’t gather one large bundle of seeds (that would be too easy!). Instead, we separate our seeds by parent plant, allowing us to map genetic differences across a geographical range. We do this because many plants are so finely tuned to their immediate location. They have adapted to the climate and co-evolved with other wild species to survive in a way they could not when planted elsewhere. For example, pickerel weed (Pontederia cordata) occurs throughout the state of Florida. But if you were to study the bloom times of pickerel weed in various regions of the state, you’d find that they all flower at different times to coincide with some evolutionary benefit specific to their location.
Timing is everything, especially when it comes to reproduction. Seeds often exhibit a dormancy, or certain criteria that needs to be met before they will sprout. It’s often an advantage to combat unfavorable conditions in the wild or drastic seasonality changes. For example, a seed may need to be hit with a period of cold to give the signal that winter has come and past, so it is now safe to grow. Part of our job requires figuring out how to break that dormancy. This entails more statistics than a standard horticulturalist may want to sign onto!
We can’t simply state what worked best; we need to show the numbers. What percentage of plants germinated per the number of seeds planted, and how long did this take? Finding the answer requires constant observation and data collection. For example, the state-endangered Florida thatch palm (Thrinax radiata) takes four months before any of the seeds begin to germinate. Not all the seeds germinate at once. Rather, they sprout over the course of a few months and taper off at the eight-month mark. Then, at the same time the next year, there is another wave of seeds that begin to germinate — from the same batch! The lesson: Don’t give up on thatch palm seeds that haven’t sprouted.
The seed’s longevity is important to know, too. Through our experiments, we can determine if a seed is orthodox or recalcitrant. Orthodox seeds are “normal” and can be stored over a period of time. Recalcitrant seeds display a drastic reduction in viability in just a few weeks. By graphing our germination data, we can figure out how long the seed lasts — and determine how quickly we must get it into soil.
Even after the plant starts to grow, we have questions. How do these plants develop? Must we assist the plant during its growth stages? Champaca (Magnolia rajaniana) seedlings, for example, burn in the sun, despite requiring full light exposure once established. Our horticulturalists need to grow these seeds in shade, then slowly introduce more sun to simulate the natural conditions of beginning on the forest floor and growing up out of the understory.
What do we do with all this data? We develop “propagation protocols” — essentially those missing “how-to manuals.” The knowledge to grow and share these plants gives us a leg up in the event of a population decline. In the cases of species that are slow growing or have limited seed availability, it can take a few years to successfully compile data. That’s why we made sure to keep up the research and documentation — even during the Garden’s extended closure for COVID-19.
We know the work is critical. There are over 1,400 species of native plants in South Florida, making it one of the most biologically diverse regions in North America. Eight percent of our natives are already extinct in the wild due to development, according to The Institute for Regional Conservation, citing data from 2016. On top of that, the nearby Caribbean islands, our environmental “cousins,” are among the world’s biodiversity hotspots. An estimated 46% of these plant species are threatened from habitat destruction, according to the Global Botanical Garden’s Congress, 2010. The conservation work we do here will pay dividends there — for the benefit of this entire part of the world.
So on your next visit, remember there’s much more to the Garden than meets the eye — even if you don’t catch us stealthy conservationists in the act!
About the Author
Jessica DeYoung is a Conservation Associate at Naples Botanical Garden. Though an avid hiker with an appreciation for old growth ecosystems, her specialty occupies growing plants from start to finish.