International research student explores local forests to unlock the secrets of bromeliads, a wonder plant of tropical ecosystems
There are two things that most people think of when they hear the word “bromeliad”. Keen gardeners will know the ornamental plants with beautiful coloured flowers, while others might remember the most famous bromeliad of all – the sweet and delicious pineapple. What is less well-known is how these plants play a unique role in ecosystems across the country.
Many bromeliads use their roots not to get food like most other plants, but to grow on a variety of surfaces, such as trees, telephone posts, or fences. To get their food, they have developed their typical tank- like form, where water and dead leaves accumulate. The dead leaves decompose in the water, and the plant absorbs the released nutrients with microscopic hairs.
Standing freshwater is usually rare in tropical ecosystems. This means that bromeliads are one of the most important, if not the most important, source of natural standing water in many places. Because of this, many animals have made bromeliads a core part of their life.
In T&T, animals such as the endangered piping‐ guan (pawi) drink from the water of bromeliads, and rare and endangered species like the golden tree frog are found exclusively within bromeliads of the highest elevations of El Tucuche and El Cerro del Aripo.
As a PhD student whose work focuses on the study of these beautiful and very useful plants, I was pleased to visit Trinidad at the end of 2022. I had two main goals: to conduct an experiment for my PhD dissertation, examining how nutrients influence the health and survival of insects, and to conduct a broad survey of bromeliad invertebrates in the country, as the last bromeliad censuses in Trinidad date back to the early 20th century.
I visited T&T as part of the Bromeliad Working Group (BWG), a network of around 50 researchers in over a dozen countries across the Americas created by Dr Diane Srivastava. Dr Srivastava is a professor at the University of British Columbia in Vancouver, Canada who has spent her career studying bromeliads.
In an effort to extend the BWG network of collaboration, Dr Srivastava and her lab have started collaborating with Dr Amy Deacon, a lecturer in Zoology at UWI St Augustine’s Department of Life Sciences.
With the invaluable help of current and former UWI students Sinead Stewart, Jillon Lewis, Renoir Auguste and Llevan Ramharrack, and the fantastic Dan Jaggernauth of the National Herbarium of Trinidad and Tobago, we sampled six sites across the central Northern Range.
Besides larger animals relying on bromeliads, the pools of water they hold are also home to many smaller organisms, especially aquatic ones. In fact, the mini ecosystem within bromeliads includes a variety of organisms, replete with everything from predatory insects to detritivorous worms and larvae.
We were truly amazed by how invertebrates varied from site to site, even if we were just a few kilometres away as the crow flies. Some sites had low diversity while others had many different species.
After fieldwork, I brought some specimens back to The University of British Columbia so that they could be identified with DNA techniques. We found that the Trinidadian bromeliads sampled hosted 48 species of invertebrates. And that is just over a small area of the Northern Range. Imagine how many species we can find if we sample more of the country.
The results of the survey were published last year in Living World: Journal of the Trinidad and Tobago Field Naturalist Club.
“We are very excited for what is to come,” says Dr Deacon. “Pierre’s work means that we have valuable information on what species are found inside Trinidad’s bromeliads. We can now build on this to learn more about these tiny hidden worlds in our forests.”
Dr Srivastava sees enormous potential for bromeliad studies internationally:
“The BWG has been coordinating experiments over several countries at the same time. Indeed, if results are consistent over vast continental areas, then researchers can be confident that they have discovered fundamental rules of ecology.”
In T&T, Dr Deacon wants to see much further research into this exciting area at UWI St Augustine.
“Undergraduate students in our Zoology programme are already continuing the research by using Pierre’s dataset to ask important ecological questions,” she says. “And this is just the start — hopefully a student will be interested in making these bromeliads the subject of a master’s or PhD project here at UWI, as there is so much more to discover about these amazing ecosystems and the creatures that live within them.”
