Costa Rica is one of the most biologically diverse places on the planet. Making up only 0.03% of the Earth’s surface it is home to nearly 6% of the world’s biodiversity. Reserva Ecológica Bijagual located in the lowlands of the Sarapiquí region, is a unique field station dedicated to the restoration and conservation of tropical rainforest habitat. Run by Paul Foster, a botanist, who seems to know everything there is to know about Costa Rican flora and fauna, the reserve is a hands-on classroom that advocates education of the environment and the protection of biodiversity.
As part of a 4th year module in the UCD Zoology degree, I got the chance to go on a two week field trip to the reserve with a team of students to explore the range of biodiversity in a tropical rainforest. We used a selection of sampling techniques to evaluate a whole range of species from mammals to insects to fish to invertebrates. Amongst other techniques, we used radio telemetry to track small amphibians and reptiles, electrofishing to evaluate fish populations, butterfly traps and light traps to study invertebrates close up and in the hand and camera traps to capture elusive species on film.
One of my favourite exercises that we employed was radio tracking. There are strict guidelines when placing a tracker on an animal, any tracker placed on a reptile for example can only be between 5-10% of its body weight, so each animal had to be extensively measured and weighed. We captured a few different animals, a toad we christened Sandy B and a small green anole named Phil and super glued trackers to their backs. Each radio tag was set to a certain frequency and then a large ariel could be used to pick up this frequency. Transmitters should be detectable 1-2 km away but this changed depending on the vegetation and terrain present. Sometimes as animals moved further into the forest their signal became more difficult to detect but we did manage to recapture our anole Phil more than once using this technique!
Another technique that we were lucky enough to be able to try out was electrofishing. Electrofishing is a great scientific survey method that is used to determine fish population density and abundance. The great thing about this technique is that, if performed correctly, there is no permanent damage to the fish and they return to their natural state in as little as two minutes after being caught. A bankside generator provides power to an electrical control box that produces a pulse of current through long steel poles held in the water which temporarily stuns the fish allowing them to be captured with a net. Then it is up to the surveyors to catch the fish as quick as they can before they come to and swim away! Using this technique we got the chance to see a whole range of fish from common cichlids to knife fish and even one marbled swamp eel.
Field trips like these are so important in the journey to become a good field biologist because they help to hone your skills and discover what methods work best for certain species. I learned more from 2 weeks in the field than I ever could have from reading about them. I got to see species up close and personal that I had only read about, butterflies the size of your face, venomous snakes and big cats like jaguars. At times it was difficult, the long hikes, the humidity and the hard work but it all paid off to experience the rainforest like very few people get a chance to. Gaining experience in the field is, in my opinion, the best thing you can do to make yourself a well-rounded zoologist. Learning skills like how to conduct bird point counts, vegetation surveys and all the other things we did are valuable skills that I will definitely be using again in my career. Whether it’s in a tropical rainforest, a desert savannah or just in your back garden, biodiversity is everywhere and the skills you gain from doing field work can help you evaluate it anywhere in the world.
Pictures provided by Jan Robert-Baars, Orna Phelan and Tara Joseph