Tropical Ecotoxicology and Exchange with Costa Rica

In this post, Lara Petschick, Sebastian Stehle and Carsten Brühl share their experiences when visiting Costa Rica to establish a collaboration on Tropical Ecotoxicology with colleagues from the University Nacional in Heredia.

Costa Rica is well known for its eco-tourism and as a hotspot of biodiversity, wildlife, and unique nature. However, at the same time, Costa Rica has among the largest banana and pineapple cultivation areas, exporting these crops to Europe. Costa Rican bananas can be found in almost every German supermarket! This extensive cultivation goes hand in hand with the largest amounts of pesticides applied per hectar globally. Those year-round applications likely impair biodiversity and ecosystem functioning.

Rainforest fragment bordering a conventional banana plantation. During aerial application of pesticides entry into the plantations is prohibited (photo by C. Brühl)

Over the past years we established a collaboration with the Institute for Studies on Toxic Substances of the National University (IRET-UNA), an ecotoxicological institute that studies the impact of pesticides on tropic ecosystems. After a visit of the Costa Rican colleagues to Landau in fall 2019, we, a group of researchers from the Institute for Environmental Sciences, spent two weeks in Costa Rica to develop a joint research proposal.

In the organic banana plantation in the Southern Caribbean Lowlands with interspersed impressive fruit trees (photo by L. Petschick)

To get an impression of the situation and to establish potential research field sites, during our first week we traveled to the Caribbean lowlands. We got the unique opportunity to learn about organic banana cultivation in an agroforestry management scheme that produces bananas for residue-free baby food.

Drainage channel in the conventional banana plantations. Inset: plastic debris and dead fish at the channel outlet (photo by C. Brühl)

In the Caribbean watershed, we followed streams, drainage canals and rivers to the Laguna Madre de Díos, a unique ecosystem draining into the Atlantic. There, we got an impression of the already established, long-term sampling sites of IRET-UNA that are used for chemical and biological monitoring. In this area, fish kills are observed after heavy rain events. On our way back, we drove through agricultural landscapes and searched for rain forest fragments bordering banana plantations as potential research sites.  In the rainforest of La Selva research station we were introduced to the long-term stream project that is running there, covering many aspects of tropical stream ecology.

At the Atlantic/Pacific watershed on Volcan Barva in the central mountains at 3 000 m a.s.l. (photo by S. E. Saenz)

Back in Heredia we discussed and developed project proposals with the Costa Rican colleagues at IRET-UNA. Unfortunately, our visits to the large vegetable growing area in the North and a meeting with the Costa Rican Environmental Ministry had to be shifted to online video-conferencing discussions due to coronavirus-related travel restrictions. Thus, during our last days in Heredia we worked remotely in “home office“ style at our hostel, while waiting for the German “Luftbrücke“ to bring us back to Germany after borders had closed.

Together with our Costa Rican colleagues we will follow up on the important question of pesticide effects on tropical biodiversity, its risk assessment, and potential management.

You may also be interested in:

Costa Rica: A tropical e(coto)xperience – Part 1 about Carsten’s first impressions and what he learned about pesticide use on tropical crops such as the bananas that get shipped to Germany

Costa Rica: A tropical e(coto)xperience – Part 2 about Clemens Ruepert who is an experienced environmental analytical chemist at the Regional Institute for Studies on Toxic Substances of the National University of Costa Rica.

Costa Rica: A tropical e(coto)xperience – Part 3 about the students Priscilla and Julian who tell us about their bat conservation efforts in agroecosystems such as banana plantations.

Costa Rica: A tropical e(coto)xperience – Part 4 about Carsten’s visit of the Laguna de Madre Dios, where researchers sample water and fish to analyse for pesticide residues originating from upstream banana and pineapple plantations.

Costa Rica: A tropical e(coto)xperience – Part 5 about air sampling in a cloud forest to detect persistent pesticides travelling to remote areas.

Costa Rica: A tropical e(coto)xperience – Part 6 about Carsten’s guest lecture in the “Tropical Ecotoxicology” masters program at National University of Costa Rica.