OTS on the Move: Science, Students, and Strategy at 2025 Conferences

Section by Elizabeth Braker. OTS CEO.

June was a busy time for OTS Academic staff, with three scientific congresses in the books. Dr. Laurence Kruger (OTS Director of South Africa Programmes) presented at the 50th Annual Conference of the South African Association of Botanists, held at   Wits Rural Facility of the University of the Witwatersrand, June 30-July 4.  Kruger’s presentation, titled “The future of savanna trees: Understanding the influence of elephants, fire and land use change on large tree demography”, discussed results of long-term studies with colleagues from University of Florida and Wits University. As a way to examine decline in large trees in Kruger National Park, the authors compared demographic resilience of two dominant tree species, knobthorn (Senegalia nigrescens) and marula (Sclerocarya birrea) in the open landscapes of the Kruger National Park, elephant-free sites in Eswatini National Park, and sites across a land use change gradient. Biotic and abiotic factors have differential effects on demography of these species, a finding that suggests that managing the decline of large trees is a complex problem for conservation scientists.   

OTS was represented at the 61st annual meeting of our sister society, the Association for Tropical Biology and Conservation, in Oaxaca, Mexico, by Dr. Sofia Rodriguez (OTS Academic Director, Costa Rica), Pablo Muñoz (Education Coordinator), and Orlando Vargas (Head of Scientific Operations). The OTS team sponsored a workshop on “Project management for impactful field courses”, participated in a round table on “Bridging the Gap: Connecting Academia, Policy, and Practice in Conservation and Ecological Restoration”, presented a poster on integrating a research and management program at La Selva with educational activities, and facilitated a mixer for friends of OTS.  

Three members of the OTS South Africa aquatic team travelled to Pietermaritzburg in to share their latest research at the annual South African Society of Aquatic Scientists (SASAqS) June 2025 conference. Under the theme Aquatic Science and Practice, the meeting brought together researchers and practitioners working at the interface of ecology, conservation, and water management. The team’s work spans diverse aspects of freshwater science — from hidden biodiversity in fish, to the resilience of macroinvertebrates in temporary rivers, and the conservation potential of artificial dams. 

Siphelele Mbangata, MSc student at the University of the Witwatersrand, presented her work on seasonal patterns in macroinvertebrate communities in Kruger National Park. Using data from ephemeral, intermittent and perennial streams, her study showed that temporary waterbodies — often overlooked in conservation — play a key role in supporting biodiversity. Her findings suggest that these seasonal systems act as important habitats and recovery zones, with macroinvertebrate communities relying on nearby perennial streams to bounce back after dry periods. Much of the fieldwork behind this project was conducted in collaboration with undergraduate students on the African Ecology and Conservation (AEC) semester programme, highlighting the programme’s unique hands-on contribution to real-world research. 

Esihle Ndeleni, an MSc student at Rhodes University, explored the genetics of the southern barred minnow (Opsaridium peringueyi). By analysing DNA sequences from populations across unconnected river systems, her research revealed evidence of hidden genetic diversity — suggesting that what we currently call one species may, in fact, be several distinct lineages. This has important implications for conservation, especially as this species is declining across much of its range. 

Dr Josephine Pegg, thesis supervisor for Siphelele and Esihle, and OTS’s resident fish lover, presented a study asking whether some of Kruger’s artificial dams — originally built for game — could now serve a surprising conservation role. The project found that several earthen, offline dams still support threatened fish species decades after their introduction. In an era of increasing drought and water scarcity, these isolated, rain-fed waterbodies may offer a lifeline for native fish, acting as unexpected refuges or “fish arks.” Like Siphelele’s work, this project also benefited from field contributions by AEC students, underscoring the value of integrating undergraduate training into applied conservation science. 

Together, these presentations highlighted the importance of bridging research and practice in freshwater conservation — a theme that resonated across the conference. As aquatic ecosystems face mounting pressures from climate change, habitat alteration, and biodiversity loss, collaborative and inclusive research like this is vital to understanding how we can protect both water and the life it supports. 

Look for OTS at the Annual Conference of the Ecological Society of America in Baltimore, MD in August 2025. OTS will sponsor an OTS-ESA Meetup. Alumni, faculty, visiting researchers, and friends of OTS will gather for collegiality, networking, and to hear (very briefly!) how OTS envisions a bold future, even in the face of current headwinds. How will we continue to provide the perfect environment for higher education in tropical ecosystems at excellent sites, host and support ecological research, and make the leap to extend our impact to support resilience and restoration of tropical ecosystems beyond our field stations? Come enjoy one another, an adult beverage, and snacks!  When: Monday, August 11, 6:30 pm. Where: Blackwall Hitch Restaurant, 700 E Pratt St. Cost: $25 (Light Hors D’oeuvres, Event Space, Cash bar). Please register for our OTS gathering at this link. 

  

Refugio 2000: Hidden Ally Supporting Tropical research  

 By Orlando Vargas, Sofía Rodriguez and the OTS Editorial Team.

The hidden shelter at 2,000 m a.s.l. in Braulio Carrillo National Park “Refugio 2000” is more than just a rustic shelter; it is a key element within a 51-kilometer biological corridor connecting La Selva Research Station to the summit of Barva Volcano (2 900 m a.s.l. ). This corridor represents a scientific legacy that began in the 1980s, aimed at understanding how forests and communities in tropical ecosystems change with elevation. 

Thanks to a landmark effort by OTS and the Costa Rican national park system, more than 10,000 hectares of forest were purchased to create this continuous corridor of protected land. This corridor not only preserved immense biodiversity but also enabled the establishment of the Altitudinal Transect, now recognized as one of the most valuable long-term ecological monitoring transects in the Neotropics. 

Earlier this year, the OTS Scientific Academic team returned to Refugio 2000 with a specific goal: to assess the condition of the forest trail and the structure of the shelter to re-enable it as a functional research base. Upcoming research efforts include the installation of acoustic recorders to continue long-term bird monitoring. This data may reveal how bird communities are shifting over time in response to land-use change and climate change. 

Continue to deliver critical scientific data along the transect, the hidden ally itself must be deployed in conditions that protect it and allow optimal data collection. 

For research to happen, the hidden ally itself must be up to the task. As Orlando Vargas, botanist and naturalist involved in the scientific- academic department at La Selva Research Station, notes, “these shelters are more than infrastructure; they are hidden facilities are crucial in the pursuit of knowledge.” Their condition is just as important as the data they help generate.  

Refugio 2000 is not just a basic shelter. It’s a link across time — connecting us to historical data and most importantly, reminding  that scientific infrastructure also needs care and investment to thrive.

Donations through this link will support the restoration and ongoing maintenance of the refugios and trails along the altitudinal transect, enabling continued long-term ecological research and biodiversity monitoring between La Selva Research Station and Braulio Carrillo National Park.  

Joyous Experiences with OTS 

By: Joy Schochet, OTS Experiences Alumni Class of 2024 and 2025 

I had the good fortune to grow up in a village on a lake in northern Minnesota.  I waited eagerly for spring, when chipmunks emerged from under the leaves in our window wells where they sheltered for the winter, and when the first birds arrived (although I never could identify many beyond “robin,” “ruby-throated hummingbird” and “red-headed woodpecker”  (I am still stuck there). My friends and I spent summers swimming, and we picked wild berries, hiked and camped.  In fall, we had gorgeous displays of leaves in festive reds and oranges and in winter nature sent us ice and snow.  We were immersed in nature.   Now, you might say, “good grief, why are you writing about yourself and not about your OTS trips?”  As Jane Austen would have said, “Wait, Dear Reader” and you will see….  
 
Well, I grew up.  I became a biologist.  I lived in urban areas for the most part, but remained attached to nature with summer research at the Marine Biological Laboratory on Cape Cod, teaching in Southeast Asia (tropical rain forest!), doing research with crabs at a Thai fisheries station, visiting several times the Peruvian Amazon while on the board of a rainforest conservation organization and spending summers at a cabin near the Boundary Waters Canoe Area in Minnesota. But living in cities takes a toll.  How does one compensate?  Perhaps with the assistance of a fine organization… 
 
The Organization for Tropical Studies first came to my attention years ago while I was still preoccupied with the struggle for survival in the academic world (a good preparation for understanding Darwinism, which is useful when viewing nature in South Africa) and I joined at the recommendation of a friend who did research in Costa Rica. One day in 2024, into my inbox popped an unexpected email from OTS, announcing a trip to South Africa.  I had traveled quite a lot, but never to South Africa and I am glad I said yes to the trip.  

How gratifying it was to have Julissa, Laurence and Ally Kruger and the OTS staff care for me as well as the spectacularly well-informed and friendly nature devotees for almost two weeks.  They kept us going by promising that we would, absolutely, not be eaten by a leopard or lion during our daily game drives excursions in the bush, giving us great accommodations, and feeding us very delicious food. We were primed to be excited by everything, and we never knew what we would see each day.  There is no coercing nature to perform.  

 

But the journey was not just an adrenalin surge.  What also helped make it an extraordinary experience were the talks by OTS researchers who provided superb mental excursions into the ecosystems and wildlife of Kruger Park. OTS ensured that we were not just mindlessly viewing nature, an activity so prevalent now that it has been excoriated often in contemporary literature. We were invited to engage with many facets of our world.

Here are just some of the things that intrigued me and inspired me to think about what I was seeing.  

A large dead giraffe, partly eaten, lying on its side, not entirely intact, and surrounded by scavenger birds – a wordless description of a food chain.

An antelope hanging on a tree branch, leopard prey, with its legs all dangling down around the branch, its final resting place, from which those legs could never carry it.  It occurred to me that wild animals, at least prey species, never do have true rest.     

Multitudes of elephants and their babies, their population recovered, but at a fast rate that had unintended consequences. We learned that conservation is effective, often, but not always with the results we expect, and learning about this during my visit with OTS sparked my interest to learn more.  

 

There were also multitudes of zebras, giraffes, and so many species of antelopes. Though you can enjoy innumerable nature videos, the sight of these heavenly animals running and bounding seemingly effortlessly through the dry vegetation and sparse trees was so much more enchanting than any two-dimensional rendering. We also saw a phenomenal variety of bird life!

Additionally, seeing a marvelous hyena mom whom we spotted on a night drive lying in a concavity near the side of the road with her newborns hugging her side and a yearling pup nearby was an incredible experience. I bought a book on hyenas before I left South Africa to learn more after that sighting.

We also spent several days in the relatively lush coastal area of South Africa.  The coastline is truly magnificent. 

We also learned about the struggle to end the apartheid from a man who knew Nelson Mandela in prison. Nevertheless, that day was a reminder that, on occasion, society can improve itself. I am glad we got local perspectives on the topic. 

The visit to see penguins was a highlight of the south. Watching them cavort and seeing them intimately close proved an almost comedic contrast to the seriousness and grand scale of Kruger Park and its wildlife.
 

After you get home, you will always be thrilled with your memories and more attentive to the non-human life around you, wherever you are. Not to mention being grateful that you are not hanging on a tree with an antelope. 

I enjoyed the superb, although not rigid, planning, the excellent food, the benevolent staff – including a cooking crew who followed us throughout the park – and everyone’s attentive care and patience made this trip close to perfection.  I cannot imagine that anyone taking this trip could leave without gaining a much deeper understanding of South African ecosystems or an appreciation of the wonderful and hospitable people who reside there.

Richard Luov, in his books “Lost Child in the Woods” and “The Nature Principle”, suggests that many of our societal and environmental problems are caused by what he calls “nature deficit disorder.”  He is someone whose advice should be considered.  

I once joked with my husband that the only trees that children see now are in shopping malls and he replied, “No, on a screen.”  Even more true now, especially when even shopping malls are fading away (although there is a Darwinian aspect to that). OTS can remedy your deficit! As someone that traveled with them to South Africa and to Costa Rica, I highly recommend joining their educational and memorable trips. You will help yourself and help OTS in its mission to remedy our culture’s serious deficiency in knowledge of nature and conservation issues. 

Wandering with Wonder: A First-Time Explorer’s OTS Experience

By Nancy Bilello  

It is still hard to put into words all the amazing sights, sounds, and experiences of my first trip to Costa Rica. Unlike most of my fellow travelers, I have no background in research or science (aside from my career in health care), so everything was brand new and wonderful to me.  

We didn’t spend time on any beaches, but that was not at all a detriment. We toured the inland of Costa Rica, staying a few nights in four different places and the last night in San José. We started at Palo Verde National Park. It is considered a “dry” rainforest, so it lacked the lushness of the tropical rainforest, but it certainly did not lack in adventure. We had monkeys, coatis, and even an anteater roaming freely right on the grounds of the research station, not to mention iguanas, frogs, and other residents of this interesting place. There was also a boardwalk that went over some wetlands, where we saw some beautiful egrets and other birds.  

La Selva was next for a taste of the tropical rainforest with its many shades of green, trees that reached to heaven, poison dart frogs, tiny insects, peccaries (aka javalina’s), and howler monkeys that made sure we were up by dawn! But that wakeup call was fine, because every morning included birdwatching before breakfast, and we wouldn’t have wanted to miss seeing the macaws, toucans, parakeets, and other remarkably colorful birds of the area. Our stay included a couple of night walks in the forest as well. During our stay, we were able to tour a small cacao plantation, where we were treated to demonstrations of how chocolate is made and, happily, were able to taste the results! Another tour was to a privately owned botanic garden, where we learned about various local plants and herbs and their medicinal uses.  

 

 

We were then fortunate enough to spend a few days in the mountains, not at a research station, but at a small resort/lodge. That is where we were privileged to see the magnificent quetzals – birds native to Central America with bright green and turquoise plumage and long, dramatic tails.  We also did some wonderful hikes along a river and to a waterfall.  

Our last stop was in the town of San Vito. The research station here is adjacent to a cloud forest and contains botanical gardens that were truly like the Garden of Eden, with so many brightly colored flowers, exotic plants, and more birds.  

We had an unflappable bus driver (Rafa) as well as a native guide (Jeisson) for the duration of the trip, but in addition, at each place we also had local guides to tell us all about the different plants and animal life in their area. Julissa was our fearless leader and “cat herder”, constantly checking in with everyone to make sure we were all doing ok and making sure everyone’s needs were met.  

All in all, it was an unforgettable experience! 

 

Ready for your own OTS experience?
This unforgettable journey is just one example of what it means to travel with the Organization for Tropical Studies. Whether you’re a scientist, a student, or simply someone curious about the natural world, OTS Experiences Trips are designed to immerse you in the richness of tropical biodiversity—guided by local experts and surrounded by breathtaking landscapes.  

Our next destination? Skukuza, South Africa—home to one of our premier research stations and a gateway to exploring African ecosystems like never before. 

Reserve your spot today through our interest form and take the first step toward your own journey of discovery. https://tinyurl.com/OTSexperiences  

Our secret Wild neighbors 

By Alexia Pereira-Casal 

When you ask, most people will say that they love nature and animals and that they enjoy a walk in the woods, observing birds, and the thrill of a close encounter with a wild creature. However, when those close encounters happen in their own homes, their opinion changes. They insist that wild animals should stay in the wild and have nothing to do in the city—this is where humans live. Needless to say, wild animals are already living in cities. We see rodents in sewers, raccoons eating trash, and coyotes moving around as if it’s their territory—because it is! We are coexisting with urban wildlife, and there is no turning back. Living organisms adapt to changing environments, and the more we convert wild habitats into cities, the more flexible species adapt to the new niche. Those that don’t are displaced to find a new home or risk extinction due to this human-induced change of land. That’s the thing: humans are so excellent at changing the environment that we are impacting the climate and natural processes the Earth has refined over thousands of years. Organisms are great at adapting—and when they can’t, they face the end of their era.  

 

 

Currently, some of the biggest threats wildlife must face are habitat loss, fragmentation, pesticides, rodenticides, and—in my opinion—domestic animals. When we build new roads and cities, we destroy habitats that have existed for millennia. We change the landscape and give it new uses, such as agriculture or cattle grazing. A vast natural environment becomes fragmented “inland islands,” making it harder for animals and plants to disperse, find food, reproduce, and simply thrive—they are forced into cities. Secondly, when we plant crops designed to produce exponentially and without pause, we pump chemicals into the land to accelerate growth. These products leach into rivers, polluting everything—including our own bodies. To extract maximum yield, we also use poisons to kill pests, indiscriminately exterminating both pests and our wild allies and even degrading soil health. Some studies show coyotes that feed on rodents previously exposed to rodenticides become sick or eventually die from secondary poisoning. Finally, when we let our pets roam unsupervised, we introduce new predators into the environment, hunting native species—birds, shrews, snakes, mice, insects—and dispersing diseases that further threaten wild populations.  

Understanding how human-made changes impact wildlife—and how animals adapt—is only possible through monitoring programs. Research on wildlife populations can now be conducted with minimal disturbance. Biologists use trail cameras, GPS collars, bioacoustic recorders, and occasional live-capture studies to track movement, assess health, and identify challenges. As someone who does a lot of trail-camera work, I’m always thrilled to check the photos and videos—especially seeing people’s reactions when they discover their silent neighbors, unbeknownst to them, sharing their backyards with bats, opossums, and wild mice. We can protect what we know, and learning we share our homes and cities with other species helps us change behaviors that harm them—like using pesticides and rodenticides or letting cats and dogs roam free.  

In June this year, I attended the International Urban Wildlife Conference in Atlanta, GA, USA. There, I learned from and connected with scientists who study, protect, and advocate for urban wildlife. Three top topics emerged: managing negative interactions with wildlife, how socio-political dynamics impact wildlife and their conservation, and how pesticide and chemical use affects animal health. OTS in Costa Rica is already working with communities and municipalities on proper waste management and coyote-human interaction protocols. Yet, it remains crucial to dive deeper into socio-political dynamics and strengthen chemical-use regulations so that better decisions guarantee a healthy, balanced ecosystem for both people and non-human inhabitants. Next steps include building bridges between organizations—such as a possible collaboration with the Wildlife Working Group—to share experiences and cooperate, just like nature does!  

Costa Rica contains 6% of the world’s biodiversity thanks to its position as a bridge between North and South America and to the Pacific and Caribbean influences that create more than 10 life zones. The country has made great strides—banning wildlife hunting in the 1990s, regulating pesticide use, and enshrining in Article 50 of our Constitution the right to a clean, balanced environment. We run on renewable energy most of the year, and over 50% of the land is covered in vegetation. Yet, there is more to do, with the recent amendment to Executive Decree No. 38924-S raising permissible pesticide levels in drinking water due to the industry of export crops—pineapple, banana, and palm trees—policymakers have twisted their arm to industrial interests. Instead of such a harmful rollback, the Executive Branch could enforce stronger chemical regulations and develop sustainable, eco-friendly pest-control and fertilization systems. Every year, dozens of biologists and science professionals graduate. There’s no shortage of expertise to guide our country—and world—toward a healthier equilibrium. We must include scientists wherever public decisions are made. We are now seeing the effects of these old-fashioned productive habits, but wildlife have had to endure these for decades now. A friend’s remark still resonates: the rights of animals are the first to go; how else do we justify destroying habitats and extinguishing species for our comfort, unaware that their decline portends our own? 

While all of these threats and factors may seem logical, imagine this: you’re an animal born in a vast forest. Suddenly, without your consent, highways slash through your backyard and concrete islands replace your shelter. It becomes harder to find food sources, and crossing roads becomes a deadly gamble. Humans cultivate crops you can’t eat—unless poisoned on purpose. You have two choices: adapt to the imposed habitat or flee, abandoning your roots and countless ancestors behind. If you resist, they call exterminators and erase every chance of survival. If this happened to people, we’d call it genocide and rise in protest. Yet, when it’s wildlife, most stay indifferent. I hope this helps you remember our interconnectedness—through shared ancestry, the land, the water, the wind, and the sun. We inherit this Earth together. Please, let’s continue doing our best. As a community, now is the time to act. We can change the world for the better, for us and our secret wild neighbors.  

Science at OTS 

Section by Elizabeth Braker. OTS CEO.

Why do large groups of harvestmen bob more frequently and longer than small groups? Aggregations of harvestmen (arachnids in order Opiolones) are often spotted on a branch or between tree buttresses in forests. When disturbed, these animals may begin to bob up and down, a behavior assumed to be a defensive response. Two research groups recently published work conducted at La Selva on the possible functional significance of this behavior as part of the defensive repertoire of harvestmen.  While aggregation is thought to be a primary defense in these animals, the bobbing behavior may be a secondary defensive response that could increase the strength of the signal to potential predators. Calhoun et al. (2025)1 tested whether bobbing behavior occurred more frequently in aggregations than in isolation in Prionostemma spp. As group size increased, so did the frequency of bobbing. The authors suggested that bobbing is a context-dependent antipredator defense behavior, depending on the relative costs and benefits of its expression. Taking a different approach, Villaseñor-Amador and Escalante (2025)2 explored potential drivers of bobbing, also in Prionostemma, finding that the duration of bobbing behavior increased with group size. The authors also explored different possible triggering stimuli for bobbing behavior, finding that a touching stimulus (gentle stick touching) triggered longer bobbing than an airflow stimulus (gentle blow). Additionally, they studied whether losing one or more legs (a common response to attempted predation) affected individual engagement in bobbing, finding that there was no relationship between these variations in leg condition and duration of bobbing. These studies on Prionostemma provide new insights into a striking yet little-studied behavior, as well as suggesting pathways to explain the relative importance of different aspects of defensive behavior in animals.  

Forest plots at La Selva provide a field baseline for estimates of efficiency and precision for ground-based sampling inventory. The CARBONO plots were established at La Selva for a multidisciplinary team study of forest carbon cycling.  The project was designed to assess forest processes at the landscape scale by sampling with replication across the within-landscape edaphic heterogeneity typical of tropical forests. Through more than two decades, forest growth and dynamics were assessed annually (data and publications in the Dryad repository; Clark and Clark (2021)3.  To validate efficiency and precision of forest sampling methods to be used for Forest Carbon Offset calculations, Tompo et al. (2024)4 used field measurements of the CARBONO plots at La Selva and, for comparison and simulations, of published tree-level data on Barro Colorado Island in Panama. Plot configurations and costs were compared using criteria commonly used by forest carbon offset project developers to meet precision of +/−10% at 90% confidence interval for above ground biomass estimation. Multiple alternative plot configurations were evaluated with one method (angle-count plots) emerging as a highly cost-efficient and versatile alternative in complex tropical forests. 

Two decades of monitoring forest restoration plots show that different initial treatments persist in forest canopy composition. Schubert et al. (2024) 5 compared the results of different approaches to forest restoration in the Las Cruces region.  The researchers assessed 16–18-year-old plots, initially established with four different restoration treatments, and compared them to plots in adjacent reference forests to compare tree recruitment patterns and community composition across treatments and in relation to the reference forests. Restoration treatments that incorporated active tree planting resulted in the establishment of more later-successional trees compared with natural regeneration. The authors caution that more time is needed to assess whether these differences will persist as the restored areas mature, and how quickly restored forests achieve similarity to mature later-successional canopy. The results indicate the need for long-term monitoring of restoration efforts. 

 

Peccary wallows are biodiversity hubs.  Wallows (isolated, water-filled depressions) created by the activity of collared peccary (Pecari (Dicotyles) tajacu) at La Selva functioned as attractors for many vertebrate species6.  Activity and diversity of these other species higher at wallows compared to the adjacent forest. A total of 42 vertebrate species used the wallows in a range of behaviors including reproductive activity, bathing, and drinking.  Wallos persisted for as long as six years and were used consistently over time. 

 

Emerald glass frog females do not provide effective parental care to egg clutches.  Although many amphibians care for their eggs and young, protecting them from predation and desiccation, the emerald glass frog (Espadarana prosoblepon) attends eggs for only a short time (1.5 hours) after oviposition. Goyes Vallejos et al. (2024)7 found that female emerald glass frogs are easily disturbed, causing them to abandon eggs even before this short interval.  Similar levels of mortality were recorded in clutches with and without female presence, and female presence did not reduce mortality due to dehydration or predation.  The authors challenge the assumption that simple clutch attendance is not enough to demonstrate effective parental care in these amphibians, and perhaps more broadly in other animal species.  

 

Sloth species do not share parasite species.  The interactions of gastrointestinal parasites and their vertebrate hosts are both difficult and messy to study, and are especially poorly known for free-ranging, arboreal mammals living in tropical forests.  Vanderhoeven et al. (2025)8  compared diversity and host specificity of gastrointestinal parasites infecting free-ranging sloths at La Selva, asking whether host-parasite interactions were structured by host identity, the habitats in which hosts occurred, or both. 

The researchers collected fecal matter from both Hoffmann’s two-toed sloth (Choloepus hoffmanni) and the brown-throated three-toed sloths (Bradypus variegatus). Both host species harbored protozoa and nematode eggs, but only C. hoffmanni had cestode eggs. The diversity of parasitic morphotypes found in this study did not differ from what has previously been described. Parasite richness did not differ between species or between habitats, despite an interesting trend of higher parasite richness for forest-living C. hoffmanni compared to that of urban individuals living in Puerto Viejo de Talamanca. However, sloth species did not share parasite species, resulting in strong differences in parasite community composition between species. Rare and possibly undescribed parasite taxa were recorded only in samples from primary forest. The study raises interesting directions for future study, including the importance of characterizing host-parasite transmission networks and the potential relevance of intermediate hosts.  

 

Hummingbird flower mites detect and respond to electrical fields. Tropical phoretic mites that feed on nectar and pollen are transported from flower to flower by hummingbirds. In this study, Garcia-Robledo et al. (2025) asked whether electric fields facilitate transportation and detection of hummingbirds by a guild of tropical phoretic mites. Using choice experiments to study mite attraction to electrical fields and electrostatic forces, the authors found that mites use electroreception detected via sensory structures on their front legs to detect hummingbirds and use electrostatics to facilitate transportation onto their hosts.9 

 

Guest Essay by Dr. Eugenio González, Director, The Soltis Center for Research and Education in Costa Rica, Texas A&M University. 

Preface by Dr. Deedra McClearn, scientific advisor to OTS. 

Research projects often expand in new and unanticipated ways. That has certainly been the case with the data rescue effort for the La Selva CANADA PLOT native tree initiative. The goal of Phase 1 was to put the original seedling data from 35 years ago into a permanent data repository. After considerable time and effort, that phase was successfully completed in 2021.  

Phase 2 was prompted by the questions “Can we still find the original trees 35 years later?” and “If so, can we tag and remeasure the trees with the goal of looking at survival and growth rates?”

This report takes a quick look at the successful completion of Phase 2 and a look ahead to Phase 3. A comprehensive treatment of the entire project is underway for publication in a peer-reviewed journal.

Data Rescue: from degraded pasture to model system

In Costa Rica, the debate about the use of native local tree species vs. well–known exotic species in timber plantations began in the late 1970s with the establishment of the first forestry plantations using native Costa Rican trees. Until this time, there was virtually no silvicultural information available regarding native tree species, and early attempts to grow trees for commercial purposes used mostly exotic species such as teak and eucalyptus. This is where OTS, in collaboration with the Dirección General Forestal of Costa Rica (today the Oficina Nacional Forestal), made a significant contribution with the establishment of research trials of native species at La Selva in the early 1980s. Within a few years, the data from seedling growth and survival of these native trees became the foundation of government guidelines on forest restoration and the national Payment for Environmental Services program. 

The Canada Forestry Plot 

Although there have been many other forestry research projects at La Selva, the “Canada Plot” project stands out as one of the first initiatives of this type. To preserve genetic integrity and for phytosanitation, seeds were collected locally and used to produce seedlings in nursery facilities near La Selva.  In June 1986, with $10,000 in funding from the Canadian Embassy, seedlings of fourteen native trees species were then planted in a standardized design, with the goal of determining each species’ establishment (early survival and growth) over a four-year period.  

In mid-2019, a team including OTS staff and Soltis Center personnel visited the site and started a preliminary discussion about recuperating the plots, managing the data, planning publications, and other topics. Since then, there have been several efforts to recover data and relocate the plots in the field. In 2020, OTS received funding from the Environmental Data Initiative to support two fully funded data fellows. By early 2021, two database packages based on the plots were available on the EDI Portal.1

 

 

 

 

 

 

 

 

 

Field Work: Marking out the Canada Plot and measuring the surviving trees 

The team completed field work in early 2025, with all the corners of the plots and subplots marked with PVC pipes and aluminum tags using an X-Y grid reference location system. All surviving trees of the species planted were measured for DBH, tagged with consecutive numbers, and located using the X-Y coordinates. 

What is next for Phase 3? 

The most significant outcome of this initiative was the rescue of the original data from the oldest known native tree forestry plantation in Costa Rica. With the publication of the data and metadata on the EDI platform, the information is now freely available to researchers to study properties of seedling establishment, growth, and early survival, or to develop new research questions. This successful project is part of an OTS-wide effort to rescue important data sets from OTS field stations and make the data freely available on indexed platforms such as EDI. 

Acknowledgments 

The team responsible for rescue of the Canada Forestry Research Plot at La Selva consisted of OTS staff and associates including B. Braker, D. McClearn, E. Castro, E. González, O. Jiménez, S. Rodríguez, and O. Vargas, with collaboration by staff of the TAMU-Soltis Center.  

Epilogue: by Deedra McClearn 

A few words about the importance of data repositories are in order. These packages are invaluable, as they contain raw data (original measurements) and relevant metadata such as maps, field notes, and photographs. “Legacy” (important information from decades gone by) and long-term ecological data can never be replicated, because they are unique to a specific time period. Even if papers have been published using the data, their charts and graphs can’t be used to ask new questions. The original numbers must be used. The original (“raw”) data must be used if synergies of data sets are planned (tree growth with weather records, for example). Furthermore, the maps and photos associated with the original data can provide critical information about changes in land use and extreme weather events. 

Beyond Endangered: A New Look at the “Guayacán Real”

By Orlando Jimenez. GIS OTS team.

Some trees are impossible to overlook—not because of their size or color, but because of the feeling they leave behind. 

During a walk with undergraduate students—part of a basic GIS workshop—we encountered one of those unforgettable trees. With a trunk over 60 centimeters in diameter, its dense, twisted form seemed to carry the weight of centuries. According to local foresters, this Guayacán real (Guaiacum sanctum) could be more than 500 years old. It may have already been standing when the first European ships reached the shores of Central America. Not as a monument to colonization, but as a quiet testament to the forest’s enduring presence.

 

 

 

 

 

 

 

 

 

The walk was part of a hands-on GPS activity. Our task was simple: identify Guayacán trees along the trail, mark their locations with waypoints, and assign each a size class. Before setting out, I estimated that—with luck—we might find 100 individuals. But the forest surprised us: along just 1.5 kilometers, we recorded more than 400 trees. An extraordinary density for a species considered endangered. 

Guaiacum sanctum grows exclusively in tropical dry forest, an ecosystem that covers only about 10% of Costa Rica. Its wood is among the densest—and most valuable—in the world. This desirability led to its overexploitation, and today, the species is protected under CITES and national bans on harvesting. In most places, finding even a single tree is rare. But here, in Palo Verde, we were surrounded by them. 

And then we saw it—the giant. A massive individual, likely the mother of many others we had recorded. Towering quietly, never demanding attention, yet impossible to ignore. Around it, students gathered, took coordinates, scribbled notes. And though no one said it out loud, I believe many of them received a lesson not listed in the workshop syllabus: every GPS point represents a living story—a life worth noticing, understanding, and protecting. 

Palo Verde National Park is well known for its birds—and rightly so. But there are other lives in its landscapes, quieter ones, just as valuable. Along its trails grow stories of resilience, like that of the Guayacán, inviting us to slow down and look more closely. 

Because in the shadow of time, the forest speaks. And if we listen carefully, we just might hear it.  

This discovery is a powerful reminder of how field-based GIS education at OTS goes beyond maps and data—it reveals hidden narratives etched into the landscape. Want to learn more or get services from us? Contact ots.gis@tropicalstudies.org 

¿Le interesa la conservación y el ambiente a las comunidades urbanas? 

Escrito por Jossy Esteban Calvo. 

English version.

Costa Rica ha sido, por varias décadas, un exponente mundial en la conservación de la biodiversidad y de áreas silvestres protegidas, sin embargo, a nuestras ciudades casi siempre debemos excluirlas de la ecuación. Omitirlas en el informe. 

¿Hemos dejado entonces, de preocuparnos los costarricenses por las ciudades? Los niveles de contaminación de ríos urbanos como el Torres en San José, o el Pirro en Heredia; la constante pérdida de paisaje y trama verde; o los muy frecuentes desastres ambientales como inundaciones urbanas, nos pueden hacer pensar que tiramos la toalla hace muchos años. Dejamos de interesarnos o nos vimos consumidos entre barreras burocráticas y falta de voluntad política. 

Sin embargo, en OET nos hemos encontrado que muchas veces las fuerzas vivas que mantienen y mejoran los esfuerzos de conservación nacen y se gestionan desde las comunidades. El Proyecto Transición hacia una Economía Verde y Urbana (TEVU), implementado por la OET con MINAE, PNUD y fondos GEF busca encaminarnos hacia la descarbonización del Gran Área Metropolitana: más allá de eso, demostrar que es posible tener ciudades limpias, verdes y azules, con justicia y equidad de género, y que generen empleos verdes.  

Más de 1500 personas participan en los conteos de aves de Corredores Biológicos Interurbanos. Participantes que reconocen que en los ríos aún hay vida y que, en nuestros parques urbanos, mucha fauna resiste y habita. Comunidades organizadas como Asociación Yo Amo mi Barrio San José lideran el monitoreo en sus barrios porque reconocen que debemos conocer nuestra biodiversidad para poder conservarla.  

 La Asociación Comunal APICAL impulsó con ímpetu la creación de un parque accesible, en su comunidad de Belén; porque tener áreas verdes urbanas significa conservar el agua, nuestra salud mental. Esto impulsó la sinergia entre la Municipalidad y TEVU para inaugurar 600 metros lineales entre bosques en regeneración en el Parque Santuario.  

Maribel Gómez, lideresa de la comunidad de La Guapil en Alajuelita, soñó, luchó y vio hacerse realidad como un espacio “muerto”, que era un botadero de basura a cielo abierto e inseguro en su barrio, se transformó en un parquelleno de árboles, senderos, juegos para niños, cancha de deportes y hasta un huerto urbano comunitario. Cambios de paradigma como este, que requieren de alta inversión y coordinación entre proyectos como TEVU, Interlace y entidades como el CBIMA, PNUD, la Municipalidad y CRUSA, solo son realidad cuando la misma comunidad es quien se apropia y los impulsa. 

 

 

 

 

 

 

 

Tras cuatro años reverdeciendo y mejorando la ciudad, hoy no solo podemos asegurar que las comunidades urbanas sí se interesan en la conservación, más aún, somos testigos de su increíble capacidad de generar cambio. El trajín y la acelerada vida urbana no limita a las personas que sueñan con algo mejor; es a pesar de eso que pueden detenerse para apreciar aquello que valoran y desean preservar. Las fuerzas vivas comunales hoy: levantan murales que reflejan su compromiso por la naturaleza y la justicia, regeneran bosques a orillas de los ríos urbanos, construyen aceras y senderos que nos unen y nos acercan, contagian a la institucionalidad con sus sueños y llenan una ciudad de colores que hoy más que nunca, requiere de nuestro cuidado y cariño. 

Sigamos contagiando nuestro amor y compromiso por ciudades verdes y azules. 

De estudiante a Coordinador: una historia de transformación vivida en OET

Escrito por Pablo Muñoz.

Hace ya 8 años y 5 meses, mi profesora de ecología nos comentó a mí y a Georgia que la OET daba cursos de campo buenísimos. Ella fue una de las mejores profes que tuvimos, y darnos cuenta de esto me hizo pensar que quizás sería buena idea aplicar a uno de esos cursos.  

Durante toda la carrera, tuvimos la oportunidad de visitar las 3 estaciones en giras de campo, participando en cursos muy variados, desde zoología, ecología aplicada, hasta ecología y fisiología vegetal. Imaginar pasar 6 semanas recorriéndolas sonaba como toda una aventura.  

Georgia, Ronny y José decidieron aplicar a la edición de Ecología Tropical y Conservación 2018. Yo todavía estaba indeciso y pensaba en aplicar a un curso similar en inglés (TropBio: An Ecological Approach) para practicar mi inglés y demás. Sin embargo, al enterarme de que mis amigos habían aplicado al curso en español para Latinos, cambié de idea fácilmente y envié mi aplicación alrededor de marzo de 2017. 

En esa época, Georgia y yo estábamos en los últimos cursos de nuestro bachillerato en Biología Tropical, con pocos cursos por delante. Nos enteramos de que se iba a impartir un curso de campo más corto en septiembre de ese año, organizado por otra entidad, y por la descripción parecía similar al de la OET. Para nosotros, era una buena oportunidad para prepararnos para el curso de posgrado en el que habíamos aplicado en OET.  

 Ya había tomado un curso similar a nivel de pregrado en el Smithsonian Tropical Research Institute, y fue una experiencia inigualable a mis 20 años. ¿Qué podría ser diferente en ese curso de septiembre? La lógica me decía que asistir me ayudaría a estar “preparado” para el gran curso en enero, pero estábamos totalmente equivocados… 

 Esa experiencia en septiembre, aunque no fue mala en sí, no ayudó mucho. La empatía con los otros participantes estuvo muy lejos del currículo, y la relación con los profesores fue escasa. A los 10 días, ambos salimos con un desasosiego tremendo, con el síndrome del impostor por los cielos, y con la noticia de que habíamos sido aceptados en el curso de posgrado en Ecología Tropical y Conservación (ETC18). Lo que aprendimos fue a cómo no hacer o como no abordar varias cosas. Hasta ese momento, nunca me había sentido tan inseguro de una decisión, pero, gracias al apoyo de mis amigos (aunque no sepan, eso fue clave) y de mi mamá, decidí seguir adelante con el proceso. 

Y de repente, ya era enero de 2018, y me estaban dejando en el hotel Ave del Paraíso, en San Pedro. La primera persona que vi fue a Alejandro Farji, que venía como profesor invitado. No sabía quién era ese argentino mechudo, que en ese momento me direccionó hacia la recepción… hasta el día siguiente, eso me dio mucha risa. 

 

Éramos 21 latinoamericanos de Perú, México, Bolivia, Colombia, Argentina, Puerto Rico, Costa Rica y Cuba. Todos con una maleta cargada de ropa de campo, inseguridades, aspiraciones e historias distintas… . Desde ese primer día en el hotel, se empezó a sentir una conexión entre el grupo. Aunque quizás esto sea algo que sucede en muchos cursos, siempre digo que el mejor curso de ETC es el en el que uno fue estudiante. 

 

A la mañana siguiente, además de descubrir quién era Farji, conocí a nuestras coordinadoras, Jenny Stynosky y Pati Salerno, y al TA Jimmy Barrantes. Jenny y Pati se encargaron que este curso siguiera brindando la esencia que estos cursos brindan a cada estudiante desde los 60s, dato que no había interiorizado hasta capaz algunos años después de mi participación cuando me incorporé como empleado de OET en el Dept. Académico-Científico (Educación en aquel entonces). Este curso fueron los estudiantes, equipo de coordinación y por supuesto los 21 profesores y profesoras invitadas con quienes compartimos el viaje. Si, debo decir que ha sido de las experiencias más extenuantes que he tenido y exigentes, pero también de las cuales he aprendido más. Esto es un aspecto personal, pero nunca hasta ese momento me había conocido a mi mismo y crecido como después de esas 6 semanas, donde al cabo capaz de una semana aquel miedo e inseguridad que me había abordado desde mediados de setiembre y que acumulé por 3 meses hasta este nuevo curso ahora se veía como un mal sueño, algo pequeño, sin importancia. Este curso me hizo querer seguir haciendo las cosas que hago hasta el día de hoy. Ahora tengo el privilegio de poder escribir este texto sentado desde la Oficina de la OET como Coordinador de Educación, luego de haber sido TA varias veces del mismo curso y haber empezado a trabajar tiempo completo hace ya 4.5 años. Hoy en la mañana justamente contesté un correo de mi amigo Eze Vaderhoeven (compañero de ETC18) sobre un financiamiento que ganó desde su laboratorio que no solo le permitirá volver a Costa Rica para continuar su investigación, sino también ofrecer un curso innovador de campo en el área de la parasitología y que organizaremos en conjunto desde OET y la Universidad de Brown a donde Eze está asociado. 

 

Estoy orgulloso de decir que estas experiencias no son aisladas únicamente al curso ETC, sino que la viven los estudiantes del curso de Sistemática de Plantas Tropicales, Helechos y Licófitos, TropBio, Ecología de Mariposas…la receta está clara, el modelo de educación OET funciona. 

 

Contacto graduate@tropicalstudies.org