Ecologist Edwin Pos measures in Costa Rica how the rainforest grows back after destruction
During his studies, Pos spent some months in Brazil to do research. It was his first meeting with the tropical rainforest, an experience which made a deep impression on him. Now, he can regularly be found in Costa Rica to research whether or not the consequences of deforestation can be undone.
Edwin, who grew up on the Veluwe, has always been a real ‘outdoor person’ since his early childhood. As an ecologist, he is especially interested in the complex puzzle called biodiversity. He wants to understands how an ecosystem works. Why does one species grow somewhere and the other one does not? “As a student, you learn about the tropical ecosystems, the amount of diversity, the position and the surfaces,” Edwin says. “But in order to actually experience being somewhere deep in the jungle, that has something special.”
In Costa Rica, he measures how a forest can bounce back after it is disrupted. “Once you're in the middle of the jungle, you realise even more that you're just a small part of a much bigger whole and that this whole is very complex. I was already fascinated by this as a child and now, it's an important academic motivation.”
About Edwin Pos
Edwin Pos studied philosophy and biology at Utrecht University and is currently employed there as an ecologist, an associate professor, Academic Director of the Utrecht Botanic Gardens AND head of the research group Quantitative Biodiversity Dynamics. In 2021, New Scientist proclaimed Edwin Pos Scientific talent of the year. He received the award because of his innovating way to combine ecological data with mathematical models and make this knowledge usable for current questions on biodiversity.
Within the university, he plays a prominent role too. At the opening of the new Evolution garden of the Botanic Gardens in 2025, Edwin took visitors along on the development of plants through time and emphasised how much biodiversity is interconnected with our daily lives.
Deforestation, agriculture and climate change
Edwin regularly returns to the jungles of Central America. “There, we try to find answers to questions you can't solve from a distance,” he says. He sees the consequences of deforestation, agriculture and climate change with his own eyes. “In the Netherlands, we hear and read much about the consequences of deforestation but don't or barely experience it as individuals ourselves.”
But when Edwin stands in the middle of the jungle and sees the vast plantations where trees used to be, it does hit home: “It gives you a perspective on the scale of deforestation and the loss of biodiversity, which you only get if you've been there. The science on their further consequences then also weighs heavier,” Edwin explains.
The influence we have on the forest is inextricably tied to the functioning of the ecosystem.
Consequences to plants and animals
“Everything is connected to each other” Edwin knows. He mentions examples: “For instance, regional climate can change if big sections of forest disappear. The biodiversity is influenced because populations lose contact with each other, animal species cannot migrate any longer or cannot get to the seeds anymore, which they feed on and help to disperse.” Edwin warns everything has effects on each other. And that humanity's actions have consequences too. “The influence we have on the forest is inextricably tied to the functioning of the ecosystem.”
Counting trees
In Costa Rica, one of the things Edwin investigates is how places like old plantations can grow back into tropical forests. With support from foundations such as Adopt Rainforest and Work with Nature, he takes stock of existing forests and – as part of the research - thousands of young trees have been planted. The recovery is meticulously watched. The plan is to measure year after year how fast the trees grow, what is happening in the soil and which species return on their own. This has to result in a timeline of change which shows how biodiversity restores itself.
Edwin says: “The project only started about three years ago. The first two years were especially about getting started, measuring and setting up the measuring areas and the training of the involved researchers. Just like the forest, the dataset is growing too. A few years from now, we can hopefully share the first results.”
Common or rare
But whether it IS possible for former plantations to grow back into forests, is what Edwin knows for sure. “The only question is what kind of forest you will then get in return.” Together with colleagues, scientists, students and local inhabitants, Edwin measures which species are returning, whether these are common or rare and whether or not that matters for the functioning of the forest. “These are the questions we're trying to answer in this project.”
Recent research projects show that half the species of trees in the Amazon region are estimated to become endangered because of climate change and deforestation by 2050.
Species on the red list
Edwin collaborated on a paper on biodiversity, based on a very big dataset. “We've estimated there are more than 15,000 species of trees in the Amazon. About 1-2 % of these are hyperdominant, which means these species are very common. The other 98-99 % of species are a lot rarer. Recent research projects show that half the species of trees in the Amazon region are estimated to become endangered because of climate change and deforestation by 2050. If you then consider that a single hectare of forest in the North-Western Amazon region can contain over 300 species of trees, you might be able to figure out how many species we can lose at any time with each disappearing hectare of forest,” Edwin explains.
It is not all doom and gloom
He worries about the loss in biodiversity, but does have an important nuance. “It's not all doom and gloom either. In some areas, we're able to bring back relatively much nature, something which is of course very beautiful and thus also shows that it's possible. Fortunately, there's still very much biodiversity left: so we must be very careful with it!”
Help Edwin and this research
Those who hear him speak, notice he believes in the resilience of nature. A plantation can become a forest again, biodiversity can return. With his project in Costa Rica, he wants to show it is possible. It provides knowledge which can be used worldwide for nature restoration.
The Utrecht University Fund raises funds for such research projects, among other things. With this support, Edwin can safeguard the research in the long run, which is needed in order to answer scientific questions. Besides this, it gives more students the opportunity to be trained in the field. Would you like to help too?
Text: Carolien Vader
Images: Hans Reitzema