New in Rainforest Conservation: Seeing the Forest and the Trees
Rainforest conservation gains new focus with the discovery that just 2% of the diverse tree species in the forest account for half the trees.
By Sofia Caetano Avritzer
When you hear biodiversity, you may think of a green, lush tropical forest filled with thousands of different species of plants, insects, birds, and all sorts of other living creatures. This image of tropical forests is not a coincidence. It results from years of hearing that tropical forests are the most biodiverse ecosystem on earth. In fact, there can be more tree species in a single hectare of rainforest than in all of the US and Canada combined.
It is this enormous biodiversity, along with the rainforest’s importance in regulating climate patterns and capacity to absorb carbon from the atmosphere, that makes rainforest preservation essential. This biodiversity, however, also poses a huge challenge for rainforest conservation: with such a diversity of species, not much is known about each individual species. With so many different species to study, where do we start? How can we protect an environment when so much about how it works is still unknown?
This is the challenge that a consortium of over 300 scientists spread across 3 different continents attempted to tackle in an article recently published in Nature. Their approach attempted to understand the composition of a specific group of organisms in these tropical environments: trees.
For rainforest conservation, we should start with the trees
Trees are one of the most essential organisms in any tropical forest. Not only do they provide food and shelter to an enormous number of animal species, they also play a crucial role in the environment’s water cycle. By collecting water with their roots and releasing it through their leaves, trees contribute almost as much to tropical forest rainfall as rivers or even the ocean. A single tree in the Amazon rainforest can release over 100 gallons of groundwater a day into the atmosphere. This gets condensed into clouds and returned to the environment as rain. So in a way, trees are what give rainforests their name.
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The scientists started their research into rainforest conservation by asking a very simple question: Are there any tree species that are particularly common in a rainforest? For this study, they chose to concentrate on three main regions: Africa, South America (Amazon rainforest) and Southeast Asia. Surprisingly, they found that a tiny fraction, around 2 percent, of all tree species in these tropical regions contribute to half of the total number of trees. Not only that, but this pattern seems to be true for all three rainforests in the study, even though they are on different continents and have very different natural histories. What this suggests is that a few key species could be very important for tropical forest ecosystems, and better understanding them can help develop new strategies for rainforest conservation.
How can we know which trees are in a rainforest?
When looking at a study like this, you may wonder: How do researchers know which trees are in all of these forests? It would take hundreds or even thousands of years to count and identify all the trees in the Amazon rainforest alone, so how can they have done it for multiple forests? The answer is that they didn’t. What they did instead was analyze publicly available databases built using a method called forest inventorying.
Forest inventorying is when a group of researchers pick a series of forest areas, called plots, to visit and identify all the trees. With enough plots spread out through the forest, you can get a rough coverage of the area of a whole forest. Because these plots usually have a standardized size, the data collected from each plot can be combined using a series of statistical methods. The results can then be extrapolated to the whole forest. By using around 2,000 forest plots spread across all 3 different rainforest areas, researchers were able to estimate the distribution of species in these tropical forests.
The scientists were also able to create a list of the most likely common tree species in each forest. This will help rainforest conservation efforts by allowing us to concentrate our studies on a few select species instead of all the thousand species in a forest. This list includes some names you might have heard before, like the açaí palm, as well as many others.
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What about the trees that are not that common?
Preserving rare tree species is still incredibly important. Rare species can produce compounds with medicinal effects, fruits and flowers that are essential for animals, and even food sources for humans. The researchers hope that studying the very common tree species will not only aid in protecting those species but also the rare ones and the rainforest as a whole.
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In the future, the researchers also would like to add data from other regions, such as Central America and New Guinea, to make even more accurate predictions on tree species number and abundance. Improving our ability to model how trees structure tropical forest environments enhances our capacity to safeguard and preserve these areas for future generations.
This study on rainforest conservation research was published in the peer-reviewed journal Nature.
References
Artaxo, P., Hansson, H. C., Machado, L. A. T., & Rizzo, L. V. (2022). Tropical forests are crucial in regulating the climate on Earth. PLOS Climate, 1(8), e0000054. https://doi.org/10.1371/journal.pclm.0000054
Coley, P. D., & Kursar, T. A. (2014). On tropical forests and their pests. Science, 343(6166), 35–36. https://doi.org/10.1126/science.1248110
Cooper, D. L. M., Lewis, S. L., Sullivan, M. J. P., Prado, P. I., ter Steege, H., Barbier, N., Slik, F., Sonké, B., Ewango, C. E. N., Adu-Bredu, S., Affum-Baffoe, K., de Aguiar, D. P. P., Ahuite Reategui, M. A., Aiba, S.-I., Albuquerque, B. W., de Almeida Matos, F. D., Alonso, A., Amani, C. A., do Amaral, D. D., … Zent, S. (2024). Consistent patterns of common species across tropical tree communities. Nature, 625, 728–734. https://doi.org/10.1038/s41586-023-06820-z
Cuadros, A. (2023). Has the Amazon reached its “tipping point”? The New York Times. https://www.nytimes.com/2023/01/04/magazine/amazon-tipping-point.html
Hubau, W., Lewis, S. L., Phillips, O. L., Affum‐Baffoe, K., Beeckman, H., Cuní-Sanchez, A., Daniels, A. K., Ewango, C. E. N., Fauset, S., Mukinzi, J. M., Sheil, D., Sonké, B., Sullivan, M. J. P., Sunderland, T. C. H., Taedoumg, H., Thomas, S. C., White, L. J. T., Abernethy, K. A., Adu‐Bredu, S., . . . Zemagho, L. (2020). Asynchronous carbon sink saturation in African and Amazonian tropical forests. Nature, 579, 80–87. https://doi.org/10.1038/s41586-020-2035-0
Infographic created by Sofia Caetano Avritzer.
About the Author
Sofia Caetano Avritzer is a neuroscience PhD student at the Rockefeller University. When she is not in the lab, she loves talking and writing about science, visiting National Parks, and making pottery. She lives in NYC with her partner and two cats. Connect with her through Twitter (@sofiavritzer).
