Converting rainforest into farming land restructures food webs (energy transfer in the ecosystem) and fundamentally changes how they operate, according to a study published in Nature.
Every day, more rainforests are cut down and replaced with plantations, reducing tropical biodiversity and affecting ecosystems. However, our current understanding of the long-term consequences is limited. Most studies look at biodiversity loss but don’t assess how energy is transferred in the ecosystem. Now, an international team led by the University of Göttingen in Germany wants to answer this question.
The team analysed a range of organisms, from microscopic mites and earthworms to beetles and birds, and compared the results from 32 locations across tropical forests and rubber oil palm plantations. The aim was to evaluate how energy is distributed and consumed by different resources (living plants, litter, bacteria, fungi, soil organic matter, and other animals) above and below the ground. This method also considers decomposition and measures the actions of predators (such as certain spiders or birds).
This analysis identified that most energy in rainforest communities flows to arthropods in soil webs following complex connections between different animals. Plantation, on the other hand, had less complex and less rich food webs both in the trees and in the soil. Instead of a thriving community including multiple arthropod communities, virtually all energy was focused towards invasive species of earthworms. As a result, there was minimal predation and high numbers of plant-feeding insects in plantations, including caterpillars and beetles.
“It is fascinating to see how all these different organisms are connected, from minute arthropods to birds, from soils to canopies. Scientists clearly need to investigate such connections in different parts of the ecosystem, particularly endangered areas of biodiversity – such as the one beneath our feet!” said Anton Potapov from the University of Göttingen.
“The ongoing conversion of rainforest into plantations is not just causing a massive decline in biodiversity, but it is also changing the way these ecosystems function,” explained Professor Stefan Scheu, also from the University of Göttingen. “For sustainable management of converted ecosystems, we need to understand how all these linked elements and connections are impacted. A more holistic approach can then be developed to promote the functioning of ecosystems both above and below ground.”
Potapov, A.M. et al. Rainforest transformation reallocates energy from green to brown food webs. Nature (2024). DOI: 10.1038/s41586-024-07083-y.