How biochar reshapes hidden life in Amazon forest soils
image: Invertebrate community responses to biochar addition in NTFP-enriched Amazonian secondary forests
Credit: Pedro Ríos Guayasamín, Sandy M. Smith & Sean C. Thomas
A new long-term field study reveals that adding biochar to tropical soils can subtly reshape underground ecosystems, influencing insects and other tiny organisms that play vital roles in forest health.
“Soil invertebrates are the unseen workforce of tropical forests, driving processes like nutrient cycling and decomposition,” said lead author Pedro Ríos Guayasamín. “Our study shows that biochar can influence these communities, but the effects depend strongly on soil type, season, and ecological context.”
Biochar, a carbon-rich material produced by heating biomass under low oxygen conditions, has gained attention as a tool to improve soil fertility and support climate mitigation. While its benefits for plant growth and soil chemistry are well documented, far less is known about how it affects soil biodiversity, especially in tropical ecosystems.
To address this gap, researchers conducted a three-year field experiment in secondary forests of the Ecuadorian Amazon. The team applied two types of biochar, kiln-produced and traditionally mound-produced, to forest plots enriched with native tree species used for non-timber forest products. They then monitored soil invertebrates, including ants, spiders, springtails, and parasitoid wasps, across multiple seasons.
The results show that environmental factors such as seasonality and soil conditions had the strongest influence on invertebrate communities. However, biochar still played a measurable role in shaping how different groups responded over time.
Predators such as ants and spiders increased in abundance over the course of the study, while microbivores, including springtails, declined. These trends were linked to shifts in soil chemistry, particularly reductions in aluminum levels, which can be toxic to some organisms. Biochar amendments helped reduce aluminum availability, creating more favorable conditions for certain groups.
In nutrient-poor alluvial soils, biochar effects were especially complex. Some microbivores declined when specific biochar types were applied, while predator populations responded differently depending on seasonal conditions and plant diversity. In contrast, in richer colluvial soils, parasitoid wasps showed consistent increases in response to biochar additions.
The study also highlights the importance of interactions between biochar and forest management practices. Plots planted with mixed tree species often showed stronger biological responses than monocultures, suggesting that biodiversity aboveground can influence how soil organisms react to environmental changes belowground.
Overall, biochar did not dramatically alter the overall composition of soil communities. Instead, its effects were subtle and context-dependent, interacting with factors such as rainfall patterns, soil fertility, and vegetation structure.
“These findings emphasize that biochar is not a one-size-fits-all solution,” said the research team. “Its ecological impacts depend on where and how it is applied, as well as the surrounding ecosystem.”
Understanding these dynamics is critical because soil invertebrates play a central role in maintaining forest productivity and resilience. In tropical systems, they can account for a large proportion of leaf litter decomposition, influencing carbon cycling and nutrient availability.
The researchers note that long-term field studies like this one are essential for evaluating the real-world impacts of biochar. While laboratory experiments often show clear benefits, natural ecosystems are more complex, and biological responses can vary over time.
As interest in biochar continues to grow, this study provides valuable insight into its ecological consequences. By revealing how soil organisms respond under realistic conditions, the findings can help guide more sustainable land management practices in tropical forests and beyond.
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Journal Reference: Ríos Guayasamín, P., Smith, S.M. & Thomas, S.C. Invertebrate community responses to biochar addition in NTFP-enriched Amazonian secondary forests. Biochar 7, 66 (2025).
https://doi.org/10.1007/s42773-025-00447-1
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.