Invasive species give ecosystems the (carbon) flux

Thakur, M. P., Gu, Z., van Kleunen, M., & Zhou, X. (2025). Invasion impacts in terrestrial ecosystems: Global patterns and predictors. Science, 390(6771), 381-385. https://doi.org/10.1126/science.adq3101

Written by Bethany Bradley, edited by Alanna Richman

Summary

Storing more carbon (‘storage’) in ecosystems and reducing the turnover (‘flux’) of that carbon are important components of enabling ecosystems to mitigate climate change. For example, if ecosystems store more carbon (e.g., by growing bigger trees in forests) and have lower carbon flux (e.g., through lower soil disturbance in agriculture), they can be a bigger part of climate change solutions. However, it is unclear how invasive species interact with carbon storage and carbon fluxes. Thakur et al. (2025) used a meta-analysis (a statistical synthesis of existing studies) to analyze 775 papers about invasive plant and animal impacts.  They focus largely on soil responses, including biotic factors like biomass and decomposition rates as well as abiotic factors like soil organic carbon and greenhouse gas emissions (CO2, N2O, CH4).

In terms of carbon storage, Thakur et al. found that soil organic carbon was higher in areas invaded by invasive plants - potentially because invasive plants also increased above and belowground biomass and were associated with disturbed areas with more rapid growth.  In contrast, invasive animals decreased carbon storage - a pattern that was largely driven by invasive earthworms consuming plant litter.

In terms of carbon flux, Thakur et al. found that both invasive plants and animals increased greenhouse gas emissions, possibly due to an association with disturbance. They note, however, that these results may not be reliable because there was evidence of some statistical artifacts in the underlying data.

The most striking pattern found by Thakur et al. was a strong negative impact of invasive plants on native plant diversity.  Where invasive plants had longer residence times (i.e. had been introduced further in the past), impacts on native plant diversity were more strongly negative.  This suggests that as plant invasions progress, they have greater impacts on biodiversity.

Take Home Points

• Areas invaded by invasive plants tended to have higher soil organic carbon.

• Areas invaded by invasive animals (mainly earthworms) tended to have lower soil organic carbon.

• Invasive plants that were introduced a long time ago tend to have greater negative impacts on native plant diversity - likely because impacts accumulate as invasions progress.

Management Implications

• Earthworms that rapidly break down litter likely increase carbon fluxes but ultimately decrease soil organic carbon storage.

• Impacts of invasive plants likely build up over time.

Related Papers

Bradley et al. 2019, Fei et al. 2019, Quirion et al. 2021

Keywords 

Impact studies, global, soils, terrestrial ecosystems