Document Type

Article

Publication Date

7-15-2026

Department

College of Forest Resources and Environmental Science

Abstract

Methane (CH4) is a potent greenhouse gas, and tropical forests account for roughly one–third of global atmospheric CH4 uptake by soils. Projected warming and more frequent hurricanes in these ecosystems may alter soil CH4 sink strength, as warmer and wetter soils enhance methanogenesis activity. We measured soil CH4 and CO2 efflux during the calendar summer months of 2023 and 2024 alongside continuous records of soil moisture, soil and air temperature, and precipitation in an in–situ warming experiment (TRACE) located in a lowland tropical forest in Puerto Rico, six to seven years after Hurricanes Irma and Maria (2017). The realized warming (∼1.95°C) enhanced soil respiration only in summer 2023 (p < 0.05), but net soil CH4 uptake was invariant in both campaigns (p > 0.05). Instead, sampling day and between–plot variability explained soil CH4 dynamics much more than treatment contrasts. Importantly, CH4 uptake was consistently coupled to CO2 efflux, suggesting tight linkages between methanotrophic and heterotrophic activities. Between treatments, CH4 and CO2 responses to soil temperature variation were less sensitive in warmed plots, which may suggest weak metabolic upregulation under elevated temperatures. Together, these findings indicate that lowland tropical soils remain CH4 sink even under warming and years after hurricane disturbance, with CH4 dynamics driven more by spatial and temporal variability than experimental warming. Long–term, high–resolution monitoring integrating soil biogeochemistry and microbial processes will be critical to determine whether the observed net CH4 uptake signal represents a sustainable or transient response under continued warming and disturbance.

Publisher's Statement

© 2026 The Authors. Published by Elsevier B.V. Publisher’s version of record: https://doi.org/10.1016/j.agrformet.2026.111225

Publication Title

Agricultural and Forest Meteorology

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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