Rodent Bioturbation Significantly Enhances Annual Methane Uptake by Tibetan Alpine Grasslands

Area of Science:

• Ecology
• Environmental Science
• Soil Science

Background:

• Tibetan alpine grasslands (AG) are crucial methane (CH4) sinks.
• Degradation of AG due to climate change and human activities increases subterranean rodent populations.
• Rodent bioturbation impacts soil properties, but its effect on CH4 uptake is not well understood.

Purpose of the Study:

• To investigate the impact of rodent bioturbation on CH4 uptake in Tibetan AG.
• To elucidate the mechanisms driving CH4 flux changes mediated by rodents.
• To compare CH4 fluxes across different grassland types globally.

Main Methods:

• Paired year-round CH4 flux measurements were conducted on Plateau zokor mounds (ZM) and healthy meadow (HM) patches.
• Meta- and synthetic analyses of CH4 fluxes were performed across Tibetan AG, temperate grasslands (TG), and tropical grasslands (TrG).
• Soil moisture and functional gene abundances (pmoA) were analyzed.

Main Results:

• Rodent bioturbation significantly doubled annual CH4 uptake in Tibetan AG.
• The net increase in CH4 uptake due to bioturbation was largely observed during the growing season.
• Decreased topsoil moisture and increased pmoA gene abundance were associated with rodent bioturbation.
• Tropical grasslands showed lower CH4 uptake than temperate and alpine grasslands due to higher precipitation and soil moisture.

Conclusions:

• Rodent bioturbation plays a significant role in enhancing CH4 uptake in alpine grasslands.
• Soil moisture is a key factor influencing CH4 sink variations globally.
• Long-term monitoring is essential to understand the ecological consequences of bioturbation in climate-sensitive ecosystems.