Soil nematode abundances drive agroecosystem multifunctionality under short-term elevated CO₂ and O₃

Area of Science:

• Agroecology
• Climate Change Biology
• Soil Ecology

Background:

• Soil biota regulate ecosystem functions, but predicting climate change impacts on multifunctionality is challenging.
• Elevated atmospheric CO2 and O3 are key climate change factors affecting terrestrial ecosystems.
• Understanding soil biota responses is crucial for predicting agroecosystem health under future climate scenarios.

Purpose of the Study:

• To assess short-term agroecosystem multifunctionality responses to combined elevated CO2 and O3.
• To identify key soil biota regulating multifunctionality under these climate change factors.
• To compare responses between two rice varieties (Japonica, Nanjing 5055 vs. Wuyujing 3).

Main Methods:

• Factorial experiment combining elevated CO2 (+200 ppm) and O3 (+40 ppb).
• Assessment of agroecosystem multifunctionality index.
• Analysis of soil biota composition (bacteria, fungi, protists, nematodes) and abundance.

Main Results:

• Combined elevated CO2 and O3 significantly increased multifunctionality by 32.3% in Wuyujing 3 rice, but not Nanjing 5055.
• Soil nematode abundance, particularly higher trophic groups (omnivores-predators), better explained multifunctionality changes than overall biota diversity.
• Elevated CO2 and O3 impacts on multifunctionality were mediated by soil nematode communities.

Conclusions:

• Short-term elevated CO2 and O3 can enhance agroecosystem multifunctionality, but varietally dependent.
• Soil nematodes, especially omnivores-predators, are critical regulators of ecosystem multifunctionality under climate change.
• Maintaining soil nematode communities is vital for agroecosystem resilience and function under future climate conditions.