Soil nematode abundance and functional group composition at a global scale.

Area of Science:

• Ecology
• Soil Science
• Biogeochemistry

Background:

• Soil organisms are vital to the terrestrial biosphere and ecosystem functioning.
• Quantitative, spatially explicit models of belowground communities, especially nematodes, are scarce.
• Nematodes are the most abundant animals on Earth, occupying all trophic levels in soil food webs.

Purpose of the Study:

• To develop a mechanistic understanding of global soil nematode abundance patterns.
• To map the composition of nematode functional groups worldwide.
• To provide data for integrating soil ecological processes into global biogeochemical models.

Main Methods:

• Utilized 6,759 georeferenced soil samples for analysis.
• Developed mechanistic models to understand nematode distribution patterns.
• Generated high-resolution global maps of nematode abundance and functional groups.

Main Results:

• Estimated global soil nematode abundance at 4.4 ± 0.64 × 10^20 individuals, with a total biomass of approximately 0.3 gigatonnes.
• Identified higher nematode abundances in sub-Arctic regions (38%) compared to temperate (24%) and tropical (21%) regions.
• Observed regional variations providing insights into local soil fertility and functioning.

Conclusions:

• This study presents the first global, high-resolution models of soil nematode abundance and functional groups.
• The findings are crucial for understanding soil fertility and ecosystem functioning.
• These models will enable predictions of elemental cycling under various climate scenarios.