Management effects on soil nematode abundance differ among functional groups and land-use types at a global scale

Area of Science:

• Soil ecology
• Biodiversity research
• Global change biology

Background:

• Anthropogenic land use poses a significant threat to global biodiversity.
• Nematodes are abundant soil animals crucial for ecosystem functions, yet land-use impacts on their populations are poorly understood globally.

Purpose of the Study:

• To investigate the global effects of land use and management intensity on soil nematode abundance across different trophic groups.
• To identify how environmental factors interact with land use to influence nematode abundance.

Main Methods:

• Utilized a global dataset of 6,825 soil samples.
• Assessed nematode abundance variation across land-use types (primary/secondary vegetation, pasture, cropland, urban) and management intensity (managed vs. unmanaged).
• Quantified interactions between land use and environmental predictors (temperature, precipitation, soil properties, vegetation biomass/productivity).

Main Results:

• Total nematode abundance and abundance of bacterivores, fungivores, herbivores, omnivores, and predators generally increased or remained stable under management.
• Managed secondary vegetation and urban areas showed higher bacterivore abundance; managed primary and secondary vegetation showed higher herbivore abundance.
• Environmental predictors had fewer significant effects and altered magnitude/direction under management; urban areas exhibited more variable nematode abundance less determined by environmental factors.

Conclusions:

• Human land use does not necessarily decrease soil animal abundance, contrary to some views.
• Land use significantly alters soil nematode trophic composition and their environmental relationships on a global scale.