Soil fertility controls the size-specific distribution of eukaryotes

Area of Science:

• Soil ecology
• Ecological stoichiometry
• Community ecology

Background:

• Soil organisms exhibit a wide range of body masses, offering insights into ecological community structure.
• Understanding the relationship between body mass and numerical abundance is crucial for assessing soil ecosystem health.

Purpose of the Study:

• To investigate the allometry between body mass and numerical abundance of soil eukaryotes across different Dutch land use types.
• To determine how soil nutrient availability influences the mass-abundance relationships in below-ground communities.

Main Methods:

• Log-transformed body mass (M) and log-transformed numerical abundance (N) of soil eukaryotes were analyzed.
• Log-linear models were used to describe the allometric slopes along soil fertility gradients.
• The influence of soil macronutrients (N, P) and micronutrients (Cu, Zn) on mass-abundance relationships was quantified.

Main Results:

• Soil nutrient availability strongly influences the allometry of soil organism body mass and abundance.
• A log-linear model effectively describes variations in allometric slopes with increasing soil fertility.
• Phosphorus concentration was the most significant predictor (72%) of shifts in mass-abundance relationships, followed by copper (59%), zinc (49%), and nitrogen (36%).
• The contribution of small invertebrates (<1 microg) to the total fauna is highest under nutrient-deficient conditions.

Conclusions:

• Soil fertility gradients, driven by nutrient availability, shape the organization of soil ecological communities.
• Nutrient dynamics, especially phosphorus, are key drivers of mass-abundance relationships in soil fauna.
• Invertebrate responses to resource supply rates and primary production are critical for understanding soil ecosystem functioning.