Fungal:Bacterial Ratio

AUS-AKW-LVG-SFB General Moderate confidence

Benchmark Value

0.1 index
Thresholds: Lower: 0.1, Upper: —
Direction: Higher is desirable ↑
Form: LowerThreshold

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 14 benchmarks together — the OptimalRange form drives the primary score, while 13 guard(s) constrain the result.

Evidence & Context

Synthesizing these points, an F:B ratio falling below 0.10 is proposed as the lower critical threshold for this biome and land use.

Metric Definition:

Fungal:Bacterial ratio measured by PLFA analysis representing the relative biomass of fungi to bacteria in soil.

Benchmark Definition:

This threshold marks the lower critical limit of the Fungal:Bacterial ratio below which the soil is considered degraded and dominated by bacteria, indicating loss of fungal biomass critical for ecosystem resilience.

Justification:

This threshold is derived from values observed in lower-functioning spinifex soils and other arid rangeland research indicating loss of fungal biomass critical for ecosystem resilience.

Sources (2)

Preview of Biochemical properties of highly mineralised and infertile soil modified by acacia and spinifex plants in northwest Queensland, Australia | Request PDF - ResearchGate
Biochemical properties of highly mineralised and infertile soil modified by acacia and spinifex plants in northwest Queensland, Australia | Request PDF - ResearchGate Journal

Biochemical properties of highly mineralised and infertile soil modified by acacia and spinifex plants in northwest Queensland, Australia | Request PDF - ResearchGate

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Preview of Soil microbial biomass in semi-arid communal sandy rangelands in the western Bophirima District, South Africa - ResearchGate
Soil microbial biomass in semi-arid communal sandy rangelands in the western Bophirima District, South Africa - ResearchGate GreyLiterature

Soil microbial biomass in semi-arid communal sandy rangelands in the western Bophirima District, South Africa - ResearchGate

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Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of How Biodiversity-Friendly Is Regenerative Grazing? - Frontiers, accessed July 29, 2025
How Biodiversity-Friendly Is Regenerative Grazing? - Frontiers, accessed July 29, 2025
Direct Evidence Journal

(PDF) Soil community changes during secondary succession to naturalized grasslands, accessed August 9, 2025,

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Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Livestock Grazing & Pasture
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 24 Mar 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. Below this level, the soil system likely lacks sufficient fungal biomass to maintain resilience and carbon storage.