Fungal:Bacterial Ratio

AUS-AMR-FOR-SFB General Low confidence

Benchmark Value

0.05 index
Thresholds: Lower: 0.05, 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 2 benchmarks together — the OptimalRange form drives the primary score, while 1 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary LowerThreshold Guard

Evidence & Context

Lower Critical Threshold: <0.05. A ratio falling below the natural baseline of Australian drylands indicates significant ecological degradation.

Metric Definition:

Fungal:Bacterial ratio, the ratio of fungal biomass to bacterial biomass in soil.

Benchmark Definition:

The critical lower threshold of the Fungal:Bacterial ratio below which ecological functions are significantly compromised in Australian Arid Mountain Ranges & Uplands under Production Forestry.

Justification:

Defined as any value falling significantly below the natural baseline of ~0.05, indicating a shift to a degraded, bacterially-dominated state.

Sources (1)

Preview of Are Fungal to Bacterial Ratios (F:B Ratio) Important for Plant Growth? - Garden Myths
Are Fungal to Bacterial Ratios (F:B Ratio) Important for Plant Growth? - Garden Myths Journal

Derived Benchmark: Analysis of Fungal:Bacterial Ratios in Australian Arid Ecosystems and Analogous Land Management Systems

View Source

Supporting Sources (9)

Additional references from the underlying research that informed this benchmark.

Preview of ausveg - fact sheet: soil microbiology, accessed July 18, 2025
ausveg - fact sheet: soil microbiology, accessed July 18, 2025
Contextual Support Journal

ausveg - fact sheet: soil microbiology

View Source
Preview of Bailey VL, Smith JL, Bolton H Jr.. Fungal-to-bacterial ratios in soils ..., accessed July 31, 2025,
Bailey VL, Smith JL, Bolton H Jr.. Fungal-to-bacterial ratios in soils ..., accessed July 31, 2025,
Contextual Support Journal

Bailey VL, Smith JL, Bolton H Jr.. Fungal-to-bacterial ratios in soils ..., accessed July 31, 2025,

View Source
Preview of Climate warming suppresses abundant soil fungal taxa and reduces soil carbon efflux in a semi‐arid grassland, accessed July 31, 2025,
Climate warming suppresses abundant soil fungal taxa and reduces soil carbon efflux in a semi‐arid grassland, accessed July 31, 2025,
Contextual Support Journal

Climate warming suppresses abundant soil fungal taxa and reduces soil carbon efflux in a semi‐arid grassland, accessed July 31, 2025,

View Source
Preview of Fungal/bacterial ratios in grasslands with contrasting nitrogen management, accessed July 19, 2025,
Fungal/bacterial ratios in grasslands with contrasting nitrogen management, accessed July 19, 2025,
Contextual Support Journal

Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - Frontiers, accessed July 30, 2025,

View Source
Preview of Land | State of the Environment Report 2011
Land | State of the Environment Report 2011
Contextual Support Journal

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 28, 2025,

View Source
Preview of Mechanisms and implications of bacterial–fungal competition for soil resources - PMC, accessed July 18, 2025
Mechanisms and implications of bacterial–fungal competition for soil resources - PMC, accessed July 18, 2025
Contextual Support Journal

Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - Frontiers, accessed July 23, 2025

View Source
Preview of Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon ... - Frontiers, accessed July 18, 2025
Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon ... - Frontiers, accessed July 18, 2025
Contextual Support Journal

The biogeography of relative abundance of soil fungi versus bacteria in surface topsoil, accessed August 1, 2025

View Source
Preview of The biogeography of relative abundance of soil fungi versus bacteria in surface topsoil, accessed on June 5, 2025
The biogeography of relative abundance of soil fungi versus bacteria in surface topsoil, accessed on June 5, 2025
Contextual Support Journal

Fungal to Bacterial Ratios: What and Why? - Ward Laboratories, Inc., accessed July 30, 2025,

View Source
Preview of The incorporation of fungal to bacterial ratios and plant ecosystem effect traits into a state-and-transition model of land-use change in semi-arid grasslands - Research @ Flinders, accessed August 3, 2025
The incorporation of fungal to bacterial ratios and plant ecosystem effect traits into a state-and-transition model of land-use change in semi-arid grasslands - Research @ Flinders, accessed August 3, 2025
Contextual Support Journal

The incorporation of fungal to bacterial ratios and plant ecosystem effect traits into a state-and-transition model of land-use change in semi-arid grasslands - Research @ Flinders

View Source

Context

  • Region Australia
  • Biome Arid Mountain Ranges & Uplands
  • Land Use Production Forestry
  • Assessment Conservation Target
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

An F:B ratio below 0.05 indicates significant ecological degradation and compromised fungal-mediated functions.

Related Benchmarks

Other benchmarks in the AUS-AMR-FOR-SFB family.

— index Low
Production Forestry · Conservation Target
OptimalRange Active v1