Fungal:Bacterial Ratio

AUS-AIF-FOR-SFB General Moderate confidence

Benchmark Value

No specific value — see range
Range: 2 to 5 index
Thresholds: Lower: 1, Upper: —
Optimal Range: 2 to 5
Direction: Higher is desirable ↑
Form: OptimalRange

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 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard OptimalRange Guard OptimalRange Guard LowerThreshold Guard

Evidence & Context

Reference Value: 2.0 – 5.0

Metric Definition:

Fungal to Bacterial Ratio as a measure of the relative biomass of fungi to bacteria in soil microbial communities.

Benchmark Definition:

This benchmark represents an inferred optimal range for sustainably managed production forests in Australia's Arid Inland Floodplains & Ephemeral River Systems, indicating a healthy, resilient soil ecosystem dominated by fungi.

Justification:

The value is derived by synthesizing data from mature Australian eucalypt forest analogues, semi-arid ecosystem studies, and large-scale international forest soil surveys, while critically adjusting for the known suppressive effect of aridity on fungal communities in Australia.

Sources (4)

Preview of Aridity differentially alters the stability of soil bacterial and fungal networks in coastal and inland areas of Australia - PubMed
Aridity differentially alters the stability of soil bacterial and fungal networks in coastal and inland areas of Australia - PubMed Journal

Aridity differentially alters the stability of soil bacterial and fungal networks in coastal and inland areas of Australia - PubMed, accessed July 20, 2025,

View Source
Preview of Environmental management of riparian tree health in the Murray-Darling Basin, Australia - WIT Press, accessed July 21, 2025
Environmental management of riparian tree health in the Murray-Darling Basin, Australia - WIT Press, accessed July 21, 2025 Journal

Soil Microbial Community Successional Patterns during Forest Ecosystem Restoration - PMC - PubMed Central, accessed July 20, 2025,

View Source
Preview of Fungal:bacterial ratio and soil microbial community structure in a national-scale monitoring network.
Fungal:bacterial ratio and soil microbial community structure in a national-scale monitoring network.
View Source
Preview of Soil respiration–driven CO2 pulses dominate Australia's flux variability
Soil respiration–driven CO2 pulses dominate Australia's flux variability Journal

The incorporation of fungal to bacterial ratios and plant ecosystem ..., accessed July 20, 2025,

View Source

Supporting Sources (17)

Additional references from the underlying research that informed this benchmark.

Preview of Analyzing your Fungal to Bacterial Ratio Results - MicroBiometer, accessed July 18, 2025
Analyzing your Fungal to Bacterial Ratio Results - MicroBiometer, accessed July 18, 2025
Contextual Support GreyLiterature

Analyzing your Fungal to Bacterial Ratio Results - microBIOMETER, accessed June 7, 2025,

View Source
Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,
Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed August 5, 2025,
Contextual Support Journal

Root Structure and Functioning for Efficient Acquisition of Phosphorus: Matching Morphological and Physiological Traits

View Source
Preview of Biogeographical patterns of the soil fungal:bacterial ratio across France - ASM Journals, accessed July 28, 2025
Biogeographical patterns of the soil fungal:bacterial ratio across France - ASM Journals, accessed July 28, 2025
Direct Evidence Journal

Beyond Bacteria: The Importance of Fungi, Protozoa and Nematodes in Soil Microbiology, accessed July 21, 2025

View Source
Preview of Biogeographical patterns of the soil fungal:bacterial ratio across France - PubMed, accessed July 28, 2025,
Biogeographical patterns of the soil fungal:bacterial ratio across France - PubMed, accessed July 28, 2025,
Direct Evidence Journal

Biogeographical patterns of the soil fungal:bacterial ratio across France - PubMed Central, accessed June 7, 2025,

View Source
Preview of Changes in Soil Microbial Community Structure Influenced by Agricultural Management Practices in a Mediterranean Agro-Ecosystem | PLOS One - Research journals, accessed August 5, 2025,
Changes in Soil Microbial Community Structure Influenced by Agricultural Management Practices in a Mediterranean Agro-Ecosystem | PLOS One - Research journals, accessed August 5, 2025,
Contextual Support Journal

Changes in Soil Microbial Community Structure Influenced by Agricultural Management Practices in a Mediterranean Agro-Ecosystem | PLOS One - Research journals, accessed July 20, 2025,

View Source
Preview of Forest succession improves the complexity of soil microbial interaction and ecological stochasticity of community assembly: Evidence from Phoebe bournei-dominated forests in subtropical regions, accessed July 20, 2025,
Forest succession improves the complexity of soil microbial interaction and ecological stochasticity of community assembly: Evidence from Phoebe bournei-dominated forests in subtropical regions, accessed July 20, 2025,
Contextual Support Journal

Forest succession improves the complexity of soil microbial interaction and ecological stochasticity of community assembly: Evidence from Phoebe bournei-dominated forests in subtropical regions - Frontiers, accessed July 20, 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 Mechanisms and implications of bacterial–fungal competition for soil resources | The ISME Journal | Oxford Academic, accessed July 18, 2025
Mechanisms and implications of bacterial–fungal competition for soil resources | The ISME Journal | Oxford Academic, accessed July 18, 2025
Contextual Support Journal

ratio of fungi to bacteria | The Prairie Ecologist, accessed June 7, 2025,

View Source
Preview of Metal Toxicity Affects Fungal and Bacterial Activities in Soil Differently - PMC, accessed July 20, 2025,
Metal Toxicity Affects Fungal and Bacterial Activities in Soil Differently - PMC, accessed July 20, 2025,
Contextual Support Journal

Metal Toxicity Affects Fungal and Bacterial Activities in Soil Differently - PMC, accessed July 20, 2025,

View Source
Preview of Microbial community composition and activity in paired irrigated and non-irrigated pastures in New Zealand - CSIRO Publishing, accessed August 3, 2025
Microbial community composition and activity in paired irrigated and non-irrigated pastures in New Zealand - CSIRO Publishing, accessed August 3, 2025
Contextual Support Journal

Microbial community composition and activity in paired irrigated and non-irrigated pastures in New Zealand - CSIRO Publishing, accessed August 9, 2025,

View Source
Preview of RIvER RED guMs AND wooDLAND FoREsts - Natural Resources Commission, accessed July 20, 2025,
RIvER RED guMs AND wooDLAND FoREsts - Natural Resources Commission, accessed July 20, 2025,
Contextual Support Journal

RIvER RED guMs AND wooDLAND FoREsts - Natural Resources Commission, accessed July 20, 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 Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - Frontiers, accessed July 20, 2025,
Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling - Frontiers, accessed July 20, 2025,
Contextual Support Journal

Revisiting the hypothesis that fungal-to-bacterial dominance characterises turnover of soil organic matter and nutrients | Request PDF - ResearchGate, accessed July 20, 2025,

View Source
Preview of Soil Microbial Community Successional Patterns during Forest Ecosystem Restoration | Applied and Environmental Microbiology - ASM Journals, accessed July 20, 2025,
Soil Microbial Community Successional Patterns during Forest Ecosystem Restoration | Applied and Environmental Microbiology - ASM Journals, accessed July 20, 2025,
Contextual Support Journal

Soil Bacterial and Fungal Communities Show Distinct Recovery Patterns during Forest Ecosystem Restoration | Applied and Environmental Microbiology - ASM Journals, accessed July 20, 2025,

View Source
Preview of The fungal-bacterial ratio for soil health - Farmer's Weekly, accessed July 12, 2025,
The fungal-bacterial ratio for soil health - Farmer's Weekly, accessed July 12, 2025,
Direct Evidence Journal

(PDF) Soil Microbial Community Successional Patterns during ..., accessed July 20, 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
Preview of Typology of arid-zone floodplain wetlands of the Paroo River (inland Australia) and the influence of water regime, turbidity, and salinity on their aquatic invertebrate assemblages - ResearchGate, accessed July 20, 2025,
Typology of arid-zone floodplain wetlands of the Paroo River (inland Australia) and the influence of water regime, turbidity, and salinity on their aquatic invertebrate assemblages - ResearchGate, accessed July 20, 2025,
Contextual Support GreyLiterature

Understanding ecosystem resilience to periods of low flow in the, accessed July 20, 2025,

View Source

Context

  • Region Australia
  • Biome Arid Inland Floodplains & Ephemeral River Systems
  • Land Use Production Forestry
  • Assessment Pristine Reference
  • Evidence Type TargetCondition

Lifecycle

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

Notes

Lower Critical Threshold: An F:B ratio below 1.0 is considered critically low, indicating a shift from a forest-like, fungal-dominated system to a bacterially-dominated system with compromised carbon storage and nutrient retention capacity. Upper Boundary Consideration: There is no evidence of a detrimental upper threshold for the F:B ratio in forest ecosystems. A high ratio is generally indicative of a mature, stable system.