Fungal:Bacterial Ratio

AUS-AKW-CON-SFB General Low confidence

Benchmark Value

0.05 index
Direction: Higher is desirable ↑
Form: MinimumOnly

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 9 benchmarks together — the OptimalRange form drives the primary score, while 8 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard Point Guard Point Guard MinimumOnly Guard OptimalRange Guard OptimalRange Guard MinimumOnly Guard MinimumOnly Guard

Evidence & Context

An F:B ratio falling significantly below 0.05 is proposed as the lower critical threshold.

Metric Definition:

Fungal:Bacterial biomass ratio in soil microbial communities

Benchmark Definition:

This benchmark represents the lower critical threshold of the fungal to bacterial biomass ratio in soil, below which significant ecosystem degradation is indicated in Australian arid karstic woodlands and shrublands under conservation management.

Justification:

Based on the mean F:B ratio for all Australian drylands including degraded sites, representing a critical low point below which ecosystem health is compromised.

Sources (1)

Preview of Land | State of the Environment Report 2011
Land | State of the Environment Report 2011 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

Supporting Sources (18)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) The measurement of soil fungal:bacterial biomass ratios as an ...
(PDF) The measurement of soil fungal:bacterial biomass ratios as an ...
Contextual Support Journal

(PDF) The measurement of soil fungal:bacterial biomass ratios as an ...

View Source
Preview of Australian Soils and Landscapes | Monitoring & Data | TERN - esoil.io, accessed July 27, 2025,
Australian Soils and Landscapes | Monitoring & Data | TERN - esoil.io, accessed July 27, 2025,
Contextual Support Government

Categories - Environmental management - CSIRO Data Access Portal

View Source
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 Climate dictates microbial community composition and diversity in Australian biological soil crusts (biocrusts) - PMC - PubMed Central
Climate dictates microbial community composition and diversity in Australian biological soil crusts (biocrusts) - PMC - PubMed Central
Contextual Support Journal

Climate dictates microbial community composition and diversity in Australian biological soil crusts (biocrusts) | Request PDF - ResearchGate

View Source
Preview of Geology of the Nullarbor Plain (Webb and James 2006; courtesy JA Webb). - ResearchGate, accessed July 26, 2025,
Geology of the Nullarbor Plain (Webb and James 2006; courtesy JA Webb). - ResearchGate, accessed July 26, 2025,
Contextual Support

Geology of the Nullarbor Plain (Webb and James 2006; courtesy JA Webb). - ResearchGate, accessed July 23, 2025

View Source
Preview of Impacts of altered precipitation regimes on soil communities and biogeochemistry in arid and semi-arid ecosystems - PubMed
Impacts of altered precipitation regimes on soil communities and biogeochemistry in arid and semi-arid ecosystems - PubMed
Contextual Support Journal

Impacts of altered precipitation regimes on soil communities and biogeochemistry in arid and semi-arid ecosystems - PubMed

View Source
Preview of Mapping Australia's soil biodiversity - CSIRO, accessed August 5, 2025,
Mapping Australia's soil biodiversity - CSIRO, accessed August 5, 2025,
Contextual Support GreyLiterature

TERN Surveillance monitoring program: Soil vis-NIR spectral library with accompanying soil measurement data for 367 specimens - CSIRO Data Access Portal

View Source
Preview of Microbial biobanking – cyanobacteria-rich topsoil facilitates mine rehabilitation - BG
Microbial biobanking – cyanobacteria-rich topsoil facilitates mine rehabilitation - BG
Contextual Support Journal

Biological soil crusts from the Australian drylands. ( a ) Typical... | Download Scientific Diagram - ResearchGate

View Source
Preview of Nullarbor - DBCA Library
Nullarbor - DBCA Library
Contextual Support Journal

Nullarbor - DBCA Library, accessed July 24, 2025

View Source
Preview of Nullarbor bioregion - DCCEEW, accessed July 27, 2025
Nullarbor bioregion - DCCEEW, accessed July 27, 2025
Contextual Support Journal

Nullarbor bioregion - DCCEEW, accessed July 24, 2025

View Source
Preview of Nullarbor Plain - Wikipedia, accessed July 25, 2025,
Nullarbor Plain - Wikipedia, accessed July 25, 2025,
Contextual Support GreyLiterature

Nullarbor Plain - Wikipedia, accessed July 24, 2025

View Source
Preview of Nullarbor Plains Xeric Shrublands | One Earth
Nullarbor Plains Xeric Shrublands | One Earth
Contextual Support Journal

Nullarbor Plains Xeric Shrublands | One Earth

View Source
Preview of Resource condition
Resource condition
Contextual Support Journal

NATURAL RESOURCE MANAGEMENT Alinytjara Wilurara State and Condition reporting South Australia 2014

View Source
Preview of Soil and Landscape Grid National Soil Attribute Maps - Soil Bacteria and Fungi Beta Diversity (3" resolution) - Release 1 - Research Data Australia
Soil and Landscape Grid National Soil Attribute Maps - Soil Bacteria and Fungi Beta Diversity (3" resolution) - Release 1 - Research Data Australia
Direct Evidence Government

Soil and Landscape Grid National Soil Attribute Maps - Soil Bacteria and Fungi Beta Diversity (3" resolution) - Release 1 - Research Data Australia

View Source
Preview of Soil Microbial Community Response to Corn Stover Harvesting Under Rain-Fed, No-Till Conditions at Multiple US Locations - USDA ARS
Soil Microbial Community Response to Corn Stover Harvesting Under Rain-Fed, No-Till Conditions at Multiple US Locations - USDA ARS
Contextual Support Journal

Soil Microbial Community Response to Corn Stover Harvesting Under Rain-Fed, No-Till Conditions at Multiple US Locations - USDA ARS

View Source
Preview of TERN - Australia's Terrestrial Ecosystem Research Network, accessed July 30, 2025,
TERN - Australia's Terrestrial Ecosystem Research Network, accessed July 30, 2025,
Contextual Support Government

Australia's State of the Forests Report 2018 - DAFF, accessed July 31, 2025,

View Source
Preview of The Abundance of Microbial Functional Genes in Grassy Woodlands Is Influenced More by Soil Nutrient Enrichment than by Recent Weed Invasion or Livestock Exclusion | Applied and Environmental Microbiology - ASM Journals
The Abundance of Microbial Functional Genes in Grassy Woodlands Is Influenced More by Soil Nutrient Enrichment than by Recent Weed Invasion or Livestock Exclusion | Applied and Environmental Microbiology - ASM Journals
Direct Evidence Journal

Contrasting Soil pH Effects on Fungal and Bacterial Growth Suggest Functional Redundancy in Carbon Mineralization - PMC

View Source
Preview of What are the optimal fungal to bacterial biomass ratios for different crops? - ResearchGate, accessed July 28, 2025
What are the optimal fungal to bacterial biomass ratios for different crops? - ResearchGate, accessed July 28, 2025
Contextual Support GreyLiterature

Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon ... - Frontiers, accessed July 21, 2025

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 8 Jun 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. This threshold marks a highly disturbed or degraded state relative to the Australian arid-zone average.