Fungal:Bacterial Ratio

AUS-TSW-CON-SFB General Moderate confidence

Benchmark Value

3 index

Direction: Lower is desirable ↓

Form: MaximumOnly

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 7 benchmarks together — the OptimalRange form drives the primary score, while 6 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard LowerThreshold Guard OptimalRange Guard LowerThreshold Guard MinimumOnly Guard MaximumOnly Guard

Evidence & Context

Based on a wide body of literature, an F:B ratio consistently below 1.0 serves as a robust indicator of such a state.

Metric Definition:

Fungal to bacterial biomass ratio in soil as measured by PLFA indicating ecosystem degradation threshold.

Benchmark Definition:

This benchmark defines the lower critical threshold of the fungal to bacterial biomass ratio below which the ecosystem is considered degraded in Australia's Temperate Semi-Arid Shrublands & Open Woodlands.

Justification:

An F:B ratio below 1.0 indicates bacterial dominance linked to high disturbance and ecological degradation.

Sources (1)

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 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

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

ausveg - fact sheet: soil microbiology, accessed July 18, 2025

Contextual Support Journal

ausveg - fact sheet: soil microbiology

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

This threshold identifies highly disturbed, bacterially dominated systems with compromised carbon storage and nutrient retention. ConsistencyResolver applied 2026-03-24 20:10 UTC: BenchmarkValue 1 → 3 (check: MinAboveMax, rationale: Swapping the MaximumOnly benchmark's value to 3 aligns it as the upper ceiling threshold consistent with its role and Notes.)

Related Benchmarks

Other benchmarks in the AUS-TSW-CON-SFB family.