Soil Moisture

AUS-TSW-CON-SMO General Moderate confidence

Benchmark Value

15 % VWC

Direction: Higher is desirable ↑

Form: MinimumOnly

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is CompositeFramework, but the benchmark data may be missing required fields (e.g., optimal range bounds for an OptimalRange benchmark). This is typically a data quality issue in the benchmark pipeline.

Contributing Benchmarks

CompositeFramework Primary OptimalRange Guard OptimalRange Guard MinimumOnly Guard

Evidence & Context

Following a prolonged dry period of six months, the flux tower instruments documented that the entire woodland ecosystem switched from being a net carbon sink to a net carbon source. This metabolic shift represents a functionally-defined critical limit at approximately 15% VWC.

Metric Definition:

Volumetric Water Content (VWC) soil moisture level below which ecosystem function is significantly compromised

Benchmark Definition:

This benchmark marks the lower critical soil moisture threshold below which the woodland ecosystem experiences stress and shifts from a carbon sink to a carbon source.

Justification:

Evidence from the site shows that during prolonged drought, the ecosystem switches from a net carbon sink to a net carbon source, indicating severe systemic stress.

Sources (1)

Preview of Soil – the driver of carbon dioxide variability over Australia, accessed July 16, 2025,

Soil – the driver of carbon dioxide variability over Australia, accessed July 16, 2025, GreyLiterature

Wired woodlands signal stress as climate dries - CSIRO

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

Great Western Woodlands SuperSite | Climate Change Impacts - TERN Australia, accessed July 10, 2025,

Direct Evidence Government

URBAN FOREST STRATEGY - Your Say South Perth, accessed July 13, 2025

View Source

Management of excess water in duplex soils - ResearchGate

Contextual Support

Management of excess water in duplex soils - ResearchGate

View Source

Context

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

Lifecycle

Status Active
Version 1
Effective From 7 Jun 2026

Notes

This threshold corresponds to the Permanent Wilting Point (PWP) for the dominant vegetation and marks the lower boundary of ecosystem health. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

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