Soil pH

AUS-TMI-CON-SPH General High confidence

Benchmark Value

No specific value — see range
Range: 5.5 to 7 pH
Optimal Range: 5.5 to 7
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.

Evidence & Context

The optimal range for ecosystem health and resilience on volcanic-derived soils is identified as pH 5.5 to 7.0.

Metric Definition:

Optimal soil pH range for ecosystem health and resilience on volcanic-derived soils.

Benchmark Definition:

Optimal soil pH range for ecosystem health and resilience on volcanic-derived soils, supporting nutrient bioavailability and native vegetation.

Justification:

Supported by direct field measurements from Mt Gower and qualitative descriptions of healthy Ferrosols in Norfolk Island National Park.

Sources (1)

Preview of Floristics and structure of the mossy cloud forest of Mt Gower summit, Lord Howe Island
Floristics and structure of the mossy cloud forest of Mt Gower summit, Lord Howe Island Journal

Norfolk Island Pine Production Guide

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Norfolk Island Region Threatened Species Recovery Plan
Norfolk Island Region Threatened Species Recovery Plan
Direct Evidence

Norfolk Island Region Threatened Species Recovery Plan

View Source
Preview of Norfolk Island Region Threatened Species Recovery Plan
Norfolk Island Region Threatened Species Recovery Plan
Direct Evidence

Norfolk Island Region Threatened Species Recovery Plan

Preview of Norfolk Island Region Threatened Species Recovery Plan
Norfolk Island Region Threatened Species Recovery Plan
Direct Evidence

Norfolk Island Region Threatened Species Recovery Plan

Context

  • Region Australia
  • Biome Tropical & Subtropical Maritime Islands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Pristine Reference
  • Evidence Type HealthyOperationalRange

Lifecycle

  • Status Active
  • Version 2
  • Effective From 15 Mar 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. This range maximizes nutrient bioavailability and supports robust native vegetation communities.

Related Benchmarks

Other benchmarks in the AUS-TMI-CON-SPH family.

— pH High
Conservation / Protected Natural Areas · Pristine Reference
OptimalRange Active v1
5.5 pH High
Conservation / Protected Natural Areas · Pristine Reference
LowerThreshold Active v1
— pH High
Conservation / Protected Natural Areas · Pristine Reference
OptimalRange Superseded v1
— pH High
Conservation / Protected Natural Areas · Pristine Reference
OptimalRange Superseded v1