Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 5.5 to 6.5 pH

Thresholds: Lower: 5.5, Upper: —

Optimal Range: 5.5 to 6.5

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.

Evidence & Context

The measured soil pH within this profile was slightly acidic, ranging from pH 5.5 to 6.5.

Metric Definition:

Soil pH measured in a plastic, clayey mineral soil profile within a high-integrity mossy cloud forest ecosystem.

Benchmark Definition:

This benchmark represents the soil pH range measured in volcanic-derived soils within a high-integrity conservation area in the Tropical & Subtropical Maritime Islands biome.

Justification:

This benchmark is based on a peer-reviewed study of a specific soil profile in a protected, high-endemism ecosystem on Lord Howe Island, providing a scientifically defensible reference for volcanic soils.

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.

Norfolk Island Region Threatened Species Recovery Plan

Direct Evidence

Norfolk Island Region Threatened Species Recovery Plan

View Source

Norfolk Island Region Threatened Species Recovery Plan

Direct Evidence

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 ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 15 Mar 2026

Notes

Lower Critical Threshold: 5.5 pH. No upper detrimental threshold — higher values are always better up to natural saturation. Calcareous soils naturally have pH >8.0 and are healthy in their own right. RangeFixup applied 2026-03-21 22:21 UTC: OptimalRangeHigh: 7 → 6.5; UpperBound: 6.5 → 7 [Migration] Original wider evidence range: 5.5 – 7 (retained OptimalRange: 5.5 – 6.5)

Related Benchmarks

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