Microbial Respiration

AUS-TSR-CON-SMR General Moderate confidence

Benchmark Value

45 mg/kg/day
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 4 benchmarks together — the Point form drives the primary score, while 3 guard(s) constrain the result.

Evidence & Context

Lower Critical Threshold: A ~50% reduction from this benchmark (i.e., <45 mg CO₂-C/kg/day) indicates significant functional impairment, consistent with degradation from a conservation to a production agriculture state.

Metric Definition:

Microbial respiration, the flux of carbon dioxide (CO2) from the soil surface resulting from microbial metabolic activity.

Benchmark Definition:

A microbial respiration rate below 45 mg/kg/day signals significant soil function loss, indicating degradation from conservation rainforest to agricultural land.

Justification:

This threshold is based on evidence from land-use change and disturbance studies showing a halving of microbial biomass and corresponding drop in respiration function, indicating significant ecological stress.

Sources (1)

Preview of Soil Respiration - Natural Resources Conservation Service
Soil Respiration - Natural Resources Conservation Service Journal

Reforestation, carbon sequestration and relationships between soil attributes in the Wet Tropics of Australia (Schmidt et al., 2014)

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Rainforests
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Vegetation Forest
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 20 Mar 2026

Notes

Respiration rates falling to approximately half of the benchmark value signal a profound shift from a complex, self-sustaining conservation ecosystem to a simplified, input-dependent agroecosystem.