Acoustic Complexity Index (ACI)

AUS-TDG-FOR-ACI General High confidence

Benchmark Value

No specific value — see range

Range: 135.7 to 139.4 index

Optimal Range: 135.7 to 139.4

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

"Grassy Dry Forest: Mean ACI: 137.5 ACI Range: 135.7 – 139.4"

Metric Definition:

Above-ground Acoustic Complexity Index (ACI) calculated as the mean of the daily 95th percentile values with 95% confidence intervals, representing the upper bound of biophonic complexity during peak morning chorus.

Benchmark Definition:

Reference-condition healthy range for Acoustic Complexity Index in grassy dry forest ecosystems during spring.

Justification:

Represents the highest quality reference state for open dry sclerophyll forests in temperate Australia, reflecting the target soundscape complexity for native forests under conservation-oriented selective harvesting9.

Sources (1)

Preview of A REPORT ON A COMMUNITY PARTNERSHIP IN ECO-ACOUSTIC MONITORING IN MOUNT WORTH STATE PARK, VICTORIA, accessed May 14, 2026,

A REPORT ON A COMMUNITY PARTNERSHIP IN ECO-ACOUSTIC MONITORING IN MOUNT WORTH STATE PARK, VICTORIA, accessed May 14, 2026, Journal

A Report on a Community Partnership in Eco-Acoustic Monitoring in Brisbane Ranges

View Source

Supporting Sources (9)

Additional references from the underlying research that informed this benchmark.

Davies et al. (2022)

Direct Evidence

Davies et al. (2022)

Davies et al. (2022)

Direct Evidence

Davies et al. (2022)

Davies et al. (2022)

Direct Evidence

Davies et al. (2022)

Open Ecoacoustics | ARDC - Australian Research Data Commons, accessed July 18, 2025,

Contextual Support GreyLiterature

Open Ecoacoustics | ARDC - Australian Research Data Commons, accessed July 20, 2025

View Source

Pieretti et al. (2011)

Methodology Source

Pieretti et al. (2011)

Pieretti et al. (2011)

Methodology Source

Pieretti et al. (2011)

Roe et al. (2019)

Contextual Support

Roe et al. (2019)

Roe et al. (2019)

Contextual Support

Roe et al. (2019)

Roe et al. (2019)

Contextual Support

Roe et al. (2019)

Context

Region Australia
Biome Temperate Dry Woodlands & Native Grasslands
Land Use Production Forestry
Assessment Conservation Target
Vegetation Forest
Season Spring
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 21 Jun 2026

Notes

Higher canopy density and vertical structural heterogeneity in this forest class drive the elevated upper limits of the ACI range9.

Related Benchmarks

Other benchmarks in the AUS-TDG-FOR-ACI family.