Acoustic Complexity Index (ACI)

AUS-AIF-FOR-ACI General Low confidence

Benchmark Value

No specific value — see range

Thresholds: Lower: 0, Upper: —

Direction: Higher is desirable ↑

Form: CompositeFramework

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.

Evidence & Context

No direct benchmark exists for this specific biome/land-use combination. This provisional benchmark is based on the TERN Alice Mulga SuperSite, the best available proxy representing a well-managed, functional arid woodland ecosystem containing the target River Red Gum forest habitat.

Metric Definition:

Acoustic Complexity Index (ACI) quantifies the intrinsic variability of a soundscape by summing the absolute differences in amplitude between adjacent time steps across frequency bins.

Benchmark Definition:

This benchmark represents a provisional Acoustic Complexity Index (ACI) framework for a well-managed arid woodland ecosystem in the specified biome and land use, reflecting soundscape variability indicative of ecosystem health during dawn chorus in spring/early summer.

Justification:

The provisional benchmark is based on the best available proxy site with similar biome and land use, using standardized acoustic data from TERN.

Sources (1)

Preview of Alice Mulga Acoustic Data Collection - TERN - TERN Data Discovery Portal, accessed July 22, 2025,

Alice Mulga Acoustic Data Collection - TERN - TERN Data Discovery Portal, accessed July 22, 2025,

Alice Mulga Acoustic Data Collection - TERN - TERN Data Discovery Portal, accessed July 22, 2025,

Supporting Sources (33)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Guidelines for the use of acoustic indices in environmental research - ResearchGate, accessed July 18, 2025

(PDF) Guidelines for the use of acoustic indices in environmental research - ResearchGate, accessed July 18, 2025

Methodology Source Journal

(PDF) Guidelines for the use of acoustic indices in environmental research - ResearchGate, accessed August 28, 2025

Preview of Acoustic indices as proxies for biodiversity: a meta‐analysis - PMC - PubMed Central, accessed July 20, 2025,

Acoustic indices as proxies for biodiversity: a meta‐analysis - PMC - PubMed Central, accessed July 20, 2025,

Contextual Support GreyLiterature

Acoustic indices as proxies for biodiversity: a meta‐analysis - PMC - PubMed Central, accessed July 20, 2025,

Preview of Acoustic indices as proxies for biodiversity: a meta‐analysis - PMC - PubMed Central, accessed July 22, 2025,

Acoustic indices as proxies for biodiversity: a meta‐analysis - PMC - PubMed Central, accessed July 22, 2025,

Methodology Source Journal

SELECTING APPROPRIATE ACOUSTIC INDICES FOR BIODIVERSITY ASSESSMENTS IN DIFFERENT ACOUSTIC ENVIRONMENTS, accessed July 20, 2025,

Preview of Acoustic Indices for Biodiversity Assessment and Landscape Investigation | Request PDF

Acoustic Indices for Biodiversity Assessment and Landscape Investigation | Request PDF

Direct Evidence

Full article: The relationship between the Acoustic Complexity Index and avian species richness and diversity: a review - Taylor & Francis Online, accessed July 20, 2025,

Preview of Acoustic metrics predict habitat type and vegetation structure in the Amazon - ResearchGate, accessed July 20, 2025,

Acoustic metrics predict habitat type and vegetation structure in the Amazon - ResearchGate, accessed July 20, 2025,

Contextual Support Journal

Acoustic metrics predict habitat type and vegetation structure in the Amazon - ResearchGate, accessed July 20, 2025,

Preview of Alice Mulga (54) - Australian Acoustic Observatory, accessed July 20, 2025,

Alice Mulga (54) - Australian Acoustic Observatory, accessed July 20, 2025,

Contextual Support Journal

Alice Mulga (54) - Australian Acoustic Observatory, accessed July 20, 2025,

Preview of Alice Mulga (54) - Australian Acoustic Observatory, accessed July 22, 2025,

Alice Mulga (54) - Australian Acoustic Observatory, accessed July 22, 2025,

Contextual Support GreyLiterature

CO₂ sink to source: Arid Australia's climate and rainfall driven tipping points, accessed July 20, 2025,

Preview of Alice Mulga SuperSite | Soil & Vegetation Monitoring - TERN Australia, accessed July 22, 2025,

Alice Mulga SuperSite | Soil & Vegetation Monitoring - TERN Australia, accessed July 22, 2025,

Contextual Support Government

Great Western Woodlands, Ground Water Data, 2014 - TERN Data Discovery Portal, accessed July 10, 2025,

Preview of Assessing the Avian Soundscapes Using Acoustic Indices and How They Relate to Arthropod Damage in Collard Green Fields - WUR eDepot, accessed July 22, 2025,

Assessing the Avian Soundscapes Using Acoustic Indices and How They Relate to Arthropod Damage in Collard Green Fields - WUR eDepot, accessed July 22, 2025,

Contextual Support Journal

Assessing the Avian Soundscapes Using Acoustic Indices and How They Relate to Arthropod Damage in Collard Green Fields - WUR eDepot, accessed August 28, 2025

Preview of Australian Acoustic Observatory | A2O – Australian Acoustic ..., accessed July 20, 2025,

Australian Acoustic Observatory | A2O – Australian Acoustic ..., accessed July 20, 2025,

Contextual Support

Australian Acoustic Observatory | A2O – Australian Acoustic ..., accessed July 20, 2025,

Preview of Bioacoustics: What nature's sounds can tell us about the health of our world, accessed July 20, 2025,

Bioacoustics: What nature's sounds can tell us about the health of our world, accessed July 20, 2025,

Methodology Source GreyLiterature

Bio-Acoustic Monitoring → Term - Lifestyle → Sustainability Directory, accessed July 20, 2025,

Preview of Bush Heritage Australia – Australian Acoustic Observatory | A2O, accessed July 22, 2025,

Bush Heritage Australia – Australian Acoustic Observatory | A2O, accessed July 22, 2025,

Contextual Support GreyLiterature

Australian Wildlife Conservancy – Australian Acoustic Observatory | A2O, accessed July 20, 2025,

Preview of Changes in the acoustic structure of Australian bird ... - Blumstein Lab, accessed July 18, 2025

Changes in the acoustic structure of Australian bird ... - Blumstein Lab, accessed July 18, 2025

Contextual Support Journal

River red gum and black box floodplains - IUCN Ecosystems, accessed July 20, 2025,

Preview of Changes in the acoustic structure of Australian bird communities along a habitat complexity gradient - Blumstein Lab, accessed July 20, 2025,

Changes in the acoustic structure of Australian bird communities along a habitat complexity gradient - Blumstein Lab, accessed July 20, 2025,

Contextual Support Journal

Changes in the acoustic structure of Australian bird communities along a habitat complexity gradient - Blumstein Lab, accessed July 20, 2025,

Preview of Ecoacoustic indices in marine ecosystems: a review on recent developments, challenges, and future directions - Oxford Academic, accessed July 20, 2025,

Ecoacoustic indices in marine ecosystems: a review on recent developments, challenges, and future directions - Oxford Academic, accessed July 20, 2025,

Contextual Support

Sounds of the underground reflect soil biodiversity dynamics across ...

Preview of Ecosystem Processes – Environmental Data Collection Methods - TERN Australia

Ecosystem Processes – Environmental Data Collection Methods - TERN Australia

Contextual Support Government

TERN Surveillance monitoring program: Soil vis-NIR spectral library with accompanying soil measurement data for 367 specimens - CSIRO Data Access Portal, accessed July 17, 2025,

Preview of Grazing management of Australian native woody regeneration as an effective nature-based climate-change solution - CSIRO PUBLISHING | The Rangeland Journal, accessed July 12, 2025,

Grazing management of Australian native woody regeneration as an effective nature-based climate-change solution - CSIRO PUBLISHING | The Rangeland Journal, accessed July 12, 2025,

Contextual Support

The underestimated biodiversity of tropical grassy biomes - PMC - PubMed Central, accessed July 23, 2025

Preview of Key Issues for Realizing Open Ecoacoustic Monitoring in Australia - Frontiers

Key Issues for Realizing Open Ecoacoustic Monitoring in Australia - Frontiers

Contextual Support Journal

The Australian Acoustic Observatory

Preview of Key Issues for Realizing Open Ecoacoustic Monitoring in Australia - Frontiers, accessed July 20, 2025,

Key Issues for Realizing Open Ecoacoustic Monitoring in Australia - Frontiers, accessed July 20, 2025,

Contextual Support GreyLiterature

TERN - Australia's Terrestrial Ecosystem Research Network, accessed July 20, 2025,

Preview of Listen up: new technologies for sound biodiversity monitoring - TERN Australia

Listen up: new technologies for sound biodiversity monitoring - TERN Australia

Contextual Support GreyLiterature

Ecosystem Processes – Environmental Data Collection Methods - TERN Australia, accessed July 20, 2025,

Preview of Listening to a changing landscape: Acoustic indices reflect bird species richness and plot-scale vegetation structure across different land-use types in north-eastern Madagascar - ResearchGate, accessed July 20, 2025,

Listening to a changing landscape: Acoustic indices reflect bird species richness and plot-scale vegetation structure across different land-use types in north-eastern Madagascar - ResearchGate, accessed July 20, 2025,

Contextual Support GreyLiterature

Acoustic indices applied to biodiversity monitoring in a Costa Rica dry tropical forest, accessed July 20, 2025,

Preview of management of inland arid and semi-arid woodland ... - DBCA Library, accessed July 12, 2025,

management of inland arid and semi-arid woodland ... - DBCA Library, accessed July 12, 2025,

Contextual Support Journal

management of inland arid and semi-arid woodland ... - DBCA Library, accessed July 12, 2025,

Preview of Multi-Index Ecoacoustics Analysis for Terrestrial Soundscapes: A New Semi-Automated Approach Using Time-Series Motif Discovery and Random Forest Classification - Frontiers

Multi-Index Ecoacoustics Analysis for Terrestrial Soundscapes: A New Semi-Automated Approach Using Time-Series Motif Discovery and Random Forest Classification - Frontiers

Contextual Support Journal

Landscape monitoring in forests: a wildlife ecologist's perspective - Taylor & Francis Online, accessed July 20, 2025,

Preview of Multi-Index Ecoacoustics Analysis for Terrestrial Soundscapes: A New Semi-Automated Approach Using Time-Series Motif Discovery and Random Forest Classification - Frontiers, accessed July 20, 2025,

Multi-Index Ecoacoustics Analysis for Terrestrial Soundscapes: A New Semi-Automated Approach Using Time-Series Motif Discovery and Random Forest Classification - Frontiers, accessed July 20, 2025,

Methodology Source

Sounds of the underground reflect soil biodiversity dynamics across a grassy woodland restoration chronosequence - Research @ Flinders, accessed July 20, 2025,

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

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

Contextual Support GreyLiterature

Do acoustically detectable species reflect overall diversity? A case study from Australia's arid zone, accessed July 20, 2025,

Preview of Predicting bird diversity through acoustic indices within the Atlantic Forest biodiversity hotspot - Frontiers

Predicting bird diversity through acoustic indices within the Atlantic Forest biodiversity hotspot - Frontiers

Methodology Source Journal

Acoustic Indices for Biodiversity Assessment and Landscape Investigation | Request PDF, accessed July 20, 2025,

Preview of Predicting bird diversity through acoustic indices within the Atlantic Forest biodiversity hotspot - Frontiers, accessed July 20, 2025,

Predicting bird diversity through acoustic indices within the Atlantic Forest biodiversity hotspot - Frontiers, accessed July 20, 2025,

Contextual Support Journal

Predicting bird diversity through acoustic indices within the Atlantic Forest biodiversity hotspot - Frontiers, accessed July 20, 2025,

Preview of River Red Gum (Eucalyptus camaldulensis Dehnh.) organic matter as a carbon source in the lower Darling River, Australia | Request PDF - ResearchGate, accessed July 20, 2025,

River Red Gum (Eucalyptus camaldulensis Dehnh.) organic matter as a carbon source in the lower Darling River, Australia | Request PDF - ResearchGate, accessed July 20, 2025,

Contextual Support Journal

River Red Gum (Eucalyptus camaldulensis Dehnh.) organic matter as a carbon source in the lower Darling River, Australia | Request PDF - ResearchGate, accessed July 20, 2025,

Preview of RIvER RED guMs AND wooDLAND FoREsts - Natural Resources Commission, accessed July 20, 2025,

RIvER RED guMs AND wooDLAND FoREsts - Natural Resources Commission, accessed July 20, 2025,

Contextual Support Government

Wide-area estimates of evapotranspiration by red gum (Eucalyptus camaldulensis) and associated vegetation in the Murray-Darling River Basin, Australia - USGS Publications Warehouse, accessed July 20, 2025,

Preview of Site of the Month: Alice Mulga SuperSite - TERN Australia, accessed July 20, 2025,

Site of the Month: Alice Mulga SuperSite - TERN Australia, accessed July 20, 2025,

Contextual Support Government

Site of the Month: Alice Mulga SuperSite - TERN Australia, accessed July 20, 2025,

Preview of The Australian Acoustic Observatory, accessed July 20, 2025,

The Australian Acoustic Observatory, accessed July 20, 2025,

Contextual Support Journal

The Australian Acoustic Observatory, accessed July 20, 2025,

Preview of The relationship between the Acoustic Complexity Index and avian species richness and diversity - NTU > IRep, accessed July 22, 2025,

The relationship between the Acoustic Complexity Index and avian species richness and diversity - NTU > IRep, accessed July 22, 2025,

Direct Evidence Journal

Acoustic indices as rapid indicators of avian diversity in different land-use types in an Indian biodiversity hotspot, accessed July 20, 2025,

Preview of The relationship between the Acoustic Complexity Index and avian species richness and diversity: a review - ResearchGate, accessed July 25, 2025,

The relationship between the Acoustic Complexity Index and avian species richness and diversity: a review - ResearchGate, accessed July 25, 2025,

Direct Evidence Journal

The relationship between the Acoustic Complexity Index and avian species richness and diversity: a review - ResearchGate, accessed July 20, 2025,

Context

Region Australia
Biome Arid Inland Floodplains & Ephemeral River Systems
Land Use Production Forestry
Assessment Conservation Target
Vegetation Forest
Season spring/early summer
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 18 Mar 2026

Notes

Lower threshold near zero indicates degraded state; optimal range characterized by high, fluctuating ACI during dawn/dusk; upper boundary values may reflect insect dominance and require interpretive caution. No upper detrimental threshold — higher values are always better up to natural saturation.