Editing Biodiversity intactness index

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|+ SIGNAL Earth Structured Data
|-
! Object type
| Damage Signal
|-
! SIGNAL Earth ID
| DS-00706
|-
! Observable type
| Fertilizer applied (nutrient mass)
|-
! Unit
| tN/year (tN/year)
|-
! Temporal structure
| Annual
|-
! Monitoring backbone
| —
|}
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The biodiversity intactness index (BII) is an environmental indicator that quantifies the average intactness of ecological communities relative to a specified reference condition. It serves as a state-form measure of habitat condition, reflecting the extent to which biodiversity remains undisturbed by human activities or environmental changes. Unlike indices that emphasize anomalies or trends, the BII focuses on the baseline condition of biodiversity intactness without embedding temporal deviations or thresholds.

BII is relevant for understanding the health and resilience of ecosystems by providing a standardized measure of how much of the original biodiversity remains intact. This information is critical for assessing the impacts of land use, habitat modification, and other stressors on ecological communities. The index supports environmental monitoring and conservation planning by offering a consistent metric for biodiversity condition across different spatial and taxonomic contexts.

Within the broader context of environmental assessment, the BII complements other habitat and disturbance metrics by focusing specifically on biological community intactness. It is particularly useful for evaluating the cumulative effects of multiple pressures, including nutrient inputs such as fertilizer application, on biodiversity status.

== Geographic / System Context ==
The biodiversity intactness index is not confined to a specific geographic region but is applicable across diverse ecosystems globally. It captures habitat condition by comparing current ecological community composition to a declared reference state that may vary depending on the spatial and taxonomic scope of the assessment. This flexibility allows the BII to be used in terrestrial, freshwater, and marine environments, adapting to regional biodiversity baselines and monitoring objectives. The index's design accommodates varying spatial scales, from local habitats to broader biogeographic regions, enabling comparative analyses and integration with other environmental signals.

== Monitoring and Measurement ==
Monitoring the biodiversity intactness index involves assessing ecological community composition and abundance relative to a reference condition. This process typically requires comprehensive biodiversity surveys, species inventories, and habitat quality assessments conducted by scientific institutions and environmental agencies. Measurement methods may include field sampling, remote sensing, and modeling approaches that integrate data on species presence, abundance, and habitat characteristics.

The observable type associated with the BII includes nutrient mass inputs such as fertilizer applied (measured in tonnes of nitrogen per year), which influence habitat condition and biodiversity intactness. Monitoring frameworks may incorporate data from agricultural statistics, land use records, and ecological studies to quantify nutrient loading and its effects on biodiversity. Although the monitoring backbone for the BII is currently to be determined, established biodiversity datasets and ecological indicators provide foundational data supporting its calculation.

Within the SIGNAL system, the biodiversity intactness index is treated as a defined environmental signal whose boundaries and measurement conventions are described below.

== Signal Definition ==
The biodiversity intactness index measures the average intactness of ecological communities relative to a declared reference condition. It is a state-form indicator capturing habitat condition by quantifying how much of the original biodiversity remains undisturbed. The index does not incorporate anomaly, trend, or threshold-event framing but focuses on the baseline biodiversity intactness under specified spatial, taxonomic, and reference conventions. The canonical unit for related observables, such as fertilizer applied, is tonnes of nitrogen per year (tN/year), reflecting nutrient inputs that can affect biodiversity.

== Boundary Conditions ==
Boundary inclusions of the biodiversity intactness index encompass the base-state biodiversity intactness condition under the declared spatial, taxonomic, and reference frameworks. This means the index accounts for the average condition of ecological communities as compared to a defined baseline or reference state.

Boundary exclusions specify that the index does not encode anomaly measurements, maximum annual anomalies, trends over time, rolling means, or threshold-event forms. It strictly represents a snapshot of biodiversity intactness without temporal or event-based modifications.

== Aggregation Semantics ==
Aggregation of the biodiversity intactness index can occur across geographic, temporal, and cross-signal dimensions, although specific rules are to be defined. Geographic aggregation involves combining data from multiple spatial units to represent broader regions or ecosystems, respecting the declared spatial conventions. Temporal aggregation may summarize annual measurements to assess average biodiversity intactness over specified periods but does not include trend calculations.

Cross-signal aggregation allows integration with related environmental signals to provide a comprehensive view of ecosystem condition. For example, combining BII with habitat fragmentation metrics or nutrient input data can enhance understanding of biodiversity drivers. Aggregation semantics ensure that the index remains consistent with its state-form nature while supporting multi-scale and multi-factor analyses.

== Observational Status ==
The biodiversity intactness index is actively monitored through various ecological and environmental data collection efforts, although a centralized monitoring backbone within SIGNAL is yet to be established. Existing datasets and research provide foundational information for calculating the index, including biodiversity surveys and nutrient input records. Future SIGNAL releases may incorporate enhanced datasets, refined spatial and taxonomic reference frameworks, and improved integration with related environmental signals to support comprehensive biodiversity assessments.

== Related Signals ==
* Coastal erosion extent
* Forest area (global)
* Habitat fragmentation metric (connectivity metric declared)
* Linear habitat corridor disturbance from infrastructure
* Mangrove area extent
* Pollinator abundance index
* Urban ecological disturbance index
* Wetland area extent

== Key People ==
* Helen Phillips
* Adriana De Palma
* Ricardo E. Gonzalez
* Sara Contu
* Samantha L. L. Hill

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== Key Associated People ==
* '''John Harte''' — University of California, Berkeley [Source author; High]
* '''Jory Griffith''' — Natural History Museum [Source author; High]
* '''Laetitia Tremblay''' — Natural History Museum [Source author; High]

Inclusion reflects material contribution to the scientific understanding of this damage signal; it does not imply review, endorsement, or affiliation with SIGNAL Earth.
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== Sources ==
* [https://doi.org/10.1038/nature02718 Biodiversity conservation: climate change and extinction risk] — Nature, 2004. [Paper; Supporting; High]
* [https://docs.cecil.earth/datasets/e9d64984-3be5-4fe2-8373-7ff33bd673fb Biodiversity Intactness Index 10 km] — Natural History Museum, 2026. [Dataset; Supporting; High]
* [https://www.arcgis.com/home/item.html?id=fb5d2e1f6431489db75212f5741f5440 The Biodiversity Intactness Index (BII) - Overview] — ArcGIS Online, 2026. [Report; Supporting; High]
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