GCRI · Biodiversity Nexus
Methods and uncertainty
The methods Biodiversity Nexus relies on: their equations and assumptions, the data they need, how they are validated and the limits of what they can show.
The workspace for methods and uncertainty.
Evidence grading
Methods and uncertainty · Review wave 2 · Example interface, not a record
Certainty by criterion
0 low to 100 high
Higher is more certain. Values are examples.
Review queue
- R-1Natural habitat extentsecond reviewer4 d
- R-2Species of concern recordedsecond reviewer4 d
- R-3Water-related dependency scoresecond reviewer3 d
Biodiversity Nexus · Evidence grading. Evidence grading: example names and illustrative values, not a record.
The methods in use.
- 01Ecology and biodiversity scienceSpecies distribution modelling · Population trend and viability analysisApplied here
- 02Earth observation and remote sensingForest loss and disturbance alerts · Wetland and mangrove dynamicsApplied here
- 03Spatial statistics and geostatisticsBias-corrected distribution surfaces · Hotspots of change and threatApplied here
- 04Geospatial information systemsOverlap with sensitive biodiversity · Connectivity and corridor analysisApplied here
- 05Complex systems and agent-based modellingEarly warning of regime shifts · Food-web and co-extinction networksApplied here
- 06Causal inference and impact evaluationProtected area effectiveness · Restoration and payment programme evaluationApplied here
- 07Hydrology and water scienceEnvironmental flow assessment · Flood regulation by wetlands and forestsApplied here
- 08Ocean and coastal scienceFish stock assessment · Marine heatwave and bleaching exposureApplied here
Each method, its role in this field and how it is checked.
- EcologyRole hereEcology is the core science of this platform: it explains how species, populations and ecosystems respond to pressure, which changes matter for ecosystem function, and how losses become changes in the services people depend on.Checks appliedIndependent survey validation; Detection and observer effects; Taxonomic verification; Sampling bias assessment
- Earth observationRole hereSatellites observe forests, wetlands, coasts and the ocean surface repeatedly and across borders, which field surveys cannot.Checks appliedAccuracy assessment with area estimation; Cross-sensor consistency; Field calibration; Coverage reporting
- Spatial statisticsRole hereBiodiversity data are clustered, unevenly sampled and dependent from place to place.Checks appliedSpatial cross-validation; Residual autocorrelation; Scale sensitivity
- GeospatialRole hereGeospatial methods provide the common frame in which species ranges, protected areas, ecosystem maps, rivers, roads, concessions and sourcing regions are combined.Checks appliedProjection and alignment; Boundary currency; Disclosure review
- Complex systemsRole hereEcosystems and the social and economic systems that use them interact through feedbacks, thresholds and networks.Checks appliedPattern-oriented validation; Sensitivity and robustness; False alarm testing
- Causal inferenceRole hereConservation and restoration spend public and private money on the expectation that interventions work.Checks appliedCovariate balance; Placebo and pre-trend tests; Sensitivity to hidden bias; Spillover and leakage
- HydrologyRole hereHydrology connects biodiversity to water: flow regimes shape freshwater habitats, wetlands store and release water, and catchment condition affects the quantity and quality of water reaching people.Checks appliedSplit-sample calibration; Ecological response validation; Paired scenario runs
- Ocean scienceRole hereOcean science provides the physics, chemistry and biology behind marine biodiversity risk: heat, acidity and oxygen in the water, the currents that connect habitats, and the stock assessments that tell fisheries managers how much can be taken.Checks appliedRetrospective analysis; Satellite against in-situ; Bleaching hindcast
How the process runs.
Process
Methods and uncertainty: Source to evidence record
A source is registered and assessed, its record labelled and classified, and a Digital Evidence Passport carries provenance; a correction reaches every dependent record.
01 Intake
- 01Identify the sourceSource · The source stewardDiscovery is not ingestion. Source identification records the source class, steward, institutional role and jurisdiction.
- 03Register the sourceStepRegistration makes a discovered source a governed participant in the evidence lifecycle. It implies no endorsement or certification.
02 Assessment
- 04Jurisdiction and rights classificationGateRights classification identifies licence, consent, confidentiality and reuse limits. The result determines access and routing.
- 05Evidence quality assessmentStepQuality assessment decides whether a record is fit for a defined use. Quality is multidimensional and never a single score.
- 06Evidence labelStepEvery finding carries one of nine evidence labels. Missing data is shown as missing, never as zero.
03 Record
- 07Evidence classificationRecordClassification gives records lifecycle states, such as source-verified, public-safe or restricted. States can coexist and set evidence use.
- 08Source release and identifierRecord · NXS-GRX (canonical data, provenance and risk)A source release records rights, temporal coverage and source lineage. A UNI is allocated through a catalogue and never typed by hand.
- 09Digital Evidence PassportRecordThe passport records provenance, quality, rights, jurisdiction, permitted use and history, so evidence keeps its context when it travels.
04 Use and correction
- 02Correction reaches dependent recordsStep · NXS-GRX (canonical data, provenance and risk)A source correction propagates to dependent cuts and products without rewriting old results.
- 10Public-safe reviewGatePublic-safe review decides whether a record can be shared publicly. It is a distinct stage and is not validation.
Data protocols: evidence lifecycle · Data protocols: core data objects and evidence records · The Global Risks Index (NXS-GRX)Designed programme process, not a record of operation. No cycle has run and every programme is at service level R0. A gate is a programme decision, never a public-authority approval, certification or deployment authorisation. The data-protocol pages describe a design, not a running system.
Where uncertainty in biodiversity analysis comes from, and how it is shown.
| Source | Why it matters here | How it is reported |
|---|---|---|
| Species distribution | Occurrence records are biased by sampling effort | Bias correction and stated sampling coverage |
| Ecosystem condition | Indicators differ by ecosystem type and reference state | Condition indices following SEEA with reference levels stated |
| Thresholds | Tipping points are uncertain and site-specific | Ranges and early-warning signals, never a single value |
| Service valuation | Depends on beneficiaries and methods | Physical flows reported before money values |
| Land-cover change | Classification error in remote sensing | Accuracy assessment with each product |
Biodiversity metrics are reported with their spatial and temporal scope; a global index is never applied to a site.
How uncertainty is reported.
- 01
State assumptions
Each analysis lists its assumptions and the data it depends on.
- 02
Quantify where possible
Ranges and confidence are reported alongside central estimates.
- 03
Validate and compare
Models are checked against observations and, where possible, against other models.
- 04
Publish limits
What an analysis cannot show is stated beside what it can.
Where this page’s references lead.
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Questions and answers.
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