GCRI · Biodiversity Nexus
Wetlands and freshwater
Wetlands, rivers and lakes cover a small part of the Earth’s surface yet hold a large share of its species, and freshwater species are consistently reported among the most threatened. These systems store floodwater, filter pollutants, recharge groundwater and hold large stocks of carbon in peat. This page sets out how watershed and wetland resilience is observed, how pressures propagate along river networks, and what the evidence means for the authorities that manage water and land.
How the work runs.
Ecosystem condition account
Wetlands and freshwater · Wetland complex · Accounting year 3
- Extent change▲ 1pct of openingWatch
- Condition index0.640 to 10.07Watch
- Species of concern14recorded
- Restoration under management407haNormal
Condition indicators
| Water level regime | 0.6 | 0.5 | 1.0 |
| Native vegetation cover | 0.6 | 0.7 | 1.0 |
| Invasive species pressure | 0.5 | 0.5 | 0.0 |
| Connectivity | 0.3 | 0.4 | 1.0 |
Condition index
Fig.Ecosystem condition account: example names and illustrative values, not a record or a live system.
Wetlands and freshwater: how the risk develops.
Watershed and wetland resilience. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Drainage and conversion
Wetlands are drained for agriculture, settlement and infrastructure, and peatlands for plantations. Drained peat oxidises and subsides, releasing carbon and raising flood risk, and the loss is slow or impossible to reverse.
Flow alteration and barriers
Dams, weirs and abstraction change the timing and volume of flow and block fish migration. Floodplains cut off from their rivers stop receiving the floods that sustain spawning grounds and wetland vegetation.
Pollution travels downstream
Nutrients, sediment, pesticides and untreated wastewater move through the river network. Excess nutrients drive algal blooms and oxygen loss in lakes, estuaries and coastal waters far from where they entered.
Resilience lost, risk shifted
Healthy floodplains and wetlands absorb flood peaks and sustain dry-season flow. As they are lost, floods and droughts reach towns and farms faster and harder, and the cost moves to infrastructure owners, insurers and households.
Habitat condition in the Amazon Basin.
Land cover, vegetation and active fires over the Amazon Basin, from NASA GIBS. Each layer carries its own date.
The interactive map needs JavaScript; the layer list and sources are below.
Layers 3
Habitat condition, for this page
About this layer
- Evidence
- Modelled (latest year GIBS publishes)
- Source
- MODIS Terra and Aqua land cover (MCD12Q1) (NASA LP DAAC)
- Provider
- NASA LP DAAC
- Licence
- NASA open data
- Vintage
- yearly; Satellite classification; latest year GIBS publishes
- Newest at build
- 2024-01-01
- Resolution
- about 500 m grid
- Uncertainty
- Satellite land cover classes for the year shown, including croplands; a classification with known errors, not a farm register.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds leave gaps)
- Source
- MODIS Terra EVI (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite index; clouds leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 250 m grid
- Uncertainty
- Satellite vegetation index for the 8 days to the date shown, a habitat condition indicator; not a measure of species or biodiversity.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds and overpass timing leave gaps)
- Source
- VIIRS NOAA-20 375 m (FIRMS) (NASA LANCE FIRMS)
- Provider
- NASA LANCE FIRMS
- Licence
- NASA open data
- Vintage
- daily; Satellite detection; clouds and overpass timing leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 500 m grid
- Uncertainty
- Satellite hot-spot detections for the day shown, including gas flares and industrial heat; not a confirmed fire, an incident report or a warning.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed
- Source
- VIIRS NOAA-20 corrected reflectance (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite image
- Newest at build
- 2026-10-14
- Resolution
- about 250 m grid
- Uncertainty
- Satellite image. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Modelled (latest 8-day period GIBS publishes)
- Source
- MODIS Aqua GPP (MYD17) (NASA LP DAAC)
- Provider
- NASA LP DAAC
- Licence
- NASA open data
- Vintage
- 8-day; Satellite-driven model; latest 8-day period GIBS publishes
- Newest at build
- 2026-09-30
- Resolution
- about 500 m grid
- Uncertainty
- Model estimate of carbon taken up by plants over the 8-day period shown; an indicator of growth, not harvest or production.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds leave gaps)
- Source
- VIIRS Global Flood Product (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite detection; clouds leave gaps
- Newest at build
- 2026-10-14
- Resolution
- about 250 m grid
- Uncertainty
- Satellite detection; clouds leave gaps. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
Keyboard, with the map focused
Hold Ctrl or ⌘ and scroll to zoom
Latest available
NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
Loading the latest NASA imagery.
Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.
Habitat condition, framed on the Amazon Basin.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.
Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · NASA JPL OPERA DIST-ALERTSources and licences
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- NASA Fire Information for Resource Management System (FIRMS), VIIRS 375 m active fire product, NASA LANCE; vector tiles via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
- Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
- © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). ODbL
- Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
- Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
- Live: NASA EONET Events are indicative, not authority warnings.
- Observed (EO): NASA JPL OPERA DIST-ALERT (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- NASA GIBS: We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- Optional layers (6 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.
Layers and dates
- Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
- Enhanced vegetation index, rolling 8 days: MODIS Terra EVI, NASA LANCE · 13 Oct 2026
- Active fires and thermal anomalies: VIIRS NOAA-20 375 m (FIRMS), NASA LANCE FIRMS · 13 Oct 2026
- True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
- Gross primary production, 8-day total: MODIS Aqua GPP (MYD17), NASA LP DAAC · 30 Sep 2026
- Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
Wetlands are where water, food and nature meet most directly.
| Domain | How it couples here | What to watch |
|---|---|---|
| Water | Wetlands store floodwater and recharge aquifers. See drought and flood. | Wetland extent in floodplains |
| Food | Inland fisheries and flood-recession farming depend on wetlands. | Inland fish catch |
| Health | Wetlands filter pollutants and can host disease vectors. | Water quality downstream of wetlands |
| Energy | Dams alter flood pulses that wetlands need. See hydropower and water. | Flow regime change below dams |
The Convention on Wetlands (Ramsar, 1971) frames wise use; its Global Wetland Outlook tracks extent and condition. Tickner and colleagues (2020) set out an emergency recovery plan for freshwater biodiversity with six actions, from environmental flows to invasive species control.
Model wetlands and freshwater as a system. Run the cascade.
Assembled from the Nexus Standards area profile Biodiversity and nature risk standards: the hazards it names, the systems and sectors that carry the loss, the controls that dampen it and the data that observe it. Choose the components, pick an initiating hazard and step through the cascade. The Map view places the run on an example geography with open data. Every coupling weight is a stated assumption you can change. A teaching model, not a forecast, an assessment or a certification. To model a place of your own choosing, open the full System Builder.
Hazards
- Deforestation
- Biodiversity loss (set off downstream)
- Soil erosion (set off downstream)
- Land-system change boundary transgression (set off downstream)
- Amazon rainforest dieback (set off downstream)
- Slope slide (set off downstream)
- Flash flood (set off downstream)
- Zoonotic spillover event (set off downstream)
- Wildfire (set off downstream)
- Emerging arbovirus outbreak (set off downstream)
- Malaria resurgence (set off downstream)
Systems and couplings
- Biodiversity and nature risk standards
- Climate risk standards Feedback
- Health risk standards Cascade
- Food and agriculture risk standards Dependency
- Environmental degradation hazard standards Shared hazard records
Controls
NS-0Constitution and principlesNS-1The UNI and the artefact catalogue (grammar v0.2: domain, sector, region and environment segments)NS-3Risk record UNIs (grammar, legacy crosswalk, allocation authority)NS-3bDataset and product metadata profile (STAC, DCAT, PROV-O)NS-5Figure, map and visualisation standard (with the UI/UX kit)NS-9Contextual UNIs (deployments, instances, programme instances)NS-11Verification and monitoring (evidence, attestations, zero-trust conformance observation)NRS-N5Biodiversity and nature risk and resilienceNRS-H65Hazard family: Planetary boundary transgressions (NHS-1 planet.boundary)NRS-H27Hazard family: Biodiversity and species stress (NHS-1 eco.species)NRS-H26Hazard family: Land and wetland degradation (NHS-1 eco.land)NRS-H28Hazard family: Climate-state shifts (NHS-1 eco.climate-state)NRS-H64Hazard family: Ecosystem regime shifts (NHS-1 eco.regime-shift)
Observation
- GBIF occurrence API and downloads (listed for reference)
- World Database on Protected and Conserved Areas (listed for reference)
- Global Forest Watch tree cover loss (Hansen/UMD) and alerts (listed for reference)
- ESA WorldCover 10 m land cover (listed for reference)
- Copernicus Land Monitoring Service products (listed for reference)
- Red List Index
- Forest area as a proportion of total land area
- Proportion of important sites for terrestrial and freshwater biodiversity covered by protected areas
Example geography
- Pacific Island states: 150 hexagonal cells
- Vegetation disturbance alerts, 30 m (OPERA DIST-ALERT), NASA GIBS
- Surface soil moisture (SMAP), NASA GIBS
- Night lights tonight, outages (VIIRS Day/Night Band), NASA GIBS
- Rain rate, last half hour (IMERG), NASA GIBS
Freshwater nature evidence.
Wetland and freshwater analyses are designed for the Country Systems Risk and Resilience series. Wetland maps would carry NS-3b metadata under the proposed Nexus Standards. Useful contributions: wetland surveys, fish monitoring and records of drainage or restoration with dates.
How wetlands and freshwater is modelled, measured and tested.
The model, its assumptions, its data and its uncertainty, in the form a scientist or engineer would check. Structures follow published methods. The values drawn are illustrative, not findings.
Earth observation chain
How a satellite or sensor record becomes evidence on wetlands and freshwater, and where each step adds uncertainty.
- 01 · Acquireorbit, sensor and revisitUncertainty: gaps from cloud and orbit
- 02 · Calibrateradiometric and geometricUncertainty: sensor drift
- 03 · Correctatmosphere and terrainUncertainty: aerosol and slope assumptions
- 04 · Retrieve or classifythe variable or the classUncertainty: model and training error
- 05 · Validateagainst ground truthUncertainty: sample design and size
- 06 · Publishwith error bars and lineageUncertainty: stated, never hidden
What is measured, and how well.
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Wetland Extent Trends index | index relative to a baseline | periodic | Compiled wetland area time series | ESTIMATED |
| Surface water extent | square kilometres | monthly | Optical and radar satellites | OBSERVED |
| River connectivity status | connectivity index per river reach | periodic | Barrier inventories on river networks | MODELLED |
| Environmental flow compliance | percent of months meeting the agreed regime | annual | Gauges against the agreed regime | Published statistics |
| Water bodies with good ambient quality | percent of assessed water bodies | periodic | National monitoring reported under SDG indicator 6.3.2 | Published statistics |
| Freshwater species extinction risk | count of species by Red List category per basin | per assessment | IUCN freshwater assessments | Published statistics |
| Drained and rewetted peatland | hectares | periodic | National inventories and satellite mapping | ESTIMATED |
| Lake chlorophyll-a | micrograms per litre | monthly | Sampling and satellite water-colour retrieval | OBSERVED |
Where the evidence comes from.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| Ramsar Sites Information Service | Wetlands of international importance, their boundaries and reported changes | Public records, terms of use |
| JRC Global Surface Water | Surface-water occurrence, change and seasonality from Landsat | Free and open, attribution |
| HydroSHEDS, HydroATLAS and the Free-flowing Rivers dataset | River networks, catchment attributes and connectivity status | Free, attribution and terms |
| Freshwater Ecoregions of the World | A biogeographic frame for comparing freshwater assessments | Free, attribution |
| Global Peatland Database and Global Peatland Map | Peatland extent and status from national and remote sensing sources | Terms per dataset |
| GEMStat (UNEP GEMS/Water) | Water quality measurements from national monitoring programmes | Terms per data provider |
| Copernicus Land Monitoring Service lake products | Lake surface temperature and water quality from satellite | Free and open, attribution |
Who decides, and what the evidence serves.
Biodiversity Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Ramsar administrative authorities and environment ministries | Whether a designated wetland’s ecological character is changing and what response is required | Extent and condition trends against the site description, with driver evidence |
| River basin organisations and water regulators | What flow regime and barrier removal sustain fisheries and wetlands | Environmental flow compliance, connectivity status, species distributions |
| Land-use planners and agriculture agencies | Where drainage or conversion should be refused and where rewetting has most effect | Peatland and floodplain maps with their carbon and flood-storage function |
Outputs this topic produces
- Wetland extent and condition maps with seasonality
- River connectivity assessments by basin
- Watershed resilience notes linking wetland loss to flood and drought exposure
- Restoration priority layers for floodplains and peat
What experts ask.
Freshwater ecologists and hydrologists share a set of core questions.
- How much wetland and floodplain remains in a catchment, and how well connected is it to the river?
- How have dams, abstraction and drainage changed the timing and size of flows that species depend on?
- Where are nutrient, sediment and chemical loads degrading water quality and aquatic life?
- How do wetlands change flood peaks and dry-season flows, and how reliably?
- Which freshwater species are declining, and which barriers block their movement?
Flow, connection and quality.
Freshwater ecosystems are organised by flow. The seasonal pattern of high and low water cues spawning and migration, moves sediment, and reconnects floodplains to rivers. Dams, abstraction and channelisation flatten and shift that pattern; levees cut floodplains off; drainage converts wetlands to farmland or development. Each change removes habitat and also changes how water moves through the landscape, often increasing flood peaks downstream and lowering dry-season flows.
Water quality is shaped by what enters from the land. Excess nutrients from fertiliser and wastewater can drive algal blooms and low-oxygen conditions; sediment from eroding land smothers riverbeds; chemicals accumulate in food webs. Because rivers concentrate the effects of everything upstream, the condition of a catchment, including its forests and wetlands, determines the risk faced by communities and infrastructure below it.
How the evidence is built, and where it stops.
- 01
Hydrological monitoring and modelling
Gauges and models from hydrology and water science estimate flows and how wetlands modify them. Gauging networks are thin in many regions and models need local calibration.
- 02
Wetland mapping
Radar and optical imagery map open water and inundation over time. Vegetated and seasonal wetlands are often under-mapped.
- 03
Biological assessment
Indicator invertebrates, fish surveys and environmental DNA reflect ecological condition. Methods and reference conditions vary between regions.
- 04
Water quality sampling
Grab samples and sensors measure nutrients and pollutants. Short events such as storm runoff are easily missed.
How it is studied, and what the methods cannot say.
- 01Hydrology and water scienceEnvironmental flow assessment · Flood regulation by wetlands and forestsApplied here
- 02Earth observation and remote sensingForest loss and disturbance alerts · Wetland and mangrove dynamicsApplied here
- 03Ecology and biodiversity scienceSpecies distribution modelling · Population trend and viability analysisApplied here
- 04Geospatial information systemsOverlap with sensitive biodiversity · Connectivity and corridor analysisApplied here
- 05Spatial statistics and geostatisticsBias-corrected distribution surfaces · Hotspots of change and threatApplied here
Where this page’s references lead.
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
- Convention on Wetlands (Ramsar, 1971)
- Global Wetland Outlook (Convention on Wetlands, 2018, with later editions)
- Tickner and others, Bending the curve of global freshwater biodiversity loss: an emergency recovery plan, BioScience 70 (2020)
- NS-3b, Dataset and product metadata profile, a proposed standard
Questions and answers.
Why are wetlands so difficult to map?
What makes a wetland internationally important?
How does wetland loss affect flooding?
Do wetlands always reduce flooding?
What is an environmental flow?
Why do freshwater species decline so widely?
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