WWF G200 Freshwater

Source: WWF Global 200 Year: 2002 Category: Transition risks · Sensitive areas · Critical areas · WWF G200 Coverage: Global Format: Boundary polygons Used in risk analysis: No (contextual layer; not used in materiality scoring)

What it shows

This layer maps the freshwater priority ecoregions identified by WWF's Global 200 project — 53 freshwater areas singled out for their exceptional biodiversity. It matters for nature-related risk because these are recognised conservation priorities, and activity that intersects or lies near them touches some of the most ecologically important freshwater systems worldwide.

How it is built

The layer is derived from WWF's Global 200 analysis, which identified Earth's key ecoregions with outstanding biodiversity in order to guide conservation toward a representative set of the world's habitats. The freshwater component comprises 53 priority freshwater ecoregions. The dataset is supplied as mapped boundaries, with no derived score — inclusion reflects an ecoregion's status as a Global 200 freshwater priority.

How to read it

This is a boundary layer. A site that intersects or lies near a Global 200 freshwater priority area is flagged as overlapping a globally important freshwater ecoregion, warranting closer review. There is no numeric scale — relevance is determined by spatial overlap or proximity.

Class thresholds

This is not a continuous physical-flux layer and has no numeric thresholds. It is a presence / boundary mask: the underlying feature is the set of 53 freshwater priority ecoregions from WWF's Global 200 analysis, stored as vector polygons. The symbolised field (G200 Freshwater Type) is a purely descriptive habitat category — Large Lake, Large River, Large River Delta, Large River Headwaters, Small Lake, Small River Basin, Xeric Basin — not a graded risk score. For any location there are only two relevant states: inside (or near) a Global 200 freshwater ecoregion, or outside it.

The single "class" is presence; the habitat types only colour the polygons. This is a contextual layer and is not used in materiality scoring (the TOML defines no proximity trigger), so no buffer distance is configured; relevance is determined purely by spatial overlap or proximity to a designated ecoregion.

How these thresholds were set. There is no Darwin classification of a continuous quantity here: membership and habitat typing are taken verbatim from WWF's Global 200 freshwater priority ecoregions (Olson et al., 2012). No breaks, bins or cut-offs are applied by Darwin.

Reference: WWF Global 200 ecoregions (Olson et al., 2012).

Source

WWF Global 200 — freshwater priority ecoregions (Olson et al., 2012).

Comparison with the WWF Risk Filter Suite

This maps to WWF Biodiversity Risk Filter indicator S14_4 Other Important Delineated Areas, covering the Global 200 ecoregions (Olson, 2012). It is drawn from the same source family that WWF uses, so Darwin and the WWF Risk Filter Suite are aligned on this layer.

Legend

Symbolised field: G200 Freshwater Type

Generated from darwin/layers/layer-wwf-g200-freshwater.toml and risk_indicator_pairs.toml (develop).