Pollinator Abundance (PA) is the final synthetic indicator of the InVEST Pollinator Model (Natural Capital Project, Stanford University). It measures the overall habitat suitability for pollinators expressed on a normalised scale of 0 to 1 (dimensionless), representing the degree to which a landscape is conducive to the presence and persistence of pollinating insect populations.
PA integrates two upstream InVEST indicators -- Nesting Sites (NS) and Floral Availability (FA), the latter derived from Nectar Potential (NP) -- into a single composite index: areas with both suitable nesting habitat and accessible floral resources receive the highest PA scores. The indicator is not inverted -- higher values indicate better conditions for pollinators and greater habitat quality.
Pollinators play a critical role in both natural ecosystem functioning and agricultural productivity. Their decline has significant consequences for biodiversity maintenance (Klein et al., 2007), food security, and ecosystem resilience. PA provides a spatially explicit measure of the landscape's capacity to sustain pollinator communities -- a key biodiversity metric under ESRS E4-5, AR 37.
ESRS alignment: E4-5, AR 37 (biodiversity and ecosystems -- pollinator indicators). Compliant with GRI-101-7-a.
The InVEST pipeline for PA runs: Land Cover -> Nectar Potential (NP) -> Floral Availability (FA) + Nesting Sites (NS) -> Pollinator Abundance (PA). NS and FA must be computed before PA can be derived. The raw InVEST value (0--1) is multiplied by 100 on the platform for display clarity, and the resulting 0--40 display range reflects the scaled quality thresholds used in the A--E grading system.
PA is calculated using the InVEST methodology (Sharp et al., 2020) as a product of two core components:
where NS = Nesting Sites index (weighted average of six nesting strategy components, 0--1 scale), FA_accessible = Floral resources reachable from the nesting area, weighted by distance using a decreasing exponential function (foraging range: 500 m for solitary bees -- 3 km for Apis mellifera)
The accessible floral resources are derived from the Aggregated Floral Resources (FA) index, which integrates Nectar Potential (NP) across the landscape within the species-specific foraging radius. This spatial weighting means that floral resources close to nesting sites contribute more to PA than distant ones.
Data are sourced from the InVEST Pollinator Model (Natural Capital Project) applied to CORINE Land Cover data at 10--100 m resolution. The platform displays values on a 0--40 scale, where the raw 0--1 value is multiplied by the InVEST model parameter cap.
Gauge. A semicircular arc chart showing the PA index value for the site (ROI) compared to the control area (CA), with a quality grade colour scale from A (excellent) to E (critical).
Purpose: To display, at a glance, the overall habitat suitability for pollinators at the site compared to the surrounding landscape as a benchmark, integrating both nesting and floral resource availability into a single indicator.
Description: The gauge is located within the "Relative abundance of pollinators" subsection of the Assessment > State of Biodiversity page (ESRS E4-5, AR 37). The semicircular arc is coloured in five quality segments. The site (ROI) value is shown as a marker on the arc with the numeric value displayed at the centre. The control area (CA) value appears as smaller text below the centre value. A delta badge appears below the gauge showing the difference between site and control (coloured green if the site exceeds the control, red if below). A compliance badge reads "Compliant With GRI-101-7-a -- Method from InVEST".
28Pollinator Abundance
How it's calculated: The displayed value is the composite InVEST PA index (NS x FA_accessible), expressed on the 0--40 display scale. The site value uses the ROI polygon; the control value uses the surrounding CA polygon. Both values are independently computed from the same land cover input.
Legend:
| Level | Range (0--40) | Color | Meaning |
|---|---|---|---|
| A (Excellent) | > 32 | ■ #00A67A | Optimal habitat; high pollinator abundance |
| B (Good) | 24 -- 32 | ■ #00DF80 | Good suitability; landscape broadly favourable |
| C (Moderate) | 16 -- 24 | ■ #FFD21E | Average suitability; partial limitations |
| D (Poor) | 8 -- 16 | ■ #FF8B16 | Low suitability; simplified or degraded habitat |
| E (Critical) | 0 -- 8 | ■ #FF367F | Unsuitable habitat; near-absence of favourable conditions |
Interpretation example:
If the gauge shows a site PA of 28 (grade B) and a control PA of 20 (grade C), the site provides better pollinator habitat than its surrounding landscape -- indicating the presence of combined nesting opportunities and adequate nectar resources that together sustain a relatively high potential pollinator abundance.
Detail Card. A dropdown selector within the PA section allowing the user to filter the PA gauge view by individual nesting strategy sub-type, showing the contribution of each nesting functional group to the overall PA score.
Purpose: To reveal which nesting strategies are contributing most to the overall PA index, enabling targeted interpretation of what drives or limits pollinator abundance at the site.
Description: A dropdown labelled "Nesting type" lets the user select among eight options: Total, Soil Excavators, Sand Excavators, Cavity Subsurface, Wetlands, Aboveground Cavities (Vegetated), Coastal Area, and Artificial Nesting. Selecting a sub-type updates the gauge to show the sub-type-specific PA contribution. Each sub-type also has an information overlay.
How it's calculated: Each sub-type value reflects the PA calculation using only the nesting component corresponding to that strategy (e.g., selecting "Soil Excavators" shows the PA score for ground-nesting species specifically). The "Total" option shows the full weighted InVEST PA index.
Interpretation example:
If "Aboveground Cavities (Vegetated)" shows grade A but "Soil Excavators" shows grade D, the site has strong aerial nesting structures but limited bare-soil availability -- constraining PA for the majority of European wild bee species that nest in the ground.
Highlights Table Row. A column in the multi-site KPI comparison table on the Highlights page, showing the PA site and control values side by side for each site in the portfolio.
Purpose: To enable portfolio-level comparison of pollinator habitat quality across all sites, identifying which locations have the best or weakest combined nesting and floral resource conditions.
Description: The table column header reads "Abundance of Pollinators". Each row shows the PA value for the site (ROI) and the control area (CA). The table supports copy-to-clipboard and CSV export. PA does not appear as a standalone summary card in the highlights grid.
How it's calculated: Each cell value is the total PA InVEST index, expressed on the 0--40 display scale, for the respective polygon.
Interpretation example:
If one site shows "34 / 20" (site/control) and another shows "10 / 22" (site/control), the first site exceeds its landscape baseline -- indicating active biodiversity-supporting habitat -- while the second is below its surroundings, suggesting land use intensification or habitat loss within the site boundary.
Assessment Sidebar Row. A labelled row within the E4 Biodiversity category group in the assessment sidebar, showing the site and control PA grade badges.
Purpose: To provide a persistent at-a-glance quality indicator for PA across all assessment pages without requiring navigation to the dedicated Relative Abundance of Pollinators section.
Description: This row appears under "E4 | Biodiversity" in the left sidebar of all seven assessment pages. The label reads "Ab. Pollinators (PA)". Coloured grade badges for Site and Control are displayed alongside.
How it's calculated: The badge colour corresponds to the A--E quality grade derived from the total PA score thresholds (see legend in gauge section above).
Interpretation example:
If the sidebar shows a green badge (A) for the site and a yellow badge (C) for the control, the site's pollinator habitat significantly outperforms the surrounding landscape -- a strong signal for the effectiveness of habitat management or the presence of high-quality natural areas within the site.
Data Table. A paired column in the historical scenarios table showing PA site and control values across polygon versions and years.
Purpose: To provide a historical record of pollinator habitat quality for the site across all computed polygon and land-cover versions, enabling trend analysis and version comparison.
Description: The Scenari table includes a "PA" column pair (site and control) alongside other InVEST and land use indicators, year, polygon version, and land use version. Each row represents a computation version. Values are plain numeric (0--40 display scale).
How it's calculated: Each cell is the total PA InVEST index for that polygon version and year.
Interpretation example:
If the table shows PA = 30 site / 22 control in 2021 and PA = 24 site / 22 control in 2023, the site's pollinator habitat quality has declined relative to a stable control -- suggesting a deterioration in either nesting conditions or floral resource availability within the site boundary over that period.
Map Layer. An interactive raster overlay showing PA values at pixel level within the CLC & Pollinator Analysis layer group, available on any map page.
Purpose: To reveal the spatial distribution of pollinator habitat quality across the site and its surroundings, identifying high-quality patches (combination of nesting habitat + floral resources) versus unsuitable zones.
Description: The layer is selectable from the "CLC & Pollinator Analysis" group under the map layer selector. The layer label in the selector reads "Ab. Pollinators (PA)". It renders a continuous colour raster using the PA quality colour scale. Sub-type layers are available within the same layer group for per-nesting-strategy spatial views.
How it's calculated: Each pixel value is the total InVEST PA score for that land cover class and location, incorporating both NS and accessible FA computed at the land cover resolution (10--100 m).
Legend: Continuous gradient from E (critical, pink #FF367F) to A (excellent, green #00A67A), matching the five quality segments of the gauge.
Interpretation example:
If the map shows a green patch (high PA) along the northern woodland-grassland mosaic transitioning to red in the intensively cultivated southern fields, the pollinator habitat is highly spatially heterogeneous -- the green corridor is sustaining the site's pollinator community, while the cultivated areas are acting as ecological barriers.
| Source | Provider | Coverage | Resolution | Period |
|---|---|---|---|---|
| InVEST Pollinator Model | Natural Capital Project, Stanford University | Site-level (derived from land cover input) | Derived from land cover resolution | Continuous |
| CORINE Land Cover / Land Cover Fusion | EEA / 3Bee geo pipeline | Europe (site-level) | 10--100 m | 1990 -- present |
PA is computed as the product of Nesting Sites (NS) and accessible Floral Availability (FA_accessible). The NS index is a weighted average of six nesting strategy components (Soil Excavators, Sand Excavators, Cavity Subsurface, Wetlands, Aboveground Cavities, Coastal Area, plus Artificial Nesting), each scored 0--1 based on land cover class suitability.
FA_accessible is derived from the Aggregated Floral Resources (FA) index, which integrates Nectar Potential (NP) across the landscape within a species-specific foraging radius. The spatial weighting uses a decreasing exponential function -- floral resources close to nesting sites contribute more than distant ones. The foraging range parameter spans 500 m (solitary bees) to 3 km (Apis mellifera); floral resources beyond this range do not contribute to PA.
The raw InVEST PA value (0--1) is multiplied by 100 on the platform. The resulting 0--40 display range reflects the model parameter cap (~0.40 for most European landscapes). If either NS or FA_accessible is zero (e.g., no suitable nesting sites or no reachable floral resources), PA is zero regardless of the other component's value.
The full InVEST pipeline runs: Land Cover -> Nectar Potential (NP) -> Floral Availability (FA) + Nesting Sites (NS) -> Pollinator Abundance (PA). NS and FA must be computed before PA is available; if land cover has not been generated for the site, PA and all its sub-types will be unavailable.
Sharp, R., Chaplin-Kramer, R., Wood, S., Guerry, A., Tallis, H., Ricketts, T., et al. (2020). InVEST User's Guide. The Natural Capital Project, Stanford University. Available at: https://naturalcapitalproject.stanford.edu/software/invest
Klein, A.M., Vaissiere, B.E., Cane, J.H., Steffan-Dewenter, I., Cunningham, S.A., Kremen, C., & Tscharntke, T. (2007). "Importance of pollinators in changing landscapes for world crops." Proceedings of the Royal Society B, 274(1608), 303--313. DOI: 10.1098/rspb.2006.3721
Potts, S.G., Biesmeijer, J.C., Kremen, C., Neumann, P., Schweiger, O., & Kunin, W.E. (2010). "Global pollinator declines: trends, impacts and drivers." Trends in Ecology & Evolution, 25(6), 345--353. DOI: 10.1016/j.tree.2010.01.007
Ricketts, T.H., Regetz, J., Steffan-Dewenter, I., Cunningham, S.A., Kremen, C., Bogdanski, A., et al. (2008). "Landscape effects on crop pollination services: are there general patterns?" Ecology Letters, 11(5), 499--515. DOI: 10.1111/j.1461-0248.2008.01157.x