Nesting Sites (NS) measures the presence and suitability of areas where pollinators can establish their nests, expressed on a normalised scale of 0 to 1 (dimensionless index). It is one of the three core indicators of the InVEST Pollinator Model (Natural Capital Project, Stanford University), alongside Nectar Potential (NP) and Pollinator Abundance (PA).
Nesting sites represent a critical resource for the life cycle of pollinators: without suitable nesting areas, even landscapes with the richest floral resources (high NP) cannot maintain stable pollinator populations. The availability of nesting sites depends on soil structure, vegetation cover, and the presence of appropriate substrates for the diverse reproductive strategies of pollinator species.
High NS values indicate landscapes with habitat structures adequate for pollinator reproduction, with positive effects on Pollinator Abundance. The indicator is not inverted -- higher values indicate greater suitability for nesting and better conditions for pollinators.
ESRS alignment: E4-5, AR 37 (biodiversity and ecosystems -- pollinator indicators). Compliant with GRI-101-7-a.
NS integrates with NP and PA in the InVEST model: areas with good nesting sites (high NS) but scarce nectar resources (low NP) will not reach optimal PA levels. The optimal combination of NS and NP determines maximum pollinator abundance.
The Nesting Sites Index is computed using the InVEST methodology (Sharp et al., 2020) as a weighted average of six nesting factors, each associated with a reproductive strategy of pollinator species:
| Factor | Description | Weight |
|---|---|---|
| Soil Excavators | Pollinators that nest by digging galleries in compact soil | 3 |
| Sand Excavators | Pollinators that nest in sandy and friable soils | 2 |
| Underground Cavities | Pollinators that occupy natural or pre-existing cavities in the subsoil | 1 |
| Aboveground Cavities (Wetlands) | Pollinators that nest in cavities of marsh and wetland vegetation | 1 |
| Aboveground Cavities (Vegetation) | Pollinators that nest in hollow stems, branches, and aerial plant structures | 5 |
| Coastal Areas | Pollinators that nest in coastal and riparian substrates | 1 |
where each component is computed as the specific suitability for that nesting strategy based on land cover and habitat characteristics.
Scale: 0 (no suitable sites) -- 1 (maximum nesting suitability). The platform displays values on a 0--100 scale.
Data are sourced from the InVEST Pollinator Model (Natural Capital Project, Stanford University) at site level, derived from CORINE Land Cover / Land Cover Fusion (EEA / 3Bee) at 10--100 m resolution.
Gauge. A semicircular arc chart showing the NS 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, whether the site's habitat structure provides adequate nesting opportunities for pollinators, compared with the surrounding landscape as a benchmark.
Description: The gauge is located within the "Nesting Sites" 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). An info button labelled "What are nesting types?" opens a tooltip explaining the six nesting strategies.
35Nesting Sites
How it's calculated: The displayed value is the weighted-average NS index, computed via the InVEST formula above, expressed on a 0--100 scale. The site value uses the ROI polygon; the control value uses the surrounding CA polygon.
Legend:
| Level | Range (0--100) | Color | Meaning |
|---|---|---|---|
| A (Excellent) | > 40 | ■ #00A67A | Abundant nesting sites; structurally rich habitat |
| B (Good) | 30 -- 40 | ■ #00DF80 | Good suitability; diversified nesting habitats |
| C (Moderate) | 20 -- 30 | ■ #FFD21E | Moderate suitability; some suitable substrates |
| D (Poor) | 10 -- 20 | ■ #FF8B16 | Scarce availability; few suitable nesting sites |
| E (Critical) | 0 -- 10 | ■ #FF367F | Near-absent nesting sites; degraded environment |
Interpretation example:
If the gauge shows a site NS of 35 (grade B) and a control NS of 28 (grade C), the site habitat provides better nesting structures than the surrounding landscape -- indicating the presence of features such as hedgerows, dead wood, or bare soil patches that support diverse pollinator nesting strategies.
Detail Card. A dropdown selector within the Nesting Sites section allowing the user to filter the NS gauge view by individual nesting strategy sub-type, with an informational overlay for each type.
Purpose: To show which specific nesting strategies are represented in the site and allow targeted interpretation of the overall NS score by nesting functional group.
Description: A dropdown labelled "Nesting type" lets the user select among seven 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 NS value. Each sub-type also has an information overlay (yellow-highlighted text) explaining the ecological category -- for example: "The selected layer, artificial nesting, represents an artificial element that hosts nesting sites for pollinators, such as honey bee hives but also shelters for wild pollinators."
How it's calculated: Each sub-type value is the individual component of the InVEST weighted formula, before aggregation. The weighted average of all six components yields the Total NS shown on the main gauge.
Interpretation example:
If the "Aboveground Cavities (Vegetated)" sub-type shows grade A but "Soil Excavators" shows grade D, the site has good tree/shrub structures but poor bare-soil availability -- management should focus on reducing ground compaction to benefit ground-nesting bees.
Highlights Table Row. A column in the multi-site KPI comparison table on the Panoramica page, showing the NS site and control values side by side for each site in the portfolio.
Purpose: To enable portfolio-level comparison of nesting suitability across all sites, revealing which locations have the best or weakest habitat structures for pollinator reproduction.
Description: The table column header reads "Nesting Sites (SITE/CONTROL)". Each row shows the NS value for the site (ROI) and the control area (CA). The table supports copy-to-clipboard and CSV export.
How it's calculated: Each cell value is the total NS index (weighted InVEST average across all nesting strategies), expressed on a 0--100 scale, for the respective polygon.
Interpretation example:
If one site shows "42 / 28" (site/control) and another shows "12 / 31" (site/control), the first site has better nesting habitat than its surroundings while the second is significantly below its landscape baseline -- prioritising the second site for habitat restoration would yield greater pollinator benefit.
Assessment Sidebar Row. A labelled row within the E4 Biodiversity category group in the assessment sidebar, showing the site and control NS grade badges.
Purpose: To provide a persistent at-a-glance quality indicator for NS across all assessment pages without requiring navigation to the dedicated Nesting Sites section.
Description: This row appears under "E4 | Biodiversity" in the left sidebar of all seven assessment pages. The label reads "Nesting Suitability". 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 NS score thresholds (see legend in gauge section above).
Interpretation example:
If the sidebar shows an orange badge (D) for the site and a yellow badge (C) for the control, the site's nesting habitat is below the landscape average -- a prompt to investigate which nesting strategy is most limited.
Data Table. A paired column in the historical scenarios table showing NS site and control values across polygon versions and years.
Purpose: To provide a historical record of nesting suitability for the site across all computed polygon and land-cover versions, enabling trend analysis and version comparison.
Description: The Scenari table includes an "NS" column pair (site and control) alongside other KPI columns, year, polygon version, and land use version. Each row represents a computation version. Values are plain numeric (0--100 scale).
How it's calculated: Each cell is the total NS InVEST index for that polygon version and year.
Interpretation example:
If the table shows NS = 38 site / 30 control in 2021 and NS = 32 site / 30 control in 2023, the site's nesting suitability has declined relative to a stable control -- suggesting land use intensification within the site boundary over that period.
Map Layer. An interactive raster overlay showing NS values at pixel level within the CLC & Pollinator Analysis layer group, available on any map page.
Purpose: To reveal the spatial distribution of nesting suitability across the site and its surroundings, identifying patches with high nesting potential (e.g., hedgerows, woodland edges, bare soil areas) versus impervious or intensively managed zones.
Description: The layer is selectable from the "CLC & Pollinator Analysis" group under the map layer selector. It renders a continuous colour raster using the NS quality colour scale. Sub-type layers are also available as separate toggleable layers within the same group. The layer label in the selector reads "Nesting Suitability (NS)".
How it's calculated: Each pixel value is the total weighted InVEST NS score for that land cover class, 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 corridor (high NS) along the northern woodland edge transitioning to red in the intensively cultivated southern fields, the nesting suitability is highly spatially heterogeneous -- targeting habitat interventions at the woodland edge buffer would preserve and strengthen the green corridor.
Detail Card. A sub-section within the species detail panel on the Survey > Explore page, showing per-nesting-type NS metrics for the selected pollinator species.
Purpose: To provide species-specific nesting habitat assessment, revealing which nesting strategies are available for the observed species in the site.
Description: Within the species detail panel (accessible by clicking a species entry on the Survey > Explore page), a section labelled "Nesting Suitability" lists the NS values for each nesting strategy relevant to that species: Soil Excavators, Sand Excavators, Underground Cavities, Wetlands, Aboveground Cavities, and Coastal Area.
How it's calculated: Each row value is the relevant NS sub-component for the site polygon, filtered to the ecological profile of the selected species.
Interpretation example:
If a bumblebee species detail shows "Aboveground Cavities: A" but "Soil Excavators: C", the site offers good aerial nesting structures but only moderate bare-soil availability for bumblebee queens that also use ground cavities.
| Source | Provider | Coverage | Resolution | Period |
|---|---|---|---|---|
| InVEST Pollinator Model | Natural Capital Project, Stanford University | Site-level (based on land cover input) | Derived from land cover resolution | Continuous |
| CORINE Land Cover / Land Cover Fusion | EEA / 3Bee | Europe (site-level) | 10--100 m | 1990 -- present |
The NS index is computed following the InVEST Pollinator Model methodology. Each pixel in the land cover raster is assigned a suitability score for each of six nesting strategies (soil excavators, sand excavators, underground cavities, wetland cavities, aboveground vegetation cavities, coastal substrates) based on a lookup table that maps CORINE Land Cover classes to nesting suitability values.
The six per-pixel suitability scores are combined into a single NS value using a weighted average with fixed weights: aboveground cavities in vegetation receive the highest weight (5), soil excavators receive weight 3, and all other strategies receive weight 1. The total denominator is 13.
The resulting NS raster is then aggregated over the site (ROI) and control area (CA) polygons by computing the mean pixel value within each polygon. The 0--1 scientific index is multiplied by 100 for display on the platform.
NS computation requires a prior land cover (CLC) layer to be generated for the site polygon. If land cover has not been generated, NS is not available. The land cover input may come from CORINE Land Cover or the 3Bee land cover fusion pipeline, depending on the site location and available data vintage.
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
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
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
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