Floral Availability (FA) is a visual representation of the distribution and density of flowering vegetation in a given geographic area. The indicator quantifies the presence and spatial distribution of floral resources available to pollinators, particularly bees (Apis mellifera and wild species), which depend on nectar and pollen as primary food sources.
High floral availability is fundamental for maintaining pollinator populations: it supports foraging activity, sustains honey production and ensures the supply of ecosystem services linked to pollination. Recent studies document an alarming decline in pollinators across Europe, correlated with the reduction in floral availability due to agricultural intensification, habitat loss and landscape fragmentation (Potts et al., 2010). The KPI is a normalised index between 0 and 1: higher values indicate greater richness and density of floral resources.
FA is calculated using the InVEST Pollinator Abundance model (Integrated Valuation of Ecosystem Services and Trade-offs), developed by the Natural Capital Project. The model estimates floral availability from land cover, assigning each class a floral supply value per season (spring/summer/autumn).
Calculation steps:
Scale: normalised index between 0 (no floral resources) and 1 (maximum floral availability).
Visualisation: colour gradient dark red → amber → green (low to high).
| Code | Name | Provider | Resolution | Availability |
|---|---|---|---|---|
WRD_INVST_99 | InVEST Pollinator Model | Natural Capital Project | land cover dependent | on request |
WRD_ESCWC_99 | ESA WorldCover | ESA / Impact Observatory | 10 m | 2020, 2021 |
WRD_CRNLC_99 | Corine Land Cover | EEA | 100 m | 1990 — 2018 |
WRD_CLCBB_99 | CLC Backbone | EEA | 100 m | 2012, 2018 |
| Indicator | Unit | Range | Inverted |
|---|---|---|---|
fa | — | [0, 20, 40, 60, 80, 100] | No |
Inverted = No: higher values indicate greater floral availability and better conditions for pollinators.
| Level | FA (%) | Interpretation |
|---|---|---|
| A (Excellent) | 80 – 100 | Very rich floral supply; ideal habitat for pollinators and honey production |
| B (Good) | 60 – 80 | Good floral availability; favourable conditions for bees |
| C (Moderate) | 40 – 60 | Moderate availability; possible seasonal resource shortages |
| D (Poor) | 20 – 40 | Low floral availability; pressure on pollinator populations |
| E (Critical) | 0 – 20 | Floral resources nearly absent; habitat inadequate for pollinators |
fa
Calculated using the InVEST Pollinator Abundance model (Natural Capital Project, WRD_INVST_99). The model assigns each land cover class (ESA WorldCover, CORINE) a seasonal floral supply index (spring/summer/autumn) based on ecological parameters. The FA value for the polygon is the weighted spatial average, normalised to the [0, 1] interval. Requires prior processing of the Land Cover and Element-e layers (FA). Scale: 0 (no floral resources) → 1 (maximum availability).