PA – Artificial Nesting

Biodiversityvv0

Responsible:Niccolò Calandri

PA – Artificial Nesting (pa_ns_artificial)

Overview

The PA – Artificial Nesting component measures the Pollinator Abundance (PA) specifically associated with pollinators that have adapted to nest in artificial structures. It is expressed on a normalised scale from 0 to 1 and is one of the sub-indicators of the InVEST Pollinator Model.

This group includes pollinators that use man-made structures for nesting: wall crevices, gaps between bricks, wooden beams, bee hotels, disused agricultural buildings and other anthropic elements. Common species include Osmia bicornis (red mason bee), Anthophora plumipes and several Megachile species that readily colonise artificial cavities.

The presence of artificial nesting sites is particularly relevant in urban and peri-urban settings, where natural resources are limited but the installation of artificial nests and conscious building management can create complementary habitats.

Calculation Methodology

Calculated using the InVEST methodology (Sharp et al., 2020). For each land cover pixel, a suitability value for artificial nesting (0–1) is assigned. The PA value integrates nesting suitability with accessible floral resources (FA), weighted by foraging distance.

Scale: 0 (unsuitable habitat) – 1 (maximum suitability)

Data Sources

Code	Name	Provider	Resolution	Availability
`WRD_INVST_99`	InVEST Pollinator Model	Natural Capital Project, Stanford University	—	—

Quality Range and Levels

Indicator	Unit	Range	Inverted
`pa_ns_artificial`	—	[0, 8, 16, 24, 32, 40]	No

Level	Value	Interpretation
A (Excellent)	> 32	Broad availability of suitable artificial structures; bee hotels and permeable walls
B (Good)	24 – 32	Good availability; buildings with crevices and old farm structures
C (Moderate)	16 – 24	Average availability; some usable structures
D (Poor)	8 – 16	Low availability; modern sealed buildings
E (Critical)	0 – 8	Near absence of suitable structures; completely open or sealed environments

References

Sharp, R. et al. (2020). InVEST User's Guide. The Natural Capital Project, Stanford University.
Potts, S.G. et al. (2010). "Global pollinator declines: trends, impacts and drivers". Trends in Ecology & Evolution, 25(6), 345–353.
Fortel, L. et al. (2014). "Decreasing abundance, increasing diversity and changing structure of the wild bee community along an urbanization gradient". PLoS ONE, 9(8), e104679.

Data Sources & References

Sources

WRD_INVST_99

Methodology

PA component for artificial nesting. Calculated using InVEST methodology (Sharp et al., 2020). For each land cover pixel, a suitability value for artificial nesting (0–1) is assigned. Scale: 0–1.