Commission Delegated Regulation (EU) 2025/2188 of 19 September 2025 supplementing Regulation (EU) 2024/1991 of the European Parliament and of the Council by establishing a science-based method for monitoring pollinator diversity and pollinator populations

For the purpose of this Regulation, the following definitions shall apply: (1) ‘bees’ means species of Anthophila (Apoidea), excluding the honeybee (Apis mellifera); (2) ‘hoverflies’ means species of Syrphidae; (3) ‘butterflies’ means species of Papilionoidea; (4) ‘moths’ means species of the following families of Heterocera: Brachodidae, Castniidae, Cimeliidae, Drepanidae, Erebidae (including Lymantriinae), Euteliidae, Geometridae, Heterogynidae, Limacodidae, Noctuidae, Nolidae, Notodontidae, Sesiidae, Sphingidae, Uraniidae, and Zygaenidae, provided they have a wingspan of 20 mm or more assessed on the basis of literature; (5) ‘day-active moths’ means species of moths that are active in the daytime at the adult stage of their lifecycle; (6) ‘night-active moths’ means species of moths that are active at night at the adult stage of their lifecycle; (7) ‘LUCAS master grid’ means a variation of the INSPIRE Lambert Azimuthal Equal Area 1 km Grid (Grid_ETRS89-LAEA_1km), based on the ETRS89 Lambert Azimuthal Equal Area Coordinate Reference System (ETRS89-LAEA), with a fixed projection centre at 52° N, 10° E ; (8) ‘stratified random sampling of monitoring sites’ means a standardised statistical sampling, where monitoring sites have an equal probability of being selected from a population that is partitioned in sub-populations (strata); (9) ‘biogeographical regions’ means biogeographical regions listed in Article 1, point (c)(iii), of Council Directive 92/43/EEC ; (10) ‘other ecosystems’ means ecosystems other than agricultural ecosystems and forest ecosystems that are aggregated in one stratum; (11) ‘transect walk’ means a data collection method in which a surveyor walks a predetermined route (transect) in order to gather field data on pollinator species; (12) ‘observation period’ means the period of the year which corresponds to the flying season of the large majority of the pollinator species; (13) ‘light trap’ means a device which attracts pollinator species during the night-time by using light and captures them in a container; (14) ‘assessment period’ means the time period over which progress to the target referred to in Article 10(1) of Regulation (EU) 2024/1991 is assessed; (15) ‘alien species’ means alien species as defined in Article 3(1) of Regulation (EU) No 1143/2014.

Member States shall collect data on the abundance and diversity of pollinator species in the following taxonomic groups: (a) bees; (b) hoverflies; (c) butterflies; (d) moths.

1 A site for data collection (‘monitoring site’) shall be a 2 km-by-2 km square centred on a point of the LUCAS master grid.

2 By way of derogation from paragraph 1, Member States may use pre-established monitoring sites, insofar as those sites were selected in accordance with the requirements set out in paragraphs 4, 5 and 6.

3 Member States shall collect data on the abundance and diversity of pollinator species on the minimum number of monitoring sites set out in Annex I.

4 Member States shall select the monitoring sites by applying stratified random sampling. The stratification shall be by biogeographical region and by the following ecosystem types: (a) agricultural ecosystems; (b) forest ecosystems; (c) other ecosystems. In addition to the stratification referred to in the first subparagraph, Member States may apply stratification by NUTS regions, classes of altitude, protection status or more refined categories of land use or land cover. The number of sites in each stratum shall be proportional to the geographical share of that stratum in the terrestrial territory of a given Member State.

5 The procedure for stratified random sampling of sites shall ensure representativeness across the national territory. The distances between the monitoring sites shall be at least: (a) 10 km for Member States with a terrestrial territory above 75000 km2; (b) 5 km for Member States with a terrestrial territory between 20000 km2 and 75000 km2; (c) 1 km for Member States with a terrestrial territory between 1000 km2 and 20000 km2. There shall be no minimum distance between the monitoring sites for Member States with a terrestrial territory below 1000 km2.

6 When applying the stratified random sampling of monitoring sites, Member States may exclude a monitoring site if it meets at least one of the following exclusion criteria: (a) more than 30 % of the monitoring site is without terrestrial vegetation; (b) the monitoring site is partially or fully located in urban centres, urban clusters or peri-urban areas; (c) at least 30 % of the monitoring site is inaccessible due to the presence of public infrastructure or because the monitoring site is located in a public area with restricted access, such as a military zone, border zone or hunting zone; (d) at least 30 % of the monitoring site is inaccessible because the monitoring site is located in a private area which is a border zone or hunting zone; (e) the monitoring site is situated at a latitude above 65° N; (f) data collection at the monitoring site is hindered for at least one of the following reasons: (i) the monitoring site is far away from the nearest road accessible with motor vehicles (more than 2 km), or it is separated from the road by significant physical or natural obstacles, making regular access difficult; (ii) the monitoring site is located on an island smaller than 50 km2 or it can only be reached by a boat trip of more than two hours from a port with a regular ferry service; (iii) at least 30 % of the monitoring site has a slope of more than 20 degrees; (g) the monitoring site cannot be attributed to one of the strata referred to in paragraph 4

7 Member States shall draw up a list of the monitoring sites selected in accordance with paragraphs 4, 5 and 6 within their territory (‘list of monitoring sites’). The list of monitoring sites shall not be changed in the course of an assessment period.

8 By way of derogation from paragraph 7, second subparagraph, a site on the list of monitoring sites may be replaced at any time if it can be concluded that it fulfils at least one of the exclusion criteria set out in paragraph 6. Monitoring sites that are excluded from the list shall be replaced by applying stratified random sampling as referred to in paragraphs 4, 5 and 6.

9 Member States shall inform the Commission and the European Environment Agency of the list of monitoring sites, and any change to it, without delay. The European Environment Agency shall make the list publicly available.

Member States shall define, for each site, the observation period during which the data collection in accordance with Articles 5 and 6 shall take place every year. The observation period shall not be changed in the course of an assessment period.

1 During the observation period set out in accordance with Article 4, Member States shall collect data on bees, hoverflies, butterflies and day-active moths on each monitoring site by undertaking transect walks.

2 Transect walks shall be undertaken separately for: (a) bees; (b) hoverflies; (c) butterflies and day-active moths.

3 The transect walks shall be carried out at the same monitoring site once a month during the observation period, with a minimum time interval of three weeks.

4 By way of derogation from paragraph 3, where the environmental conditions referred to in paragraph 7 are not met over an extended period of time which prevents the execution of the transect walks once per month, the transect walks may be carried out less frequently than once per month.

5 By way of derogation from paragraph 3, Member States may carry out transect walks at higher frequency at monitoring sites where the observation period is shorter than six months. In this case, the minimum time interval shall be less than three weeks.

6 For each transect walk, the following environmental parameters shall be recorded: (a) temperature (in °C); (b) cloud cover (in oktas); (c) wind speed (in m/s); (d) fog (presence/absence); (e) precipitation (presence/absence); (f) start time (hh:mm); (g) any other relevant parameters that may affect the data collection.

7 Transect walks shall be undertaken under environmental conditions during which the species referred to in paragraph 1 are active at the adult stage of their lifecycle. For this purpose, for the environmental parameters listed in paragraph 6, points (a) to (f), Member States shall specify the conditions under which the transect walks are to be undertaken. Those conditions may be adapted to local circumstances and shall not be changed in the course of an assessment period.

8 The length of each transect walk shall be 1 km.

9 The same transect trajectory shall be used for bees, hoverflies, butterflies and day-active moths at each monitoring site. The transect trajectory shall be fully positioned within the boundaries of the monitoring site. The transect trajectory may be continuous or split in parts. It shall be geo-referenced and mapped before the data collection starts. Each part of the transect trajectory shall be attributed to one of the ecosystem types referred to in Article 3(4), first subparagraph. The transect trajectory on each monitoring site shall not be changed unless it becomes partly or fully inaccessible due to force majeure.

10 The transect shall be walked in a forward direction at constant speed for a total effective observation time of 60 minutes. The observation time shall not include the time needed for catching, handling, identifying or recording of specimens.

11 Data shall be collected within the following delineated three-dimensional observation space around the person carrying out the transect walk (‘the surveyor’): (a) for bees and hoverflies: 1,5 m to each side of the surveyor, 1,5 m ahead of the surveyor, and 1,5 m above the surveyor; (b) for butterflies and day-active moths: 2,5 m to each side of the surveyor, 5 m ahead of the surveyor, and 5 m above the surveyor.

12 Each recording of a specimen shall be attributed to one of the ecosystem types referred to in Article 3(4), first subparagraph.

1 During the observation period set out in accordance with Article 4, Member States shall collect data on night-active moths at each monitoring site by using light traps.

2 The light traps shall be active for one night a month during the observation period, with a minimum time interval between active periods of a light trap at the same monitoring site of three weeks.

3 By way of derogation from paragraph 2, where the environmental conditions referred to in paragraph 6 are not met over an extended period of time which prevents the monthly placing of light traps, the light traps may be placed less frequently than once a month.

4 By way of derogation from paragraph 2, the light traps may be placed more frequently than once a month at monitoring sites where the observation period is shorter than six months. In this case, the minimum time interval shall be less than three weeks.

5 During the active period of each light trap, the following environmental parameters shall be recorded: (a) temperature (in °C); (b) cloud cover (in oktas); (c) wind speed (in m/s); (d) fog (presence/absence); (e) precipitation (presence/absence); (f) principal moon phase (new moon, first quarter, full moon, last quarter); (g) any other relevant parameters that may affect the data collection.

6 Light traps shall be placed under environmental conditions during which the species referred to in paragraph 1 are active at the adult stage of their lifecycle. For this purpose, for the environmental parameters listed in paragraph 5, points (a) to (f), Member States shall specify the conditions under which the light traps are to be placed. Those conditions may be adapted to the circumstances at each site and shall not be changed in the course of an assessment period.

7 Two light traps shall be placed at each monitoring site, with a distance of at least 50 m between them. The light traps shall be placed at least 10 m from water bodies, and at least 50 m from artificial light sources. They shall be placed in such a manner that the top of the light source is between 30 cm and 1 m above ground level. A 1 m radius around each trap shall be free of obstructions that could block the light of the trap.

8 The position of the light traps shall be georeferenced and mapped for each monitoring site before data collection starts. Each light trap shall be attributed to one of the ecosystem types referred to in Article 3(4), first subparagraph. The location of each light trap shall not be changed in the course of an assessment period, unless it becomes inaccessible due to force majeure.

9 Member States shall use an identical light trap design and an identical light source type at all monitoring sites. The light trap design and the light source type shall not be changed in the course of an assessment period. By way of derogation from the first subparagraph, a different light trap design and light source type may be used in latitudes higher than 60° N. The light source of each light trap shall have a high output in the ultra-violet and blue light range (350-550 nm). The light sources shall be duly maintained with no substantial changes in light intensity or spectral composition over time.

1 Member States shall carry out targeted monitoring of all bee, hoverfly and butterfly species that are assessed as critically endangered. For this purpose, Member State may use the EU Red List of Threatened Species , or a national red list of species, or both.

2 By way of derogation from paragraph 1, if the number of species established in accordance with paragraph 1 is higher than 15, Member States may limit the number of species to be monitored to 15.

3 Member States shall draw up a list of species to be monitored in accordance with paragraphs 1 and 2 and notify it to the Commission. That list shall not be changed in the course of an assessment period.

4 Species on the list referred to in paragraph 3 shall be monitored by targeted field visits at least once per year at known locations of the species, establishing their presence or absence. Member States may discontinue the monitoring of a species in a given year once its presence has been established at least at one location.

5 All recordings of species referred to in paragraph 3 shall be geo-referenced.

Member States shall identify observed or caught specimens of target species to the species level by using expert-based diagnostics, DNA-based methods, artificial intelligence, or other scientifically proven methods.

1 The trends in pollinator abundance and diversity shall be assessed based on the data collected by Member States in accordance with this Regulation.

2 To carry out the assessment referred to in paragraph 1, a common pollinator indicator shall be calculated for each Member State using the method set out in Annex II, and a pollinator species richness indicator shall be calculated for each Member State using the method set out in Annex III.

3 Alien species shall be excluded from the scope of the assessment.

4 The first assessment period shall start 16 December 2026 and shall end in 2030. Thereafter, each subsequent assessment period shall last six years.

For the purpose of assessing the effectiveness of the restoration measures in accordance with Article 10(3) of Regulation (EU) 2024/1991, the common pollinator indicator shall be calculated separately for each of the ecosystem types referred to in Article 3(4), first subparagraph.

This Regulation shall enter into force on the twentieth day following that of its publication in the Official Journal of the European Union.