The document summarizes research conducted on pollinators inhabiting urban green roofs in Slovenia. Studies were performed at sites in Ljubljana and Škofja Loka, observing pollinator activity and plant diversity. A variety of bee species were identified, with wild bees like bumblebees and solitary bees more common than honeybees. Pollinator densities increased with percentage of flowering roof plants. The conclusion is that green roofs can provide important habitat and food sources for pollinators in cities, and connecting them with other green spaces can support a pollinator network across urbanized landscapes. Recommendations include planting a diverse mix of native floral species blooming throughout the summer.

1. Dr. Danilo Bevk, National Institute of Biology, Ljubljana, Slovenia
Vegetated roofs and walls to enhance living conditions in cities,
Knauf Insulation Experience Center,
Škofja Loka, 24. 9. 2020
Contact: danilo.bevk@nib.si
RESEARCH OF POLLINATORS ON
URBANSCAPE GREEN ROOFS

2. National Institute of Biology (NIB)
Research of pollinators on Urbanscape Green Roofs
 Department of Organisms and
Ecosystems Research
 Diversity, ecology, monitoring and
protection of pollinators
(bumblebees, solitary bees)
 Management of pollinators in
agriculture
 Green infrastructure and
pollinators in cities
 Cooperation with ministries and
local authorities
 Transfer of knowledge
danilo.bevk@nib.si

3. The aim of the research
 Investigate the number and
diversity of pollinators on
Urbanscape green roofs.
 Determine their potential as
habitat for pollinators.
 Based on the findings, suggest
improvements.
Photo: Danilo Bevk
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

4. Metode dela – lokacije – Škofja Loka
Raziskave opraševalcev na zelenih strehah Urbanscape
Škofja Loka
Photo: Danilo Bevk

5. Škofja Loka
Photo: Danilo Bevk

6. Metode dela – lokacije – Ljubljana
Raziskave opraševalcev na zelenih strehah Urbanscape
Ljubljana
Photo: Danilo Bevk

7. Metode dela – lokacije – Ljubljana
Raziskave opraševalcev na zelenih strehah Urbanscape
Ljubljana
Photo: Danilo Bevk

8. Metode dela – lokacije – Ljubljana
Raziskave opraševalcev na zelenih strehah Urbanscape
Ljubljana
Photo: Danilo Bevk

9. Ljubljana
Photo: Danilo Bevk

10. Methods – Monitoring of activity of pollinators
 Observations were conducted
between 8 a.m. and 11 a.m.
 The percentage of flowering
roof area was estimated and
flowering plants were
inventoried.
 Pollinators were counted on 5
sampling sites. Sampling site
was 1 square meter of flowering
plants.
 20 counts on each sampling site
were carried out (together 100
on five sampling sites per day).
Photo: Mojca Pibernik
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

11. Photo: Danilo Bevk

12. Photo: Danilo Bevk

13. Photo: Danilo Bevk

14. Photo: Danilo Bevk

15. Photo: Mojca Pibernik

16. Photo: Danilo Bevk

17. Photo: Danilo Bevk

18. Photo: Danilo Bevk

19. Photo: Danilo Bevk

20. Photo: Danilo Bevk

21. Overall results - structure of pollinators'
communities on green roofs
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Škofja Loka Ljubljana Together
Relativeabundance
Location
Honeybee Bumblebees Solitary bees
Hoverflies Butterflies
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Jun Jul Aug Sep
Relativeabundance
Month
Honeybee Bumblebees Solitary bees Hoverflies Butterflies
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

22. Škofja Loka Ljubljana
Andrena subopaca Andrena subopaca
Lasioglossum politum Lasioglossum politum
Lasioglossum laticeps Hylaeus punctatus
Lasioglossum lineare Megachile willughbiella
Lasioglossum malachurum Megachile leachella
Anthidium oblongatum
Bombus terrestris/lucorum
Overall results - List of bee species

23. 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
Honeybee Bumblebees Solitary bees Hoverflies Butterflies All pollinators
Averagedensity(N/m2)
June July August September
Results – Density of pollinators
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

24. Photo: Danilo Bevk

25. Results – flowering of roofs
0
5
10
15
20
25
30
Thepercentageoffloweringgreenroof(%)
Sedum sexangulare Sedum hispanicum Sedum album 'Coral carpet'
Sedum reflexum 'Angelina' Sedum spurium 'Summer glory' Sedum spurium 'Album superbum'
Sedum spurium 'John Creech' Sedum album 'Murale' Sedum kamtschatikum
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

26. 0
10
20
30
40
50
60
0.00
0.50
1.00
1.50
2.00
2.50
3.00
Thepercentageoffloweringgreenroof(%)
Averagedensity(N/m2)
Sedum sexangulare Sedum hispanicum Sedum album 'Coral carpet'
Sedum reflexum 'Angelina' Sedum spurium 'Summer glory' Sedum spurium 'Album superbum'
Sedum spurium 'John Creech' Sedum album 'Murale' Sedum kamtschatikum
Honeybee Bumblebees Solitary bees
Hoverflies Butterflies
Results – Density of pollinators and
flowering of green roof
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

27.  Results show high importance of green roofs
for pollinators. In blooming period they
provide food.
 Wild pollinators were even more numerous
than honeybees.
 Green roofs can play an important role in
developing cities friendlier to pollinators and
biodiversity in general.
 Green roofs and green walls can act as refuge
habitat for pollinators and allow pollinators to
move and disperse within urbanized areas.
 Together with parks and gardens and by
connecting to natural and semi-natural areas
in the countryside, they support a network of
pollinator habitats in the wider landscape.
Results – Conclusions
Photo: Danilo Bevk
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

28. Recommendations for improvements
 Selection of plants that provide
good source of nectar and/or
pollen
 Selection of combination of
plants that provide food during
the whole summer
 Higher diversity of plants
 Use of native plants
Photo: Danilo Bevk
Research of pollinators on Urbanscape Green Roofsdanilo.bevk@nib.si

29. Let's make cities
more pollinator friendly!
Photo: Danilo Bevk