Research has found that gardens, parks, and other green spaces in cities can be favorable environments for supporting pollinator insects. But urbanization can also reduce plant density and abundance, presenting challenges to the survival of urban pollinator communities. Indeed, because of their human-built landscapes and fragmented green spaces, there is a perception that pollinators cannot thrive in dense urban environments. 

Paris, however, is an exception — despite being a heavily-populated city, it surprisingly boasts a diverse range of pollinators. Between 2011 and 2018, researchers identified 119 wild bee species and 47 hoverfly species within Paris’ green spaces. This is likely a result of the city’s ban on pesticides in public places and its ongoing efforts to create pollinator-friendly green spaces. 

In an effort to update the list of pollinator species, understand their seasonal activity, and promote their conservation, researchers monitored 12 green spaces in Paris that were evenly distributed throughout the city from spring to fall in 2019 and 2020. This assessment included four categories of green spaces: 

1. Restricted areas maintained for pollinators (e.g., no weeding, limited mowing, native plant growth)
2. Small parks open to the public with pollinator-friendly management
3. Dedicated pollinator areas within large, public parks
4. Decorative gardens (e.g., ornamental plant growth, heavy weeding)

During the study, researchers discovered 118 wild bee species, including 26 that hadn’t been documented before. They also discovered 37 hoverfly taxa, including six species that had not been previously documented in Paris. In total, they found 3,142 individual wild bees, 1,168 domesticated honeybees, and 394 hoverflies, along with other common species of insect pollinators (13 species of butterflies and moths, four species of beetles, and three species of bee flies).

Despite previous research showing that specialist and parasitic bee species are more negatively affected by urbanization, several of these species were found in Paris. Furthermore, three bee species had “near-threatened” status according to the European IUCN red list and others had regional conservation status in France. Designated biodiversity refuges in large public parks followed by small public parks had the most specialist bee species. Furthermore, green spaces with high plant diversity had the most species with conservation status.

Most of the bee species were observed to be active during late spring and summer, although active bees were observed from March to October. Some bee species, especially social species, remained active for a few months, while others were only active for a shorter period. The same variations were observed in hoverflies. 

Overall, this survey found that 43% of wild bee species and 25% of hoverfly species found in the greater Ile-de-France region can be seen in Paris. This is slightly less than in other large European cities such as Poznan and Zurich, but it’s still a positive sign that heavily-populated urban spaces can help pollinators thrive. The authors point out that the presence of specialist and parasitic bee species is an especially positive sign of biodiversity success. 

The results of this survey indicate that the most helpful way to support pollinators in cities is by managing green spaces in environmentally-friendly ways. This includes reducing mowing and pruning, avoiding pesticides and weeding, and encouraging native plant growth (including weeds). Small, protected areas within public parks can provide a supportive environment for specialized and rare bee species. Finally, although cities are often overlooked as hubs of biodiversity, conservation policies should account for urban green spaces as opportunities to protect pollinators.