Wild bees on roadsides

It is an accepted fact: wild bee populations are in decline! This affects wild flora and food chains in our ecosystems,  leading to cascading effects on many other species. How can we make road verges more wild bee-friendly?

Denis FRANÇOIS et Violette LE FÉON

The ecological potential of roadsides

There are many causes for the decline in wild bee populations: general land denaturing, intensive farming, climate change, etc. The construction of transport infrastructure plays a role by destroying natural habitats and causing the fragmentation of ecosystems. Today France is criss-crossed by more than a million kilometres of roads. For the national highway network, it is estimated that the green spaces included within the road rights-of-way (called “road green verges”) cover a total area of 5,000km². 

These areas have the advantage of receiving few human visitors (just a few highway workers), and the use of pesticides (weed-killers and insecticides) was banned several years ago. Moreover, in some areas, the so-called “late mowing” has favoured the reappearance of a large number of flowers belonging to various local species, similar to what is found in traditional mowed meadows, which are also becoming increasingly rare in France. Yet, these provide particularly favourable environments for many pollinating insects, in particular bees and butterflies. 

Roadsides can thus play a decisive role in the conservation of pollinating insects in zones that are affected by human activities.

The diversity of wild bees

Mainland France hosts almost 1,000 species of wild bees. Most of them are solitary and inconspicuous, therefore much less known to the general public than the one honey bee species which is raised by beekeepers to provide us with hive products. These numerous wild species come in a wide range of colours, shapes and sizes (from a few millimetres to 3cm in length).They house, feed themselves and contribute to  pollination without any need for humans, thanks to the resources in their environment. Bumblebees are without doubt the wild bees which are best known to the general public.

The diversity of wild bees, through their form and flower visiting behaviour, enhances the overall pollen flow between plants of the same species (cultivated or wild) which increases the efficiency of their reproduction. For cultivated species this improves production, both in terms of quality and quantity.

A book to bolster inititatives in the field

In areas which are affected by human activities, road green verge provides easily exploitable potential for the conservation of wild bees, the restoration of ecological continuity (green networks) and insect pollination. 

The book Wild bees on roadsides provides information, encouragement and assistance to road managers regarding their actions to safeguard and conserve wild bees in their area of operation.