by Claire Wallace, PhD student.
Road verges. A buzzword in pollinator conservation. Here in the UK there is an estimated 500,000 kilometres of road verge just waiting to be transformed. With over 700 species of wildflower found in road verges, it is no surprise that they have been branded a “refuge” for pollinators. Current scientific research generally supports this idea, with studies often showing that verges host a greater number of pollinator species and individuals than surrounding agricultural or semi-natural habitat (Gardiner et al., 2018; Villemey et al., 2018). The increasing profile of verges and their potential for pollinators is reflected in the demand for more research from scientists, and better management plans from councils and highways managers.
This year Plantlife published their “Managing Grassland Road Verges” report, which is a wonderfully detailed guide for anyone involved in the management of grassland verges. It very clearly outlines the 3 key steps for good verge management: assessment, management, and monitoring. They advise two annual cuts, with the removal of cuttings to maintain low soil fertility. Low fertility is good for pollinators, as wildflowers thrive in the absence of more competitive grass species which require nutrient rich soils. The lack of these dominant species is also beneficial for verge managers, as it means less cuts are required reducing costs and disruption to road users. Another way of suppressing vigorous grasses is the planting of yellow rattle. This is a semi-parasitic plant, reducing grass growth by up to 60%, eliminating the need for excessive cutting and creating space for wildflowers to grow.
Buglife also produced a report earlier this year which highlights the potential of verges for pollinators, again emphasising the need for a good management plan. The report summarises key scientific literature, looking at the benefits and costs to pollinators, as well as identifying knowledge gaps. It concludes that under a well thought out and effective management strategy, verges could be a “lifeline” for our pollinators and ensure that their vital services are protected.
Are wildflowers the bee-all and end-all?
When you think of pollinators, you think of wildflowers, but incorporating scrub and bare ground into a verge management plan is important too. A sea of wildflowers is lovely to look at, but as with the majority of conservation efforts, diversity is key. Patches of bare ground will not only encourage wildflowers to grow, but will allow space for mining bees to nest. Early flowering scrub is a crucial resource for queen bumblebees gathering pollen and nectar for their newly established nests. Of course scrub will require more management, as if left unchecked it will quickly take over the verge, but the benefits of well-maintained scrub will be tremendous for pollinators.
Native VS. Non-native
Another important point to address with planting which is frequently ignored is the issue of native vs non-native. Turning road verges into wildflower meadows has been a prominent discussion topic in mainstream media this year. Many local councils have received torrents of praise online for creating a “pollinator paradise” on our roadsides. However, many of the pictures circling social media are not of native British wildflowers. But why does that matter? It can certainly be argued that having something is better than nothing, but it is important that we understand the difference between our natives and non-natives. A lack of understanding can lead to a verge full of clover, buttercups, and bird’s-foot trefoil, being branded “untidy” and cut down to make way for Californian poppies, clarkias, and cosmos. Having lost 97% of our wildflower meadows since the 1940s, I do believe it is important to promote our native species, not only because they are declining, but because they have evolved along with our native pollinators and are therefore the ideal resource for them.
With all that in mind, what can you do? Write to your council – make sure the voices supporting pollinator friendly verges are louder than those crying “Weeds!” Show your support for organisations and people doing their bit for our verges, sign Plantlife’s road verge petition. And finally, the most important point in my opinion, is to keep the conversation going. Our pollinators can’t tell people about the fantastic potential of verges, but you most certainly can on their bee-half!
For further information on my PhD project, please click here.
Gardiner, M.M., Riley, C.B., Bommarco, R., Öckinger, E., 2018. Rights-of-way: a potential conservation resource. Front. Ecol. Environ. 16, 149–158. https://doi.org/10.1002/fee.1778
Villemey, A., Jeusset, A., Vargac, M., Bertheau, Y., Coulon, A., Touroult, J., Vanpeene, S., Castagneyrol, B., Jactel, H., Witte, I., Deniaud, N., Flamerie De Lachapelle, F., Jaslier, E., Roy, V., Guinard, E., Le Mitouard, E., Rauel, V., Sordello, R., 2018. Can linear transportation infrastructure verges constitute a habitat and/or a corridor for insects in temperate landscapes? A systematic review. Environ. Evid. 7, 1–33. https://doi.org/10.1186/s13750-018-0117-3