Worcestershire Record No. 27 November 2009 p. 14

ROAD VERGES – A LARGE AND VALUABLE NATURE RESERVE OR A WASTED RESOURCE?

John Partridge

Worcestershire has 695 ha of road verge according to the Road Verges Habitat Action Plan, and just 4.4 ha are managed as Road Verge Nature Reserves (same source).

For many years I have felt considerable annoyance when seeing road verges cut at times which remove plants in flower – if there are no pollen sources, then there will be none of the insects that need them. It isn’t just the rare plant species that need protecting, anything can be valuable to the insect that uses it as a food plant. Additionally, there are many species that live on the plants but do not use the pollen, such as weevils and plant-hoppers, and many others in the ground layer living on decaying vegetation, or on the fungi that exist there, or on other fauna.

Although the BAP makes mention of fauna, not least in the Vision Statement, there is nothing else there to suggest appropriate management for invertebrates. The work that John Meiklejohn and I have done on tussocks has made it clear that cutting has a considerable effect on the winter refuges for invertebrates, but I have felt that I lacked the evidence to make a case for more sympathetic cutting in summer.

However, in recent years I have expanded the range of species that I can identify, and the availability of a suction sampler this year suggested that it was time for me to get some evidence.

The evidence that I have collected suggests that a good deal more could be done to encourage invertebrates in road verges by changes in management, and, incidentally, I believe that the same arguments can be applied to the edges of canal tow-paths, manicured churchyards and many urban parks. With ever-more intensive farming removing rough field corners, these are some of the last areas of rough grassland available to invertebrates, and they have the advantage that they are largely insecticide and herbicide free. Not only are many insects important plant pollinators, they are for the most part near the bottom of the food chain, supporting, eventually, both mammals and birds.

The conclusions that I have drawn in the following article are:

Close cutting of verges removes most of the invertebrate fauna.
Even where the cutting is rather longer, there is a considerable reduction in the number of species present, at least until there has been perhaps 100 mm of re-growth.
Different vegetation structure gives a different range of species.
Variety (of treatment and vegetation) is the spice of Biodiversity.

Some councils publish their grass-cutting policy (and costs), and it is evident that no-one has much idea of why they have a particular regime, or of what height of grass is acceptable in different circumstances. The research papers that I have found seem to concentrate on increasing grass growth, rather than reducing it, but there does seem to be an opinion that more frequent cutting encourages growth – so why do it on road verges? There are councils that have at least thought about wild flowers – see http://tinyurl.com/yjg7gbu and others that have not – see http://tinyurl.com/yjgq2em

I have not been able to find any policy document on the web, but I suspect that Worcestershire comes into the latter group.

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