Allt Dolanog Common, above the River Vyrnwy, five miles north-west of Llanfair Caereinon in Powys, is home to all five species of the fritillary butterfly present in the UK. Dr Simon Spencer explains how this and other commons are being managed to provide an ideal refuge for these butterflies.

In the 1970s and 1980s most of the agricultural land in lowland Wales was drained and reseeded, largely at government expense, to increase our self-sufficiency in food production. For decades after the Second World War agricultural policy was dominated by the perceived threat of the submarine.

Few areas escaped this onslaught. Commons, with their complex grazing rights and ownership, became islands in the bright green desert that is now lowland Wales. The commoners had rights that reflected an age long gone: estovers and turbary (collecting wood and cutting turf for the fire) and the right to graze a specified number of animals.


Untouched

It was in nobody’s interest to spend his own money in improving something that would be enjoyed by everybody. So the commons remained untouched, which was fortunate for wildlife.

I do not blame the new generation of farmers who had struggled to buy their tenanted farms from the estates, then needed to double their stock numbers every 20 years to remain competitive. It was cheaper to improve their land at government expense than buy more ground. I drained my smallholding in 1979 on a 90 per cent government grant: it was too good a deal to refuse.

Only the commons escaped all this. They remained unploughed and untamed, infested with bracken and agriculturally unproductive. They were used as dumping grounds for unproductive stock, barren ewes and theaves (ewes which have not yet borne lambs) through their second summer. They were a source of disease for sheep and arguments for farmers. To do anything required unanimity so nothing was done.

The commons evoked memories of bitter injustices and jealousies from generations past. They became the refuge of whinchats and yellow-hammers and the last home of some rather special butterflies.


Violets

In the UK there are five species of fritillary butterfly that all feed on violets (usually Viola riviniana). Violets do well in the woodland-like habitat created by bracken, as they can flower before the bracken canopy closes over during the summer. In the long gone days of coppice woodland some of these fritillaries occurred in woodland after the coppice had been cut and a carpet of violets sprung up.

Each species of fritillary has different habitat requirements. The silver-washed fritillary (Argynnis paphia) is associated with woodland and is tolerant of shade. The dark green fritillary (Argynnis aglaja) usually occurs on grassland but can also be found in bracken. The small pearl-bordered fritillary (Boloria selene), which can also feed on marsh violet (Viola palustris) most often occurs in wet places but is also found in bracken.

Some of these fritillaries are among our rarest and most threatened butterflies. The high brown fritillary (Argynnis adippe) was widespread and locally common in the 1950s but has declined dramatically since then. According to The Millennium Atlas of Butterflies in Britain and Ireland (Asher J et al 2001, OUP), it was lost from 77 per cent of ten-kilometre squares in the UK between 1970-82 and 1995-99 and is now only found at 50 sites. The larvae bask in the sun on bracken litter, where they can get very warm quite early in spring and retreat into the bracken when it gets cold.

The pearl-bordered fritillary (Boloria euphrosyne) was originally a common coppice-woodland butterfly but is now in Wales mainly found in a few bracken-dominated sites. It can also occur on limestone grassland and in coastal grassland where gorse is regularly burnt. It has been lost from many areas of the UK and, in Wales, is now restricted to about ten sites (down from about 100 in 1980). Many of the sites in Wales are on bracken-dominated commons in Montgomery-shire, part of Powys.

Though the benign neglect these commons have enjoyed until now has spared these fritillaries from agricultural improvement, the butterflies are still threatened. The overgrazing of some commons, particularly in spring, can reduce the violets and other spring flowers which provide a source of nectar for the adult pearl-bordered fritillary butterfly.

On the other hand, abandonment of grazing can be equally damaging as the common becomes infested with bramble which forms an impenetrable thicket with bracken, excluding all light from the delicate violet plants underneath.

In 2003 the commoners of Allt Dolanog Common signed an agreement with the Countryside Council for Wales (CCW) to restrict sheep grazing on the common in spring. This was the first time section 39 of the 1981 Wildlife and Countryside Act (as amended by the Countryside and Rights of Way Act 2000) had been used in the UK to protect a site that is not a site of special scientific interest. This agreement needed and obtained European Union approval.

At the same time the commoners signed an agreement with Powys County Council (PCC) which, among other things, restricted the cutting of bracken for cattle bedding to certain areas. Bracken cutting is another traditional right that passes with the farm. These agreements required the unanimous consent of all nine commoners and would not have been signed without the considerable civic pride in these butterflies felt by the local community. The amounts of money involved are small and the time it took on all sides to get an agreement was considerable.
 

Pearl-bordered fritillary upperside on violets.   Photo: Simon Spencer

Signed

We (CCW, PCC, wildlife trusts and others) have now started to tackle the issues on some of the other commons to try and protect the last few remaining sites for pearl-bordered
fritillary. Botanical and grazing surveys have revealed the extent of the abandonment, particularly since foot and mouth, on some commons. For the last two winters, scrub has been cut on some of the sites on a large scale with a flail mower. Other sites have had extensive clearance by wildlife trust volunteers.


Bid

A bid is being made for funding to extend this work and CCW is actively considering buying some commons that are pearl-bordered fritillary sites. It is essential to retain or restore low-intensity grazing if these rare butterflies are to survive, and commons provide an ideal opportunity to do this.
Dr Simon Spencer does surveys and monitoring work on butterflies in Wales. He is also studying butterfly conservation and grazing issues in Europe for a part-time MPhil at the University of Wales, Aberystwyth. He wishes to acknowledge the contribution of the following to this work: Countryside Council for Wales, Powys County Council, Radnorshire Wildlife Trust, Montgomeryshire Wildlife Trust, Allt Dolanog Commoners’ Association and Butterfly Conservation.

 

Flail mowing to clear scrub and bramble on the pearl-bordered fritillary site of Y Golfa Common, near Welshpool in Powys.   Photo: Simon Spencer

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