Upright Spurge in the Wye Valley

Yesterday I paid a visit to Ravensnest Wood in the Wye Valley, to see one of the rarest plants found in this area, Upright Spurge (Euphorbia serratula). As a native species, Upright Spurge is found in Britain only in an area centred on the Wye Valley and the Forest of Dean. It is also naturalised in scattered locations, mainly in southern England. Although a rare plant in Britain, globally, it is found eastwards to central Asia.

Upright Spurge’s habitat is woodland on limestone, but not the dense dark parts: instead, it is found in the open, and does best on disturbed ground. Newly created forestry tracks and clearings are where it does best, particularly if limestone chippings are laid. Ravensnest wood held 500 plants in 1997, presumably when the access track there was very new. Yesterday I counted a much more modest 17 plants: along much of the track, grassland had become established, crowding the spurge out, and it was only present in areas where there was still very sparse vegetation. Here is a map of the location:

According to Sell and Murrell’s Flora of Great Britain and Ireland, the most authoritative reference work on Britain’s flowering plants, Upright Spurge occurs in only about 24 British localities. The densest concentration is around Tintern and so, predictably, it has acquired the local name “Tintern Spurge”. Other locations in the Wye Valley are spread throughout a 10km-long stretch from about Wynd Cliff in the south to around Whitebrook in the north. In the Forest of Dean, its main concentration is just to the west and north of Lydney. Much further east, it grows in Highnam Woods, just west of Gloucester. West of the Wye Valley, it occurs in Chepstow Park Wood and in Coed Wen Wood, east of Newport (note that the Grid Reference in Trevor Evans’ Flora of Monmouthshire for this last site is incorrect).

Seeds of Upright Spurge can lay dormant in the soil for years, possibly decades, and so if a site becomes overgrown, fresh disturbance can boost the population. At Highnam Woods, the RPSB does just that, using a rotavator, and so the population there is likely to be secure. At other sites, Upright Spurge has declined or even vanished, but could no doubt be encouraged to flower again if similar techniques were applied. How about it, Gwent and Gloucestershire Wildlife Trusts?

Common Clubtail on the River Wye

I haven’t featured a dragonfly on this blog yet, so I’m going to remedy that now with a rather good one. This is a female Common Clubtail (Gomphus vulgatissimus), photographed by Martyn Hall next to the River Wye at Monmouth yesterday.

Common Clubtail, 9 June 2013, River Wye, Monmouthshire, Martyn Hall (www.martynhallphotography.com)

The river here is a well-known site for this species, and with the good weather today, Martyn & I thought we’d give it a try. We walked north-east up the west bank from the Wye Bridge, and eventually found this individual on a stretch of the river to the north of St Peter’s church, at this location:

Older books just call this species the “Club-tailed Dragonfly” but there are several other closely-related species in Europe that this name could apply to, and this is the one with the widest range, hence the newly-coined name. In Britain, however, it’s not common at all, being confined to just eight river-systems. As well as the Wye, it’s found on the Severn, reaching downstream as far as Tewkesbury, on the Thames in Oxfordshire, the Lugg in Herefordshire, the Dee in Cheshire, the Arun in Sussex and two rivers in west Wales, the Teifi and Tywi. A slow water flow, lack of pollution, a silty river bottom, plenty of bankside vegetation and nearby woodlands are all essential habitat requirements, which explains the restricted British range.

Common Clubtail has quite a short flight period, but should be on the wing here for a few more weeks. After emerging in May, they leave the river to feed in surrounding woodlands and then return to set up territories, so numbers on the river may not yet be at their peak given the late spring. There were also around 20 Banded Demoiselles (Calopteryx splendens), but no other dragonflies on this visit, although this site does also have White-legged Damselfly (Platycnemis pennipes) later in the season.