An upland grassland community in Shropshire

Shropshire Botanical Society Newsletter 5 - Spring 2001 - page 5

Alex Lockton, Sarah Whild & Kate Thorne

 

U1 Festuca ovina-Agrostis capillaris-Rumex acetosella grassland is quite a widespread type of vegetation, being found throughout England and Wales and as far north as the Scottish border. It is described in the NVC (Rodwell 1992) as a "very diverse but highly distinctive" community, and a number of sub communities are listed, each with a more restricted distribution. In most cases it tends to be a short, grazed sward with tussocks of Sheep's Fescue, Festuca ovina, and patches of bare ground in between. It would be familiar to anyone who walks in the Shropshire hills, and most people would take no notice of it. At first glance you might consider it to be a poor quality habitat, but if you look closer you will see that it has hidden secrets.

This "upland" grassland community is not necessarily upland at all. It was once widespread in the lowlands, and is not known in the north or on high mountains. The word "upland" in this context distinguishes it from calcareous and neutral grassland types, and is used to describe grasslands that tend to be free-draining and acidic. In fact, because of agricultural intensification in the lowlands, U1 has indeed retreated to the upland fringes in counties like Shropshire and Radnorshire, and good examples of it are now rare in the lowlands. Perhaps it should be termed a "foothill community?"

In studies of vegetation, the Breckland grass-heaths (U1c) of East Anglia are generally considered the best examples of this community, and our western grasslands are by comparison neglected and poorly understood. But there is very little good quality Breckland U1 left, and our studies suggest that the more westerly examples of the community may be far richer than is generally appreciated. It could be argued that it should be considered a rare and endangered community, and worthy of protection in its own right.

 

Habitat and distribution

U1 grassland is indeed a variable type of vegetation, but it is generally quite easy to recognise. It will always have small tufts of fescue - usually Sheep's-fescue, Festuca ovina, and often patches of bare ground between them. It occurs on dry, loose, stony soils. The Precambrian Longmyndian shales of the Long Mynd, Earls Hill and Haughmond Hill are perfect, but it also occurs over the igneous Dolerite on Titterstone Clee and at The Lump, Priestweston.

Sometimes there are no gaps between the tufts of fescue. Especially where there is little slope, and it is not too exposed, the soil can build up and progress towards the richer MG5 hay-meadow community. This can be seen on the east side of Earl's Hill, for instance, where meadows full of the hills produced by Yellow Meadow-ants, Lasius flavus, are intermediate between U1 and MG5 grassland. In general, however, U1 is found on south-facing slopes, where the soil is very dry, and it will often look more like a scree than a grassland in summer.

A recent study of the Long Mynd by Kate Thorne, for the National Trust, showed that there was about 27 hectares of U1 within the common. It is difficult to estimate the total area, as it often occurs in small fragments, but it would not be unreasonable to suggest that there may be 200-300ha in total in the county. A lot of this is really quite poor quality grassland, but the best examples are definitely of considerable conservation value.

 

Plants of U1 grassland

This type of grassland is best in the spring, especially in May. The commonest species are Festuca ovina, with Sheep's-sorrel, Rumex acetosella, Early Hair-grass, Aira praecox, Common Whitlowgrass, Erophila verna, Common Bent, Agrostis capillaris, and often Mouse-ear-hawkweed, Pilosella officinarum. Bryophytes and lichens are often frequent.

The most characteristic and interesting species of this community are the spring ephemerals. One of these is Shepherd's Cress, Teesdalia nudicaulis, which has a very localised distribution in Britain, and has declined in many parts of the country, but is still abundant in parts of Shropshire. Another is Upright Chickweed, Moenchia erecta, which also has a restricted distribution, but much more southerly and lowland than Teesdalia. With these two will often be found Bird's-foot, Ornithopus perpusillus, and these three together seem to guarantee that you have a good stand of U1.

Many of the plants that occur in U1 are tricky to identify. Little Mouse-ear, Cerastium semidecandrum, is easy to overlook. It is much more common than Field Mouse-ear, C. arvense, in this community, although the two do occur together at Boreton Bank near Condover. You are only likely to encounter Dark-green Mouse-ear, C. diffusum, on Titterstone Clee, but it is worth looking out for elsewhere, particularly in more base-rich stands. Common and Sticky Mouse-ears, C. fontanum & C. glomeratum, also occur frequently.

The Forget-me-nots, Myosotis spp., cause endless problems. Ours is nearly always Changing Forget-me-not, M. discolor, with Early Forget-me-not, M. ramosissima, confined to a few locations. If there is thyme in the grassland, it will be Wild Thyme, Thymus polytrichus, never Breckland Thyme, T. serpyllum, and unlikely to be Large Thyme, T. pulegioides. The Parsley-pierts also cause problems, but Aphanes australis, Slender Parsley-piert, seems to be the common one in U1.

In Shropshire you are unlikely to find Maiden Pink, Dianthus deltoides, in any other community. There are only three places where it has been recorded in the wild in the last ten years - The Lump at Priestweston, a roadside near Clun, and Downton Quarry on Haughmond Hill. It may in the last few years have gone from the latter site, where it was first recorded over 200 years ago. In the past it was quite frequent around Bishops Castle, and it used to occur in U1 grassland on several of the hills around Shrewsbury, including Sharpstone Hill and Bayston Hill. It was even once found on Earl's Hill. A stronghold for this species is in Radnorshire, where it presumably occurs in a similar community.

Buck's-horn Plantain, Plantago coronopus, is another uncommon species that is largely confined to U1 grassland. It can withstand trampling and close grazing, so it survives in some fairly impoverished stands. It can be found at Titterstone Clee, on Haughmond Hill, Lyth Hill, and the Long Mynd, among other places. It still occurs on Nesscliffe Hill and The Cliffe, where forestry has destroyed what might have once been extensive areas of grassland.

Two other uncommon but characteristic species of U1 are Small Cudweed, Filago minima, and Knotted Clover, Trifolium striatum. The former can be found on the Long Mynd, at Earl's Hill and Titterstone Clee, while the latter occurs on the Long Mynd, at Pulverbatch Castle, Haughmond Hill, The Lump, Priestweston, and on the roadside verge at Clun.

Rock Stonecrop, Sedum forsterianum, is a bit less choosy about its habitats, and often persists on rock screes and ledges in woodland. But there is some evidence that it is also a characteristic U1 plant, especially on rocky outcrops. An intriguing question is whether it survives in grassland after the tree cover is taken away, or persists in woodland and scrub after the grassland has reverted. Generally, S. forsterianum does seem more luxuriant in woodland; but is that because so many stands of U1 are overgrazed?

One species that appears to be very rare in Shropshire is Smooth Cat's-ear, Hypochaeris glabra. The few records that do exist suggest that it could be largely confined to U1 grassland. It used to grow on Earl's Hill, and was once on The Cliffe, The Wrekin and Harmer Hill. The only recent record is from Boreton Bank.

Looking further afield, U1 grassland is listed by Rodwell as the home of some of Craig Breidden's rarities - Lychnis viscaria, Sticky Catchfly, Veronica spicata, Spiked Speedwell, and Pilosella peleteriana, Shaggy Mouse-ear-hawkweed.

 

Further work

This is very much a provisional account of U1 grassland - there is plenty of work still to do to determine the precise extent and nature of this community. What we have in Shropshire and neighbouring counties might not fit all that comfortably into the NVC, as it appears to have been under-represented in the data in comparison to the more well-known Breckland vegetation. It is easy enough to recognise a really good stand of U1, but the boundaries are not so obvious, especially in the transitions to other grassland types.

Members of the Botanical Society can always look out for those characteristic species - Moenchia erecta, Teesdalia nudicaulis and Ornithopus perpusillus. If the theory is correct, they should together signify a stand of U1. It would be useful to us to have information about any site where they occur. You do not have to record a quadrat. Notes on which species are there, and the nature of the vegetation (tussocky, open turf, loose scree) is probably enough. If you would like to see some good stands of U1, try the south-facing slopes of Carding Mill Valley, or the corner of Haughmond Hill above Downton Hall. Places where it might occur, but we have no details, include Caer Caradoc and other hills around Church Stretton, Brown Clee, Sharpstones Hill and Bayston Hill. With luck, anyone hunting for U1 might discover a patch of Dianthus deltoides or Viola lutea.

 

Reference

Rodwell J.S. 1992. British Plant Communities Volume 3 - Grasslands and montane communities. Cambridge University Press, Cambridge.

 

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