Mean Serth is an ancient hilltop standing stone a couple of miles northwest of Rhayader town. Surrounding the stone there is an extensive mixture of open treeless moorland vegetation – grasses and sedges, bilberry, heather and other dwarf shrubs. Some areas, where soil is thin over the underlying rock, it is dry and quick draining while other areas are permanently damp and peaty. Exposed rock occurs occasionally.
It was here on 8 August 2010 that members and supporters of our pilot biodiversity survey met for a moorland wildlife recording day. The heather (Calluna vulgaris) was in full bloom and among the invertebrates of the drier areas were a few of the brightly marked mountain bumblebee (Bombus monticola). Disturbed moths included hundreds of the grass-moth Agriphila straminella and a few twin-spot carpets and silver-y’s. Four large fury caterpillars of the Northern Eggar moth were found along with some smaller brown and yellow banded fox moth caterpillars. Butterflies were scarce, just a few small heaths with a couple of passing green-veined whites (on a casual visit here earlier in the summer several green hairstreaks were on the wing). Grasshoppers too were scarce with just five of the common green grasshopper being seen (this is no surprise as one doesn’t expect to find many in moorland vegetation). Occasional dung beetles (the Dor beetle) were encountered along grassy sheep paths as they are throughout our local uplands. Among the birds were meadow pipits, skylarks, wheatears and whinchats the expected upland species but in areas of bracken, a very long way from any trees, to our surprise were several blue and great tits and a redstart. One or two red kites and ravens passed by overhead. It was a mammal however that surprised us most, an adult common shrew that ran about, seemingly at random, in an area of dwarf bilberry. Plants in bloom were scarce, the heath bedstraw and others already over for the year. Purple swaths of heather with occasional cross-leaved heath provided the brightest colour among the greens but in dry grassy areas the bright yellow of tormentil studded the ground. A goodly list of records had been gathered by the end of the day and as we made our way back to town we looked forward to further ‘moorland sorties’.