Caeau Tan y Bwlch

Location: Capel Uchaf, near Clynnog Fawr, Gwynedd

Grid Reference: SH 431 488


The grassland of Caeau Tan y Bwlch has been little disturbed or “improved” by agriculture, which makes it precious.

Greater butterfly-orchids and other typical grassland species are in delightful abundance.

Caeau Tan y Bwlch – “the fields below the mountain pass” – lies 215m up on the northern slopes of Bwlch Mawr at the eastern end of the Lleyn Peninsula, with magnificent views towards Anglesey and Snowdonia. The reserve’s small fields are bordered by “clawdd” walls – a stone-faced earth bank, where the stone is set on edge almost like the wall of some Medieval castle. These walls attest to the site’s history: the previous owner believed that the fields had never been fertilised, nor ploughed by anything other than horses. Certainly, the gaps in the walls are too small for tractor access.

Its history helps explain why the reserve is so important botanically. Its Site of Special Scientific Interest (SSSI) citation commends it as one of the few remaining examples of traditionally managed, enclosed pastures on the Lleyn, not agriculturally improved by artificial fertiliser or reseeded in recent times.

Meadow to bog

Meadow grasses are dominant in the upper fields, including creeping bent, sweet vernal-grass, red fescue and crested dog’s-tail. Common knapweed and yellow-rattle are abundant, along with rare eyebrights, lady’s-mantle and the wonderful population of greater butterfly-orchids. Scattered through are heath spotted-orchids, the larger, richer purple heads of northern marsh-orchid, and even a few hybrids of the two to excite the orchid enthusiast.

The lower slopes are wetter, with a flora dominated by various sedges. Bog mosses underfoot attest to their perpetual wetness. Marsh violet, bogbean, cuckooflower and sneezewort are here, along with delicate, ethereal patches of wood horsetail. Creeping over the bog mosses are a few straggly stems of cranberry with berries much smaller than the commercially-harvested

Canadian species. Grasshopper warblers rattle their call from the willow scrub, and pearl-bordered fritillary and ringlet butterflies fly over the grassier slopes. The best way to maintain this diversity is to maintain the traditional land use that has allowed it to survive. The fields are therefore grazed in autumn each year and the drier meadows are cut for hay in late summer.

Purchase of the reserve was made possible by Unilever (Timotei).