Bryological Highlights - Pembrokeshire 2020

Thought I’d start the blog with a review of my year in Pembrokeshire. Thanks to Paul Culyer at NRW, I’ve had a good few days recording and monitoring bryophytes at Stackpole and on the army ranges at Castlemartin. At Stackpole, Scapania cuspiduligera was added to the assemblage of rare calcicolous bryophytes on the south side of Barafundle Bay – this small area is now pretty much the best place for these bryophytes in Wales. Microbryum curvicollum was found on the top of a cliff between here and Broadhaven south – not one for the vertigo-sufferer as you have to lie down and look over the edge…..

Microbryum curvicollum location, Box Bay

Sam Bosanquet had previously uncovered a lot of the interest at Castlemartin, but it’s a big site and takes a bit of getting to know. The major habitats - sand dune, limestone cliffs, grassland and heath – have all been diversified by the army activities, and there are extensive areas where top-soil has been scraped off to create shelters, banks and target gullies. These are full of rare species. Three new mosses for the county – Aloina rigida, Pottiopsis caespitosa and Microbryum floerkeanum – were found here this year. They are all tiny calcicoles, and all rare elsewhere in Wales. Another new calcicole – Platydictya jungermannioides - was found on the limestone cliffs at St Govans, lurking under a couple of rocks, then in an old quarry on Range West. Damp clay in the target gullies often has Fossombronia species in abundance, and F. maritima, F. foveolata and both sub-species of F. caespitiformis were recorded. Two of the ‘rare’ Cephaloziellas - C. calyculata and C. integerrima, are proving to be pretty widespread on the site. In contrast, the C. dentata which was found new to Wales on Linney Head last year has only turned up in one other location. The exposed heathland on Linney Head also produced Acaulon mediterraneum. This was unknown in Wales until last year, but I’ve now also found it on St David’s Head and the Deer Park, Marloes. Tom and I have both found it in Ceredigion too.

Aloina rigida (a 'Section 7' species of conservation importance)

grows in stony ground on Castlemartin Range West

Lockdown wanders in my local patch around Redberth have yielded new sites for Fissidens monguillonii and Weissia rostellata, but I haven’t been able to find anymore Micromitrium tenerum. After appearing briefly last winter on the neighbour’s field following fence-line clearance, it’s quickly disappeared again. I wonder whether I should try an ex-situ conservation effort with the few ripe capsules that I collected. Another pond edge plant, Riccia fluitans, was collected new to the county from a small lake near Tavernspite.

The almost black shoots of Fissidens monguillonii 

form a band just above the water level on this clay stream bank

Further north, Pohlia lescuriana from a flush-edge on Mynydd Dinas was rarer than the Calliergon giganteum alongside, but considerably less attractive. Cliff exploration at Pwll Deri, west of Strumble, yielded new sites for Dicranum scottianum and Plagiochila punctata (as well as northern buckler fern, new for the county). Cladopodiella francisci is a scarce liverwort, and I added it to the Carn Ingli site-list from a flush on the northern side. More of another rare liverwort, Harpalejeunea molleri, was found on a willow branch near Mynachlog-ddu, downstream from the rocks it was found on last year. Haplomitrium hookeri was in wet ground nearby.

Willow with Harpalejeunea, Afon Tewgyll

Thanks to a recommendation from Mary Chadwick at PCNPA, I visited a small but interesting old slate quarry to the east of Foel Dyrch. Plathypnidium lusitanicum and Philonotis arnellii were among the diverse range of mosses on the wet rocks here, and a new site for the rare Fossombronia fimbriata was found just outside the quarry, in typically small quantity (3 thalli).

Foel Quarry, near Glandy Cross

The county list edges slowly towards 600!