THE FIRST WINTER OF SBAL IN WALES - A COUNTRY WITH ALMOST NO ARABLE

Sam Bosanquet (Mons. & Pembs.)
March 2003

According to the maps presented at the SBAL workshop there is almost no arable in Wales: they showed a few arable hectads on Gower and the Vale of Glamorgan, in northwest Pembrokeshire and in southern Monmouthshire. I was a little taken aback by this as I grew up in rural Mons surrounded by weed-filled arable fields; it is a fair reflection of arable in Wales however - you have to search pretty hard to find an arable field in this country!

With England dominating SBAL and Scotland pretty well represented it was important for Welsh pride to show that Wales’ arable can compete with that of its neighbours. Unfortunately our lack of arable fields is equalled by our lack of arable bryologists; it looked as though SBAL here was going to be a solo event. I have concentrated on my home county, Monmouthshire (35), and the county I live in, Pembrokeshire (45), but hope to cover a few of the other southern counties by the end of the season. The following is a summary of what has turned up in Welsh arable so far; my observations are not backed up by science but may spark some debate amongst other SBALers.

Monmouthshire
In winter 2001/02 I looked at four fields in VC35 and was amazed to find Phaeoceros carolinianus in three of them. My guess is that this is a relatively frequent species in the borderlands of England and Wales (and maybe Scotland), where agriculture is not too intensive and the climate is not sufficiently Atlantic for P. laevis to thrive. None of the fields was particularly outstanding in other ways, although Anthoceros agrestis and Entosthodon fascicularis were present in all of them, and Riccia spp. were frequent. Both E. fascicularis and Riccia spp. are a relatively constant feature of Monmouthshire arable, possibly in contrast to most of England.

I have yet to find Phaeoceros carolinianus or Anthoceros agrestis in winter 2002/03, maybe last winter was a particularly good one for Hornworts. Two visits to a field near Dingestow (SO40P) that held almost 100 rosettes of A. agrestis and at least 3 P. carolinianus the previous year have drawn a blank for both species. The only Phaeoceros I have seen in Mons this winter, at Michaelston-y-Fedw (ST28M), was male and was therefore provisionally assigned to P. laevis, although the lack of tubers makes this a questionable placement.

One species that does seem to be doing well at Dingestow this winter is Weissia rostellata. Two fields, adjacent to the one with P. carolinianus, had locally abundant W. rostellata when I searched them in early 2003. Both were set aside by the farmer after the 2000 harvest and are therefore in their third winter as stubbles. They were topped in the autumn as Juncus effusus and various grasses were taking over; maybe as a result, the W. rostellata was fruiting happily by January. The puzzle is that I looked at this field in early 2001 and failed to find any Weissia spp.; these mosses are thought to take some time to produce sporophytes - might many individuals take a few months to germinate as well?

Another regular feature of Dingestow’s arable is tuberous Fissidens taxifolius: tubers were found on all four samples of Dingestow F. taxifolius searched in 2003. The only pH I have measured from one of these fields was 7.3; all were on the red clay typical of the Raglan Marls group of the Old Red Sandstone. The tubers tend to hide near the middle of the dense rhizoid-ball of F. taxifolius as they are produced on short tubers. Thorough ‘Fisking’ of material should dislodge enough mud to reveal them if they are present.

A regular feature of Monmouthshire fields seems to be the frequency of Pleuridium spp. In one of the Dingestow fields (SO40P) fruiting P. subulatum is by far the most abundant moss and in several others in the county it is frequent. Ephemerum serratum var. minutissimum is present in most arable fields that have been searched, although it is usually only occasional. A mysterious form of E. serratum with very broad leaves, very slight teeth on the margins but the typical spores of E. s. var. minutissimum has turned up twice at Dingestow; it may be the intermediate between the vars. mentioned in Nyholm’s Nordic Flora. In contrast, Dicranella varia seems to be rare or absent in south Wales arable despite being an abundant species on natural calcareous habitats and on many forestry tracks, metal mine spoil heaps, sand dunes etc. I have found it in small quantity in a few fields, but it seems to be largely replaced by D. staphylina, often the most abundant moss in the fields of Mons. and Pembs.

Maize fields are usually bryo-deserts. Unfortunately the first two maize fields I searched, at Rogiet (ST48P) and Monmouth Cap (SO32Y), held 11 and 13 spp. respectively - hardly exciting but not exactly a desert. A more typical maize field at Llandevaud (ST39V) supported just a few tufts of Bryum rubens and a few scraps of Eurhynchium hians. Maize fields are generally ignored in favour of cereal as it is well known that they tend to be species-poor, but we should all survey potentially tedious fields now and again to balance things up.

Pembrokeshire
The arable fields of Wales’s far south-west seem to differ little from those of Monmouthshire. Riccia spp. are frequent in many of them, Dicranella staphylina is often the most abundant bryophyte, Tortula acaulon is rather patchily distributed and Bryum violaceum is widely scattered (although it hadn’t been found in the VC before). Clay and loam are the principal soil types, whilst the pH ranges from 5.7 on a ridge near Haverfordwest to 7.3 on the southern limestone.

Four species are of some interest. The first field I visited, near Johnston (SM90J), looked promising every time I drove past it on my way to work; sure enough, it produced Dyfed’s first (and S Wales’s second) Weissia longifolia. It may be widely scattered through the county, if the sterile Weissia spp. found in other Pembs. fields are this species, as seems likely. The next day, a field near Angle (SM80R, pH 6.2) held Fossombronia caespitiformis, apparently new to Wales. Mature sporophytes were only present on one of the plants of Fossombronia in the field so I can’t be sure if F. caespitiformis is found throughout the field or whether the principal Fossombronia is F. pusilla (as it is everywhere else I go). The only Phaeoceros I have found so far was on the shaded edge of a field near Lamphey (SN00F). It was male and had tubers on the underside of the thallus, surely sufficient to allow placement in P. laevis. This field also held tuberous Fissidens taxifolius. Nearby, just east of Pembroke Dock, a field at Upper Nash (SN00B, pH 7.2) was one of two to hold Microbryum rectum. This is rather an uncommon plant in south Wales and has not yet appeared in Monmouthshire’s arable.

A two year old setaside field on the coast at Little Haven (SM81L) was a bit further from the Monmouthshire norm. It held almost as many write-in species as typical arable plants, despite the large number of gaps in the cover of coarse grasses. Amongst the more interesting write-ins were Riccardia chamedryfolia, which was scattered throughout, Fissidens exilis, Scleropodium purum and one tuft of Epipterygium tozeri. A mysterious large Fossombronia, with non-tuberous costae and spores that don’t match any of the British species precisely, remains a puzzle; it is probably just a bizarre form of F. pusilla.

Anglesey
A meeting in Bangor, carefully arranged for a Friday, allowed me to spend a weekend checking out the arable flora of north Wales. I concentrated on Anglesey, but discovered that finding fields was enough of a challenge to keep me busy for a whole morning. Eventually I located three suitable fields in the southern half of the island and secured permission to survey them from their owners. All were cereal stubble field and one was both Organic and in Tir Gofal (the Welsh agri-environment scheme).

The lack of liverworts was probably the biggest difference between the Anglesey fields I searched and those further south: scraps of Fossombronia sp. were present in two fields whilst Riccia glauca was occasional in one. The mosses were more interesting and included frequent Weissia longifolia var. longifolia (new to VC52) in two fields, at Brynsiencyn (SH46Y) and Beaumaris (SH67E), tuberous Pohlia melanodon and non-tuberous Fissidens taxifolius in one and non-tuberous Pseudephemerum nitidum in another.

So far, the total number of Welsh fields surveyed with the SBAL methodology is 26: 15 in Monmouthshire, 8 in Pembrokeshire and 3 in Anglesey. These totals would probably be higher if the bryological delights of hills, gorges and limestone didn’t constantly tempt me away from the arable!