Gloucestershire Group: Llwyn-on Reservoir, Merthyr Tydfil

HomeEventsGloucestershire Group: Llwyn-on Reservoir, Merthyr Tydfil

9 January 2022 (10:30 - 16:00)

Meeting report

There were a few last-minute drop-outs from this meeting due to various health problems, so, sorry you couldn’t make it Des, Jean and Gary – and others who had already said they were unable to come. However the 5 of us who did attend – Claire, Sharon, Pete, Ian and Wendy – had a very enjoyable day amongst the lush bryophytes of this humid woodland. We were also remarkably lucky with the weather which stayed fine until about 2.30pm.

The forestry track banks where we start were covered with Sphagnum and several large pleurocarps (Pseudoscleropodium purum, Pleurozium schreberi, Calliergonella cuspidata); there were streams flowing down towards the reservoir to explore and the track itself which had limestone chippings and provided habitat for plentiful Jungermannia atrovirens, a Mesoptychia (probably M. badensis), Didymodon ferrugineus and other calcicoles. There were regular shouts of ‘Colura‘ from Sharon (how come I never seem to spot this species?) on the willow trees growing along the track at the edge of the coniferous woodland.

Shortly before lunch the track curved left and ran parallel to the Nant Aber-nant for a while. The sound of rushing water drew us down the hill to the stream, with the thought of lunch in a nice sheltered spot along the banks uppermost in our minds for the moment.

Lunch over, those of us in wellies walked up the stream adding Hyocomium armoricum, Chiloscyphus polyanthos and Rhynchostegium riparioides to the list. We lost contact with the others for a while but finally met up back on the track. A couple more Sphagnums and a lovely patch of Schistochilopsis incisa and then we reached a fork in the track. After some discussion it was decided to strike north across forestry plantation to the lane and gradually make our way back to the cars. This is when the rain started 🙁

We added a few more species as we went – a small tuft of Bartramia pomiformis in the crevice of a stone wall being a nice one. A visit to the reservoir margin yielded lots of Fontinalis antipyretica and some Cinclidotus fontinaloides. Back on the road, a bridge over one of the streams had Tortella tortuosa, Bryoerythrophyllum recurvirostrum, and a robust, spiral-leaved Didymodon growing in abundance (to be investigated). A large rock gave us at least 2, possibly 3 Racomitriums. Last but not least, sharp-eyed Sharon found some fruiting Sanionia uncinata growing on twigs of a tree along the lane. Most of us would undoubtedly have missed this, mistaking it for the Hypnum (andoi?) which was also abundant on these twigs / branches.

By now the rain had set in and it was starting to get a bit dark. 4pm isn’t a bad time to finish a meeting in early January though!

Claire Halpin Jan 10th 2022

Note: the species list below includes the time recorded, so you can sort in time sequence to get some idea of when and where things were found.

Download the species list

Meeting details

Leaders: Peter Martin & Claire Halpin

In a slight break from tradition, we have moved our Welsh meeting forwards to January instead of making it the last one of the season. We will visit the woodland area to the southwest of the Llwyn-on Reservoir – Cwm Dyry and the Nant Aber-nant. This is the first reservoir along the A470 north of Merthyr Tydfil.

The woodland is primarily coniferous forestry plantation and we will walk along forestry tracks (Didymodon ferrugineus and associates) with ditches, banks with several Sphagnum species, and small streams crossing the tracks. It is also possible to get down to a small section of the reservoir which is edged with some kind of calcareous rock (lots of Tortella).

Meet in the parking area to the south of the reservoir, across the dam, at around SO 00830 11298. It’s a popular dog-walking area, but if this parking area is full, people seem to park along the road verge as well.

Walking boots should be fine, but if you fancy splashing around in the ditches looking at Sphagnum, wellies advised.

Please ensure that you download and read the Risk Assessment below before the meeting

Download the Risk Assessment