A visit to Darren Fach SSSI

A week ago I visited Darren Fach and Darren Fawr - on the Carboniferous Limestone north of Merthyr Tydfil - with 4 NRW colleagues to remember the massive role that David Stevens played in Welsh nature conservation.  We paid our respects to Sorbus leyana and Dryopteris submontana, following in David's footsteps, and I made a search for one of David's favourite Welsh bryophytes, Tortella densa.  His initial discovery of this species, new for Wales, was on the limestone of Great Orme's Head, and the only other Welsh record comes from the Clwyd limestone near Llangollen, but I hoped that Darren Fawr might offer a good chance.  The Tortella hunt was disappointing, as were the bryophytes of the general area, which is very dry and exposed.  Final tally for the area (split between SO0110, SO0210 & SO0209) was less than 50 species, with a few additions to tetrads I hope.  Highlights were Seligeria acutifolia and Grimmia hartmannii in the woodland below Darren Fach.  My previous visit to the southern end of Darren Fawr in SO0209 was similarly bryo-poor.

Nedd-fechan in pictures 1

Part of a length cliff with lots of, mostly non-fruiting, Seligera (photo 2), though Sam did manage to find a few with capsules [of acutifolia (photo 3) and donniana (photo 4)]. Also there were good patches of Cololejeunea calcarea (photo 5) all along the same face.

Lower down the valley, where the woodland flora reflected more neutral-acidic conditions, there were areas in which Loeskeobryum brevirostre pretty much blanketed every surface on the woodland floor, along with with frequent Rhytidiadelphus triquetrus and a little R. subpinnatus.

Grimmia hartmanii was noted on millstone grit boulders and would appear to be thinly but widely distributed through this section of ravine.

Lower Mellte Lower Hepste

Graham and I have agreed that we really must finalise our evaluation of the bryophytes of Coedydd Nedd a Mellte this winter, as we have been adding records for over 15 years now.  There are still several areas that we haven't searched, and so it was with high hopes that I set off upstream from the Craig y Ddinas carpark towards the Hepste confluence this morning.  The Mellte has been surveyed under contracts for the BBNPA by both Martha Newton and Nick Hodgetts, but there were no records of notable species from the east bank downstream of the Hepste for at least 1km.  The habitat looked pretty good, with bouldery reaches reminiscent of Eryri, and plenty of low cliffs, but a general paucity of waterfalls.

The only medium-sized falls below the confluence was edged with Anastrophyllum hellerianum oaks, but there were no Ash in its mist zone and no interesting Lejeuneaceae.  Rock shelves on a sharp bend in the river held Grimmia hartmanii and Scapania subalpina, and there were several logs with Cephalozia catenulata and Riccardia palmata.  An oak overhanging another low waterfall supported the only Jamesoniella autumnalis I saw during the day, and sphagna on the woodland slopes had me puzzling because none seemed to fit Sphangnum quinquefarium (just S. fimbriatum, S. subnitens and I hope S. russowii, but I have bits to check).

I turned into the Hepste relatively late in the day, so only had time to work upstream to the first pair of waterfalls.  These were pretty splendid, but again lacked small Lejeuneaceae.  The base of the waterfall cliff appeared to be Carboniferous Limestone, complete with a colony of Seligeria cf. donniana (fruiting, to be checked) and some Neckera crispa.  The ravine around the upper falls held a nice patch of Hymenophyllum tunbrigense, perhaps previously unknown, whilst a crevice near the lower falls had scattered patches of Killarney Fern gametophyte over a 20x20cm area.  The fungus Macrotyphula juncea was growing out of some damp leaves, and I also saw what I think is Cortinarius cinnabarinus among the Rhytidiadelphus loreus in steep woodland.  At the west end of the valley there was a log covered with liverworts, including abundant Lophozia incisa.

 

A long trudge back past Cilhepste revealed a tuft of Colura on birch on the edge of the woodland/plantation, as well as some lovely growths of various Usnea species.

 

Sometimes one builds a day up too much and ends up disappointed: this was a good day out by almost any standards, but the Nedd-fechan left me expecting excitements every time!

Waterfall Country - a bryological paradise

The Nedd, Mellte, Hepste and Pyrddin valleys are bryologically outstanding, with oceanic species such as Aphanolejeunea microscopica and Plagiochila exigua reaching their southern British limit, and some scarce woodland species in quite remarkable abundance.  Graham had to formulate a view on likely management impacts in an area of the Dyffrynnoedd Nedd a Mellte SAC that had no previous bryophyte records, and I accompanied him on a visit yesterday so that we could get as full a picture of the locality's richness as possible... and boy was it rich!

Jubula and Jamesoniella were in here

The day started with Bartramia ithyphylla and Pohlia wahlenbergii both with sporophytes on outcrops above the track, then a check of some crags in the river's flood zone produced Distichium capillaceum and fruiting Mnium marginatum, with plentiful Grimmia hartmanii on boulders nearby.  A log by the path held the first Cephalozia catenulata of the day, alongside Nowellia, and these were soon followed by the first Jamesoniella autumnalis on a log in a ravine.  A side-valley of the main river held an incredible abundance of both Jamesoniella (on logs and rocks) and Anastrophyllum hellerianum (on humid oak trunks), as well as the 3rd known colony of Jubula hutchinsiae in the SAC.  I suggested that the rocks looked suitable for Tetrodontium brownianum, and sure enough some overhangs in a ravine were bristling with this species.  Highlight of the day came as we made our way back south along the foot of a sunny crag: peardrop-scented Frullania fragilifolia, new for the SAC and the hectad, with Plagichila bifaria at its 2nd SAC locality nearby.  The day was thoroughly worthwhile because we can now work out exactly how to carry out management that will benefit the woodland and its outstanding bryophyte flora.

Photos of most of those highlights follow: only the Anastrophyllum and Plagiochila escaped my camera.


Bartramia ithyphylla

teeny tiny Cephalozia catenulata

a cushion of Distichium capillaceum

Frullania fragilifolia (peardrop scent unfortunately not apparent from this photo)

Grimmia hartmanii with typically falcate leaves

Male Jamesoniella autumnalis on a log

Brackets of Jubula hutchinsiae in a ravine

fruiting Mnium marginatum

fruiting Pohlia wahlenbergii (not something I see fruiting very often at all)

Tetrodontium brownianum growing vertically downwards

a few more pics showing fertile / reproductive features to look out for

I just had a quick look through photos to see if I had examples of other features to look out for ....

large gemmae on leaf tips of Grimmia hartmanii (lots in Neath waterfalls area and near Penderyn so should hopefully get into Glam - it may well be on the Glam side of the Afon Nedd above the Angel Inn); tiny plantlets on Leucodon;  male Lunularia; short fruits on Breutelia usually well tucked away in middle of tufts.