Block scree habitat above Blaengwynfi
High above Blaengwynfi, in the Afan Valley, a forestry road straddles the border between NPT and RCT. Not far away, the Pen y Cymoedd wind farm development is transforming the landscape on a geographical scale. Some nice habitat mosaics survive (just!) at least for the time being, such as small areas of wet peatland with abundant
Drosera and heathy banks with clubmosses. In a few places, sandstone block scree, the remnants of old quarry workings, provide the sort of bryophyte habitat that George has been showing us recently.
Racomitrium ericoides is common on rock in places like this. As Sam tells us, we should look for and perhaps expect
R.elongatum in these habitats and I have spent hours looking at likely specimens - but to no avail. Spotting
R.elongatum in these places might be tricky and serendipity will probably play a big part. On our trip to the site in the photo above (SS9009/9858), we saw a smallish dark-coloured
Racomitrium growing in a fairly tight, cushion on a rock. It looked pretty good for
R. sudeticum in a likely habitat not far (as the crow flies) from the Craig y Llyn population, and not that far from the Afan Argoed colony. However, leaf sections clearly revealed a bistratose costa - so it's
heterostichum. All other
R. heterostichum that I've seen has been the typical dark grey in colour with conspicuous hyaline points on the leaves. I think I'm beginning to appreciate how variable this species is - and this also ties in nicely with George's recent post.
Racomitrium heterostichum
Other species on rocks here included R.aciculare and R. fasciculare, the former frequently encountered by us in habitats like this, away from any water course. The iron-rich sandstone rock typically supports crustose lichens like Porpidia macrocarpa and Lecidea lithophila but there was also a significant population of Stereocaulon dactylophyllum scattered over the scree.
Stereocaulon dactylophyllum
Hilary was struck by the large amount of fruiting Polytrichum piliferum here with attractive red seta (completely lost on me, of course!!!).
Polytrichum piliferum
Other interesting stuff included Tortella tortuosa, in the company of other calcicoles like Ctenidium molluscum and Campyliadelphus chrysophilus, mostly confined to the calcareous edges of the road. This is a rare species in NPT (there's no limestone in the county) but is also found on a coal tip in Afan Argoed and on an old wall near Cwnllynfell.
It's not always easy to get to these upland sites and, invariably,it requires quite a bit of hiking. But since that has probably put off others doing it before you, there's always a high probability that you'll be doing some trail-blazing surveys. RCT is full of places that fit into that category.
Nice images Charles - looks more like the Rocky Mountains than NPT!
ReplyDeleteAre the conifers are self-seeded or planted?
More like the Cascade Mountains of the Pacific Northwest perhaps!
ReplyDeleteGood question. Yes they are self seeded as far as I can tell. This is often a problem with these fabulous scree sites and I presume that the Racomitriums will be shaded-out eventually. Here it's mostly Sitka colonising but in other quarries we've seen Sitka, Japanese Larch, Lodgepole Pine and Western Hemlock forming a naturalised mixture. It's amazing how well these conifers have adapted to these environments - a good example of recombinant ecology.
I expect that when I work up the courage to look through the many Grimmia packets I have accumulated over the years, a good few will turn out to be Racomitrium heterostichum!
ReplyDelete