Sphagnum Medium - A first for VC41

In July of 2020 I was fortunate enough to stumble (quite literally!) onto a hummock of Sphagnum medium within the Eastern area of the Pen-y-Cymoedd wind farm on Mynydd Ystradffernol. The area in which it was found is far from what anyone would be able to describe as optimal for bog vegetation. It exists on an area in between extensive spruce coupes and Molinia dominated wet modified bog with large amounts of associated drainage, although the hummock I found sits along the edge of a more natural looking erosion feature with a higher Calluna presence. The peat itself is around 0.6m in depth around the location, which is less that I originally expected, grading into over 2m deep within 100m.

General habitat surrounding Sphagnum hummock

A return visit on the 31^st to search for any further species of interest didn’t yield any more results for Sphagnum medium but there are some impressive hummocks containing a variety of species (including but I’m sure not limited to capillifolium var. capillifolium, palustre, papilosum, subnitens and fimbriatum)  within 50 or so metres, although broadly speaking these are all restricted to the lower areas within the ridge/furrow microtopography.

A fairly majestic hummock to the south west

I’ve been searching for some of the former Sphagnum magellanicum species (medium and divinum) for the better part of 8 months (fuelled by jealousy over what I’d seen on Cors Fochno last summer).  However, before this, efforts had been fruitless, despite having now walked over extensive areas of the Afan and Rhondda Fawr Uplands. What it is about this particular location versus the others in the uplands of NPT and RCT that I’ve been to that makes it more suitable for the species I’m not sure, but after sending off a voucher to the BBS and receiving confirmation of the species and it being the first record for VC41 I will be returning to scope out the wider area and see what else is hiding there.

Sphagnum medium on Ystradffernol

The story of the finding of this species often seems to be more enjoyable for people I tell than the actual finding. For those of you with glasses like myself, you’ll understand the dilemma presented by consistent heavy rain, it is a choice between not seeing because of the water on the lens or not seeing because you have to take your glasses off. Cue the heavy rain as soon as I get to the area, after pushing through sitka and finally reaching some clearer air I took my glasses off, made it about 10 steps before tripping and falling over. Three inches from the end of my nose was what I’d been searching for 8 months, no doubt without the fall I wouldn’t have found it as it was off my route.

So there we have it, an 8 month goal realised and a lovely record for VC41. Thank you for the invitation to write here and may all your stumbles be so fortunate.

An extreme close up of Sphagnum medium voucher courtesy of Barry Stewart 

Medium Excitement

Yesterday I took a quickish walk with Jonathan Saville to a bog on Mynydd Llangattock to download data from some dipwell loggers.   The bog has changed considerably since I first visited in about 1999.  Back then, this common was quite heavily grazed and much of the bog surface consisted of scattered tightly grazed patches of vegetation with more bare peat than vegetation and hardly any Sphagnum, although there were strong populations of round-leaved sundew Drosera rotundifolia growing on the peat and Splachnum sphaericum growing on the abundant animal droppings.   The area was also suffering from the effects of a deep drainage ditch, almost a canal, which had been dug through the middle of the bog to feed the Garnlydan reservoir, and no doubt the site was also being affected by the poorer air conditions back then - the Ebbw Vale Steels Works only 7km to the south was just about still working then.       


Twenty years on, the area looks very different – grazing levels are much reduced and the ditch has largely filled in.  There is now almost a complete cover of vegetation, with a nice mix of bog plants and an abundance of Sphagnum, including much S. papillosum.    

About 7 years ago I managed to refind a mid 1970s record of Bog Rosemary Andromeda polifolia somewhere on this bog -  I walked over to a colleague to share the excitement and then walked back and couldn't find it again! 


Whilst discussing the vegetation changes with Jonathan I suggested that it would be wonderful if, before he retires, he finds S. magellanicum growing on this bog – as it happens we didn’t have to wait that long as a few minutes later we bumped into a large patch of the moss. 

There are very few records of S. magellanicum in south Wales and at most of the sites where it does occur there is often only a tiny population of one patch or so.  Mynydd Llangattock is a good distance from the next nearest sites in N. Brecks and Carmarthenshire and I presume it has colonised since my first visit.   
        

After 40 years of making references to Sphagnum magellanicum it might take me a long time to get used to calling our plant of ombrotrophic bogs S. medium.  If anyone missed the paper in the Journal of Bryology a couple of years back a summary is given here: https://www.tandfonline.com/doi/abs/10.1080/03736687.2018.1474424