Friday, 14 October 2016

Action for Meesia

Meesia uliginosa has only ever been seen in Wales at Tywyn Aberffraw - the best dune system for bryophytes in Wales because of its highly calcareous sand and extensive slacks.  David Holyoak found it in one slack in 2001, alongside Amblyodon dealbatus and carpets of Leiocolea badensis, confirming the continued presence of Meesia in Wales following no records since 1968.  Despite David's precise (paced) directions I failed to find Meesia in 2013 and 2015, and a hands & knees search for 2 hours on Tuesday 11/10/2016 also produced no sign of this species.  The habitat has undoubtedly changed since 2001, with Leiocolea now patchy and no Amblyodon: maturation of the slack has surely caused the loss of Meesia from its one well-localised site.  Tragically this is not all - Aberffraw has also lost the last remaining Bryum calophyllum since 2001 and most of its Bryum warneum, and the lack of recent records of Catoscopium nigritum suggests that this pretty little moss has also been lost from Wales.  Even Southbya tophacea, which occurred in reasonable abundance when I first visited Aberffraw in ca. 2002 with David Stevens, has gone from the slack where we saw it.
AONB volunteers hard at work in the former Meesia slack

We have got to hope that it is not too late though: NRW have applied for EU funding to rejuvenate a suite of Welsh dunes, and large-scale action at Aberffraw may bring some of the rare mosses back from the brink.  Meesia may not be able to wait for rejuvenation to work, though, so we have tried a bit of scraping in its last slack, just in case there might be some dormant spores or buried plant fragments that could be encouraged into life.  Hannah Shaw from the Freshwater Habitats Trust organised a band of volunteers from the Anglesey AONB to dig out some shallow scrapes, carefully located to avoid damage to the bryophytes and vascular plants that remained in the slack.  Who knows if this will work, but at least we have tried!

Abietinella, with stem leaves showing features of both A. hystricosa and A. abietina

After my 2 hour crawl around the Meesia slack, marking out the scrapes, I had a short while to spare and headed north through the big (former Southbya) slack past a few relict patches of Abietinella and over a dune ridge.  Pete Jones told me last year that there was a slack with Pinguicula and Parnassia there, and as far as I knew this had never been checked by a bryologist.  To my great relief, this slack has less mature vegetation than the former Meesia site, and a richer flora, including good carpets of Leiocolea badensis and at least 20 patches of Southbya tophacea (SH36726949, but don't under any circumstances collect any!).  I only searched about 1/3 of this slack before my time ran out, so there is still a faint hope that Amblyodon or even Meesia or Catoscopium could survive there...

Southbya male and female


  1. I hope you find them there eventually Sam. But I can't help thinking that the loss of Boreal-Arctic species (e.g. Meesia and Catoscopium) from their southernmost stations has a certain ring of destiny about it.

  2. I have been tabulating my results to date on the Kenfig scrapes, which provides some optimism that rejuvenation work provides benefits for pioneer species. The worry is populations of some key species such as Petalophyllum seem to be critically low. Whilst northern species might appear to be struggling, let's hope the future will be brighter for southern element of our bryo-flora.