Wednesday, 25 March 2020

Daltonia update

Daltonia splachnoides habitat in Pentreclwydau Forest

Apologies for labouring on this subject, but I thought this might be of interest. Firstly, we have searched for Daltonia in 5 likely sites in NPT over the past few days. Most trips have been disappointing, but we have managed to locate a large population in Pentreclwydau Forest where at least 10 willow trees have conspicuous tufts, probably 30 + plants in total. This may be just the tip of the iceberg. There are lots of willow here and the habitat is more 'typical' of the places described in Irish Sitka forests and Brechfa, i.e. willows in the vicinity of streams and wet ditches. Some of the tufts are relatively large (15mm or more in diameter) and they occur in places where they are easy to spot. In fact the glossy, dry colonies, that stick out like little shelves, are fairly easy to see from a couple of metres away. It looks as if the population has produced lots of sporophytes although some  have finished fruiting and several don't seem to have any capsules. Judging by the size of the population and the size of some plants, I guess it has been in this forest for several years. 
We now have Daltonia in 3 NPT tetrads, making a total of 4 for VC41. There must be more sites in the county, but it has a long way to go to catch up with Colura. Presumably it is a more recent colonist but I also suspect that it is a bit more fussy about where it grows. Daltonia associates on the Pentreclwydau willows include: Zygodon conoideus (abundant), Radula complanata, Lejeunea patens, Colura calyptrifolia, Orthotrichum pulchellum, Metzgeria temperata, Cryphaea heteromalla, Ulota bruchii, Ulota crispaUlota phyllantha, Hypnum andoi, Brachythecium rutabulum.


Large Daltonia tuft on willow, Pentreclwydau
Daltonia splachnoides with abundant capsules, on willow in Pentrecwydau  Sitka Spruce Forest

1 comment:

  1. It was only a matter of time before you spotted Daltonia given how much you scrutinise Glamorgan's forests. Nevertheless, it's really exciting to know that this species is now well established in south Wales. It does feel like a recent arrival rather than an overlooked 'native' and my suggestion 10+ years ago that it was a spore vagrant from Ireland that has now established itself here (just like Colura) still makes sense. I assume this is a combination of Climate Change and coniferization creating both suitable habitat in GB and a much larger spore bank in Ireland.

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