Where it is Oceanic and Humid

Where it is Oceanic and Humid

Yesterday, I had a successful bryophyte day in Ferryhill Glen, Fathom

There is a lovely wooded ravine in southwest Newry that I have blogged about before, which forms the border between the townlands of Upper Fathom in Armagh and Cornamucklagh in Louth. It is the eastern ridge of the Ring of Gullion, containing small hills in which the Fathom Line runs along. Bounded by commercial forestry (a lot of which is currently being clear-felled), it is a steep-sided river glen, with rocky outcrops, waterfalls, cascades, fallen-tree bridges and a nice array of wildlife.

I go here regularly because it has some botanical rarities that always make me feel better. And pretty much every time I go, I find something new. Yesterday was no exception.

Along the glen there are plunge pools caused by the erosive power of falling water. This coupled with overhanging vegetation creates ideal conditions for certain bryophyte species which demand constant humidity and are therefore only found in places with high rainfall and/or wooded glens. I wrote a bit about this in my Local Biodiversity page.

I happened to find this bryophyte that I was confused by. So, I took a sample and a picture and carried on down the stream. I then came across another patch, in the open, growing on bedrock right beside the river. I then realised that it was the elusive Hutchin’s Hollywort (Jubula hutchinisae) – a hyperoceanic liverwort which grows in a shelf-like habit. This beautiful liverwort, I had only seen up-close photos of, and was aware of its existence, but had never seen it in the flesh. Very pleased to have found it here, since it is the first record for Co. Armagh and the second for Co. Louth (it is hard to know what county you are in along this glen since it forms the boundary). The closest site is a 2004 record in Cloghmore Glen, Rostrevor, only across the mouth of Carlingford Loch. It is named after Irish naturalist Ellen Hutchins, who discovered the liverwort. Be prepared to get soaked when IDing this one; I was drenched from the waterfall spray!

I also found two additional firsts for me: Lepidozia reptans and Chiloscyphus polyanthos. These are not oceanic species, but they have not been recorded here before and it is always great to find species that you haven’t seen before. I had originally thought that C. polyanthos was Porella pinnata, but was thankfully corrected by experienced bryologist Ben Averis. The glen has copious Saccogyna viticulosa, Plagiochila spinulosa, P. asplenioides, P. porelloides, Diplophyllum albicans and many others. This glen has been my classroom, helping me on my bryophyte journey, especially liverworts which I think I prefer over mosses!

I would love to see this place afforded more protection since I am worried that clear-felling nearby plantations will impact humidity regimes which many bryophytes cannot tolerate. There are additional considerations here since it forms the border between DAERA and Coillte land. There is some nice (but tiny) hazel stands, hinting towards hazel woodland, some oak, downy birch, rowan, holly and ash. However, beech, sycamore, rhododendron, cherry laurel and western hemlock are all present and sometimes abundant, overshadowing native species. There has been clear-felling nearby recently and it is worrying. Even within the plantation that was harvested, I have recorded Saccogyna viticulosa and other species of ecological importance.

Overall, this is a wonderful place, and I have not seen it in Summer yet, having only found it in October. I am excited to see what wildflowers appear here. I am pretty sure that it is also a blue-bell woodland, with some already popping up.

Image: Jubula hutchinsiae on riverside rock