Author: Caz Walker

Great How is a small (c330m) but imposing hill at the north end of Thirlmere – map. It’s part of the Thirlmere Woods SSSI, designated for Atlantic bryophytes, with a mix of oak, hazel, birch and ash trees. It was last assessed by Natural England in 2009 when its status was “Unfavourable-Recovering”. Almost all the woodland around the reservoir is non-native conifer plantation but three fragments of old broadleaved trees remain to make up the SSSI. There are ongoing efforts to remove exotic conifers from these woods.

Our route left the minor road by the Thirlmere dam where a footpath skirts the western side of the hill. For once the weather was kind to us – when benign it allows everything to be seen much better in the field, not to mention the enjoyment/comfort factor. The day dawned very cold with frost encrusting the sheets of Peltigera praetextata we saw at the start on the north-facing wall by the road but the mist burned off (it really did) and by lunchtime, when we made it to a south-facing point looking down Thirlmere, it was positively balmy in the sun.

Recent stormy weather had brought many canopy lichens down to the ground for easy viewing so a good range of common acidic bark species were examined. This was great for showing the diversity of lichen morphology to the keen beginners who’d come along. The path skirted some intermittently damp rock faces with interesting crustose species, including the common Baeomyces rufus with pink-brown “mushroom” fruiting bodies, Lepraria membranacea in drier recesses (powdery, yet forming marginal lobe-like structures with upturned rims), red and purple-brown mosaics of Opegrapha gyrocarpa and Enterographa zonata, and a possible example of the rarer Schismatomma umbrinum with a pale brown scurfy crust breaking down into soredia. Close examination of oak trunks nearby revealed a tiny species growing over moss with minute isidia-like structures. Looking under the microscope later these turned out to be pycnidia and we were able to identify this as Micarea stipitata.

As we got further round the base of the hill the slope above became more gentle so we decided to leave the path and head directly up, examining trees as we went. This was a good move as Cetrelia olivetorum, Arthonia vinosa, Lopadium disciforme and Pachyphiale carneola, the latter on hazel, were found here. After rejoining the track below the summit we refound the copious Bryoria fuscescens seen on our earlier recce, though sadly the old oak had been brought down in the storms. Also near here were Mycoblastus sanguinarius, good quantities of Sphaerophorus globosus and beautiful clear grey-blue patches of Hypotrachyna laevigata, all indicating acidic bark.

There was a total for the day of 68 species. We didn’t visit the steeper areas on the north side of the hill where no doubt further lichens could be found. The east side is mainly a beech plantation and large parts of Great How have in the past been planted with exotic conifers, now slowly being removed with evidence of recent native tree planting. The remaining fragments of good quality old oaks on the western side are a sad reminder of what the wider Thirlmere woods might once have been like before the Sitka monoculture we see today. Hopefully they will survive to help regrow a future oak forest.

Caz Walker

Photos: Pete Martin, Judith Allinson, Clare Shaw and Chris Cant

Judith Allinson’s blogpost about the field trip.

The Coniston Coppermines area is part of the Coniston Mines and Quarries SSSI, designated for its volcanic geology which has produced veins rich in metals, especially copper. These have been mined over centuries, leaving a landscape of spoil heaps, walls and derelict buildings. Specialist metallophyte lichens grow here on a variety of substrates that might not otherwise be exposed. Parts of the area have been well-surveyed: the monad containing the main workings has 124 lichen species reported over a 40 year period, many refound in recent years and a few seriously rare. This, combined with the challenging weather, meant that we decided to treat the visit as a chance to see and try to identify these species, rather than record anything.

From the start it was very wet. The rain cleared somewhat later, but getting any books out wasn’t possible and lenses and glasses were steamed up. Rather than drive up the 1.5km track we decided to walk, which warmed us up. The owner gave us a talk about the history of the site and showed us where James and Purvis found rare lichens 40 odd years ago.

Despite it being dripping the four of us looking at lichens were able to work out several crustose species on a retaining wall. Minute differences in precisely where the soredia arise on the tiny areoles, as well as its colour, helped separate Lecanora epanora (yellow soredia on the surface) from Lecanora handelii (grey areoles with grey soredia arising at the margins). The common Lecanora soralifera (some similarities) was seen elsewhere. Several rust-coloured species turned out to be Acarospora sinopica (dark red chunky “lobes” with immersed fruit), Rhizocarpon oederi (more orange in colour with tiny but distinctive apothecia) and probably Lecidea silacea (orange very convex areoles). The commoner rusty Tremolecia atrata was seen nearby.

The combination of grazing and high metal content in the thin gravelly soil between workings has led to stunted vegetation, including heather, replicating the kind of heaths normally seen at higher altitudes. Cetraria aculeata, Dibaeis baeomyces and a range of Cladonia species were seen here.

Stereocaulon pileatum (tiny pseudopodetia tipped with soredia), Placopsis lambii, Ionaspis lacustris and Agonimia tristicula (very tiny lobes amongst moss with mortar influence) were on a ruined building.

We had an enjoyable diversion up the hill on the trail of the rare Lecidea inops which eluded us. Stereocaulon vesuvianum was abundant, as well as Stereocaulon dactyllophylum. The becks in spate were spectacular and the wet fairly mild conditions had produced a mollusc paradise with many slugs out and about feeding on lichens.

Caz Walker