(Leaders: Nigel
Milbourne and Helena Crouch)
Glorious sunshine greeted the sixteen who
assembled for this joint meeting of BNHS and Cam Valley Wildlife Group. After an introduction to the history,
management and geology of the reserve, we began to explore this fascinating
site, where the legacies of lead mining are evident in the vegetation seen
today. Much of the site comprises uneven
gruffy ground where surface layers have been disturbed during mining, resulting
in a mosaic of limestone grassland and heathland species, with calcicoles such
as Bird’s-foot-trefoil (Lotus
corniculatus) and Stemless Thistle (Cirsium
acaule) growing alongside calcifuges such as Heather (Calluna vulgaris) and Purple Moor-grass (Molinia caerulea). Ubley
Warren is home to several rare plants.
Much of the turf is Soft-leaved Sedge (Carex montana), so abundant here, yet nationally scarce. One of the rarest plants in Somerset is
Mountain Everlasting (Antennaria dioica),
which occurs only on a precarious turf ledge beside a path at Ubley
Warren. For 75 years it was believed to
be extinct, but was discovered here in 2005 and persists ... just. Members were not hugely impressed by this
species, or by Slender Bedstraw (Galium
pumilum) which was seen on rocks nearby and is not only Nationally Rare but
also red-listed as Endangered. An
aberrant Bee Orchid (Ophrys apifera var.
badensis) resulted in far more
photographic activity. This variety has
two pink sepaloid petals in addition to the three pink sepals.
The larger-scale lead workings (rakes) have
produced rocky ravines and limestone crags, which provide a habitat for several
rare plants. We saw the skeletal remains
of Hutchinsia (Hornungia petraea), a
tiny white-flowered crucifer, in Somerset now found only here and in the Avon
Gorge, surviving at both sites on the soil-rock interface thanks to lack of
competition in this harsh environment. A
single Wild Service-tree (Sorbus
torminalis) clings to the rock face in one rake and was bravely viewed from
above by hardy members. Ubley Warren is
home to two rare hawkweeds, both of which were seen in flower on rocks. Chalice Hawkweed (Hieracium cyathis) grows only here, in Cheddar Gorge and in several
sites in south Wales. Red-tinted
Hawkweed (Hieracium angustisquamum),
with dark purplish undersides to the leaves, has a very scattered distribution
in Britain and Ireland and was seen on a single north-facing rock face.
After exploring the Rakes, we headed out to the
western edge of the reserve where Frog Orchid (Coeloglossum viride) was formerly found. Sadly none were found, but Skylarks (Alauda
arvensis) sang overhead
as compensation. Returning across the
less frequented southern part of the reserve, a search for Mullein Moth (Cucullia verbasci) caterpillars on Water Figwort (Scrophularia auriculata) was more successful. There were lots of Dark Green Fritillaries (Argynnis aglaja) flying over the reserve, and we saw several Six-spot
Burnets (Zygaena filipendulae) and Forester Moths (Adscita statices) as
we walked across the heath. The
walk ended with a fantastic view of a Viviparous Lizard (Zootoca
vivipara) basking on the boundary wall and a brief sighting of a
Small Pearl-bordered Fritillary (Boloria selene) on the
other side.
[HJC and NM]