Area: 2.03 hectares.
Talland Barton Farm is a nationally important site for a population of the many-fruited beardless-moss Weissia multicapsularis, a critically endangered species known from only two sites globally, and for its assemblage of nationally rare and nationally scarce bryophytes.
Talland Barton Farm is located on the south coast of eastern Cornwall. The site is a single pasture field sloping west and south-west to the top of a low sea-cliff of Devonian rocks (Whitsand Bay Formation). The same rocks are exposed in a small disused quarry inside the northern end of the site, close to its boundary with Talland churchyard. The pasture comprises grassland of the National Vegetation Classification (NVC) type MG5 crested dog’s-tail Cynosurus cristatus – common knapweed Centaurea nigra grassland on mainly acidic to neutral soils that has not been affected by agricultural improvement. Steep banks beside paths and tracks expose patches of un-shaded stony soil that are important for supporting the bryophyte assemblage.
Talland Barton Farm is one of only two extant sites globally where the critically endangered many-fruited beardless-moss Weissia multicapsularis is known to occur, with several colonies growing on the steep banks in the site. Many-fruited beardless-moss has shown a long-term decline in Britain and is no longer present at the only locality from which it has been recorded in continental Europe (western France).
In addition to many-fruited beardless-moss, the assemblage of bryophytes growing on the steep banks in the SSSI includes the nationally rare Portuguese pocket-moss Fissidens curvatus, Wilson's pottia Tortula wilsonii and a pygmy-moss Acaulon mediterraneum. Thin soil on ledges of the small quarry supports the nationally rare wedge-leaved screw-moss T. cuneifolia and the nationally scarce dog screw-moss T. canescens. Both of these species have shown a long-term decline in Britain.
The extraordinary richness of the site for rare and scarce bryophytes probably arose from its favourable topographic, soil and climate conditions. However its richness has apparently been maintained because of the long history of traditional grazing management of the pasture, without any inputs of artificial fertilisers or herbicides, or any nutrient inputs from surrounding land.