Status and ecology of the boreal moss Dicranum undulatum Schrad. ex Brid. at its last location in southern Britain

Abstract

ABSTRACT Introduction. Dicranum undulatum has been lost from many sites due to destruction of peatlands. This study investigates its status and ecology at the last surviving location in southern Britain. Methods. The study site, Fenn’s, Whixall, Bettisfield, Wem and Cadney Mosses, is one of the largest lowland raised bogs in Britain. Distribution and abundance of Dicranum undulatum was documented with GPS-based survey and habitat and community composition via relevés. Elevation of D. undulatum and Rest Water Level (RWL) relative to the peatland surface was measured at a sample of colonies and a search for sporophytes undertaken at all colonies. Results. Dicranum undulatum was found in two areas, the vast majority at Cranberry Beds plus a small amount at Welsh Bettisfield Moss. Its community is dominated by mosses and vascular plants, most frequently Aulacomnium palustre, Erica tetralix, Eriophorum vaginatum and Vaccinium oxycoccos. Soil pH is highly acidic, similar to the upper water table. Electrical conductivity of the upper water table is low. Elevation of RWL relative to soil surface averaged −10.8 cm. Minimum and maximum elevation of shoot tips of D. undulatum relative to soil surface averaged 7.4 and 24.8 cm, respectively. Maximum height of the moss above RWL averaged 35.6 cm. No sporophytes were found. Conclusions. Strictly limited to uncut peatland, the study site supports a strong population of Dicranum undulatum. It survives at Welsh Bettisfield Moss despite it being covered by dense woodland until tree clearance in 2001. Reproduction appears limited to clonal spread via detached shoot tips.