Summary details for Baryphyma gowerense (Locket, 1965)

Distribution

The species was recorded from Whiteford Burrows and Oxwich Burrows, Glamorgan in 1967 and 1971 where it was apparently then well established; Ruston Common, East Norfolk, in 1974; and in 1988 from Cors Erddreiniog on Anglesey, Cors Geirch in Caernarvonshire, Carmarthenshire, and Woodbastwick Fen in East Norfolk. It was found in 2007 at the adjacent Sutton Fen and again in 2009 at Woodbastwick Fen (Lott et al., 2010). It has been recorded from the Republic of Ireland, Co. Fermanagh in Northern Ireland, Sweden (where it is included in their Red List (Gardenfors 2000)), Siberia and Canada.

Habitat and ecology

Saltmarsh and fens. The first example was found in seaweed drift at spring tide mark on Whiteford dunes. However, further searching failed to locate specimens in the drift material but revealed large numbers in the high inter-tidal zone of nearby saltmarsh. It occurred only in a narrow band on the shore in vegetation dominated by Juncus maritimus and Festuca rubra. It has been found in similar habitat at Oxwich. Ruston Common is an inland marshy area with acidic fen grading into less acidic saw-sedge Cladium and reed Phragmites stands. It is not known which vegetation type was being used by this spider. At Woodbastwick Fen, on each occasion, a female was found in a sedge-bed managed by mowing, while at Sutton Fen the species was found among dense Juncus subnodulosus, with some Myrica gale. Adults of both sexes have been found in May and June. In Sweden, it was recorded from seasonally flooded meadows around a eutrophic lake, on wet substrate under old vegetation such as Deschampsia tussocks (Kronestedt 1979).

Status

Although recorded from 11 hectads in total, not recorded since 1992 at the time of this analysis, though found again in the Norfolk Broads in late 2007. Area of occupancy is very limited, the spider has been found in just two hectads since 1992. It was recorded from 11 locations before 1992, an apparent decline of 82% but more field work is required in Wales to establish its current status at previously recorded sites.

Threats

At Oxwich, natural changes in the dune system have led to an increase in the accretion rate in the saltmarsh, with consequent changes in the vegetation. The habitat at Whiteford is thought to be stable. The vegetation at Ruston Common is largely the result of management by the commoners (including cutting of reed and saw-sedge for thatch), but these practices ceased in the mid-1970s and scrub invasion is a problem at this site. More efficient drainage and increased water abstraction in the vicinity of Ruston Common had a dramatic effect on the marshy area in the late 1980s, and it remains to be seen whether the wetland flora and fauna are permanently damaged.

Management and conservation

Scrub clearance may help restore the reed and sedge beds at East Anglian sites. Sutton Fen, where the spider was recorded in 2007, is now an RSPB reserve actively managed for its rich invertebrate fauna and flora as well as the bird life, including controlled grazing and sedge cutting. The Welsh saltmarshes need surveying to check for the continued presence of this species in the type locality. Text based on Dawson, I.K., Harvey, P.R., Merrett, P. & Russell-Smith, A.R. (in prep.).