Summary details for Thanatus formicinus (Clerck, 1757)

Distribution

The species has been recorded from Beaulieu Heath near Brockenhurst, New Forest, South Hampshire in 1894 and Legsheath and Duddleswell, in Ashdown Forest, East Sussex, in the 20th century. Adults were found at Legsheath in the 1930s and juveniles at both Sussex sites in 1969. This species is widespread in western and central Europe, but has not been recorded from Ireland.

Habitat and ecology

The spider occurs in boggy areas with Sphagnum, tall Molinia caerulea and mature Calluna vulgaris and Erica tetralix. Adults are found in March or April.

Status

The spider was recorded from three locations before 1969 but it has not been collected at any of them since that date. It was apparently well-established when found in Ashdown Forest, but searches in recent years have not rediscovered the spider, and the habitats have become degraded. Juveniles would still be recognisable in the field, so it is unlikely to have been under-recorded.

Threats

Fire on heathland and loss of the heathland habitat to other land-uses. Drainage of some New Forest bogs has been carried out in the past in order to increase the area and quality of grazing land. There is now very little grazing in Ashdown Forest, partly because the main roads crossing the unfenced common land are a danger to livestock. Consequently, scrub and bracken invasion of the heath is a problem.

Management and conservation

Scrub clearance is required to restore heathland and open boggy areas. Text based on Dawson, I.K., Harvey, P.R., Merrett, P. & Russell-Smith, A.R. (in prep.).