Summary details for Cloud-living Spider (Semljicola caliginosus (Falconer, 1910))

Species Details

Species name
Semljicola caliginosus (Falconer, 1910)
Common name
Cloud-living Spider
Synonyms
Eboria caliginosa Falconer, 1910, Semljicola caliginosa (Falconer, 1910), Semljicola caliginosa
Taxonomy
Animalia :: Araneae :: Linyphiidae
habitat
acid & sedge peats

Distribution

The species is widespread in northern England but scattered in Scotland. It was thought to be endemic to Britain but has recently been recorded in Siberia (Tanasevitch & Koponen, 2006). Nevertheless, our populations are globally important.

Habitat and ecology

S. caliginosus occurs in wet places, among Sphagnum, Juncus, grass and moss, mostly on high ground, but down to almost sea level in the north. Adults are found in June, July, August, September and in early spring. It may be adult for most of the year.

Status

UK Biodiversity Action Plan priority species. The spider is local and never particularly common. There has apparently been a highly significant decline over the past 30 years. Trend analysis of the continuing decline in area of occupancy over the period 1976 to 2005 indicates a reduction in population size of 69% over a ten year period. The spider has been recorded from just three locations since 1992 although there may have been some under-recording. Its area of occupancy has declined from 22 hectads before 1992 to just two hectads since that date.

Threats

Some sites might be threatened by drainage for afforestation.

Management and conservation

Ensure suitable wetlands are protected from drainage for forestry or other land-use. Text based on Dawson, I.K., Harvey, P.R., Merrett, P. & Russell-Smith, A.R. (in prep.).

Stats

First recorded
1900
Last recorded
2025
Total records
198
Total visits
184

Conservation status

Semljicola caliginosus
SourceReporting categoryDesignationDate designatedComments
Scottish Biodiversity List (incorporating 2007 updates and 2012 categorisation)Biodiversity Lists - ScotlandScottish Biodiversity List39234Terrestrial/Freshwater Species. Added to UK BAP list in 2007. Criteria: Threat, International responsibility/ threat , Decline
A Review of the scarce and threatened spiders (Araneae) of Great Britain: Species Status No. 22 (Sep 2017)Rare and scarce speciesNationally Rare. Includes Red Listed taxa42979
A Review of the scarce and threatened spiders (Araneae) of Great Britain: Species Status No. 22 (Sep 2017)Red listing based on 2001 IUCN guidelinesEndangered42979This species has shown a major decline in its AOO and has been found at only three locations since 1993. Although formerly considered endemic, it is now recorded from Siberia and Norway. However the British populations are considered to be globally important. Its wetland habitats are under threat from eutrophication and both land-use and climate change. Threats: Some sites might be threatened by drainage for afforestation.
Natural Environment and Rural Communities Act 2006 - Species of Principal Importance in England (section 41)Biodiversity Lists - EnglandEngland NERC S.4139753
UK list of Priority Habitats and SpeciesBiodiversity Action Plan UK list of priority speciesPriority Species39322not on former UK BAP list

Photos and media

Spatial distribution - hectad map

Click on one of the date ranges in the key to highlight that particular range. Click anywhere else on the map to go back to all three date ranges.
Thresholds:
Move mouse cursor over dot for info
Rejected records are excluded from this map. Unverified records are included.

Temporal distribution - records by year

Records that span more than one year are not included in this chart.

Temporal distribution - records by week