Summary for Haplodrassus soerenseni (Araneae)
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About this speciesRecorded altitude range
225m to 280m
In Britain, the species has been recorded only from Abernethy Forest, East Inverness-shire and from the Black Wood of Rannoch, Mid Perthshire. It has also been found in Sweden, Norway, Finland, Russia, Poland, the former Czechoslovakia, Switzerland and Austria.
Habitat and ecology
In Britain, the spider is apparently confined to Caledonian pine forest. It is found among ground vegetation in open pinewoods. Females with eggs have been noted in July and adults also occur in June.
Collected from six locations within a single extended site since 1992. Area of occupancy has declined from three hectads prior to 1992 to just one since that date. Rather few specimens have been found, although it was recorded at Abernethy in 1999 and 2006, and it was taken in some numbers in pitfall traps between 2002-2005 in a study on experimental field-layer burning and cutting in native pinewood, at Abernethy forest RSPB reserve.
The loss of Caledonian pine forest, often to more intensive forestry. Planting is usually at a density of 2,500 trees per hectare, and this produces 'blanket' forest with little light reaching the ground and virtually no ground flora. Such conditions eliminate H. soerenseni along with most of the other fauna and flora. The establishment of plantations adjacent to native forest precludes the natural expansion of the forest and threatens existing forest through allowing its invasion by the exotic species. The exotics frequently out-compete the native Scots pine Pinus sylvestris.
Management and conservation
Management should aim to conserve and expand the native component to ensure the future of the native pine, but closing-in of the forest canopy needs to be avoided. Fencing and deer-culling are promoting strong regeneration of pine in parts, and much thinning with the creation of glades may need to be implemented if the ground vegetation is to be maintained in a state suitable for H soerenseni. Abernethy Forest has been owned and managed by the RSPB since about 1990 and the primary aim is to develop a self-sustaining native pine forest over the whole potential woodland area (Taylor in Aldhous 1995).
Text based on Dawson, I.K., Harvey, P.R., Merrett, P. & Russell-Smith, A.R. (in prep.). References
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