SPIDER RECORDING
SCHEME


David R. Nellist
"Roundwood"
198A, Park Street Lane,
Park Street,
St Albans
Herts. AL2 2AQ

Tel 01727 872981

email davidnellist@compuserve.com

NEWSLETTER NUMBER 32.
November, 1998.

1. EDITORIAL.

1.1 Publication of the Provisional Distribution Maps.

Recorders will be sorry to learn that the publication of the provisional distribution maps, which we had been expecting late in 1999, has been delayed again, until 2001 or possibly even later. At my request Paul Harding, the Head of the Biological Records Centre, has contributed an article to this issue reviewing the progress of the SRS and setting out reasons for the delay. So, regrettably, the vast amount of information which we have accumulated since the scheme began in 1987 will now remain locked away for a few more years yet. But recording must continue as we strive to fill the gaps in our coverage of the country, and to generate text to accompany each map - points which Paul emphasises in his article. Generating text will be a big task. Little work has been done so far in the belief that such text would not be needed for the provisional maps, but would be included in the full Atlas when that was published a few years later.

1.2. The Newsletter.

Accompanying this issue are newsletters from the Pseudoscorpion and Harvestman Recording Schemes. These have been provided by the National Organisers of these schemes, Gerald Legg and Paul Hillyard, and they will in future be a regular feature of the November mailing.

1.3. News of Members.

{This section omitted to comply with the Data Protection Act}


2. PROGRESS TOWARDS THE PROVISIONAL ATLAS OF SPIDERS.

Paul Harding. (Head, Biological Records Centre, Institute of Terrestrial Ecology)

Why does anyone want an Atlas?

As a spider recorder, you would like, and deserve, to know how the recording scheme is progressing, where species have been recorded and where more recording is needed. But many other people also want to use the Atlas (and the data that the atlas will summarise), particularly in relation to nature conservation, and for assessing the importance of species for local site protection, for biogeographic research and for increasing awareness of and interest in spiders.

What should an atlas offer the user?

Maps - Above all it should give an authoritative, comprehensive and meaningful summary of the known distribution of spiders. For this, the overall coverage of the recording needs to be good: for example, a minimum number of species recorded from more than 60% of the 10km squares in the country. There are no settled wles for this type of threshold, but there is little point in publishing maps of all or most species in an atlas, when the majority of the maps will show more about the activity of the recorders than about the distribution of species.

Text - A set of maps with no explanatory text is of limited use to everyone except the most experienced and knowledgeable spider recorder. Other types of users require some explanation about a species and why it occurs everywhere, or just, say, in Sussex, Norfolk and Derbyshire. So we need some ecological notes on the species. Almost every atlas published by or on behalf of the Biological Records Centre (BRC) in the last 20 years has had explanatory text about the species mapped. This sort of text is all the more important for spiders because this information is not readily available in the standard British works.

Who is supporting the preparation of the atlas?

BAS and spider recorders - The most important supporters are you the recorders - without your enthusiasm and ability to collect, identify and contribute records to the scheme there would be no data and no prospect of an atlas. Similarly the collection and collation of records would not happen without the National Scheme Organiser, David Nellist (and before him the late Clifford Smith), the Area Organisers and others, such as Stan Dobson, with responsibilities for other aspects of the success of the SRS. That gets us to the point where a lot of data exist on record cards and in several personal databases - then what?

BRC - BRC’s job is to bring all these data together, computerise the data on the cards, get it all into a single database, validate the data (in collaboration with the scheme organiser and others), manage the database, produce the maps, advise on the preparation of text, edit the text and see the atlas through to publication. BRC’s role is dependent on resources being available, and funding from the Institute of Terrestrial Ecology (ITE) and the Joint Nature Conservation Committee (JNCC).

So what is the progress?

SRS is making really good progress in view of the small number of recorders and the large number of species, many of which are difficult to identify. In earlier newsletters, it has been suggested that the Provisional Atlas of spiders will be published in 1999. This is now looking increasingly unlikely for various reasons. The following explains where we have got to and what is proposed and why.

Coverage from fieldwork - The geographical coverage of records is still quite patchy. Even with some 22,000 completed RA65 record cards (probably about 150,000 individual records of some 630 species) there is still a long way to go with recording in many areas of Britain. There needs to be a significant effort to get into areas from where there are presently few records.

Coverage from collections and the literature - David Nellist and I have discussed the need to get some information, at least for selected species, from the more important museum and personal collections and from the more recent and reliable literature. SRS does not need every record of Araneus diadematus but SRS should be sure that every available record of, say, Argiope bruennichi or Xysticus luctator has been put into the database.

Drafting the text - David Nellist has begun to assemble literature to help in the drafting of the species accounts, but he urgently needs help to make progress with the first draft of some text which can then go out to appropriate ecological, taxonomic and regional experts for their comments. It could take over a year just to prepare brief species accounts for most of the species.

Resources at BRC - BRC has been undergoing a great deal of change in recent years and has had less time and resources to devote to many of the national recording schemes that it had hoped to support, including SRS. ITE and JNCC are just about to sign a new 6-year partnership agreement for BRC which will enable it to bring increased appropriate resources to help societies and schemes, such as SRS, develop their own potential and get the results they deserve. It is early days yet but BRC hopes to be able to target work on the SRS data and atlas during 1999/2000 and 2000/2001.

Jam tomorrow, again?

It may sound like this, but I hope you will agree that there are several good reasons for delaying the publication of the Provisional Atlas, probably until 2001. In the interim, BRC and David Nellist will look into the possibility of increasing the level of feedback on progress with recording nationally, especially coverage, and we hope to include a few maps in future newsletters. Finally, thank you for your contribution to the Spider Recording Scheme - long may it continue.


3. SHINGLE AND GRASSLAND SPIDERS ON HAVERGATE ISLAND.

Matthew Shardlow.

Coastal Suffolk is an area of outstanding importance for spiders. The combination of shingle, saltmarsh, reedbed, coastal grassland, coastal heaths, sand dunes and geographical position contributes to a unique and internationally important spider fauna, including at least six RDB species. Havergate Island, one of the RSPB’s Suffolk reserves and an NNR, with an area of some 108ha, is situated in the estuary of the River Ore and is important for its breeding birds, coastal vegetation and saline lagoon fauna. As part of the RSPB’s Biodiversity Monitoring Programme (BMP) it was decided that the spider fauna of the island should be regularly sampled to check for the presence and distribution of six key species - Euophrys browningi (RDB3), Haplodrassus minor (RDB3), Trichoncus affinis (RDB2), Sitticus inexpectus [= rupicola] (Na), Baryphyma duffeyi (RDB3) and Enoploanatha mordax (Na). Coastal grassland and shingle habitats were investigated to see if there were differences in the spider fauna. Although methodologies are not comparable it is possible to put the spider fauna of the island into context using the 1994 survey of Orford Ness by the British Arachnological Society [Nellist, D.R., A Survey of the Spiders of Orford Ness on the 18th. and 19th. June, 1994, Unpublished Report, BAS].

Six pitfall traps were placed randomly in each of three grassland habitats (long grass and bare patches; scraped baked clay; long grass). Fisher shingle traps were used to sample fauna moving in the shingle interstices, in five areas (including disturbed, vegetated and tideline shingle). Traps were run for 3 weeks, for three periods ending on 4th. May, 1st. June and sometime during September, 1997. In addition a small amount of hand collecting and sweep netting was carried out by Stephen Denny and Bill Welstead on the 2nd. May and 18th. August 1997.

1579 spiders were identified of 67 species. Twenty of these species were not found on the NNR during a survey by Morris and Parsons in 1992, and were not recorded on Orford Ness in 1994. Of the target species three of the six were recorded. Five specimens of Haplodrassus minor were trapped, two in the shingle trap on the tide line and three in the pitfall traps on Long Meadow (long grass and bare patches). Twelve specimens of Trichoncus affinis were taken. Eight of these were in vegetated shingle, but two were found in disturbed shingle and two in the pitfall trap on the tide line. A single specimen of Sitticus inexpectus was taken in the pitfall on the tide line. Of particular interest was the following list of eleven gnaphosid spiders recorded during the survey: Drassodes lapidosus (local), Drassodes cupreus (common), Haplodrassus minor (RDB3), Drassyllus lutetianus (Na), Drassylus pusillus (local), Zelotes electus (local), Zelotes latreillei (local), Zelotes apricorum (local), Zelotes subterraneus (local), Zelotes petrensis (Na) and Gnaphosa lugubris (Na).

A scoring system was used to determine the Species Quality Indices (SQls) for the spider assemblages in which points were allocated to each species depending on its status (32 for RDB, 16 for Na, 8 for Nb, 2 for local and 1 for common). Lists of species were scored, summed and then divided by the number of species trapped in that habitat to give the SQl. While only part of the assessment of any site, SQls can be used to provide an indication of the quality of the assemblage of any biological group and, for example, a high SQl is a good indication that there is an assemblage, or individual species, that are worth considering when managing a site. A review by Ball [Ball, S. G., The Importance of the Invertebrate Fauna of Thorne and Hatfield Moors; An Exercise in Site Evaluation, Thome and Hatfield Papers, 3, 34-65, 1992], of invertebrates caught in pitfall traps, listed 48 sites with SQls ranging from 1 .3 to 2.9. The 1994 Orford Ness survey produced a spider SQl of 3.6, close to the overall SQl of 3.37 recorded for Havergate. The SQl of 4.42, recorded for the shingle habitats on Havergate, is exceptionally high and potentially the highest spider SQl yet recorded in Britain. If there are any higher SQIs it would be interesting to hear about them. An SQl of 2.62 for the grassland area compares well with good natural habitats, such as the Mid-Yare Valley, which has an SQl of 2.23. Certainly the spider fauna of the shingle is of high national, and probable international, importance, but the same does not apply to the grassland fauna.

Clearly Havergate Island has a very important spider fauna with a species content markedly skewed towards rarity. This situation highlights the fact that biodiversity is about more than species richness. Havergate shingle is species poor but rarity rich. The island is situated in the estuary of a river system and, as such, its status is dynamic in the long term. Careful management of this dynamism will ensure that habitat for the saltmarsh and shingle species remains available on the site. Monitoring of the spider populations will continue and this will inform us of the success, or otherwise, of our management.

[Note: Further trapping in 1998 has so far added the following species to the Havergate list; Euophrys browningi (RDB3), Meioneta simplicitarsis (Na) and Agraecina striata (Nb)].


3. Theridion pinastri (L. Koch) NEW TO HERTFORDSHIRE

David Carr

With the site at Lippitts Hill, Epping Forest, Essex, where I had found Theridion pinastri in 1992, being approximately 8 miles away across the Lea Valley, the likelihood that the species occurred in the Broxbourne Woods NNR seemed high. However, habitat similar to that at Lippitts Hill with widely spaced oaks on grassland, I have found to be very limited at Broxbourne Woods. A small area of heath that had escaped becoming conifer plantation in Broxbourne Wood itself (TL 324073) appeared the most likely place to find the species. This area had several variously sized, widely spaced oaks on short, heathy-type grassland with a large patch of blackthorn and silver birch scrub. The whole site is surrounded by a conifer plantation.

On the 29th. May 1998, I was beating the outer branches of the oaks and a single, immature male was taken from a moderately sized tree. The spider was kept in a tube and fed on greenfly until it matured on the 8th. June 1998. Articles in BAS Newsletters No. 67 (Peter Harvey, David Carr and Helen Read), and No. 75 (David Carr and Peter Harvey) describe Theridion pinastri as being taken from deciduous trees at three sites in Essex, and at Burnham Beeches, where in each case there were no pines present. The Broxbourne Wood record differs in that although taken from oak, the wood is predominantly coniferous.


4. Argiope bruennichi (Scopoli) IN SURREY

David Baldock

On the 4th. October 1998 I was searching for Roesel’s Bush-cricket (Metrioptera roeselii) in a south-facing, overgrown, grass field in Milford. As I was leaving I saw a female Argiope bruennichi on her web. I had seen this spider in France on various occasions but never in England. I returned three days later but failed to find any more specimens as the weather was windy and cold. However I did find a dozen egg-sacs in a small area of the field. I opened one of these and found it to be full of well-grown spiderlings, which already had faint stripes on the abdomen.


My thanks go to those who have supplied notes and information for this issue. Newsletter No. 33 will be published in March 1999 and I do need contributions for that. So, do please send in your articles and notes as soon as possible. Thank you.

David R. Nellist.
National Organiser
“Roundwood”, 198A Park Street Lane, Park Street, St Albans, Harts., AL2 2AQ.


All material is Copyright British Arachnological Society
British Arachnological Society 1999

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