Carorita limnaea (Araneae: Linyphiidae) and other Araneae at Wybunbury Moss, Cheshire - a unique refuge for two relict species of spider in Britain

5 Pages·1997·0.24 MB·English

by  Felton, C

298 Effectofstarvationonwebgeometry
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W.Nentwig(ed.),Ecophysiologyofspiders:357–370.Springer,
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Bull.Br.arachnol.Soc.(1997)10(8),298–302
Carorita limnaea (Araneae: Linyphiidae) and other The site
Araneae at Wybunbury Moss, Cheshire—a unique
Wybunbury Moss is a National Nature Reserve
refuge for two relict species of spider in Britain
(NNR) and a Site of Special Scientific Interest which is
givenGrade1StatusintheBritishNatureConservation
C. Felton and S. Judd
Review(Ratcliffe,1977).Itispositionedalmostcentrally
ZoologyDepartment,
in the recently designated Midlands Meres and Mosses
LiverpoolMuseum,
WilliamBrownStreet, Ramsar Site and is one of the two best examples of
LiverpoolL38EN schwingmoorintheBritishIsles(EnglishNature,1991).
ChartleyMossNNR,Staffordshire(Gridref.SK02-28-)
and Wybunbury Moss are ‘‘subsidence raised mires’’
Summary
andarestructurallyuniqueinBritain.Theyareofgreat
The distribution of the endangered, British Red Data scientific importance within a national and a European
Bookstatus1,linyphiidspider,Caroritalimnaea(Crosby& context (English Nature, 1991).
Bishop) is described at Wybunbury Moss, Cheshire. The Reserve is small (11.43ha), very compact, with
C. limnaea was not recorded during a survey of ten different habitats compressed together, and is sur-
other schwingmoors in Cheshire, Shropshire, Staffordshire
roundedby3.8haofwetpasture,whichisalsomanaged
and Clwyd. Both it and Gnaphosa nigerrima L. Koch
are relict species, apparently restricted in Britain to by English Nature. It is not contiguous with any areas
Wybunbury Moss. One hundred and thirty-three spider of known ecological importance, being isolated in an
species are recorded from the site. Eleven species of agricultural and urban landscape.
harvestmenandonepseudoscorpionarealsorecorded.
Four major plant communities occur in the
Reserve—Sphagnum lawn; pine woodland; fen wood-
land; and mixed birch, oak, and rowan woodland
(Poore&Walker,1958;Green&Pearson,1968).These,
Introduction
together with the surrounding wet grassland were most
In 1994 English Nature funded a Liverpool Museum recently mapped in the site management plan (English
surveytodeterminethestatusandconservationrequire- Nature, 1991). The post-glacial history of the site was
ments of Carorita limnaea, a minute linyphiid spider discussed by Green & Pearson (1977).
knowninBritainonlyfromWybunburyMoss,Cheshire Its small size and isolation make the site vulner-
(Gridref.SJ697503).Itwasfirstrecordedtherein1962 able, particularly to run-off water containing fertiliser
(Duffey & Merrett, 1963) and subsequently by J. R. fromsurroundingagriculturallandanduntilrecently,to
Parker in 1970 and C. Fulton in 1982 (English Nature, eutrophic water from adjacent houses. This pollution
1991), and S. Dobson and J. D. Stanney in 1993 (Scott, extends across nearly two-thirds of the site and has led
1993).Thepossiblethreatstoitssurvivalatthissitewere to the deterioration of the surface-floating peat raft and
briefly summarised by Merrett (1991). inseveralplacestoitscollapseandalsotothespreadof
Little is known about the biology of this species. It is rheophilous mire communities (Rieley & Page, 1990).
rare throughout its extensive Holarctic range and is ThisisapotentialthreattoC.limnaeaandotherspiders.
recorded from the United States, Belgium, Germany, Recent management at the site has included the
Sweden and Finland (Duffey & Merrett, 1963) and reversal of the successional advancement of pine/birch
recently,fromanumberofriverbasinsitesinnorth-east woodland on the Sphagnum lawn and the successful
Asia (Marusik, Eskov & Kim, 1992), and Canada and instalment of a pumped drainage system to stop house-
throughout northern Asia (see Eskov, 1994). hold pollution.
C.Felton&S.Judd 299
Wybunbury Moss is treacherous and access is strictly diameter sieve with 7mm square mesh. The concen-
controlled by English Nature. tratedsampleswereplacedinplasticbagsandsortedby
heat extraction at the Museum, over a 10-day period,
using Burkard Tullgren funnels.
Methods
Sweep-netting: Fifty sweeps were made along two
Field collecting skills were balanced by repeatable transects on the schwingmoor and four in the marginal
fixed-point trapping, sieving and sweep-netting which wet meadows (Fig. 1).
maximisedtherecordingofspidersandreducedtherisk Hand-searching: Three person days, spread over six
of failure due to over-reliance on one technique. The visits,werespentsearching22‘‘promising’’areaschosen
repeatable samples were collected at 14-day intervals at the discretion of the surveyor.
between30Juneand8September1994.Hand-searching Othersites:Fivepersondayswerespentsearchingten
beganon23June1994.Voucherspecimensarestoredat other schwingmoors: Abbots and Shemmy Moss,
Liverpool Museum. Cheshire(SJ59-68-),19July1994;BlackLake,Cheshire
The Sphagnum recurvum-dominated lawn was inten- (SJ538709), 19 July 1994; Flaxmere, Cheshire (SJ
sively surveyed because all previous site records for 555724), 19 July 1994; Little Budworth Country Park,
C. limnaea were from Sphagnum. Areas where the lawn Cheshire (SJ587657), 19 July 1994; Brown Moss,
grades into tall pine woodland were surveyed and the Shropshire (SJ56-39), 26 July 1994; Clarepool Moss,
marginalwetgrasslandwasalsoinvestigatedbecausethe Shropshire (SJ43-34), 26 July 1994; Chartley Moss,
closely related C. paludosa Duffey occurs in open fens. Staffordshire (SK02-28-), 29 July 1994; Cranberry Bog,
Thefenwoodlandwasonlybrieflyvisitedandthemixed Staffordshire (SJ74-50-), 20 July 1994; Llay Bog, Clwyd
woodland was ignored. (SJ322554), 12 July 1994; Vicarage Moss, Clwyd
Pitfalltrapping:Eleven,10msquarepitfallgridswith (SJ360540), 12 July 1994.
nine 80mm diameter catering cups in a 3(cid:1)3 matrix,
containing 10% formalin/ethylene glycol solution, were
Results
set—seven on the schwingmoor along two transects
laid out at right angles across the axes of the mire, one C. limnaea: Ninety-three specimens were collected
in pine woodland and three in marginal wet grassland from 16 June–8 September from 29 sampling stations
(Fig. 1). Wire mesh domes prevented the capture of (Fig. 1). Thirteen (11(cid:3) 2(cid:4)) were from pitfalls, 37 (8(cid:3)
small mammals and a ‘‘double cup system’’ minimised 29(cid:4))fromconcentratedsievings,and43(13(cid:3)30(cid:4))from
disturbance when the traps were emptied. Pitfalls were hand-searching, but none was sweep-netted. It was
foundunsuitableforuseinwetfenandunstablepartsof found to be widely distributed in the schwingmoor,
the schwingmoor. where it occurs in low numbers, always in Sphagnum.
Sieving: A two-gallon (9l) bucket was filled with ‘‘Hot spots’’ were along the south-facing northern
Sphagnum/fen/carr litter from nine points within a 3m marginoftheschwingmoor(14specimens),inarecently
square, at eight sampling stations on the schwingmoor cleared area to the north of the schwingmoor (17
and four in the peripheral wet grassland (Fig. 1). specimens) and on the extreme eastern end of the lawn,
Samplesweresievedtwice,for10minutes,usinga35cm where there is some stunted pine (15 specimens). One
Fig.1: LocationandnumberofCaroritalimnaeaspecimenscollectedatWybunburyMoss.Allfixed-pointsamplingandsuccessfulhand-search
areasareindicated.
300 WybunburyMossAraneae
specimen was recorded from Sphagnum in the pine Lophopilio palpinalis (Herbst), Leiobunum rotundum
woodland, but none was recorded from the fen wood- (Latreille) and L. blackwalli Meade, and the pseudo-
land or wet grassland, nor was it recorded at any of the scorpion Neobisium muscorum (Leach) were also
other ten sites visited. recorded.
Females were recorded in all sampling periods from
16 June to 8 September, and males from 16 June to 25
Discussion
August. There was some indication that peak numbers
ofmalesoccurredinJuneandearlyJuly,andfemalesin Caroritalimnaea:TheRedDataBook1(Endangered)
late July and August, but the numbers were small. status, given to this species in Bratton (1991), is fully
Other species: One hundred and thirty-three spider justified. The invertebrates of British lowland peat
specieswererecordedfromthesite,ofwhichforty-seven mosses have been surveyed intensively during the last
are new site records and are printed in bold type in ten years, e.g. at Thorne Moors, Yorkshire (Skidmore
Table 1. A further seven species previously recorded et al., 1985), Welsh sites (Holmes et al., 1991), five
from the site, but which were not found during this Cumbrian sites (Drake et al., 1989), Chartley Moss
survey, are: Gnaphosa leporina (L. Koch), Clubiona NNR, Staffordshire (Procter, 1987), Fenn’s, Whixall
corticalis (Walckenaer), Xysticus erraticus (Blackwall), and Bettisfield Mosses NNR (Liverpool Museum,
Tegenaria silvestris L. Koch, Theridion melanurum 1994). There were, however, no additional records for
Hahn, Hypselistes jacksoni (O. P.-Cambridge) and C. limnaea and the species is still only known from
Agyneta subtilis (O. P.-Cambridge). The record of Wybunbury Moss in Britain.
Agyneta cauta (O. P.-Cambridge) in Duffey & Merrett TheresultssuggestthatC.limnaeaisnotinimmediate
(1963) is A. olivacea (Emerton) (P. Merrett, pers. danger at Wybunbury Moss. It is restricted to the
comm.). Sphagnum lawn where it is widely distributed, but un-
It must be emphasised that recording at the site was common. It was caught in pitfalls and must, therefore,
greatly biased towards the Sphagnum lawn and limited sometimes occur on the surface of the lawn. However,
to a short time period. The lower number of species the small numbers trapped compared with those found
given for the other habitats in Table 1 does not reflect in the concentrated sieving samples suggest that it is
their likely fauna. more abundant within Sphagnum.
The first British specimens of Gnaphosa nigerrima Itwasmostfrequentlycollectedinthreewarm,south-
were discovered in two pitfall grids in the south-east facing, sheltered areas, where there is a transition be-
corner of the schwingmoor at Wybunbury Moss on tween open Sphagnum lawn and pine. This habitat is
30 June 1994. This species also appears to be restricted, being actively created by felling pine and ‘‘opening-up’’
in Britain, to this site (Felton, 1997). the margins of the Sphagnum lawn or by allowing pine
The schwingmoor at Wybunbury supports a unique to invade the Sphagnum lawn and remain in isolated
andnationallyimportantassemblageofRedDataBook pockets. Post-1985 management work aimed at revers-
spiders. Two species, C. limnaea and G. nigerrima, are ing the successional advancement of pine/birch wood-
recorded from nowhere else in Britain and a third, the land on the Sphagnum appears to have been successful.
RDB3jumpingspider,Sitticusfloricola(C.L.Koch)is Continued management of this pine/Sphagnum ecotone
veryrestricted(Merrett,1991;Wallace&Wallace,1991) willbeessentialforthefutureconservationofthisspider
(at least four other Red Data Book invertebrate species at the site.
are also recorded from the Reserve). C. limnaea is unlikely to suffer from human distur-
TheonlyothernotableBritishspiderspeciesrecorded, bance, as the site is a restricted access Reserve and its
thatisassociatedwithSphagnumbogs,wasthelinyphiid use for educational purposes has been generally dis-
Notioscopus sarcinatus (O. P.-Cambridge). Paradoxi- couraged. Aerial pollution and global warming are
cally, the remaining species are all local or common in potential long-term threats to the sensitive Sphagnum
distribution throughout Britain. Many species on the communities which support C. limnaea.
Sphagnum lawn, such as Salticus cingulatus (Panzer), Collecting techniques: The pitfall trapping was not
Theridion mystaceum L. Koch and Nuctenea umbratica particularly effective in relation to the collection of
(Clerck) were associated with dead and dying pine and C. limnaea, but it was very successful for other spider
birch. Others, such as Episinus angulatus (Blackwall) species. It was difficult to set pitfalls flush to the surface
and Crustulina guttata (Wider), were on and under of the Sphagnum and the lip of the cup may have
heather. prevented capture of C. limnaea. Sieving and hand-
Interestingly, although Pirata piraticus (Clerck) and searchinginthefieldprovideddistributionalrecordsand
Trochosa terricola Thorell were present, their respective were slightly more productive than the concentrated
congeners P. tenuitarsus Simon and T. spinipalpis sampling/Tullgren funnel method.
(F.O.P.-Cambridge), which are also associated with The sampling programme has enabled an assessment
Sphagnum, were not recorded. of the distribution and abundance of C. limnaea at
The harvestmen Nemastoma bimaculatum (Fabrici- Wybunbury.Itdoesnotexplaintheprecisemicrohabitat
cus), Oligolophus tridens (C. L. Koch), Paroligolophus requirements, which might, for instance, be the raised,
agrestis (Meade), Lacinius ephippiatus (C. L. Koch), drier areas around pine stumps. The absence of
Mitopus morio (Fabricius), Phalangium opilio Linnaeus, C.limnaeafromSphagnumelsewhereinBritainsuggests
Opilio parietinus (Degeer), Rilaena triangularis (Herbst), that there may be something special about Wybunbury.
C.Felton&S.Judd 301
A B C A B C
Amaurobiusfenestralis(Stroem) + + (cid:5) W.nodosa(O.P.-Cambridge) + (cid:5) (cid:5)
Dictynaarundinacea(Linnaeus) + (cid:5) + W.atrotibialis(O.P.-Cambridge) + (cid:5) (cid:5)
Segestriasenoculata(Linnaeus) + (cid:5) (cid:5) W.nudipalpis(Westring) + (cid:5) (cid:5)
Drassodescupreus(Blackwall) + (cid:5) (cid:5) W.furcillata(Menge) + (cid:5) (cid:5)
Haplodrassussignifer(C.L.Koch) + (cid:5) (cid:5) W.vigilax(Blackwall) + (cid:5) (cid:5)
Zeloteslatreillei(Simon) + (cid:5) (cid:5) Dicymbiumnigrum(Blackwall) + (cid:5) (cid:5)
GnaphosanigerrimaL.Koch + (cid:5) (cid:5) D.tibiale(Blackwall) + (cid:5) (cid:5)
ClubionareclusaO.P.-Cambridge + + (cid:5) Hylyphantesgraminicola(Sundevall) (cid:5) + (cid:5)
C.lutescensWestring + (cid:5) (cid:5) Gnathonariumdentatum(Wider) + (cid:5) (cid:5)
C.brevipesBlackwall (cid:5) + (cid:5) Gongylidiumrufipes(Linnaeus) (cid:5) + (cid:5)
C.diversaO.P.-Cambridge (cid:5) + (cid:5) Hypommabituberculatum(Wider) + (cid:5) (cid:5)
Scotinagracilipes(Blackwall) + (cid:5) (cid:5) Masosundevalli(Westring) + (cid:5) (cid:5)
Phrurolithusfestivus(C.L.Koch) + (cid:5) (cid:5) Peponocraniumludicrum(O.P.-Cambridge) + (cid:5) (cid:5)
Zoraspinimana(Sundevall) + + + Pocadicnemispumila(Blackwall) + (cid:5) (cid:5)
Xysticuscristatus(Clerck) + + + P.junceaLocket&Millidge + (cid:5) (cid:5)
X.ulmi(Hahn) + (cid:5) (cid:5) Oedothoraxgibbosus(Blackwall) + (cid:5) (cid:5)
Ozyptilatrux(Blackwall) + (cid:5) (cid:5) O.fuscus(Blackwall) + (cid:5) (cid:5)
PhilodromusdisparWalckenaer (cid:5) (cid:5) + O.retusus(Westring) + (cid:5) (cid:5)
P.cespitum(Walckenaer) (cid:5) + (cid:5) Cnephalocotesobscurus(Blackwall) + (cid:5) (cid:5)
Tibellusoblongus(Walckenaer) + (cid:5) (cid:5) Tapinocybapallens(O.P.-Cambridge) + (cid:5) (cid:5)
T.maritimus(Menge) + (cid:5) (cid:5) Lophommapunctatum(Blackwall) + (cid:5) (cid:5)
Salticuscingulatus(Panzer) + (cid:5) (cid:5) Gongylidiellumvivum(O.P.-Cambridge) + (cid:5) (cid:5)
Heliophanusflavipes(Hahn) + (cid:5) (cid:5) Micrargusherbigradus(Blackwall) + (cid:5) (cid:5)
Neonreticulatus(Blackwall) + (cid:5) (cid:5) Notioscopussarcinatus(O.P.-Cambridge) + (cid:5) (cid:5)
Euophrysfrontalis(Walckenaer) + + (cid:5) Diplocephaluspermixtus(O.P.-Cambridge) (cid:5) + (cid:5)
Sitticusfloricola(C.L.Koch) + (cid:5) (cid:5) D.latifrons(O.P.-Cambridge) + (cid:5) (cid:5)
Pardosapalustris(Linnaeus) + (cid:5) (cid:5) D.picinus(Blackwall) + (cid:5) (cid:5)
P.pullata(Clerck) + + + Araeoncuscrassiceps(Westring) + (cid:5) (cid:5)
P.amentata(Clerck) + (cid:5) + Erigonedentipalpis(Wider) + (cid:5) (cid:5)
P.nigriceps(Thorell) + (cid:5) + E.atraBlackwall + (cid:5) (cid:5)
Alopecosapulverulenta(Clerck) + (cid:5) + Leptorhoptrumrobustum(Westring) + (cid:5) (cid:5)
TrochosaterricolaThorell + (cid:5) (cid:5) Caroritalimnaea(Crosby&Bishop) + (cid:5) (cid:5)
Piratapiraticus(Clerck) + (cid:5) (cid:5) Aphiletamisera(O.P.-Cambridge) + (cid:5) (cid:5)
P.hygrophilusThorell + (cid:5) + A.olivacea(Emerton) + (cid:5) (cid:5)
P.uliginosus(Thorell) + (cid:5) (cid:5) A.ramosaJackson + (cid:5) (cid:5)
P.latitans(Blackwall) + (cid:5) (cid:5) Meionetasaxatilis(Blackwall) + (cid:5) (cid:5)
P.piscatorius(Clerck) + (cid:5) + Micronetaviaria(Blackwall) + (cid:5) (cid:5)
Pisauramirabilis(Clerck) + (cid:5) + Centromerusarcanus(O.P.-Cambridge) + (cid:5) (cid:5)
HahniapusillaC.L.Koch + (cid:5) (cid:5) C.dilutus(O.P.-Cambridge) + (cid:5) (cid:5)
Episinusangulatus(Blackwall) + (cid:5) (cid:5) Saaristoaabnormis(Blackwall) + (cid:5) (cid:5)
Crustulinaguttata(Wider) + (cid:5) (cid:5) Bathyphantesapproximatus(O.P.-Cambridge) + (cid:5) (cid:5)
Steatodabipunctata(Linnaeus) + (cid:5) (cid:5) B.gracilis(Blackwall) + (cid:5) (cid:5)
Theridionsisyphium(Clerck) + + (cid:5) B.nigrinus(Westring) + (cid:5) (cid:5)
T.impressumL.Koch + (cid:5) (cid:5) B.parvulus(Westring) + (cid:5) (cid:5)
T.pictum(Walckenaer) + (cid:5) (cid:5) Kaestneriapullata(O.P.-Cambridge) + (cid:5) (cid:5)
T.mystaceumL.Koch + (cid:5) (cid:5) Poecilonetavariegata(Blackwall) + (cid:5) (cid:5)
T.pallensBlackwall + + (cid:5) Drapetiscasocialis(Sundevall) (cid:5) + (cid:5)
Enoplognathaovata(Clerck) + (cid:5) (cid:5) Tapinopalongidens(Wider) (cid:5) + (cid:5)
Robertuslividus(Blackwall) + (cid:5) (cid:5) Floroniabucculenta(Clerck) + (cid:5) (cid:5)
R.arundineti(O.P.-Cambridge) + (cid:5) (cid:5) Stemonyphanteslineatus(Linnaeus) + (cid:5) (cid:5)
Tetragnathaextensa(Linnaeus) + + + Lepthyphantesminutus(Blackwall) + + (cid:5)
T.montanaSimon + (cid:5) (cid:5) L.alacris(Blackwall) (cid:5) + (cid:5)
PachygnathaclerckiSundevall + (cid:5) (cid:5) L.tenuis(Blackwall) + (cid:5) (cid:5)
P.degeeriSundevall + (cid:5) (cid:5) L.zimmermanniBertkau + (cid:5) (cid:5)
Metellinasegmentata(Clerck) + + + L.cristatus(Menge) + (cid:5) (cid:5)
M.mengei(Blackwall) (cid:5) + (cid:5) L.mengeiKulczynski + (cid:5) (cid:5)
M.merianae(Scopoli) (cid:5) + (cid:5) L.ericaeus(Blackwall) + (cid:5) (cid:5)
Zygiellax-notata(Clerck) + (cid:5) (cid:5) L.pallidus(O.P.-Cambridge) + (cid:5) (cid:5)
Z.atrica(C.L.Koch) + + (cid:5) Helophorainsignis(Blackwall) (cid:5) + (cid:5)
AraneusdiadematusClerck + + (cid:5) Linyphiatriangularis(Clerck) (cid:5) + (cid:5)
A.quadratusClerck + (cid:5) + L.hortensisSundevall (cid:5) + (cid:5)
Larinioidescornutus(Clerck) + (cid:5) + L.montana(Clerck) + + (cid:5)
Nucteneaumbratica(Clerck) + (cid:5) (cid:5) L.clathrataSundevall + + (cid:5)
Araniellasp. (cid:5) + (cid:5) L.peltataWider (cid:5) (cid:5) +
Ceratinellabrevipes(Westring) + (cid:5) (cid:5) Microlinyphiapusilla(Sundevall) + (cid:5) (cid:5)
C.brevis(Wider) + (cid:5) (cid:5) Allomengeavidua(L.Koch) + (cid:5) (cid:5)
WalckenaeriaacuminataBlackwall + (cid:5) (cid:5) TOTALS 133 116 30 16
Table1: WybunburyMossspiders.Namesinbold=newsiterecord.A=Sphagnumlawn,B=Pineandfenwoodland,C=Wetgrassland.
302 WybunburyMossAraneae
Historical perspective: It is important to interpret the ENGLISH NATURE, 1991: Wybunbury Moss Management Plan.
distribution of C. limnaea and G. nigerrima in geo- Shrewsbury,EnglishNatureWestMidlandsRegionalOffice.
graphical space and time. The apparent restriction of ESKOV,K.Y.1994:CatalogueofthelinyphiidspidersofnorthernAsia
(Arachnida, Araneae, Linyphiidae). 1–144. Pensoft, Sofia and
these species, in Britain, to Wybunbury Moss, is a
Moscow.
biogeographical puzzle. Both species must have been
FELTON,C.1997:GnaphosanigerrimaL.Koch(Araneae:Gnaphos-
present in Britain, but not necessarily at Wybunbury, idae), a spider new to Britain. Bull. Br. arachnol. Soc. 10(8):
during the Boreal period, before the severance of the 311–312.
landconnectionwithcontinentalEurope(c.8,300).It GREEN, B. H. & PEARSON, M. C. 1968: The ecology of
is most unlikely that they are more recent immigrants. Wybunbury Moss, Cheshire. 1. The present vegetation and
some physical, chemical and historical factors controlling its
They could possibly have been widely distributed
natureanddistribution.J.Ecol.56:245–267.
throughout Britain during the extension of ombrog-
GREEN, B. H. & PEARSON, M. C. 1977: The ecology of
enous mires in the Atlantic Period (c.6,000), with Wybunbury Moss, Cheshire. 2. Post-glacial history and the
their distributions contracting due to subsequent de- formation of the Cheshire mere and mire landscape. J. Ecol.
struction and fragmentation of this habitat, until they 65:793–814.
became restricted to Wybunbury Moss, which has been HAMMOND,P.M.1974:ChangesintheBritishcoleopterousfauna.
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Britain:323–369.TheSystematicsAssociationSpecialVolume
Relict populations, restricted to one, or a few,
No.6.London,AcademicPress.
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