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/\e(old, (1[lhe Western /1/1'1111111I11 ;\1I1S,'1I1I1 Supplement No, 67: 217~230 (2004), Biogeographical patterns of zodariid spiders (Araneae: Zodariidae) in the wheatbelt region, Western Australia. Bradley J. Durrant Department of Conservation and Land Management, Science Division. 1'0 Box 51 W'lIlneroo. Western Australia 6946, Australia Abstract - 117 zodariid species were recorded from the Wheatbelt region of Western Australia after 12 months ot continuous pit trapping ,lt 306 quadrats (12 landform types at each of 24 survey areas), with an average richness of 3,98 per quad rat. Analysis of the data at the landscape scale showed no significant relationships between species composition and substrate at each quadrat, other than a weak north-south changeover in composition. Strongly localised patterns of composition at the species level were overt, with a high proportion of short-range endemic species. However a regional-scale analysis (of species compositional patterns by survey area) showed a distinct relationship with precipitation in the driest period. Also, species richness for each survey area and each landform type revealed a correlation between low richness and both high rainfall and low drainage. Greater knowledge of zodariid ecology is required to determine the possible influence of microhabitats on species composition, INTRODUCTION of zodariids had been collected from the wheatbelt The Zodariidae are medium-sized spiders, region, 'which is the main focus of the survey. currentlv divided into five subfamilies and Only 26';.(, of the wheatbelt region's area remains approximately 60 genera. They are ground-dwelling native vegetation, primarily consisting of small spiders, constructing a simple burrow with a silken uncleared bushland remnants surrounded by wheat retreat, although some Australian species construct fields (Ceorge and Coleman, 2(02). The large scale a palisade around the burrow entrance (Main, clearing of deep-rooted perennial vegetation, 1975). The use of burrows by all species has not combined with land irrigation (Hart cl Ill., 1990), been substantiated. Zodariids are obligate ant has resulted in an overall rise in the ground water feeding spiders (Jocque, 1991), many of which have and consequently an increase in the salinity of the behavioural attributes to capture prey. The lack of valley floors and lower slopes. This increase in aerial dispersal by juveniles ensures that zodariids salinity causes death of vegetation (Mulcahy, 1978; have potential for detailed biogeographic analyses Ruprecht and Schofield, 1991; Ceorge et 111.,1995). of relictual organisms (Jocque, 1993; Ramirez and In this paper, data collected during a detailed wet Beckwitt, 1995). Of the five recognised subfamilies, pitfall trap program, covering all major onlv three have been recorded from Australia: geomorphological units in the wheatbelt, are used to: Cvriocteinae (see Platnick and Criffin, 1988); a. Examine diversity of zodariids at species level Lachesaninae (Jocque, 1991); and Storeninae (see in an internationally recognised biodiversity ]ocqUE>, 1991, 1992, 1995; ]ocquE' and Baehr, 1992, hotspo!. 1995). b. Investigate patterns in zodariid species The Australian fauna is reasonablv well-known at composition and richness across the wheatbelt the generic level and the publication of a key to in terms of environmental attributes. subfamilies and genera (JocqUE>, 1995) has allowed c Determine whetlll'r secondan' salinisation is the rapid identification of adult males in museum liable to affect zodariid assemblage collections to these ranks. Ilowever, rnost genera composition. are unrevised and numerous species await description. Two genera have been revised. 51mcIlII Walckenaer nmv has 29 specie's (JocquE' and Baehr. METHODS II and As/cmll ]ocquEo h,lS been split into 8 new genera with over 100 species (Baehr and Study area )ocqm;, 1(96) of which 37 are described (Baehr and The wheatbelt studv area comprises all or part of locquEo, 2000, 20Ul). Revision of the As/a(lll complex fin' biogeographical regions (Figure I): the entire is continuing. Prior to this survev only eight species Avon Wheatbelt bioregioll, west\'rn two-thirds of 218 B. J. Durrant 11 118 KALBARRI 16 120 28 IBRA Regions o Geraldton Sandplains 2 & 3 o /!won Vllheatbelt 1 & 2 D Jarrah Forest 1 & 2 o Mlllee 1 &2 o Esperance Plains 1 & 2 o 100 Kilometres 118 120 Figure 1 Wheatbelt study area, showing the 304 quadrats, and relevant IBRA biogeographical region boundaries (Thackway and Cresswell, 1995). The different symbols indicate the 12 to 13 quadrats in each of the 24 survey areas. the Mallee, sou them half of the Gerald ton Ranges (ST), Unicup (U ); and the Dandaragan Sandplains, western edge of the Jarrah Forest and Plain (D ). the central quarter of the Esperance Plains. It covers Within each survey area, a quadrat was 205 000 km2 and extends from Esperance to Hill positioned as a typical example of each of the 10-12 River. For a more detailed explanation of the landform units (Mulcahy and Hingston, 1961) bioregions see McKenzie et al. (2004). comprising the wheatbelt landscape. One or two salt affected examples were also chosen resulting in Field sampling 12 to 13 quadrats in each survey area; Dandaragan, A three year survey was undertaken in 24 survey Kellerberrin, Morawa, arrogin, Northampton and areas (304 sites) in three bands, northern, central Quairading had 12 each, the rest had 13. This and southern (Figure 1). The survey areas are: decision was related to the number of salinised northern band; Beacon (BE), Julimar-Bolgart (JB), landforms present that could be used as pseudo Mullewa (ML), Morawa (MO), orthampton ( 0), replicates of the non-salinised landforms. Quadrat Wongan Hills (WH), Wubin (WU); central band; locations are provided in Appendix 2. Three Hyden (HY), Kellerberrin (KL), Kondinin (K ), quadrats were removed from the analysis due to Merredin (MN), Narrogin (NR), Quairading (QU), inundation of traps resulting in poor sampling Wickepin (WK), York (YO); southem band; Darkin (PI04, WK03 and UN13). (DA), Dumblyung (DU), Esperence (ES), Grass The survey areas served as pseudoreplicates Patch (GP), Lake King (LK), Pingrup (PI), Stirling because each of the landform units were sampled Zodariid spiders of the wheatbelt 219 PLATEAU Duricrust Breakaway ~ Spillway deposits / / Qe Quailing Erosional / K Kauring Qd Quailing Depositional M Monkopen Bg Belmunging B Balkuling Mg Malebelling Y York A Avon Mo Mortlock Sf Saltflat Sw Swamp (fresh) Figure 2 Wheatbelt landforms from McKenzie et nl. (200..J.; modified from Mulcahy and Hingston, 1961). The plateau profile comprises the top five lanc!forms (Qe, K, Qc!, M and Bg), with the dissection profile the bottom seven (B, Mg, Y, A, Mo, Sf and Sw). within each survey area; Sw (swamp), Sf (saltflat), metres apart. Each trap was a two litre plastic Mo (Mortlock), A (Avon), Y (York), Mg container (80 mm neck diameter and 25 cm deep) (Malobellin), B (Balkuling), Bg (Belrnungin), M set flush with the ground surface. It contained 400 (Monkopen), Qd (Quailing Depositional), K mL of preserving liquid, comprising 320 ml (Kauring) and Qe (Quailing Erosional) (Figure 2); ethylene glycot 64 ml tap water and 16 ml for detailed explanation of landforms see McKenzie formaldehyde. It was protected with a square plate et nl. (2004). of wood (15 cm x 15 cm) set 5 cm above the pit Traps were open for one calendar year (1825 pit mouth. trap nights per quadrat). Each band was sampled Samples were taken back to the laboratory, rinsed, separately with the central band traps open from sorted and then stored in 75% ethyl alcohol. All October 1997 to September 1998, northern band specimens were lodged with the W.A. Museum. September 1998 to October 1999 and traps in the southern band and Dandaragan Plain open from Data Analysis October 1999 to October 2000. The effect of seasonal The data matrix was constructed based on the sampling bias was minimised because quadrats presence and absence of species collected at each were sampled for an entire calendar year. However quadrat. The computer package PATN (Belbin, 1999 and 2000 were unusually dry years. This may 1995) was used to explore and expose species have influenced study outcomes. composition patterns. Similarities in species The five wet pitfall traps at each quadrat were composition between quadrats were compared positioned in different microhabitats and at least 5 using the Czekanowski association measure, and 220 B. J. Durrant the quantitative relationship between each pair of Table 1 List of recognised zodariid species identified species was determined using the Two-step from the survey. association measure. Dendrograms of the resulting Species Author association matrices were created using a modified unweighted pair group arithmetic averaging Australutica quaerens Jocque 1995 (UPGMA) hierarchical clustering strategy (Sneath Chilumena reprobans Jocque 1995 and Soka\, 1973), which was also used to reorder Habronestes australiensis (O.P.-Cambridge 1869) the data matrix as a two-way table. Habronestes grimwadei (Dunn 1951) Raven and Baehr 2000 Twenty-three geographic, 13 climatic Hetaenca harveyi Neostorena victoria Jocque 1991 (ANUCLIM; McMahon et al., 1995), 15 soil, four Pentasteron intermedium Baehr and Jocque 2001 vegetation, and three geomorphic variables Phenasteron longiconductor Baehr and Jocque 2001 including salinity risk (see McKenzie et al., 2004) Phenasteron machinosum Baehr and Jocque 2001 were taken for each quadrat (Appendix 3). Storena Formosa Thorell

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