Arachnid fauna from the Castro Verde Special Protection Area, Southern Portugal

Study Extent

Sampling was conducted in 80 open grassland parcels located inside the Castro Verde SPA (Beja District, southern Portugal). Sampling occurred between April and May, 2012.

Sampling

Sampling was conducted in 80 open grassland parcels selected based on a network of sampling sites established in 2012 to study the effects of grazing regimes on farmland birds (Ramos et al. 2022). Specifically, parcels were selected following a stratified random procedure with some restrictions. We started by identifying fallows and permanent pastures grazed by either sheep or cattle, based on parcel-level statistical information from 2010 provided by the Portuguese Ministry of Agriculture (Ribeiro et al. 2014). To minimize potentially confounding effects of adjacent land uses and other noncrop elements within parcels, we excluded parcels less than 100 m from shrubland or forested areas, with shrub and tree cover bigger than 5% and with a size smaller than 10 ha. Then, we randomly selected 120 parcels and performed fieldwork to confirm land uses and select a balanced proportion of 80 fallow and permanent pastures, grazed by sheep and cattle.

Quality Control

All specimens were morphological identified by specialist in Iberian arachnids taxonomy. Prior submission to GBIF, data was checked for errors and inconsistencies with OpenRefine 3.4.1 (http://openrefine.org/)

Method steps

1. Specimens were collected in 80 open grassland parcels located inside the Castro Verde SPA (Beja District, southern Portugal), and field fieldwork was carried out between April,4, and May, 9, 2012. The sampling scheme comprised 10/12 sampling plots positioned at 50-meter intervals around the central point of each parcel.
2. Each sampling plot consisted in a 3-meter radius circle, in which we collected 10 sub-samples of 15 s duration (total area per sample=1.94 m) using a Vortis suction sampler (Burkard Manufac-turing Co., Ltd., UK) (Fig. 1). Sub-samples were stored in vials with 70% ethanol.
3. Vegetation height was estimated for each plot by taking ten measurements at random locations within the plot using a 50 cm ruler, and recording the highest point of vegetation projection within three centimeters of the ruler to the nearest half-centimeter (Ramos et al. 2021).
4. Samples were cleaned and sorted into major taxonomic groups at the CIBIO/InBIO laboratory in Lisbon, using relevant general bibliography. To facilitate the separation of invertebrates from soil debris and vegetation in the samples, a mixture of magnesium sulfate (MgSO4) was added to the alcohol, causing the invertebrates to float (Zaborski and Cloyd 2004). Sorted invertebrates were preserved in 70% ethanol with 5% glycerine.
5. Taxonomic identification of the Araneae was carried out by José A. Barrientos in his personal office, following the general guidelines: observation and manipulation with a binocular microscopy and cold illumination, and the help of the relevant bibliography (Locket and Millidge 1951, 1953; Locket et al. 1974; Nentwig et al. 2023; Roberts 1985, 1987, 1995; Simon 1914, 1929, 1932, 1937; Wiehle 1956, 1960).
6. Taxonomic identification of the Opiliones was carried out by Carlos E. Prieto at the Zoology Laboratory of the Basque Country University, following classical procedures (observation under binocular stereomicroscope, penis removal and temporal mounting for microscopical study) with the help of the relevant bibliography (Rambla 1967, Martens 1978, Prieto and Merino-Sáinz 2020).
7. Spider samples were deposited at JAB personal collection (Barcelona, Spain), and the harvestmen samples were deposited in the Zoology Collection of the Basque Country University (ZUPV). All the specimens reported in the manuscript are available under request.

This dataset is composed of data relating to 9809 arachnids specimens (Orders: Acarina, Araneae, Opiliones and Pseudoescorpiones). All specimens were morphologically identified, 45% to species level, 36% to genus level and 18% to family level. Overall, 73 species are represented in the dataset, 71 Araneae and two Opiliones species. These species belong to 27 families. Two families (Thomisidae, 36.7%; Linyphiidae, 28.7%; both Araneae) account for 65.4% of the total collected specimens. Five families account for 64.4% of the total species represented (Linyphiidae, 20.5%; Theridiidae, 15.1%; Gnaphosidae, 11.0%; Salticidae, 9.6%; Thomisidae, 8.2%; all Araneae). Thirteen families are represented by a single species. The most abundant species in the dataset was the linyphiid spider Agyneta pseudorurestris Wunderlich, 1980, accounting for 14% of the total specimens collected.

1. Animalia
   rank: kingdom
2. Arthropoda
   rank: phylum
3. Arachnida
   rank: class
4. Acarina
   rank: order
5. Araneae
   rank: order
6. Opiliones
   rank: order
7. Pseudoescorpiones
   rank: order
8. Agelenidae
   rank: family
9. Anyphaenidae
   rank: family
10. Araneidae
    rank: family
11. Cheiracanthiidae
    rank: family
12. Clubionidae
    rank: family
13. Dictynidae
    rank: family
14. Dysderidae
    rank: family
15. Gnaphosidae
    rank: family
16. Linyphiidae
    rank: family
17. Liocranidae
    rank: family
18. Lycosidae
    rank: family
19. Mimetidae
    rank: family
20. Miturgidae
    rank: family
21. Nemesiidae
    rank: family
22. Oonopidae
    rank: family
23. Oxyopidae
    rank: family
24. Philodromidae
    rank: family
25. Pisauridae
    rank: family
26. Salticidae
    rank: family
27. Scytodidae
    rank: family
28. Synaphridae
    rank: family
29. Tetragnathidae
    rank: family
30. Theridiidae
    rank: family
31. Thomisidae
    rank: family
32. Zodariidae
    rank: family
33. Phalangiidae
    rank: family
34. Sclerosomathidae
    rank: family
35. Oribatidae
    rank: family

Southern Continental Portugal