Optimising spider survey techniques

Harris, Rachael (2021) Optimising spider survey techniques. Honours thesis, University of Southern Queensland. (Unpublished)

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Spiders have important ecological roles as generalist predators and bioindicators of environmental health but are poorly studied. To determine spider diversity and abundance, the most commonly used techniques for surveying spiders are pitfall trapping and hand collection, however, each technique has sampling bias as they target different vegetative strata and therefore different spider species. Furthermore, these survey techniques are often time consuming or are primarily used for capturing other arthropods with spiders as secondary capture. A new survey technique based on vibration to attract a wide diversity of spiders was tested. The hypothesis tested was that the vibration-based technique would produce a greater diversity of spider species and a greater species richness quicker than pitfall trapping and hand collection, and thus improve survey techniques for spiders to improve conservation management strategies.

This research (1) compared the two mostly commonly used survey techniques with a new vibration-based survey technique to compare the diversity of spider species captured and time required to undertake each technique; (2) explored the relationship between spider species captured over time in pitfall traps, night collection and from use of the vibration-based technique; (3) provided a species list of spiders in open dry sclerophyll woodland in south-east Queensland; and (4) provided information to expand the limited literature on survey techniques for spiders.

In four locations eight similar 900 m2 sites in open dry sclerophyll woodland were used; four sites (A) incorporated use of pitfall traps, hand collection and the vibration-based technique, and in four adjacent sites (B) only the vibration-based technique was used to collect spiders. These sites were 30 x 30 m and situated on the property iii Stewartdale, in south-east Queensland. The 900 m2 area was used to conduct nocturnal hand collection for an hour once a fortnight, for three consecutive fortnights. Six pitfall traps were placed at each of four sites, outside of the 900 m2 area, 5 m apart in two rows, starting at the back corner of the site. These pitfall traps were emptied every fortnight on the day of the night spider collections. The spider survey using vibration involved placing an idling John Deere tractor, for one hour, in a clearing at the front of each of the eight sites and collecting spiders attracted to the tractor.

The pitfall traps were left open during this hour and spiders collected. There were 34 families, 138 genera and 226 species identified. Night collections caught a greater species diversity and richness than pitfall traps and vibration. The vibration-based technique in sites A and B had no significant difference in species diversity and species richness. The pitfall traps left open for six weeks had a greater species diversity than the pitfall traps left open for one hour with the vibration-based technique. Collection of spiders using the night collection and vibration-based techniques were very similar in efficiency and overall material cost. Of all the spider species, 80% were captured during night collection and would be the best technique to use to define the species diversity of an area. As night collection and vibration-based technique are similar in efficiency and overall material cost, it would be recommended to use this technique in conjunction with vibration-based technique as there were species captured during the vibration-based technique that were not captured in night collection. Further research is needed into refining the vibration-based technique in terms of frequency output and portability.

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Item Type: Thesis (Non-Research) (Honours)
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Sciences (6 Sep 2019 - 31 Dec 2021)
Supervisors: Murray, Peter; Raven, Robert
Qualification: Bachelor of Science (Honours) (Environmental Science)
Date Deposited: 28 Jun 2023 00:12
Last Modified: 28 Feb 2024 01:47
Uncontrolled Keywords: Spider survey, comparison, diversity index, methods, night collection, optimising, pitfall traps, species, species richness, techniques, vibration
Fields of Research (2020): 41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring
31 BIOLOGICAL SCIENCES > 3103 Ecology > 310308 Terrestrial ecology
URI: https://sear.unisq.edu.au/id/eprint/46523

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