Comparison of methods used to capture herpetofauna: an example from the Carnarvon basin

WA Museum Records and Supplements | Updated 8 years ago

ABSTRACT – We used a combination of pitfall-trapping and hand-foraging methods to sample the frog and reptile species on 63 quadrats in the southern Carnarvon Basin of Western Australia. The quadrats were positioned to represent the geographical extent and diversity of terrestrial environments in the 75 000 km2 study area.

We compared the three types of pit-traps that systematically captured species: fenced tubes (125 mm diameter and 550 mm deep), fenced buckets (300 mm diameter x 450 mm deep) and unfenced invertebrate-pits (300 mm x 450 mm, containing glycol and covered by a sheet of wire mesh with square 10 mm x 10 mm holes). The buckets contributed only 5 (0.12%) of the 820 quadrat species intersections derived from the trapping programme. After standardising for differences in the number of trap-nights, the average tube caught 1.33 times more reptiles than the average bucket.

We compared the classification structure derived from the entire datamatrix with that from a reduced matrix, which excluded difficult-to-sample taxa as well as data derived by hand-foraging. We could have ignored handforaging as a sampting technique, as well as the snake, pygopid and varanid components of the fauna, without changing the patterns in species composition revealed by the analysis, or reducing its ecological discrimination.