Comparison of Two Techniques for Surveying Headwater Stream Amphibians.

Quinn, Timothy; Hayes, Marc P.; Dugger, Daniel J.; Hicks, Tiffany L.; Hoffmann, Annette

We compared rubble-rousing versus light-touch stream amphibian survey techniques in multiple 1 m plots across 10 streams in southwest Washington, USA. Specifically, we wanted to determine if light-touch surveys provide unbiased estimates of abundance (i.e., provide counts correlated with rubble rousing counts) and which method would provide more cost-effective presence or absence information. Rubble-rousing, a common technique for surveying stream-associated amphibians in the Pacific Northwest, took 12 times as long as fight-touch to apply. Abundance estimates and standard errors for rubble-rousing were consistently higher than those for light-touch for all life stages for the coastal tailed frog (Ascaphus truer) and Columbia torrent salamander (Rhyacotriton kezeri). Except for eggs, light touch detected all [its stages found during rubble-rousing. For frogs, only some rubble-rousing abundance estimates, mostly involving second-year larvae, were highly correlated with their fight-touch counterparts, whereas for salamanders, similar comparisons generated high correlations across most life stages. Correlations between methods were consistently greater for salamanders than for frogs. However the smaller tailed frog sample sizes and the cryptozoic nature of some life stages may have contributed to this pattern. Depending on the degree to which researchers can tolerate false-negative error rates, fight touch may prove less costly than rubble rousing for detecting species presence. For the cost of obtaining one rubble-rousing sample, many fight-touch samples can be used across a range of habitats for detecting species patchily distributed.

WASHINGTON (State); WILDLIFE research technique; TAILED frog; AMPHIBIANS; SALAMANDERS; FROGS

Journal of Wildlife Management, 2007, Vol 71, Issue 1, p282

0022-541X

Academic Journal

10.2193/2006-342