Vertebrate by-catch in invertebrate wet pitfall traps
Royal Society of Western Australia Inc.
Faculty of Business and Law
School of Marketing, Tourism and Leisure
Wet pitfall traps used to sample invertebrates, in particular, short-range endemic invertebrates for the purpose of supporting environmental impact assessments, killed, as by-catch, numerous small vertebrates. For the five surveys reported here, vertebrate by-catch rates varied between 0.4 and 15.6 individuals per 1000 trap nights using two litre plastic containers half-filled with ethylene glycol. No satisfactory alternative trapping strategy is available that provides quantitative data for sampling short-range endemic invertebrates (e.g., terrestrial molluscs, spiders and millipedes), which are a focus of the Western Australian Environmental Protection Authority. We discuss the trade-off between catching short-range endemic invertebrates as part of an environmental impact assessment against killing small vertebrates as by-catch. We urge government environmental regulators to provide greater clarity on the specific locations of where short-range endemic invertebrate surveys should be undertaken as an interim measure for reducing vertebrate trapping deaths until improved trapping protocols are available and to be more cautious when requiring surveys for short-range endemic invertebrates.