Charlton, O. & T. R. Lewis

Artificial egg-strip surveying for detection of pond-breeding newts: Does egg-strip substrate matter? pp. 494-500.

Abstract. Survey methods for detecting newts (Salamandridae: Pleurodelinae) in ponds by identifying presence of eggs laid during their aquatic breeding condition are useful and often deployed across various population surveillance activities. Egg-strip surveying is an effective way of detecting newt presence in a pond by providing an egg-laying medium for newts that can be selectively inspected by a surveyor. In this study we deployed a series of different plastic substrates to investigate substrate laying preference by three species of newts; Lissotriton helveticus, L. vulgaris and Triturus cristatus. Our results revealed that L. helveticus and L. vulgaris significantly preferred green and longer varieties of black egg-strip substrate over a thicker less pliable plastic substrate. Contrastingly T. cristatus exhibited no significant preference between substrates. Results from this study indicate that if surveyors choose to use black long, black short, black, green, yellow, or red coloured substrates, or thicker black plastic substrates for egg-strip surveys, detection for T. cristatus remains constant but with improved detection and mild preference on more pliable plastic substrates. However, for L. vulgaris and L. helveticus the thicker gauge black egg-strips may significantly reduce the effectiveness of detection and are discriminated against compared to more pliable grades of green and longer varieties of black plastic substrate. We recommend that surveyors constructing and deploying their own home-made egg-strip substrates should carefully consider their choice of which plastic substrate material to use in constructing the equipment.

Key words. Amphibia, Caudata, egg-strip, oviposition, substrate preference, Lissotriton helveticus, Lissotriton vulgaris, Triturus cristatus.