Relative use of three types of artificial retreats by terrestrial lizards in grazed coastal shrubland, New Zealand

Abstract

Artificial retreats are increasingly used to sample animal populations and in attempts to boost animal numbers in degraded habitats. Understanding how animals use artificial retreats and which designs are most effective is therefore important. We tested the influence of retreat type, time-of-year and site on the use of artificial retreats by three species of terrestrial lizards (McCann's skink Oligosoma maccanni, common skink O. nigriplantare polychroma, and common gecko Hoplodactylus maculatus) in a remnant of grazed coastal shrubland at Birdlings Flat, New Zealand. Monthly capture sessions took place at two sites between December 2003 and November 2004. During 2160 retreat checks, 898 captures of 388 individual lizards were made. Geckos dominated the sample and displayed strong preferences for artificial retreats made of Onduline over corrugated iron and concrete tiles. Skinks used all types of artificial retreats without apparent preference. For all species, use of artificial retreats varied with time-of-year and was lowest in winter months. We also operated pitfall traps at these sites and made 329 captures of 205 individuals during 1920 trap-checks. Pitfall traps produced samples dominated by skinks. We conclude that Onduline retreats are a promising method for detecting terrestrial species of gecko in open habitats. Long-term studies are required to quantify the benefits of providing artificial retreats in restoration projects.