New Zealand Journal of Zoology abstracts

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Effects of a mouse, Mus musculus, eradication programme and habitat change on lizard populations of Mana Island, New Zealand, with special reference to McGregor's skink, Cyclodina macgregori

DONALD G. NEWMAN

Science and Research Division
Department of Conservation
P.O. Box 10 420
Wellington, New Zealand

Abstract  During 1984 an unsanctioned farm road was constructed through the known range of McGregor's skink (Cyclodina macgregori) on Mana Island (217 ha). Monitoring of the island's lizard populations commenced in 1986 to assess the effects of habitat changes caused by the construction of the road. Between 1987/88 and 1988/89 the capture rate (pitfall traps) for McGregor's skink declined significantly. This decline is attributed to increased predation by mice (Mus musculus) following a build-up of mouse numbers after cattle (the only stock then present) were removed from the island in 1986. In August 1989 a successful programme to eradicate mice was implemented, and no mice or their sign have been seen since February 1990. Since then, the capture rates have increased significantly for C. macgregori, the gecko (Hoplodactylus maculatus), and the Cook Strait giant weta (Deinacrida rugosa) (Orthoptera). Even though individual C. macgregori show strong site fidelity and are potentially long-lived (10+ years), only three of 64 caught to April 1988 have been recaptured since the last mouse was trapped. Adults appeared more vulnerable to predation than juveniles. All captures of McGregor's skink on Mana Island were made within a small area (<5 ha) along the north-east coast; within this area, shrub cover is increasing relative to that of grasses and herbs.

Keywords  Cyclodina macgregori; species recovery; conservation; Mus musculus; rodent eradication; Cyclodina aenea; Leiolopisma nigriplantare polychroma; Hoplodactylus maculatus; Deinacrida rugosa; Mana Island

New Zealand Journal of Zoology, 1994, Vol. 21: 443-456

0301-4223/2104-0443 $2.50/0   (c) The Royal Society of New Zealand 1994

PDF file of entire paper: medium quality (822K); (scanned from paper original: notes about this process)

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