NEW ZEALAND LIZARDS The neglected animals

Forest and Bird, Volume 19, Issue 3, 1 August 1988, Page 15

NEW ZEALAND LIZARDS The neglected animals

by

Robert Porter

irtually ignored by scientists until the last two decades, New Zealand's lizards only received the security of legal protection in 1981, although their large cousin the tuatara has been protected since the end of last century. Our small lizards are no less unique than the tuatara, all of them occurring only in this country. Unfortunately several species are now dangerously rare.

Inconspicuous nature

These reptiles have no doubt been somewhat overlooked because of their inconspicuous nature, especially if compared with

New Zealand's birds. Yet the lizard fauna is no less exceptional and not much smaller in number. To date almost 40 species of gecko and skink have been named (though there is still some disagreement over some of these) and this is likely to increase further in the near future. Research on the common skink (Leiolopisma nigriplantare maccani), found in the South Island and southern North Island, has shown that there are five or possibly more distinct species currently combined under one name. Preliminary results also indicate the common gecko (Hoplodactylus maculatus) may also be a group of several species.

Two new species of gecko have been described in the past six years. One of these, the aptly named harlequin gecko (Hoplodactylus rakiurae), is undoubtedly one of the most strikingly coloured lizards in the world. Making its home in the Tin Ranges of Stewart Island, it also has the rather unenviable title (for a cold-blooded reptile at least) of being one of the most southerly occurring lizards in the world. The other new species only inhabits areas of the Seaward Kaikoura Ranges and was originally discovered when a specimen was found swimming in a water container belonging to an ornithological party in the area. An especially exciting extra to the lizard fauna is the enormous 600mm long gecko recently discovered as a museum specimen in Europe. Unfortunately, it appears that this is a posthumous addition which has followed in the footsteps of New Zealand's other extinct giant, the moa. Urgent priority Conservation of endemic lizards has become an urgent priority in recent years because of human pressures on them. Habitat destruction and modification has seriously depleted numbers of some species, particularly the arboreal geckos. These reptiles primarily inhabit scrubland of varying types, especially the kanuka-manuka-mingimingi associations which often contain a high percentage of introduced plants such as acacia and gorse. Such habitat is often regarded as useless and unattractive, despite its important function as a protective cover for regenerating forest. In suburban Auckland the demand for housing is ever increasing and scrubland is usually the first to go under the bulldozer's blade. A similar situation occurs in rural areas where the scrub is turned into more ‘useful’ farmland. Unable to disperse as other fauna may, many hundreds of lizards must be killed this way every year. The New Zealand Herpetological Society is primarily an Auckland-based amateur group of enthusiasts who have been taking steps to stop some of this slaughter. Over the past three years NZHS members have

salvaged over 400 Auckland green geckos (Naultinus elegans elegans) and forest geckos (Hoplodactylus granulatus) from several salvage sites due for development on Auckland's North Shore. This has been carried out after obtaining permission from the owner of the land and by requesting a permit to rescue protected lizards from the Department of Conservation. Small numbers of protected Pacific geckos (Hoplodactylus pacificus), moko skink (Leiolopisma moco) and rata skink (Cyclodina ornata) have also been salvaged. In 1986 a further salvage site was located in Northland. The draining and destruction of the Kaimaumau Swamp, north of Kaitaia, for kauri gum extraction is a depressing loss of tremendously valuable wetland habitat for such species as the fernbird, bittern and black mudfish as well as the Northland green gecko (Naultinus grayi), all of which are rapidly declining in range because of habitat loss. Clearance in this area is particularly severe for the geckos as the small amount of land to be preserved is near the centre of the swamp where there appears to be a lower density of lizards as compared with the unsecured margins. Constant vigil The NZHS maintains a constant vigil for further threatened habitats of any protected lizard species so such salvage operations can be carried out. Under present legislation these rescued animals cannot be re-released into the wild and thus they are absorbed into captive breeding programmes.* Ideally it would be preferable to save some of these habitats to ensure the continued survival of these species in the wild. Usually the threat to these areas is not discovered until a late stage. However, the NZHS is currently assembling a case to present to DOC for part of one of the Auckland sites to be preserved as, not only have no fewer than six lizard species been located there, but there is also an excellent representation of native birds, fish and plants in scrub, forest and swamp habitats, all within fifteen minutes drive of downtown Auckland.

As an alternative to maintaining the salvaged animals in captive collections, the NZHS is also attempting to obtain permission to transfer some specimens to nearby reserves. This would establish viable populations of geckos that will thrive in the Greater Auckland region for the future. Such colonies would provide valuable information on the population dynamics, growth, reproduction and behaviour of these lizards, while also providing a population of known size and age for future field research. Such experimentation with relatively common species could also provide information on the techniques required for establishing populations of rarer species in the future. Predators, particularly rats, have had a devastating effect on native lizards. Almost half of the recognised species are now only found on off-shore islands or have extremely restricted ranges on the mainland, with evidence suggesting that many of these were once more widely distributed. The large skinks have been particularly vulnerable to rat predation because they are ground-dwelling and often nocturnal. DOC is currently endeavouring to consolidate the status of one species, Whitaker's skink (Cyclodina whitakeri), by attempting to establish a new and hopefully secure population (see Forest & Bird, February 1988, pp 3233). DOC's field work is being supplemented by a captive breeding and research programme at Auckland's Heritage Park. Here the only existing captive colony of these skinks is maintained by park staff in the hope that it will provide valuable data on individual and population growth, reproduction and habitat requirements. Similar ventures The success of the Whitaker's skink project could conceivably pave the way for similar ventures with other endangered species. Perhaps some of the species which are restricted to dangerously small mainland populations, such as the striped skink (Leiolopisma striatum), could be rescued from the brink of extinction by establishing groups on safe off-shore islands, as is being attempted with the kakapo on Little Barrier Island. The importance of captive breeding as a conservation tool should not be underestimated. This is often left as a last resort for endangered animals at which stage the available gene pool is much reduced and valuable specimens can be lost through ignorance of the species’ requirements in Captivity. Techniques for successful captive maintenance and breeding should be learned while sufficient numbers of specimens are available to set up captive colonies. The Great Barrier skink (Leiolopisma homalonotum) is restricted to Great Barrier Island where DOC, with the help of NZHS members, have invested a great deal of time and effort into this species for little return. This is mostly due to the habits and habitat * Forest and Bird also prefers saving habitat to salvage and captive rearing. The Society has achieved major successes in saving habitat through the land allocation process, our wetland protection campaign, planning controls on urban subdivision and campaigns against shrubland clearance at Te Paki, Kaimaumau and Aotuhia, and against tussock development in Otago — Editor.

of the animal. More emphasis has now been placed on three captive groups, held on the island and in Auckland, to produce at least some of the information which is proving So difficult to collect from wild populations. To date two of these groups have successfully bred and accurate and methodical record taking will yield useful facts and figures. Other rare species Similar captive groups have been set up with other rare species. The distinctive robust skink (Cyclodina alani) has been recorded as breeding for the first time in

Captivity over the last two seasons and an effective programme has also been installed for the Giant Otago skink (Leiolopisma otagense), both under the care of NZHS members. Heritage Park, as well as holding Whitaker’s and Great Barrier skinks, is also trying to breed McGregor’s skink (Cyclodina macgregori), while Rainbow and Fairy Springs in Rotorua is working with the grand skink (Leiolopisma grande). Several experienced NZHS members in Nelson, New Plymouth and Auckland are carrying out similar work with the geckos, including the harlequin gecko, black-eyed gecko (Hoplodactylus ka-

hutarae) and the Taranaki goldstripe gecko (H. chrysosireticus). This, at least, will ensure the continued survival of these species in captivity and, with correctly organised breeding programmes, perhaps some of these species could be re-released into areas of the country that they have declined or disappeared from, providing the populations and habitats are managed precisely. New Zealand herpetology, despite its late start, has never looked as healthy as right now. Through the cooperation of professional and amateur herpetologists, the future for several endangered (and some not so endangered) species, which a decade ago was rather fragile, now appears considerably more secure. The emergence of the new Society for Research on Amphibians and Reptiles in New Zealand is an indication that the science has reached a level of maturity in this country. There is certainly a great deal of catching up required and for some species such as the striped skink and the Stephens Island goldstripe gecko (Hoplodactylus stephensi) it may already be too late. However, with the ever increasing pool of accumulated knowledge both from field and captive research, and the continued dedication of a small but increasing band of herpetologists there may be a glimmer of light at the end of the tunnel for all of New Zealand's unique and, most importantly, irreplaceable lizards. # ’ Robert Porter is the secretary of the New Zealand Herpetological Society, and assistant natureworld supervisor, New Zealand Heritage Park, Auckland.