Study

The role of ecological restoration in the conservation of whitaker’s skink (Cyclodina whitaken), a rare new zealand lizard (lacertilia: Scincidae)

  • Published source details Towns D.R. (1994) The role of ecological restoration in the conservation of whitaker’s skink (Cyclodina whitaken), a rare new zealand lizard (lacertilia: Scincidae). New Zealand Journal of Zoology, 21, 457-471.

Actions

This study is summarised as evidence for the following.

Action Category

Remove or control predators using lethal controls: Snakes & lizards

Action Link
Reptile Conservation

Remove or control invasive or problematic herbivores and seed eaters

Action Link
Reptile Conservation

Translocate adult or juvenile reptiles: Lizards

Action Link
Reptile Conservation
  1. Remove or control predators using lethal controls: Snakes & lizards

    A before-and-after, site comparison study in 1986–1993 on two islands near North Island, New Zealand (Towns 1994) found that removal of Pacific rats Rattus exulans and European rabbits Oryctolagus cuniculus resulted in an increase in the abundance of lizards, and when compared to a predator free island, abundance was initially lower but after two years was similar or higher on the removal island. The effects of predator and herbivore control cannot be separated. In forest sites, lizard numbers remained stable for five years following eradication (1986–1991: 2 lizards/100 trap days) before increasing suddenly (1992–1993: 16 lizards/100 trap days), and in coastal sites there was a gradual increase from the year of eradication (3 lizards/100 trap nights) to six years after eradication (70 lizards/100 trap nights). In 1986–1987, lizard abundance was lower on the removal island compared to a predator free island (coastal areas only: removal: 2–5 lizards/100 trap days; predator free: 16–49), but in 1988–1992, abundance was similar in two (1988: 14–15; 1992: 60–69) and higher in two years (1990–1991: removal: 61–67; predator free: 20–36; no data collected in 1989 on predator free island). Rats and rabbits were eradicated in 1986–1987 from one island (rodenticide and shooting) and a nearby island was historically free of invasive mammals. Lizards were counted using pitfall traps along four transects (20 traps/transect, two each in coastal and forested areas) on the removal island (March and November 1986–1993), and on the predator free island (November 1986–1992).

    (Summarised by: Maggie Watson, William Morgan)

  2. Remove or control invasive or problematic herbivores and seed eaters

    A before-and-after study in 1986–1992 on two islands near North Island, New Zealand (Towns 1994) found that eradication of European rabbits Oryctolagus cuniculus and Pacific rats Rattus exulans resulted in an increase in the abundance of resident lizards. Results were not statistically tested, and effects of herbivore and predator control cannot be separated. In forest sites, lizard numbers remained stable for five years following eradication (1986–1991: 2 lizards/100 trap days) before increasing suddenly (1992–1993: 16 lizards/100 trap days). In coastal sites there was a gradual increase from the year of eradication (3 lizards/100 trap nights) to six years after eradication (70 lizards/100 trap nights). On a nearby predator free island, lizard abundance was 4 lizards/100 trap nights in forested areas and 15–60 lizards/100 trap nights in coastal areas. Rats and rabbits were eradicated in 1986–1987 from one island (rodenticide and shooting) and a nearby island was historically free of invasive mammals. In 1986–1993, lizards were counted using pitfall traps (initially 49, increased to 69 traps over 580 m2 on removal island) that were monitored twice/year (March and November).

    (Summarised by: Maggie Watson, William Morgan)

  3. Translocate adult or juvenile reptiles: Lizards

    A study in 1987–1993 on two islands near North Island, New Zealand (Towns 1994) found that translocating Whitaker’s skinks Oligosoma whitakeri to an island following removal of Pacific rats Rattus exulans and European rabbits Oryctolagus cuniculus resulted in some individuals surviving for at least five years and reproducing. Over a five-year period, 15 of 28 skinks (54%) were recaptured at least once, along with five offspring of translocated skinks. Trapping success ranged from 0.4 skinks/100 trap days (2.5 year after release) to 3.1 skinks/100 trap days (5 years after release, but larger area trapped). On another predator free island 25% of marked skinks were recaptured and trapping success was 0.3 and 0.9 skinks/100 trap days. In 1987, twenty-eight skinks (15 adults, 3 gravid females) were captured using pitfall traps on a predator-free island and translocated to the release island from February 1988 to March 1990. Each skink was released into an artificial burrow and stacks of plywood were provided as extra cover. Pitfall traps were placed in the release are (initially 49, increased to 69 traps over 580 m2) and were monitored twice/year.

    (Summarised by: Maggie Watson, William Morgan)

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