Terrestrial plant and animal species: Reptiles and amphibians

2016
Biodiversity
State and trends
Cocos Christmas

Reptiles and amphibians

As was the case in SoE 2011, there has been little improvement in the status of listed reptile and amphibian taxa at the national level. However, some species are known to be performing better than previously thought—this is because increased survey effort has revealed greater ranges or additional, previously unknown populations. Examples are Allan’s lerista (Lerista allanae), pygmy bluetongue lizard (Tiliqua adelaidensis), Eungella torrent frog (Taudactylus eungellensis) and waterfall frog (Litoria nannotis). Numerous species have been delisted or downlisted in state and territory legislation, whereas others have been uplisted. For example, in Queensland, 30 amphibians and reptiles were downlisted in December 2014, and 21 species were uplisted in August 2015. The uplistings include 3 from endangered to extinct, although these species were long recognised by the scientific community as being extinct.

A close-up photo of a waterfall frog sitting on a log.

A close-up photo of a waterfall frog sitting on a log.

The nationally endangered waterfall frog (Litoria nannotis) is endemic to the Wet Tropics of Queensland. 

Photo: Eric Vanderduys

The Christmas Island forest skink (Emoia nativitatis) has become extinct since 2011, with the last remaining captive individual dying on 31 May 2014 (Woinarski et al. 2017). Limited monitoring indicates that the species declined rapidly (along with other native reptiles on Christmas Island) after the late 1980s. The forest skink was listed as critically endangered in January 2014, only 4 months before its extinction. Two other Christmas Island reptiles are now considered extinct in the wild (see Box BIO10).

Box BIO10 Ongoing declines of Christmas Island reptiles

Christmas Island covers an area of about 135 square kilometres, consisting of a large central plateau surrounded by a series of steep cliffs, terraces and slopes.

Five native terrestrial reptile species occur on the island, 4 of which are endemic. A sixth species that was endemic became extinct in 2014—Christmas Island forest skink (Emoia nativitatis). Five terrestrial reptile species have been introduced to Christmas Island (Smith M et al. 2012).

In the past 20–30 years, 4 of the remaining 5 species have declined significantly ; 2 are listed as critically endangered under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act; Christmas Island blue-tailed skink—Cryptoblepharus egeriae, and Lister’s gecko—Lepidodactylus listeri), and 1 is listed as endangered (Christmas Island giant gecko—Cyrtodactylus sadleiri). The coastal skink (Emoia atrocostata) has not been recorded in the wild since 2004 (it is not currently listed under the EPBC Act), the blue-tailed skink was last recorded in the wild in 2010, and Lister’s gecko has not been recorded since 2012 (Webb et al. 2014). All were recorded as abundant in 1979 (Cogger et al. 1983). A fourth species, Christmas Island blind snake (Ramphotyphlops exocoeti), has been recorded so infrequently that the data are insufficient to assume a decline; it is listed as vulnerable under the EPBC Act.

Captive breeding programs have been successful for blue-tailed skink and Lister’s gecko; by late 2016, more than 890 blue-tailed skinks and more than 700 geckos were in captivity on Christmas Island and in Taronga Zoo. However, the future of these species remains uncertain, since the processes threatening their persistence in the wild are not well understood (Webb et al. 2014). The success of the breeding program has provided the opportunity for the trial release of blue-tailed skinks into predator-proof compounds on the island to help assess effectiveness of predator control.

Predation by introduced predators is thought to be the key factor in the decline of native reptiles on Christmas Island. Many known reptile predators have now been introduced to the island, including the domestic/feral cat (Felis catus), house mouse (Mus musculus), giant centipede (Scolopendra subspinipes), red jungle fowl (Gallus domesticus), yellow crazy ant (Anoplolepis gracilipes), Asian wolf snake (Lycodon capucinus), black rat (Rattus rattus), and barking or house gecko (Hemidactylus frenatus) (Smith M et al. 2012).

‘Gump’ pictured sitting in a leaf.

‘Gump’ pictured sitting in a leaf.

‘Gump’, the last remaining captive forest skink (Emoia nativitatis), died in May 2014.

Photo: Parks Australia

In contrast to the situation for mammals and birds, no new national action plans have been developed for amphibians and reptiles since SoE 2011. Both The action plan for Australian frogs (Tyler 1997) and The action plan for Australian reptiles (Cogger et al. 1993) are out of date. The action plan for Australian frogs, for example, was published before chytridiomycosis was identified as the likely cause of many frog declines and extinctions (Figure BIO22), and before the description of the pathogenic species Batrachochytrium dendrobatidis (see Pathogens).

SoE2016_bio_fig22_EPBC_reptile_amphibian-01.png
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Source: Environmental Resources Information Network, Australian Government Department of the Environment and Energy, 2016

Figure BIO22 Numbers of reptile and amphibian species listed under the Environment Protection and Biodiversity Conservation Act 1999 in each Interim Biogeographic Regionalisation for Australia region

Terrestrial plant and animal species: Reptiles and amphibians

Gynther I, Waller N & Leung LK-P (2016). Confirmation of the extinction of the Bramble Cay melomys Melomys rubicola on Bramble Cay, Torres Strait: results and conclusions from a comprehensive survey in August–September 2014, report to the Queensland Department of Environment and Heritage Protection, Brisbane.

Martin TG, Nally S, Burbidge AA, Arnall S, Garnett ST, Hayward MW, Lumsden LF, Menkhorst P, McDonald-Madden E & Possingham HP (2012). Acting fast helps avoid extinction. Conservation Letters 5(4):274–280.

Perry JJ, Vanderduys EP & Kutt AS (2015). More famine than feast: pattern and variation in a potentially degenerating mammal fauna on Cape York Peninsula. Wildlife Research 42(6):475–487.

Lindenmayer DB, Blair D, McBurney L & Banks SC (2015). Ignoring the science in failing to conserve a faunal icon—major political, policy and management problems in preventing the extinction of Leadbeater’s possum. Pacific Conservation Biology21(4):257–265.

BirdLife Australia (2015). The state of Australia's birds 2015: headline trends for terrestrial birds, Birdlife Australia, Sydney.

Garnett ST, Szabo JK & Dutson G (2011). The action plan for Australian birds 2010, CSIRO Publishing, Collingwood, Melbourne.

Pavey CR & Nano CEM (2013). Changes in richness and abundance of rodents and native predators in response to extreme rainfall in arid Australia. Austral Ecology 38(7):777–785.

Woinarski JCZ, Garnett ST, Legge SM & Lindenmayer DB (2017). The contribution of policy, law, management, research, and advocacy failings to the recent extinctions of 3 Australian vertebrate species. Conservation Biology doi:10.1111/cobi.12852.

Smith MJ, Cogger H, Tiernan B, Maple D, Boland C, Napier F, Detto T and Smith P (2012). An oceanic island reptile community under threat: the decline of reptiles on Christmas Island, Indian Ocean. Herpetological Conservation and Biology 7 (2): 206-218.

Tyler MJ (1997). The action plan for Australian frogs, Wildlife Australia, Canberra.

Cogger HG, Cameron EE, Sadlier RA & Eggler P (1993). The action plan for Australian reptiles, Australian Nature Conservation Agency, Canberra.

Assessment summaryState and trends of biodiversityView assessment summary
Leaf-tailed gecko (Phyllurus sp.). Photo by Eric Vanderduys

Leaf-tailed gecko (Phyllurus sp.)
Photo by Eric Vanderduys

Cresswell ID, Murphy H (2016). Biodiversity: Terrestrial plant and animal species: Reptiles and amphibians. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/biodiversity/topic/2016/terrestrial-plant-and-animal-species-reptiles-and-amphibians, DOI 10.4226/94/58b65ac828812