David A. Newell

Overview of the conservation status of Australian frogs

A review of the current conservation status of Australian amphibians was recently completed as part of a World Conservation Union (IUCN) sponsored Global Amphibian Assessment (GAA). Fifty of 216 amphibian species (23%) in Australia are now recognized as threatened or extinct in accord with IUCN Red List Categories and Criteria. Here we report on the categories and criteria under which individual species qualified for listing and provide a summary of supporting information pertaining to population and distribution declines. Major threatening processes contributing to listing of species are also reviewed.

Population Recovery following Decline in an Endangered Stream-Breeding Frog (Mixophyes fleayi) from Subtropical Australia

Amphibians have undergone dramatic declines and extinctions worldwide. Prominent among these have been the stream-breeding frogs in the rainforests of eastern Australia. The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has been postulated as the primary cause of these declines. We conducted a capture-mark-recapture study over a 7-year period on the endangered Fleay’s barred frog (Mixophyes fleayi) at two independent streams (30 km apart) in order to assess the stability of these populations. This species had undergone a severe decline across its narrow geographic range. Mark-recapture modelling showed that the number of individuals increased 3–10 fold along stream transects over this period. Frog detection probabilities were frequently above 50% but declined as the populations increased. Adult survival was important to overall population persistence in light of low recruitment events, suggesting that longevity may be a key factor in this recovery. One male and female were present in the capture record for >6 years. This study provides an unambiguous example of population recovery in the presence of Bd.

Population estimation of the Green and golden bell frog Litoria aurea at Port Kembla

Estimates of population size are fundamental to the development of effective management of threatened species. We conducted a tagging study of a population of the endangered Green and Golden Bell Frog Litoria aurea at Port Kembla, on the New South Wales south coast. Over 200 adult frogs were tagged across three breeding sites between November 1998 and January 2000. Population estimation based on the mark and recapture of frogs in 1999-00 suggested that the two larger breeding sites together contain >300 adult frogs.Although these sites were only 500 m apart, no tagged frogs were recorded to move between them. In contrast, one female bell frog moved 1.25 km between one of these and the third site over a 14 month-period.The ratio of male to female frogs was 2.5: 1, suggesting either that the population is male-dominated or that females are more cryptic in their behaviour than males and use habitat differently. Based on this ratio the sites contained at least 85 adult females in 1999-2000. Only 13 frogs were recaptured outside the season of initial capture.The longest interval between captures was 14- 16 months, for three of these frogs. This suggests that few frogs live longer than about 2 years as adults. Given that a small number of other breeding sites occur in Port Kembla, the total population size is estimated to exceed 400 adult frogs. Further study of this important population is needed to refine these estimates of population size and to confirm population stability.

Priorities for management of chytridiomycosis in Australia: saving frogs from extinction

Abstract. To protect Australian amphibian biodiversity, we have identified and prioritised frog species at an imminent risk of extinction from chytridiomycosis, and devised national management and research priorities for disease mitigation. Six Australian frogs have not been observed in the wild since the initial emergence of chytridiomycosis and may be extinct. Seven extant frog species were assessed as needing urgent conservation interventions because of (1) their small populations and/or ongoing declines throughout their ranges (southern corroboree frog (Pseudophryne corroboree, New South Wales), northern corroboree frog (Pseudophryne pengilleyi, Australian Capital Territory, New South Wales), Baw Baw frog (Philoria frosti, Victoria), Litoria spenceri (spotted tree frog, Victoria, New South Wales), Kroombit tinkerfrog (Taudactylus pleione, Queensland), armoured mist frog (Litoria lorica, Queensland)) or (2) predicted severe decline associated with the spread of chytridiomycosis in the case of Tasmanian tree frog (Litoria burrowsae, Tasmania). For these species, the risk of extinction is high, but can be mitigated. They require increased survey effort to define their distributional limits and to monitor and detect further population changes, as well as well-resourced management strategies that include captive assurance populations. A further 22 frog species were considered at a moderate to lower risk of extinction from chytridiomycosis. Management actions that identify and create or maintain habitat refugia from chytridiomycosis and target other threatening processes such as habitat loss and degradation may be effective in promoting their recovery. Our assessments for some of these species remain uncertain and further taxonomical clarification is needed to determine their conservation importance. Management actions are currently being developed and trialled to mitigate the threat posed by chytridiomycosis. However, proven solutions to facilitate population recovery in the wild are lacking; hence, we prioritise research topics to achieve this aim. Importantly, the effectiveness of novel management solutions will likely differ among species due to variation in disease ecology, highlighting the need for species-specific research. We call for an independent management and research fund of AU

Crowd Sourcing for Conservation: Web 2.0 a Powerful Tool for Biologists

15 million over 5 years to be allocated to recovery actions as determined by a National Chytridiomycosis Working Group of amphibian managers and scientists. Procrastination on this issue will likely result in additional extinction of Australia’s amphibians in the near future.

Recent invasions of World Heritage rainforests in north-east New South Wales by the cane toad Bufo marinus

The advent and adoption of Web 2.0 technologies offers a powerful approach to enhancing the capture of information in natural resource ecology, notably community knowledge of species distributions. Such information has previously been collected using, for example, postal surveys; these are typically inefficient, with low response rates, high costs, and requiring respondents to be spatially literate. Here we describe an example, using the Google Maps Application Programming Interface, to discuss the opportunities such tools provide to conservation biology. Toad Tracker was created as a prototype to demonstrate the utility of this technology to document the distribution of an invasive vertebrate pest species, the cane toad, within Australia. While the technological aspects of this tool are satisfactory, manager resistance towards its use raises issues around the public nature of the technology, the collaborative (non-expert) role in data collection, and data ownership. We conclude in suggesting that, for such tools to be accepted by non-innovation adopters, work is required on both the technological aspects and, importantly, a cultural change is required to create an environment of acceptance of the shifting relationship between authority, expertise and knowledge.

Distribution and habitat assessment of the Broad-headed Snake Hoplocephalus bungaroides

The cane toad Bufo marinus is well recognised as a threat to biodiversity in northern Australia. Concern about this impact has grown in recent years as the species spreads geographically. Previous ...

Translocation of the threatened Growling Grass Frog Litoria raniformis: a case study

Conservation reserves are commonly relied on as a primary means of conserving threatened species. We conducted surveys for the endangered Broad-headed Snake Hoplocephalus bungaroides across 236 sit...

Population stability in the endangered Fleay’s barred frog (Mixophyes fleayi) and a program for long-term monitoring

Translocation is occasionally suggested as a last resort strategy for dealing with ‘unavoidable’ loss of Growling Grass Frog Litoria raniformis habitat in urbanising landscapes. However, examples of attempts to translocate an entire population of L. raniformis are rare and their success (or lack of success) is poorly documented in the literature. In this study, we detail the translocation of a population of L. raniformis from a farm dam being destroyed for residential development to a purpose-built wetland 480 m away.The population was translocated between November 2010 and May 2011. We used mark-recapture to estimate the number of frogs in the population prior to translocation. Visual counts of L. raniformis at the dam indicated a maximum of 39 adult frogs to be present while 355 frogs were marked over the course of a single season (November 2010 to March 2011).Translocation of 156 frogs and unassisted colonisation by 32 frogs resulted in an estimated 70% of adults marked at the dam moving to the wetland...

Australian land snails: a review of ecological research and conservation approaches

Abstract. In the wake of the global decline in amphibians there is a need for long-term population monitoring. Previous research suggested that the endangered Fleay’s barred frog (Mixophyes fleayi) had recovered after a severe decline. We aimed to determine whether this recovery has been sustained and to test an example of a monitoring program that could be employed at intervals of five or more years to assess long-term population stability. We conducted capture–mark–recapture five years after the last detailed census at Brindle Creek in Border Ranges National Park, New South Wales. Frogs were captured along a 200 m creek transect between September 2013 and February 2014. We used program Mark to estimate demographic parameters of adult male frogs using two modelling approaches: robust design (RD) and the POPAN formulation of the Jolly–Seber model. Abundance was estimated at 38.2 ± 0.5 (s.e.) (RD) and 46.0 ± 2.7 (POPAN). Abundance in 2008 was estimated at 53.2 ± 10.0 (POPAN) male frogs. Estimates of apparent monthly survival over our five-month-long study were very high (RD: 1.0 ± 0.0; POPAN: 1.0 ± 0.02). Recapture estimates were also high (RD: 0.40 ± 0.07 to 0.72 ± 0.05 per session; POPAN: 0.84 ± 0.05 per month). These data suggest that the Brindle Creek population has remained relatively stable over a period of ∼10 years.