City Croakers

TRANSLOCATING FROG POPULATIONS TO URBAN WETLANDS, MELBOURNE

Spotted Marsh Frog (Limnodynastes tasmaniensis).  Photo: N. Clemann 

Worldwide, amphibians are facing an extinction crisis.  Urbanisation (the construction and expansion of cities) threatens many amphibian species,

Urban areas, however, are also important for amphibian conservation.  Conserving frog populations in urban areas will help prevent extinctions, and will also give people who live in cities more opportunities to connect with nature.

Amphibian Ark, a partnership between the world’s zoos and the IUCN, declared 2008 as the International Year of the Frog.  Two key components of Amphibian Ark are:

  1. The captive breeding of frogs in zoos. 
  2. The release of captive-bred frogs to the wild to re-establish or expand declining populations. 

However, protocols for releasing frogs to the wild (translocation) are poorly developed, and many translocations have failed.

In order to improve the success of this key conservation strategy, Dr Kirsten Parris (University of Melbourne), Dr Andrew Hamer (Royal Botanic Gardens, Melbourne), and Dr Graeme Gillespie and Ms Raelene Hobbs (Zoos Victoria) are conducting a formal experiment of frog translocation, including adequate replication (releasing at multiple sites) and ongoing monitoring of the released animals.  Developing successful translocation protocols for common species may contribute to the recovery of endangered species.

AIMS

  1. To establish a partnership with Zoos Victoria to help conserve urban frogs and educate the zoo-going public about the importance of urban conservation.
  2. To refine captive-husbandry protocols for common species of frogs at Melbourne Zoo.
  3. To breed tadpoles of the Spotted Marsh Frog (Limnodynastes tasmaniensis) for experimental release at 10 wetland sites around Melbourne, with the aim of establishing (or re-establishing) frog populations.

METHODS

Two species of frogs will be collected from the wild for captive breeding at Melbourne Zoo:

  • Up to 20 Southern Brown Tree Frogs (Litoria ewingii) for captive-husbandry trials. 
  • Up to 40 Spotted Marsh Frogs to breed large numbers of tadpoles for the translocation experiment.

The captive-bred tadpoles will be released at various urban sites around Melbourne, and tadpole survival and recruitment monitored regularly (including future breeding success).  The project will follow careful quarantine and disease-testing procedures to ensure that the translocations do not spread chytrid fungus, a deadly frog disease.

RESULTS

Southern Brown Tree Frogs have been collected from the wild and will be bred in winter 2010 for captive husbandry trials.  In spring 2010, Spotted Marsh Frogs will be collected for captive breeding, and the tadpoles released at wetlands around Melbourne for the translocation experiment.

PROJECT PARTNERS

FOR MORE INFORMATION:

- on Amphibian Ark - click here.

DID YOU KNOW?

Thirteen species of native frogs occur in urban and suburban Melbourne, including the nationally Vulnerable Growling Grass Frog (Litoria raniformis).

Proposed urban release sites:

McAlpin Reserve, Ringwood North

University of Melbourne, Parkville. 
Photos: A. Hamer

Southern Brown Tree Frog (Litoria ewingii). 
Photo: N. Clemann