Australian Frogs

From EnvironmentWiki

Frogs of the Daintree Rainforest

Neil Hewett lives and works in the Daintree Rainforest of North Queensland. He has photographed some of the unique frogs of this region. To see his photographs click here Frogs of the Daintree Rainforest.

Frog Population Numbers

--Nichole Hoskin 13:55, 24 July 2008 (EST)

Green and Golden Bell Frog (Litoria aurea)? photographed by Phil Cole at a reptile show in Castle Hill, NSW.

For information on identifying Australian frogs, see Frogs of Australia

“There is a global decline in frogs which is also occurring in Australia, with dramatic declines in frog species over the last 15 years. The first indication of Australian frog decline was in 1979 when two species disappeared simultaneously throughout their entire geographic range (the Conondale and Blackall Ranges in Queensland), without apparent reason: the gastric brooding frog Rheobatrachus silus and the day frog Taudactylus diurnus.”^[1]

“Range decline (often recent and dramatic) has been recorded for 19 Australian species, and decline in abundance and/or local disappearances for another 13. Tyler lists eight species as vulnerable and 11 as endangered, compared with two vulnerable and seven endangered species in ANZECC (1991). Twenty-four of the thirty-six species in decline (including those categorised as insufficiently known) are closely associated with water, suggesting that water quality is a likely factor in their decline.”^[2]

“Unfortunately there are few population studies against which population change can be quantified.”^[3]

“Possible causes of frog decline include use of pesticides near aquatic environments, loss of breeding habitat through drainage of wetlands, conversion of temporary ponds to dams for stock use resulting in destruction of peripheral sheltering sites, use of insect killers which destroy the nocturnal food of frogs in suburban environments, and disease.”^[4]

“In Australia, as elsewhere, many amphibian species have experienced dramatic population declines and even apparent extinctions...Since the late 1970s at least 14 frog species have declined sharply in the montane areas of eastern Australia. All of these species breed and live near rain-forest streams.” ^[5] The sudden and apparent global decline of frog populations has led scientists to develop numerous hypothesises to explain why this decline is occurring. However, scientists do not yet understand what is causing these declines, “Years after the first realization of global patterns of amphibian declines, we are still uncertain about how to determine whether declines are "normal population fluctuations" or whether they are due to anthropogenic changes in the habitat, nor is there agreement as to whether these concurrent declines around the world are isolated incidents or whether global changes are responsible.”^[6]

"In April 2002 the APVMA released this report, the Atrazine Draft Final Review Report for public comment. At the time of its release, a number of studies were published in the international literature which raised additional concerns that atrazine might cause adverse developmental and reproductive problems in frogs. Because of these new concerns, the APVMA delayed finalisation of the review in order to investigate these new claims and reassess the toxicological and environmental risks of using atrazine. In December 2004 the APVMA released the Atrazine Second Draft Final Review Report. This report considered previous findings, regulatory actions that had been undertaken and published information on developmental and reproductive effects on frogs. In this report the APVMA found that atrazine was unlikely to have an adverse impact on frogs at existing levels of exposure. However, it concluded that the issue of atrazine and frogs should be revisited if additional data demonstrated that atrazine posed a hazard to frog populations at these levels."^[7]

“As it turned out (as is often in the case in science), the new research findings continue to be contradictory and controversial, and no clear consensus among scientific experts has yet emerged.”^[8]

“In the case of atrazine a number of studies have been published suggesting a relationship between low concentrations of the chemical and endocrine disruption in frogs. Scientific panels and regulators have been assessing these studies, as well as other contradictory research. Currently there is ongoing debate as to the relevance of this research to likely exposures in field (frogs and other animals) and more particularly, its relevance to humans.”^[9]

References

--Nichole Hoskin 13:55, 24 July 2008 (EST)

1. Jean Jackson, for Environment Australia, State of Habitat Availability and Quality in Inland Water, 1997, prepared as part of Australia: State of the Environment Technical Paper Series (Inland Waters), p 63.

2. Jean Jackson, for Environment Australia, State of Habitat Availability and Quality in Inland Water, 1997, prepared as part of Australia: State of the Environment Technical Paper Series (Inland Waters), p 63.

3. Jean Jackson, for Environment Australia, State of Habitat Availability and Quality in Inland Water, 1997, prepared as part of Australia: State of the Environment Technical Paper Series (Inland Waters), p 63.

4. Jean Jackson, for Environment Australia, State of Habitat Availability and Quality in Inland Water, 1997, prepared as part of Australia: State of the Environment Technical Paper Series (Inland Waters), p 63.

5. William F Laurance, Keith R McDonald and Richard Speare, Epidemic Disease and the Catastrophic Decline of Australian Rainforest Frogs, Conservation Biology, 10(2), April 1996, p 406.

6. Karen R Lips, ‘Decline of a Tropical Montane Amphibian Fauna’, Conservation Biology, 12(1), February 1998, p 106.

7. Australian Pesticides and Veterinary Medicine Authority (APVMA), Frequently Asked Questions Concerning the APVMA’s Review of Atrazine, p 2.

8. Australian Pesticides and Veterinary Medicine Authority (APVMA), Frequently Asked Questions Concerning the APVMA’s Review of Atrazine, p 2.

9. Australian Pesticides and Veterinary Medicine Authority (APVMA), Frequently Asked Questions Concerning the APVMA’s Review of Atrazine, p 4.

10. Australian Pesticides and Veterinary Medicine Authority (APVMA), Frequently Asked Questions Concerning the APVMA’s Review of Atrazine, p 1.

Tyrone B. Hayes, Atif Collins, Melissa Lee, Magdelena Mendoza, Nigel Noriega, A. Ali Stuart, and Aaron Vonk, Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses 2002.

Australian Pesticides and Veterinary Medicine Authority (APVMA), Technical Report Atrazine, The reconsideration of the active constituent, registration of products containing Atrazine and approvals of their associated labels, March 2008

Australian Water Conservation and Reuse Research Programme, CSIRO and AWA, Endocrine Disrupting Chemicals (EDCs) and Pharmaceuticals and Personal Care Products (PPCPs) in Reclaimed Water in Australia.

Tyler, M.J., The Action Plan for Australian Frogs, 1997, Wildlife Australia, Canberra, ACT.