It’s a comforting thought that we sometimes need very little to inspire us to carry on. This morning, it was the calls of peaceful doves sounding like muted horns of a hundred sentinels announcing my arrival at a farther, and then farther point on the path I ran and walked. That was all it took, and I completed the return half of my intervals faster than my outgoing half, led on and on by the doves.
While running, I checked out the great bowerbird bower I had photographed a month ago, and found that it was still as it had been then, although no male bowerbird hissed at me from the protecting shrubs. Yesterday, I observed that the beautifully decorated bower near the library at JCU had been completely destroyed. Just a mat of twigs remained, along with a few decorations. I wondered if heavy rains or rival males had trashed it, or perhaps some other factor.
During breakfast, ABC Radio National reported severe flood damage and still rising rivers in the southern interior of Queensland, some areas having received hundreds of millimetres of rain during the past several days. The devastating storms with their torrential rains seem to be making their rounds of the state. Today, Townsville was all sunshine, and I dried laundry outdoors without having to race outside to save it from the rain.
Today’s news also included the announcement that a colony of a hundred yellow-spotted bell frogs, a species presumed to be extinct for the past 30 years, had been found in the Southern Tablelands of New South Wales.1 Luke Pearce, a fisheries conservation officer in pursuit of an endangered southern pygmy perch, spotted one of the frogs, reported his finding, and led frog experts to the site last October, where the discovery was confirmed.2 Once conservation measures were put in place, the good news was revealed.2 Frank Sartor, Environment Minister for New South Wales, described the finding as the amphibian equivalent of discovering a living Tasmanian tiger, a large marsupial carnivore also called the thylacine that was last sighted alive in the 1930’s.2
Finding the colony of yellow-spotted bell frogs is a ray of light in an otherwise dark world for eastern Australia’s frog populations. A dozen of Australia’s 216 described frog species are critically endangered, and most of those live on the country’s east coast, primarily in Queensland and New South Wales.2
Like other countries around the world, Australia has observed a shocking decline in frog populations within the past 30 years.3 The country has lost 7 frog species within that time period.2 In 1989, a world congress confirmed that such disappearances were happening in many parts of the world, and that common and easily visible frog species had shown rapid declines, often in a matter of weeks.3 The trend toward disappearances began within a five-year period between 1978 and 1983 and has continued at an alarming rate since then.3
This rapid extinction of frog species was eventually linked with a fungus that causes an infectious skin disease called chytridiomycosis.4 First observed in Queensland in 1993 in dead and dying frogs, the disease was back-tracked to a first appearance in the country in 1978, when it may have arrived on an imported African frog species.4 Within the past three decades, the fungus has spread throughout much of Australia and presently infects 48 species of native frogs in the wild, as well as the introduced cane toad.5 On a world scale, it has caused possible extinction or decimated populations of 200 frog species in North, Central, and South America, Africa, New Zealand, and Europe.4
Yesterday, while reading through the December issue of James Cook University’s Discover magazine, I learned that a team of researchers, including Dr. Jamie Voyles and Dr. Lee Berger of JCU, has demonstrated that chytridiomycosis, which attacks the skin of frogs, blocks the skin’s ability to function normally.6 In particular, the disease impedes the passage of electrolytes such as sodium and potassium across the surface of the skin, which acts like a membrane facilitating ion exchange between a frog’s insides and the environment beyond its skin.6 The researchers found significantly lower concentrations of sodium and potassium in diseased green tree frogs when compared with healthy green tree frogs and speculated that such an electrolyte imbalance could lead to cardiac arrest, just like electrolyte imbalances in humans can lead to cardiac arrest.6
Unfortunately, there’s no cure for chytridiomycosis. The frogs are still dying, still disappearing. Dr. Lee Berger is quoted in the article as stating, “Chytridiomycosis is resulting in the greatest loss of biodiversity due to disease in recorded history.”6 So, the prognosis isn’t good, but once in a while a species thought to be extinct makes a reappearance and we all start to hope again.
References:
1. Greg Miskelly. ‘Extinct’ frog species found alive after 30 years. ABC News, Thursday, March 4, 2010. 7:30 Report. Accessed 4-Mar-2010. http://www.abc.net.au/news/stories/2010/03/04/2836418.htm
2. Owen Pye. ‘Extinct’ frog species found again after 30 years. Science, msnbc.com. 3/4/2010. Accessed 4-Mar-2010. http://www.msnbc.msn.com/id/35706909/ns/technology_and_science-science
3. Gerry Swan. Green Guide: Frogs of Australia. 2001. New Holland Publishers (Australia) Pty Ltd., Sydney, p.58.
4. Wikipedia. Chytridiomycosis. Updated 15-Nov-2010. Accessed 19-Nov-2010. http://en.wikipedia.org/wiki/Chytridiomycosis
5. R. Speare and L. Berger. Chytridiomycosis in amphibians in Australia. James Cook University. Updated 626 January 2005. Accessed 4-Mar-2010. http://www.jcu.edu.au/school/phtm/PHTM/frogs/chyspec.htm
6. James Cook University. Frogs dying from electrolyte imbalance. Discover Magazine, December, 2009, p. 13.
