Frogs - The Global Frog Crisis

Around the world, the disappearance of frogs has received a great deal of attention by scientists, government departments and the media. Extensive monitoring programs and research projects are taking place. We know already that not all frog species are affected by the same causes and threats. However, in some cases, no cause for the decline or disappearance has been identified at all. These are being called "mystery declines". They are occurring at high altitude locations within a particular latitudinal range around the earth. Despite World Heritage protection, several species of frogs have disappeared from pristine, high altitude rainforests in tropical Queensland and elsewhere further south.

Researchers in Australia, Panama and elsewhere have discovered a fungus which is killing frogs. This fungus has also been found in Queensland Museum specimens collected from the Wet Tropics uplands prior to the disappearance of the high altitude frogs. This fungus (Batrachochytrium dendrobatidis) is usually referred to as chytrid fungus. You can learn all about this serious amphibian disease by going to the Amphibian Disease site created by the James Cook University researchers who are studying this disease menace.

What are these disappearances telling us?
Frogs are very sensitive to even subtle changes in the environment. A frog's skin contains secretions to prevent infections (important for an animal that likes to live in a wet habitat). But a frog's skin is also porous and allows the animal to absorb water without drinking through its mouth. This is why frogs succumb so quickly to any pollutants in the environment. They are one of the first species to be affected and so, serve as an 'early warning system', alerting us to problems that should be examined and corrected.
Since the early 1990's, several species of north Queensland rainforest frogs have vanished within a very short period of time from altitudes above 300 or 400 metres. If those species only occurred at high altitudes to begin with, then they ceased to exist (as far as we can tell). Some species, thankfully, also ranged below 300 metres and it is these low altitude populations that still exist.

The species affected by the "mystery declines" are the:

• Northern Tinker frog (Taudactylus rheophilus)
• Sharp-snouted Day frog (T. acutirostris) pictured right,
• Mountain Mist frog (Litoria nyakalensis), and
• Little Waterfall frog (Litoria lorica).

Because three out of four of these have not been seen by researchers since the early to mid 1990's, they are referred to as the "missing frogs".
Some fantastic news was that one of the missing frogs (the Northern Tinker frog) was rediscovered at two mountaintop locations in late 1996. Its numbers, however, are critically low and it is possible that we could still lose this species.
Similarly, the little waterfall frog (Litoria lorica), was previously known from only four upland rainforest sites in the Wet Tropics and had disappeared from all these sites by 1991. In 2008, a healthy population was located in dry forest on the western Carbine Tableland It is now only known to occur in this one location along a 2 kilometre stretch of the McLeod River.
 
These four additional species have vanished from their high altitude sites but are still found at lower elevations:

• Common Mist frog (Litoria rheocola),
• Waterfall frog (L. nannotis) pictured at the top of this page,
• Australian Lace-lid (Nyctimystes dayi), and
• Green-eyed Tree frog (L. serrata)

These four frogs are referred to as the "declining frogs". Researchers and the community are involved in close monitoring of all these endangered frogs as well as periodic searches for the "missing frogs".