We should be lucky to have people care so much for amphibians as Robin Moore does. He is the author of a book called “In Search of Lost Frogs: The Quest to Find the World’s Rarest Amphibians” that recounts the epic quest of many scientists, Robin Moore being one of them, focused on rediscovery of a 100 lost amphibians. It has received a lot of media attention, not unlike Paul Rosolie, who starred in the Discovery special “Eaten Alive”. Both projects aimed at raising awareness for the greater good, conservation of our natural world, by using unorthodox methods. In an interview with Mongabay Robin Moore elaborates on the book, the campaign and how we can get the general public interested in saving amphibians.
I have written earlier this year about the alarming decline of the axolotl, this weird looking salamander that retains its juvenile characteristics throughout its life and is only to be found in lake Xochimilco in the megacity of Mexico-City. Numbers have been going done drastically in recent decades up till the point that only a few individuals could be found in survey efforts earlier this year. Luckily scientists have been creating ‘shelters’ for these salamanders in which they pump clean water and keep the fishy predators out. Other efforts are now underway and we might again have some hope that this amazing animal survives.
After introducing the not so very attractive, but very interesting Chinese giant salamander to you, now is the time to shine the spotlight on a gigantic aquatic frog, the Helmeted water toad. Not really a stunner either, but esthetics should not be a criterion for me or for the conservation community. Alas, some alarming news has reached me from Chile, where this frog (despite the name it is a frog) has its home, that its numbers are declining rapidly and therefore scientists are setting of the alarm bells.
Wood frogs (Lithobates sylvaticus) naturally occur in Canada and the northern and eastern parts of the United States, even in the cold region of Alaska, where they have to survive during harsh winters. It is one of the very few amphibians that has been found living above the Arctic circle. Mind you, these are ectothermic animals, meaning they cannot generate their own body heat and therefore rely on environmental conditions to regulate their body temperature. So, if they are to survive during the cold winters of Alaska, they probably should have a trick up their sleeve. And they do, because these animals are known to go into hibernation for several months and during that period are able to freeze up to 60% of their body. And then when the warm spring sun returns, slowly but surely their vital functions will return as well, one heartbeat at a time. Remember this whenever you tell someone: “I am freezing”. Because these animals can stay literally frozen for at least six months. They should be dead, but evolution has decided otherwise.
This month saw a press release about some very peculiar frog behavior, that even made it into the mainstream media. Scientists discovered that frogs living in the urban parts of Taiwan make clever use of manmade storm drains during the mating season to amplify their love serenade.
It has become a classical example of how man’s interference with nature might have disastrous consequences: the introduction of the cane toad to Australia. It was introduced in 1935 to control the numbers of the native grey-backed cane beetle, whose larvae feed on the roots of the sugar cane. These toads turned out to be very ineffective beetle predators (as the beetles resided in the top of the plant where the toad couldn’t reach them) but very effective at finding other food sources and reproducing themselves. This turned out to be an ecological experiment with dire consequences, as native Australian carnivores have been decimated due to their appetite for this poisonous toad. A letter that has been published in Nature this week, warns about a similar ecological disaster that could be happening soon in Madagascar. It is a close relative of the cane toad, the Asian common toad, that has set foot in Madagascar and potentially poses a threat to the endemic wildlife of this great and biodiverse island.
Last week the discovery was announced, in the Ceylon Journal of Science, of no less than fourteen new species belonging to a remarkable group of frogs, referred to as the ‘dancing frogs’ of India. The dancing part of their name points to their unusual behavior of foot-flagging that males use to attract the attention of the females. A combination of intensive survey efforts in the Western Ghats spanning more than a decade and the usage of modern molecular techniques enabled the Indian researchers to identify this incredible amount of new species, thereby more than doubling the known total of species in this amphibian taxon.
Yesterday an article appeared in the Scientific American on exciting new research that suggests that predatory microorganisms can have a significant impact on the occurrence of the chytrid fungus Batrachochytrium dendrobatidis. This chytrid fungus is the cause of the disease chytridiomycosis, responsible for wiping out amphibian populations worldwide. So the discovery that natural predators exist, able to significantly reduce the number of these fungi present in an ecosystem, could have interesting repercussions for amphibian survival.
As we have seen in an earlier blogpost, predation by salamanders might have a positive effect on the amount of carbon that is stored in the soil. This is because they are the apex predators in temperate forests and eat the invertebrates responsible for shredding the leaf litter. Less invertebrates means that more leaf litter ends up locked away in the soil through humification. In this way salamanders provide a service to us humans, as they help to mitigate some of the human-induced CO2 in the atmosphere and hopefully evade too great a climatic change. However, a recent research has shown how salamanders themselves can be the victims of climate change. Scientists compared measurements on present day woodland salamanders in the Appalachian habitats to measurements on the same species that were done from the 1950s onwards. The results showed that size in these salamanders had decreased notably in only a few generations in most species. The researchers suggest this is a response to climate change. A warmer environment leads amphibians like these salamanders to expend more energy on metabolism, leaving less energy left for growth. This may impact their survival rates: a smaller salamander for instance has more potential predators and therefore is more prone to predation.
As a relic from the past the odd-looking Chinese giant salamander (Andrias davidianus) is still among us, but for how long? This salamander is the largest and heaviest amphibian in the world, reaching a maximum length of 2 meters and weighing in at a maximum of 50 kg. They can also live up to a respectable age of around 50 years. With its small, almost invisible eyes and broad and flat head, it is not an animal we would consider to be beautiful (because it seems not at all anthropomorphic), however it is a unique creature that hardly has changed in over 30 million years. It belongs therefore to the group of ‘living fossils’ like the coelacanth. The Chinese giant salamander is a member of the group of cryptobranchids, together with its cousins the Japanese giant salamander (Andria japonicas) and the Hellbender (Cryptobranchus alleganiensis). They constitute a lineage that has diverged from the rest of the salamanders around 170 million years ago in the Jurassic period. To put this in perspective: the reign of the dinosaurs would last longer, 105 million years more, than that dinosaurs have been extinct, since 65 million years. No wonder that the Chinese giant salamander is number 2 on the EDGE list, that set out to identify the most evolutionary distinct amphibians. This means that evolutionary speaking they are about as unique as an amphibian nowadays can get.