Saturday 6 February 2010

More on the Giant Salamander (warning long post)

As we pull into Toyohira, an unusual and unexpected welcome committee is lined up ready to receive us. The group of primary-age children breaks into a song about the bonds of friendship between human and salamander. "It's everyone's friend," they warble through the chilled afternoon air.A small river burbles its accompaniment - a river flowing past their school, which contains along its length a number of concrete structures designed to make sure the Japanese giant salamanders, or hanzaki, are still around by the time the next generation of children stands in the same spot and sings the same song. The "hanzaki holes" are a key conservation tool in a land where many rivers are now sculpted not by nature, but by the hand of man. When I ask Professor Masafumi Matsui from Kyoto University, a leading Japanese authority on all matters amphibian, to name the single biggest modern threat to this animal that has been around roughly unchanged since the time of the dinosaurs, he answers without demur: "The construction of dams and roads, which destroys the habitats". "We can't do without constructing such things; and [the habitat] will be cut upstream and downstream." Many Japanese rivers are now, in reality, canals - boxed in concrete, guided down valleys to keep floodwaters away from homes and secure a supply to the irrigation systems. To breed, hanzaki need to find nesting dens in the riverbanks. Without dens, there will be no more hanzaki; hence the holes. And while the idea of a concrete nest might not seem very appealing to the human constitution, the salamanders themselves seem OK with it. Lifting the lid on one of the dens, we see the rear half of a big, mature male. Its head is poking through a small connecting tunnel into the river, where it can protect the nest from any would-be usurpers. The breeding plan appears to be working; along the river we can find larvae just a few months old, and presumably some at least have sprung from these nests. Is keeping the species alive with such a surgical strike a valid substitute for the much wider restoration of these concreted channels that would also help everything else in the ecosystem? "Obviously in these kinds of managed landscapes you do need to do some management, and what they've been doing here in these artificial nests and so forth is a tremendous management approach," says Claude Gascon, an amphibian specialist with Conservation International. "But obviously that's not sufficient, and you do need to protect some of these natural habitats, these watersheds, in their natural form so that you're protecting all of the needs of this animal, which is a tremendous animal." Move a curious finger down the Red List of Threatened Species, and the factor you see more often than any other as a cause of decline for just about every kind of creature - amphibians, birds, mammals - is precisely what is facing the Japanese giant salamander: loss of habitat. Its sister species in China, by contrast, must contend most urgently with the wiles of poachers - hardly surprising, when the meat from an adult giant salamander can fetch upwards of $1,000 on the black market. Hunting has brought the Chinese giant salamander to the unwelcome status of Critically Endangered. After protection was conferred in the 1950s, some bright spark had the idea of importing the Chinese species, farming it, and supplying the meat demand that way. In the inevitable way of these things, the idea quickly proved a busted flush. But the Chinese animals escaped; and though the farm itself is long gone, the once farmed salamanders are thriving. With Masafumi Matsui and his team of assistants - one sporting the perhaps inevitable soubriquet of "ninja turtle" - we clamber out into the bed of the Kamo river as it hurries down a narrow valley between wooded slopes. They find one larva, small and black - then two, then three - and finally a roseate miniature of the real thing, several years old. Without DNA analysis it is impossible to be sure, but the professor is pretty sure this is a hybrid. "Last year, more than 50% were hybrids," he says. Back in his lab at Kyoto University, he demonstrates the extra aggressiveness of the Chinese species. With a fish dangled in front of its nose, it turns in a flash from dopey sloth to snapping tiger. The aggressiveness is helping the Chinese males take over the dens of the local rivers - and with the dens, the right to breed. The Japanese giant salamander may soon be extinct as a separate species in these waters.
Source and video:

No comments: