From the fossil record, we know that frogs naturally go extinct at a rate of about one species every 500 years. But in the last 30 years, up to 200 species have gone extinct, and a far greater number of species have dwindled significantly in population size. The current rate of frog extinctions is thus 3,000 times faster than than it should be, and we stand to lose at least one-third of the world’s 6,485 amphibian species in our lifetime if we don’t work swiftly to stop the extinctions.
In no particular order, here are the top ten steps that must be taken to prevent further frog extinctions.
(1) We need to minimize the damage being done by the chytrid fungus Batrachochytrium dendrobatidis, which is being transported globally via the amphibian pet trade, food trade, lab trade, zoo trade and bait trade, and is responsible for up to 100 amphibian extinctions worldwide in the last three decades. We must also prevent future extinctions due to other diseases. To accomplish this we need to implement and enforce a virtually complete ban on all unnecessary long-distance trade and transport of amphibians (i.e. dismantle the food trade, bait trade and pet trade, though captive-bred, locally purchased species would be fine). Zoos and laboratories that require amphibians from afar would need to drastically reduce their number of shipments, and implement stringent quarantine/testing procedures. It should be clear that we currently lack the money, the equipment and the trained personnel to conduct disease testing on the millions of amphibians that are transported inter-continentally each year. Furthermore, no diagnostic tests are perfect, and it is impossible to test for diseases that have yet to be identified by science. Chytrid was causing extinctions for decades prior to its discovery by scientists. The continued intercontinental trade and transport of amphibians will inevitably result in future amphibian extinctions.
(2) We need a drastic reduction in the amount of pesticides and other pollutants, including coal combustion residues. The millions of tons of these chemicals that we put in the atmosphere each year cause gonadal deformities, limb deformities, mouthpart deformities, decreased immune response and other problems.
(3) We need to ban the stocking of non-native fish as many amphibians have evolved in fishless areas and lack appropriate defenses. Many of these invasive fish species are voracious predators of amphibian eggs and tadpoles, and the fish and frogs cannot co-exist.
(4) We need laws protecting ephemeral wetlands (wetlands that hold water for only a portion of the year), which currently have few legal protections. Amphibians like these fishless habitats, but humans drain them in order to create land for house, parking lots and shopping malls.
(5) We need to ban the import of any wild-caught amphibian species, not solely because they spread disease, but because many of them are taken out of the wild from developing countries with few regulations, and the harvest is unsustainable.
(6) We need appropriate underpasses/overpasses or some means of dealing with amphibian road mortality in areas where this is a problem. I conservatively estimate that 60 million amphibians are killed by cars each year. (If each of the world’s 600 million vehicles hit only one amphibian per decade, this would be the case).
(7) We need funding and logistical support for the hundreds of critically endangered amphibian species that require and lack any captive breeding assistance.
(8) We need immediate action to combat global warming and climate change, which is drying waterbodies and cloud forests on which amphibians depend, and is causing the decline of mountaintop amphibian species that are unable to move further up the mountain to cool off (they are already at the top and have nowhere left to go). Global warming also weakens amphibian’s immune defenses and can alter host-parasite interactions.
(9) We need to halt the destruction of Earth’s remaining wilderness areas and restore habitats where possible. The rainforests of the world are being converted to agricultural areas or timber. Closer to home we have rampant urban expansion that destroys habitat and fragments remaining populations, leaving them more susceptible to inbreeding and related problems.
(10) We need to significantly increase the number of herpetologists, and conservationists in general. There are approximately 2,000 endangered amphibian species, but only about 2,000 full-time herpetologists. We simply do not have enough herpetologists to (a) determine the precise threats to individual species, and (b) implement the actions necessary to protect those species. This will only be possible with an increase in the number of scholarships and grants available, and through improved environmental education programs at the elementary, middle and high school level, which will produce undergraduates interested in pursuing careers in environmental conservation.