An invasive species of toad is gearing up to wreak ecological havoc on Madagascar, and the country’s government must act quickly to dodge the bump-laden bullet.
In a letter of correspondence published in the journal Nature on May 28, Jonathan Kolby, a conservationist at James Cook University in Queensland, Australia, and 10 co-signatories, warn that the Asian common toad was found near Madagascar’s largest seaport, Toamasina, as early as last March.
The toad, indigenous to South and Southeast Asia, is thought to have arrived via shipping containers, and poses a serious threat to Madagascar’s indigenous wildlife because of its toxic venom. Animals likely to prey on the toad would die after ingesting it, Kolby claimed.
“Time is short, so we are issuing an urgent call to the conservation community and governments to prevent an ecological disaster,” Kolby and his colleagues wrote in the letter.
Nikhil Advani, a senior program officer with the World Wildlife Fund (WWF), told VICE News that the threat is very real and very troubling.
“Madagascar is a place that, by virtue of being an island, and by virtue of actually missing many taxonomic groups, is very prone to invasives,” Advani said. “It’s also a very high concern because it has a very high level of endemism.” (Endemics are species that are unique only to a specific region.)
According to the WWF website, 92 percent of the country’s mammals and 95 percent of its reptiles can’t be found anywhere else on Earth.
Cases like this are particularly dangerous in regions such as Madagascar, where much of the ecosystem is very isolated and the introduction of an unfamiliar, non-native species could be catastrophic, Advani said.
'Madagascar has over 400 known species of frogs that are found nowhere else — their loss would be irreversible.'
Robin Moore, a conservation officer with the Amphibian Survival Alliance, told VICE News that the effects of the Asian common toad could be devastating to the island.
“The sudden appearance of a toxic, non-native toad does pose a serious ecological threat because it can kill those animals that prey upon it (such as snakes, lemurs, and birds) and it could displace native frogs such as the beautiful and unique mantellas,” he said. “Madagascar has over 400 known species of frogs that are found nowhere else — their loss would be irreversible and catastrophic.”
A perfect example of this was the introduction of the cane toad (a relative of the Asian common frog, ironically enough) to Australia, by way of Central and South America. First introduced in 1935 as a way to control the population of the native cane beetle — a species detrimental to Australia’s historically lucrative sugar cane fields — the cane toad ultimately wound up ravaging the country’s ecosystem.
“[The introduction of the cane toad] has led to widespread impacts on native species and ecosystems. It has displaced many native species — through predation and competition — and it has effectively poisoned those animals that have fed upon it,” Moore said. The width of the heads of some Australian snakes has even rapidly evolved to favor those that cannot feed upon the toad — for the snakes' own safety.
According to Advani, however, one of the most catastrophic examples of invasive species was the introduction of the brown snake in Guam just after World War II.
'Because most of us now live in man-made concrete jungles, we feel disconnected from nature, and we feel immune from changes to our world that don't impact us directly and immediately.'
“That really devastated the ecosystem and not only had an impact on birds and small mammals, but also affected humans,” he said. “People were bitten by the snake, and it also caused a lot of electrical outages because it would climb up electricity poles.”
In the US, while bullfrogs are common in the Northeast, these cannibalistic frogs have wreaked havoc on native frog populations in western states since their introduction in the late 19th century.
In the letter, Kolby said that the unfriendly amphibians in Madagascar are still in the early stages of population growth and suggested several ways to quell the invasion. These included killing or capturing the adult toads and their larvae, installing low fences to prevent them from reaching water and spawning, and even temporarily draining ponds entirely.
If the government and conservation groups there don’t act quickly, the cost of controlling the population of Asian common toads could be tremendous, Advani said.
In the US, the Department of the Interior spent $100 million on invasive species prevention in 2011 alone.
Statistics for Madagascar’s annual spending on invasive species were unavailable, but according to the Australian Bureau of Statistics, the annual cost of controlling invasive species in Australia, coupled with production loss estimates, was upwards of AUD 720 million ($666m) a decade ago.
And of course, the risk doesn’t end with Madagascar.
“There is now a high dispersal risk of these toads spreading from Madagascar to other Indian Ocean islands such as the Mascarene Islands, Comoros, and Seychelles,” Kolby said in the letter.
Madagascar’s conservation groups are aware of the problem and understand that there is a “window of opportunity” to adequately handle the invasion, Moore said. But once it spreads, all bets are off.
Ultimately, the fault lies in humans. “Because most of us now live in man-made concrete jungles, we feel disconnected from nature, and we feel immune from changes to our world that don't impact us directly and immediately,” Moore said.
“I think it is important to remember that we are actually an integral component of larger ecosystems that sustain us all — ecosystems that provide clean water, clean air, and that buffer us from extreme events such as floods and droughts. Biodiversity — that is, animal and plant species — are the building blocks of these ecosystems.”
We should probably get our shit together.
Follow Maxwell Barna on Twitter: @MaxwellBarna
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