Madagascar is a biodiversity hotspot, and of the known species on the island, 90% are endemic – found nowhere else on earth. This is thanks to the island being isolated for about 88 million years, but the passage of ships to and from the island might be changing this, as non-native species from other countries catch a lift and invade the island.
In a letter to the journal Nature 11 researchers have warned that the Asian common toad (Duttaphyrnus melanostictus) has been seen near Madagascar’s largest port – Toamasina.
It is feared that the invasion of the Asian common toad to Madagascar could be as devastating as the introduction of the cane toad (Rhinella marina) to Australia. The cane toad was introduced just 80 years ago in order to control crop pests, but soon devastated native animal populations by spreading disease, poisoning predators and outcompeting other herptiles.
The Asian common toad is a close relative of the cane toad, and is also toxic to predators. It has already been reported to be toxic to the ground boa, endemic to Madagascar, and the researchers therefore warn that more than 50 endemic snake species could be in danger.
Other species at risk include the fossa (Cryptoprocta ferox) which is already vulnerable to extinction, and Madagascar’s 101 endemic lemur species, over 94% of which are at least threatened with extinction.
The toads could also spread disease to other amphibians, spread parasites and contaminate water sources. The toads’ presence has left Jonathon Kolby, the lead author, imploring:
“an urgent call to the conservation community and governments to prevent an ecological disaster.”
It is hoped that the presence of the Asian common toad has been caught early, with the first sighting being reported on the 26th March this year. However, it has already been found just 25km away from the Betampona nature reserve and close to other hotspots.
It has been suggested that the island provides “ideal resources and climate” for the toads to spread quickly to the island’s interior, and the Madagasikara Voakajy are already making efforts to halt the spread of the invasive toad. Kolby recommends that the toads should be hunted and their spawn should be destroyed whilst populations are still small and manageable.
Kolby, J. E. et al. Nature 509, 563 (2014).