Australians are banned from keeping non-native reptiles as pets, but there is a nevertheless a thriving illegal trade in these often highly prized animals. We have documented the threat that these species – many of them venomous or potentially carrying exotic diseases – pose to people and wildlife in Australia.
In a study published in Conservation Letters, we estimate that of 28 alien reptile species illegally traded in Victoria between 1999 and 2012, 5 of them (18%) would have the potential to establish themselves in the wild if they escape or are released. Our findings also indicate that smaller alien reptiles are more likely to establish in the wild in Australia.
Worryingly, more than a third of these illegal reptile species are highly venomous snakes (10 out of the 28 species). The presence of 10 alien venomous snakes represents a serious human health hazard, even in Australia which is already home to some of the most venomous snakes in the world.
Previous research has focused on the overharvesting of wild populations to meet the demand for illegal wildlife products such as traditional medicine ingredients and other commodities, as well as live animals themselves.
But the trade in illegal wildlife poses a risk not just to the species being trafficked, but also to the people and ecosystems potentially exposed to new hazardous alien species as a result. Unfortunately, these risks are often overlooked or underestimated by wildlife agencies.
Frogs take their diseases with them
Effective biosecurity measures are crucial for tackling these threats. Are Australia’s biosecurity activities as good as they are made out to be in popular television shows about customs officers policing our borders?
Let’s look at the example of ranaviruses, an emerging disease that kills huge numbers of amphibians around the world. The introduction of these viruses to Australia could be catastrophic for native frogs. Alien frogs transported as unintentional stowaways can carry ranavirus, so intercepting those alien frogs will also prevent the spread of these pathogens.
In an earlier study, we examined the effectiveness of Australian biosecurity activities for stopping the introduction of dangerous alien ranaviruses. Our main conclusion was that existing biosecurity measures have significantly reduced the likelihood of introduction of alien ranaviruses.
Moreover, biosecurity activities do not need to intercept every single incoming alien frog in order to reduce significantly the likelihood that new diseases will be introduced. This is particularly good news for threatened native frogs.
A way forward
Unfortunately, many other countries seem to have inadequate systems for keeping unwanted species out, despite the many social, economic and ecological impacts that alien species cause across the world.
This situation paints a bleak picture for the future of biodiversity, with alien species increasingly wreaking havoc across all environments. But we believe there is hope and a way forward – as long as countries are willing to work much harder to combat the threats posed by alien species.
Foremost, we need to improve our understanding of the importance and drivers of transport pathways through which alien species travel. Armed with that knowledge, we can plan more effective management – although a lack of data is no excuse for delay in the meantime. Prevention is always better than cure, so our number one goal should be to prevent the introduction of alien species, rather than simply tackling the problems they cause.
Some important lessons emerge from our research. The illegal wildlife trade and the transport of stowaways are global issues. Therefore no country, however effective its biosecurity, can solve its problems on its own. Multilateral biosecurity agreements will be necessary to manage both stowaways and the illegal wildlife trade.
In Australia, we need to raise public awareness about alien species. We have to enlist the public in reporting suspicious activities and the presence of alien species at large. Meanwhile, supporting biosecurity activities is a no-brainer. Biosecurity is a responsibility shared by all Australians, and the general public have a role to support biosecurity activities, even if that means a few more minutes to clear biosecurity ports and airports. Be on the lookout for potential alien species, and if you spot anything unusual, report it to the Department of Agriculture and Water Resources.
Pablo García-Díaz, PhD candidate in invasion ecology, University of Adelaide; Joshua Ross, Associate Professor in Applied Mathematics, University of Adelaide, and Phill Cassey, Assoc Prof in Invasion Biogeography and Biosecurity, University of Adelaide