Spread of harmful species despite early warnings

12 10 2020

The goal of developing an alien-species warning system is to remove the species locally and to allow others enough time to take actions that prevent further spread.

For the green iguana (Iguana iguana) however, its > 50-year spread around the globe continues as we show in our latest study by using citizen-science data. We demonstrate how pet owners and recreational parks have facilitated the green iguana’s spread to mainland Asia, and project its potential future Asian range in the absence of immediate actions.

Do you know how best to deal with an invasive species? Avoid them in the first place.

There is broad agreement among scientists and conservation practitioners that the first line of defense against invasive species is prevention. Once established, invasive species can cause agricultural damage, compete with native species for space, become predators, or carry with them and introduce new diseases. We’ve seen this time and again, with some infamous examples including zebra mussels in the Great Lakes of North America (1), cane toads in Australia (2), and Asian tiger mosquitoes around the world (3). 

To stop the list of invasive species from growing, it is important to detect spreading and newly arriving species early, ideally before they become established. Early detection is especially evident for green iguanas, given their high rates of population growth (females can lay up to 70 eggs), although detectability can be particularly challenging in forested spaces.

Two green iguanas reported on iNaturalist in Jurong Bird Park, Singapore. Free-roaming green iguanas could escape the limits of parks and become a source of new populations throughout Asia. Picture Credit: user pseudomonasry. Used under a Creative Commons licence.

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How much is that iguana in the window?

25 08 2020

In our latest study, we examine the downstream effects of publicising an elevated species description for a reptile that is highly prized in the international commercial wildlife trade.

We describe how iguanas from an insular population of the common green iguana (Iguana iguana) entered commercial trade shortly after an announcement was made indicating that the population would be described as a new species.

The international commercial wildlife trade presents a known risk factor for wild populations of threatened species. One organisation in particular regulates the international trade in species — the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Although most people probably know about the illegal practices involving iconic elephants and rhinos, reptiles are also targeted and traded. For example, after its discovery and description in 2016, and even though locality data were safeguarded, China’s endemic Mountain spiny crocodile newt (Echinotriton maxiquadratus) quickly entered the trade. This put conservation pressure on this small-range species (1, 2). Therefore, CITES signatory countries placed this species on its Appendix II in 2019, which lists animals and plants in need of protection.  

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