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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