Not All Invaders Are Bad

During a trip south, naturalist Don Scallen gets a closer look at introduced lizards in Florida and asks questions about our own invasive species in Ontario.

February 7, 2023 | | Notes from the Wild

I travelled to Florida recently and spent time photographing reptiles in Miami parks. I was, unabashedly, a kid in a candy store. There were iguanas, of course, evoking the dinosaurs that thrilled me when I was ten. But also, a potpourri of other lizards including anoles, geckos, agamas and basilisks.

Peter’s Agama, male

Peter’s Agama, female

Brown Basilisk, male

Almost none of the lizards I saw are native to Florida. Bad news, right? We’ve been conditioned to view any introduced plant or animal as “invasive” – harmful to the local ecology.

It is true that many introduced plants and animals cause great damage – the pathogens that destroy our elm, ash, and beech trees, for example. Or the phragmites reeds that choke our waterways and the starlings that usurp the nesting cavities of native birds.

But nuance is called for. Introduced species exist along a continuum. Some are dangerously invasive, but others bring a mix of negative and positive traits to their new homes. And, I would argue, a few end up being welcome additions.

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  • The introduced lizards of Florida illustrate this. One, the Cuban brown anole, bullies the native green anole, taking over prime habitat throughout the state. But many other introduced lizards are primarily city dwellers that seem only to enhance urban ecology.

    The Knight Anole

    Our modern cities are novel habitats that are unsuitable for many native species. That some introduced species can survive and even thrive in such heavily modified environments should be perceived as an ecological win.

    A male House Finch in action.

    Do we have any introduced city dwellers here in southern Ontario that merit our acceptance? House finches, native to western North America, would qualify. The males are pretty, and their melodic voices buoy human spirits.

    In my view, another welcome newcomer is the red-eared slider, the common pet store turtle of yesteryear. This lovely reptile lives in wetlands in Toronto and other urban areas. It inhabits places long vacated by native turtles unable to endure life with us.

    A juvenile Red-Eared Slider warming up in the sun

    Invasive or not, I’m now irredeemably smitten by Florida’s lizards. They will draw me south again.

    About the Author More by Don Scallen

    Don Scallen enjoys sharing his love of nature through his writing and presentations. Check out his blog "Notes from the Wild".

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