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Paul Hormick's avatar

For the general public they may not see the ramifications of invasive species. For example, I work in the middle of a wildlife refuge. Folks come there and see the osprey, pelicans, seagulls, and an abundance of flowers. The impression they may get is that all is fine in this corner of Southern California.

Yet the island is completely overrun by invasive ants from Argentina. In the ten years that I've been there, I've never seen a native ant. Recent science confirms that the Argentine ants push out the native ants. When I go to the mountains, the landscape can be abuzz with native carpenter, sweat, and mason bees, bumblebees too! Although I see these creatures from time to time at my worksite, it's mostly populated by European honeybees.

About half of the flowers folks see at the refuge are invasive iceplant from South Africa and daisies from Europe. If we didn't push them back, they would take over the island.

In the meantime, native plants and animals are evolving to adapt to the presence of the invasives. The Argentine ants spread parasites and disease for almost all the native plants, placing evolutionary pressure on them.

And people just get used to invasive species and think of them as natural. The vistas of California, with the tan hillsides is said to be iconic, views seen in thousands of Hollywood movies. Those tan hillsides are covered with invasive European grasses.

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Will Lyons's avatar

Amber waves of [brome].

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Jonathan Tonkin's avatar

A great example of shifting baselines syndrome, Paul. Thanks for your thoughts.

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Lynn Broaddus's avatar

I will never get all the Japanese honeysuckle and Russian privet removed from our woods but that doesnt stop me from trying. The reward of seeing a redbud tree that had previously been obscured or an orchid peeking up through the leaf litter is all the reward I need. Every little but counts.

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Jonathan Tonkin's avatar

Absolutely, Lynn! Keep fighting the good fight.

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J.M. Ransom's avatar

Yes, I’ve seen the articles on Substack arguing that invasive species shouldn’t be a big concern. As someone who also lives in an area heavily impacted by this issue, they disturbed me. Thanks for setting the record straight

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Jonathan Tonkin's avatar

My pleasure! I'll never get my head around that perspective. To be honest, my take is that it's dangerous to spread such messages when you have a relatively large audience.

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J.M. Ransom's avatar

Totally agreed

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Tara A. Pierce's avatar

I confess I’m shocked anyone could think invasive species are beneficial bc… “invasive”. It’s amazing how one can choose words so carefully and yet…

Anyway, love the expansion on impacts—I’m sure this work will help broaden and deepen the understanding of invasive species, and help keep the narrative more accurate.

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Jonathan Tonkin's avatar

Thanks Tara! Yes, it makes no sense to me either.

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Amanda Royal's avatar

Feral cat feeders are the worst. Hawaii is my childhood home and they are experiencing many of the same things as New Zealand. I was shocked on a recent visit to see a woman pull up with cartloads of food to feed the feral cats at the bottom of a beautiful canyon. The justification is that feeding them prevents them from hunting local wildlife, but any cat I've known eats their food and kills birds and rodents out of instinct. Meanwhile, at the local bird sanctuary, a volunteer was very forthright: "We kill the cats." Kudos!

There's also a feral cat feeding society of Google employees that have helped decimate burrowing owl populations in the Bay Area. It's astounding. https://www.nytimes.com/2018/05/26/technology/google-cats-owls.html

I was also surprised to find the invasive species defenders here on Substack. What a strange lot! You throw them a bone by saying, "Don't demonize" species. But hey, some really need to be demonized!

There are some great channels on YouTube showing people hunting lion fish by the hundreds in the Caribbean. They are sold to local restaurants for fish tacos. Win win!

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Jonathan Tonkin's avatar

Feeding those cats is about as silly as it gets. All it’s doing is growing the population and causing spillover effects on the natives.

Yes, I don’t understand why folks would try to say we should shift our default mindset to thinking of them as having positive impacts. This includes environmental writers with more than 10k readers. The posts I’ve seen focus on a few cherry picked examples and build a case using them for all invasives being harmless. 🤷‍♂️

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Theodore Rethers's avatar

Then dingo was introduced into Australia 4000y ago and man arrived with fire 65000 years ago both have had a tremendous impact but both are seen now as indigenous. Where is the line drawn? in time or in impact?

I do believe we now have the technology to genetically sterilize the invasive species through hereditary genetic modification but if this then returns to the country of origin one assumes we could reverse it?

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Jonathan Tonkin's avatar

Once you start meddling in such ways, things can get very complicated. Hard to reverse such things. In NZ, we brought in predators to control invasive herbivores, which went onto decimate birds.

Re: where the line is drawn -- that's a very tricky one. There's no right answer here. But obviously the focus should be on the ones with the clearest impacts.

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Kate Howlett's avatar

Brilliant paper, brilliantly explained 🙏

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Jonathan Tonkin's avatar

Thanks so much, Kate! :)

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Emily's avatar

really interesting and important work! Thanks for sharing this.

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Jonathan Tonkin's avatar

Thanks Emily!

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