Move or Change: How Plants and Animals Try to Survive in a Warming World

Image credit: Jo-Anne McArthur/We Animals Media

When it comes to climate change, nature hasn’t had the luxury of waiting for dragging politicians, evasive corporations or science deniers. Countless species are already on the move.

“Just as the planet is changing faster than expected, so are the plants and animals that inhabit it,” writes the biologist Thor Hanson in a new book that explores the field of climate change biology.

In Hurricane Lizards and Plastic Squids: The Complex and Fascinating Biology of Climate ChangeHanson talks to scientists around the world about how plants and animals move and change, and why some are inherently better prepared to succeed than others. Hanson also discusses evolution in action, what happens when hundreds of thousands of species hit the road at once, and what we can learn from scientists with a leading view on the climate crisis.

Hanson’s own understanding of the climate crisis comes from decades of work in the field where climate issues have come to the fore, even when it was not the intended area of ​​investigation. “You would go into the field expecting to study one thing and come home with a very different set of data because the conditions on the ground had changed so much,” he said. The developer.

What did you learn about which species are most vulnerable to climate change and which are most able to adapt?

If you start looking for general themes in the field of climate change biology, the one that quickly stands out is the difference between nature specialists and generalists. And by that I mean creatures or plants that are very flexible and general in how they can behave and adapt. These are the ones that are particularly good at thriving in a variety of conditions. And there are many examples of this that we know so well, like dandelions, which can bloom at any time of the year. They can grow in the gravel of your driveway and be small and tiny. Or they can grow in the lush area of ​​the lawn you water and be gigantic. They’re just extremely flexible generalists.

Thor Hanson
Author and biologist Thor Hanson. Photo: Kathleen Ballard Photography

Thus, animals or plants that belong to this category are already well adapted to cope with change.

Those who often stand out as the most vulnerable are the specialists who depend on a particular type of habitat or relationship. For example, the very closely co-evolved relationships between pollinators and the flowers they pollinate. Sometimes it is a specialized pollinator on a particular flower. This type of close relationship is very threatened by this type of rapid environmental change.

Is it possible to quantify how many species are moving in response to climate change and how this is changing ecosystems?

I’ve spoken with a number of people about this, but one in particular, a scientist named Greta Pecl, said we know that between 25% and 85% of species on the planet are already moving in response to change. climatic. But in terms of what that means and how these new ecosystems with all these new neighbors will get along in the future, she said “we haven’t really figured out what we’re doing on that.”

It is extremely complicated to try to predict how these ecosystems will settle during this period of change. Animals, plants, pests, pathogens – all of these things move and recombine in habitats in ways they never have before.

Are you surprised at how quickly some changes happen?

Yes, the speed of responses for some things was almost instantaneous. One of the best examples would be the Humboldt squid in the Gulf of California. When the waters warmed up, the fishermen and everyone else thought the squid was gone. It’s a mobile species and things had gotten too hot and they disappeared.

But when people got out and took readings, they actually found that the squid was still there and more abundant than ever. But the hot water or the stress of that heat had triggered a complete lifestyle change where they were maturing twice as fast, reaching only half their normal size and eating different foods.

Their adult bodies were so much smaller and so different that they were too small to bite the hooks people had used for decades to catch those big squids. The few they could catch, they assumed were juveniles or maybe even another species, and they discarded them.

It is therefore an example of the inherent flexibility inherent in a species. We all have a bit of what they call in biology, plasticity. It is built into your genome to be able to cope with a certain amount of environmental change. Some species, like this squid, have a lot of them. Some species have very few. It is therefore those who lack plasticity who are most at risk.

It’s an example of what we’re seeing a lot in nature right now, these plastic responses that are already built into the genomes of species. But there are now a few examples of evolution occurring in response to climate change that are unfolding rapidly.

One such story comes to us from a scientist named Colin Donihue, who did work on a small anole lizard that lives in the Turks and Caicos Islands in the Caribbean. Colin and his team were there to inspect and take all these measurements of the lizard because there was going to be a project to eliminate the non-native rats that ate the lizards. And they wanted to see the answer to getting rid of those rats.

But two weeks into their on-the-ground season, two category four hurricanes hit the island with extreme winds, uprooting trees and destroying structures and causing flooding. This took the rat eradication project off the books, but Colin and his team realized it was a rare opportunity to examine the hurricane’s impact on these lizards.

So they went back there, repeated the same measurements in the field, and learned that the surviving lizards had noticeably larger toes and stronger forelegs to grip tightly to the branches and tree trunks they were hitting. stood during these strong winds. And the weird part was that their hind legs were smaller.

To understand why they simulated hurricane-force winds with a leaf blower and observed the behavior of lizards. They learned that in fact they cling tightly to these strong front legs and their hind legs and tail spread out like a sail in the wind. So if you have smaller hind legs, it’s less drag and you’re more likely to hang on to the hurricane.

They documented all of this, then came back later and showed that indeed these traits were passed on to the next generation. And then they looked at a wide range of anoles across the Caribbean and found that this type of selection – this evolution – continued in response to hurricanes everywhere. Wherever you have frequent and powerful hurricanes, anoles in these populations have those wider toes and stronger front legs.

So you can really see the effects of extreme weather happening over a few generations.

Have you ever worried that when people read about how certain species are adapting, it might make them think that climate change won’t be a problem for most plants and animals?

Yes, that’s a concern, I think, for anyone working in this field. They want to document what’s going on, but not give people the impression that everything will be fine. In fact, it’s not going well. There is still a great cause for concern. It’s still a crisis.

It is always important in a discussion of the biology of climate change to point out that we have very compelling and even inspiring examples of rapid change, response and survival. But these are counterbalanced by the many species that cannot react quickly — which do not have this flexibility — and which are in danger of perishing.

But what studying the biology of climate change allows us to do is not stop worrying, but rather worry intelligently. This puts us in a much stronger position in terms of how we allocate limited resources to these issues. If you understand which species and systems are most vulnerable, if you understand which ones have some natural resilience, you are in a much better position to manage the crisis.

And another thing that may be lacking is emotional capital. I think it’s very easy to feel hopeless, to feel overwhelmed by such a big problem. So worrying intelligently also allows us to allocate our emotional capital.

On that note, did you come away from this research feeling more worried or hopeful?

When you think of all those scientists who have spent their entire careers studying species or ecosystems that could really suffer, you would think they would have more reason to worry and lose hope than anyone.

Yet what I encountered, without fail, was people who remained passionate and engaged in their research endeavors genuinely felt like what they were doing was making a difference. And I came away surprised and somewhat gratified by the power of curiosity as an answer to this crisis. It is a balance with negative feelings.

I mean, desperation, if you will, just leads to more desperation. But curiosity leads to learning. And that leads to action. I’ve really seen this across the board with the scientists I’ve spoken with. And I took that as an inspirational message.

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