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, obscene 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 biologist Thor Hanson in a new book that explores the field of climate change biology.

In Hurricane lizards and plastic squids: the heavy and fascinating biology of climate change, Hanson discusses with scientists around the world 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 the same time, and what we can learn from scientists with a leading vision for the climate crisis.

Hanson’s own understanding of the climate crisis comes from decades of fieldwork where climate issues have peaked, even when this was not the intended area of ​​investigation. “You would go out into the field hoping 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 Revealer.

What have you learned about which species are most vulnerable to climate change and which are most able to adapt?

If you start looking for general topics in the field of climate change biology, the one that quickly stands out is the difference between specialists and generalists in nature. And by that I mean creatures or plants that are very flexible and general in the way they can behave and adapt. These are the ones who 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 that you water and be gigantic. They are just extremely flexible generalists.

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

Thus, animals or plants that fall into 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 close co-evolutionary relationships between pollinators and the flowers they pollinate. Sometimes it’s a specialized pollinator on a particular flower. This kind of close relationship is very threatened by this kind of rapid environmental change.

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

I’ve spoken to a number of people about this, but one in particular, a scientist by the name of Greta Pecl, said that we know that between 25% and 85% of species on the planet are already moving in response to climate change. But when it comes to 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 thought about it.”

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

Are you surprised at how quickly some changes are happening?

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 thought the squid was gone. It’s a mobile species and things got too hot and they’re gone.

But when people got out and did some polls, 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 ripened twice as fast, only reached half their normal size, and ate 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 these big squids. The few they could catch, they assumed, must be juveniles or maybe even some other species, and they rejected them.

It is therefore an example of the flexibility inherent in a species. We all have what we call in biology, plasticity. It is integrated into your genome to be able to cope with a number of environmental changes. Some species, like this squid, have a lot of them. Some species have very little. It is therefore those who lack plasticity who are most at risk.

This is an example of what we see a lot in nature right now, it is these plastic responses that are already integrated into the genomes of species. But there are now a few examples of developments unfolding in response to climate change that are unfolding rapidly.

One of those stories comes to us from a scientist named Colin Donihue, who worked on a small anole lizard that lives in the Turks and Caicos Islands in the Caribbean. Colin and his team were there to study and take all of these lizard measurements 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 these rats.

But two weeks into their field 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 this 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 much larger toe pads and stronger front legs to grab onto branches and tree trunks. which they stood during those high 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 the lizards. They learned that in fact, they hold on tightly to those strong front legs and that their hind legs and tail flap 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 it all, then came back later and showed that these traits were indeed passed down to the next generation. And then they looked at a wide array of anoles across the Caribbean and found that this kind of selection – this evolution – happened in response to hurricanes everywhere. Wherever you have frequent and strong hurricanes, the anoles of these populations have those bigger toe pads and stronger front legs.

So you can really see the effects of extreme weather conditions unfold just over the course of a few generations.

Have you ever worried that when people read the ways that certain species adapt, it would make them think that climate change won’t be a problem for most plants and animals?

Yes, that’s a concern, I think, of anyone who works in this area. They want to document what’s going on, but don’t make people feel like everything is going to be okay. In fact, it’s not going well. There is still cause for concern. It’s still a crisis.

It is always important in a discussion of the biology of climate change to remember that we have very compelling and even inspiring examples of rapid change, response and survival. But these are outweighed by the many species that cannot respond quickly – that lack that flexibility – and that are in danger of perishing.

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

And another thing that can be scarce is emotional capital. I think it’s very easy to feel hopeless, to feel overwhelmed by such an important issue. So worrying intelligently also allows us to allocate our emotional capital.

On that note, did you come out of this research with more concern or hope?

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

Yet what I have met, without fail, are people who have remained passionate and engaged in their research efforts, truly feeling that what they are doing is making a difference. And I came away surprised and somewhat gratified by the power of curiosity as a response to this crisis. It’s a balance for negative feelings.

I mean, desperation, if you will, just leads to more despair. But curiosity leads to learning. And that leads to action. I really saw this everywhere with the scientists I spoke with. And I took that as an inspirational message.


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