A recent study looks at how different mammals respond to climate change. Bears and bison are examples of long-lived, low offspring-producing species that are more adaptable than small, short-lived creatures like mice and lemmings.
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As the average global temperature rises, extreme weather events like lengthy droughts and torrential downpours are becoming more frequent and will only worsen in the coming decades. It is still unclear how the planet's ecosystems will react to this.
A Clear Pattern
Researchers from the University of Oslo and SDU compared data on weather and climatic conditions when the animal data were obtained with the analysis of population changes from 157 mammal species worldwide. At least ten years of data is available for each species.
A better understanding of how animal populations have responded to periods of extreme weather has been obtained, with questions like "Did they grow or shrink in numbers?" and "Did they produce more or fewer offspring?" addressed.
We can see a clear pattern: Animals that live a long time and have few offspring are less vulnerable when extreme weather hits than animals that live for a short time and have many offspring. Examples are llamas, long-lived bats and elephants versus mice, possums and rare marsupials such as the woylie.
Owen Jones, Associate Professor, Department of Biology, University of Southern Denmark
Quick Drop—But Also Quick Boom
The ability of large, long-lived animals to survive, breed, and raise their young is not as significantly impacted by environmental factors like extended drought as it is for small, short-lived animals. When circumstances become difficult, they can, for instance, focus their efforts on only one child or perhaps wait for better times.
Small, short-lived rodents, on the other hand, experience more pronounced short-term population changes. For instance, during a prolonged drought, a significant portion of their food supply—insects, flowers, and fruits—may disappear more quickly, and as they have minimal fat stored, they may be left to starve.
Since these small mammals can generate more offspring than large mammals, their populations could increase to capitalize on favorable conditions.
Jackson, a co-author of the study, added, “These small mammals react quickly to extreme weather, and it goes both ways. Their vulnerability to extreme weather should therefore not be equated with a risk of extinction.”
He also reminds us that while determining an animal species’ susceptibility to extinction, it is important to consider other factors as well, such as its ability to adapt to climatic change.
“Habitat destruction, poaching, pollution and invasive species are factors that threaten many animal species-in many cases even more than climate change”, Jackson emphasized.
Animals People Do Not Know Much About
The study not only sheds light on how these particular 157 mammal species respond to current climate changes. The research can help advance our understanding of how animals on Earth will react to ongoing climate change.
“We expect climate change to bring more extreme weather in the future. Animals will need to cope with this extreme weather as they always have,” Owen Jones stated.
So, our analysis helps predict how different animal species might respond to future climate change based on their general characteristics—even if we have limited data on their populations.
Owen Jones, Associate Professor, Department of Biology, University of Southern Denmark
The woylie, a rare Australian mammal, serves as an illustration. Although biologists know very little about this species, it could be assumed that it will react to extreme weather like mice because of its lifestyle, which is comparable to mice in that it is small, has a short life, and reproduces quickly.
Entire Ecosystems Will Change
“In the same way, there are lots of animal species that we don’t know very much about, but whose reaction we can now predict,” Jackson stated.
According to the researchers, this relationship between animal species’ capacity to adapt to climate change and their life choices can assist in predicting ecological changes.
Climate change could cause habitat suitability to shift, forcing species to relocate as their current habitats become uninhabitable. These changes are based on a species’ life strategy and can significantly alter how an ecosystem function.
Independent Research Fund Denmark has funded this study.
Journal Reference:
Jackson, J., et al. (2022) Life history predicts global population responses to the weather in terrestrial mammals. eLife. doi:10.7554/eLife.74161.