Danger zones: Climate change is altering predator-prey dynamics

The impact of climate change on wildlife behavior, particularly predator-prey dynamics in snowy environments, is a growing area of interest among ecologists. 

Laura Prugh, a wildlife ecologist and associate professor at the University of Washington’s School of Environmental & Forest Sciences, is exploring how changing weather patterns and snow consistency due to global warming will affect hunting strategies in various species.

Advantages and disadvantages 

“When you wear snowshoes in deep snow, you stay on top of the snow. But if you take the snowshoes off, you might go up to your waist. Certain species, such as wolves and lynx, have adapted to deep snow conditions because their feet act like snowshoes,” Prugh said. 

However, she points out that their prey, like caribou and moose, are at a disadvantage due to their weight and hoofed feet, leading to deeper sinking in snow. 

Focus of the study

“As climate change is making things warmer and changing the amount of precipitation, it’s going to affect how deep and hard the snow is. And that’s going to affect how deep the animals are sinking into the snow. Few scientists have looked at this before.”

To delve deeper into this phenomenon, Prugh collaborated with Jessica Lundquist, a professor of Civil and Environmental Engineering at the University of Washington. 

Danger zones

Together with their research team, they studied snow properties to identify “danger zones” where prey animals are more likely to sink, while predators remain on the surface. Their recent paper focuses on these zones for ten predator-prey pairs in Washington’s Methow Valley and Denali National Park in Alaska.

“Imagine having a snow fort – you’ve got this cave under the snow and it has a roof. And when people run on top of your snow fort, you hope it doesn’t collapse on you, right? This is what we are trying to measure: the strength of the snow to support itself against collapsing,” Lindquist said. 

“But snow is such a dynamic thing. It’s not even one phase; you can’t call it a solid, liquid or gas. It’s all of the above, and that makes snow really fun to study.”

Snow density 

The team used snow density as a proxy for its strength, hypothesizing that denser snow would better support an animal’s weight than light, fluffy snow. They tested this theory in the field, traveling through Denali National Park and the Methow Valley to examine animal tracks and study the surrounding snow’s density and other properties.

Study significance 

Both Prugh and Lundquist emphasized the value of interdisciplinary collaboration in this study. Prugh gained a deeper understanding of snow types, while Lundquist learned about identifying animal tracks. They also relished the opportunity to conduct research outdoors. Lundquist shared an anecdote to illustrate this point: 

“There’s this Calvin and Hobbes cartoon where Calvin’s standing in front of his class holding a box of water. And he says, ‘this was a snowflake outside.’ It’s unique and exquisite, but when you bring it into the classroom, it melts. The science is outside. You cannot bring snow inside and have the same characteristics as the snow outside.”

This study – published in the journal Oikos – underscores the complexity of ecological systems and how climate change could significantly alter predator-prey dynamics.

“Understanding when and where danger zones occur remains an outstanding, urgent need for resource managers to anticipate and proactively adapt to changing snow conditions,” wrote the study authors. 

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