Surviving intensifying heat waves

When I tell people that I study ecological modeling for a living, the typical response is a wide-eyed stare and some variation of the question, “What on earth is that?”

Assuming most people don’t want to hear about differential equations and population dynamics, I’ve developed an abbreviated response: “Math about plants.”

“Math about plants” is a bit of an oversimplification — I also do math about animals —but it’s an accurate enough description of the research I do as a graduate student in ecology.

My daily work revolves around using equations to understand what is happening in the natural world and why. The questions we ask with those equations are key to the management and use of the environment around us; they range from predicting outbreaks of invasive insects (like the spongy moth) or infectious diseases (like COVID-19), to determining how much carbon is stored in a tree or how many black bears live in Connecticut.

Ecological modeling covers all that and more, but a childhood of canoeing on the Housatonic River and exploring the stonewall-studded forests of Kent has provided my specific equations with a clear central goal: figuring out how to best support these natural places as they face the novel challenges of a changing world.

Right now, we are all recovering from one of those challenges: heat waves.

Long stretches of unusually warm weather can be very disruptive to wildlife. Heat-induced worries for our songbirds and garden toads have real urgency, because while most humans are focused on issues of comfort, like sweaty skin or body odor, these creatures face a real risk of dying.

Most species have spent thousands of years carefully adapting to the very specific temperature ranges in which they usually live. When their internal temperature increases too far above the range they’ve adapted to, their cells become less efficient and more error-prone — problems that are exacerbated by other stressors, like water scarcity, as caused by this summer’s persistent drought.

Luckily, most species have a few tools to deal with uncomfortable heat. Some simply change their behavior, reducing their temperatures by hunting at dusk instead of midday or moving into “temperature refuges” of shady forest canopies and cooling bird baths. Those that cannot capitalize on such refuges rely on much smaller helpers: proteins.

The tiny proteins found in every living organism are both the problem and the solution of overheating. At the microscopic level, our cells build new proteins all the time. However, as cells heat up, they get much worse at making proteins that are the right shape. Misshapen proteins cannot perform their vital functions of building, regulating, and maintaining our anatomy — meaning that, left unchecked, flawed proteins eventually render their cells useless and their overheated organism dead.

Given the prevalence of this problem, cells experiencing heat stress evolved a defense. They produce a new kind of  proteins — called “heat shock proteins” — that specialize in fixing or removing the misshapen proteins before they make a mess.

Here’s where the math comes back in. A key goal of climate scientists is predicting how changing conditions on our planet will affect future temperature patterns. For many places around the world, including our corner of Connecticut, those predictions indicate more intense and frequent heat waves in our future.

If we want to know how those predicted heat waves will impact the ecosystems that experience them, then we must know how likely that ecosystem’s organisms are to survive the higher temperatures. To make this prediction, we need to know how high temperatures can get — and how long they can stay there — before heat shock proteins are no longer a match for the heat’s devastating impact on an organism’s cells.

Better foresight about how future temperatures will impact different species helps us make informed decisions about which species to plant while restoring natural areas or as street trees. It also tells us when and where creating and maintaining temperature refuges, like cooling forest canopies or shady ponds, will be most important for protecting plants and animals from the hottest weather.

So as heat waves roll through, provide some shade and water in your greenspaces; your local wildlife appreciates it!

Alison Robey is a volunteer at the Sharon Audubon Center and a second-year PhD student in Ecology and Evolutionary Biology at Yale University.