Leafy trees, babbling brooks, a path winding through a meadow—many of us conjure up visions of nature when we imagine tranquility. Whether it be camping or a peaceful walk in the woods, forests have a way of helping us unwind. If a forest can take away our stress, does it follow that taking away a forest might cause stress? It might for the animals that call it home.
Researchers wondered what effect deforestation was having on small mammals’ stress levels in the Atlantic Forest, South America’s second largest forest, which stretches down the coast of Brazil to Argentina and Paraguay. Once, the Atlantic Forest covered about 463,000 square miles, but today, due to farming and urban development, less than a third of it remains. Deforestation is tough for animals: with less land and food comes fiercer competition for resources, and prey are more likely to come into contact with predators. Usually, stress is a good thing in these situations—a spike in stress can give an animal the energy it needs to escape a predator—but prolonged stress can cause illness and other negative effects.
The researchers decided to study areas of the forest in Paraguay. They trapped over a hundred rodents and marsupials in both small and larger areas of forest and took samples of their fur, where stress hormones are deposited as the hair grows. Analysis showed that animals from the smaller patches of forest had higher stress levels than animals from the larger patches.
Deforestation isn’t on anybody’s list of favorite things, but it’s probably a lot more stressful if it’s your home getting smaller and smaller, tree by tree.