Curious Humans and Other Animals

Article excerpt

Humans are a curious lot, and our intrusions, intentional and inadvertent, have significant impacts on animals, plants, water, the atmosphere, and inanimate landscapes. Often our influence is subtle and long-term. Many animals who we want to protect and conserve experience deep emotions, and when we step into their worlds, we can harm them mentally as well as physically. It's important to keep in mind that when we intrude on animals we are messing not only with what they do but also with how they feel--we're messing with their minds and hearts, and in many instances, they don't like it.

In my home state of Colorado, many people enjoy the outdoors and many work to protect a wide variety of animals. Many of us live here and travel elsewhere to experience nature. Our understanding and appreciation of wildlife result from various types of research and "just being out there."

There is plenty of research that shows the (often unintentional) effects humans have on other animals, their behavior, abundance, survival, and habitat use, as we conduct research, and engage in various recreational activities, including photography and travel (ecotourism), trying to help individuals and species along, and expanding our own habitats. Many of these findings apply to multiple situations and species.

Mere human presence can influence animals' behavior. Elk and many other animals avoid skiers. My students and I have done research showing that humans have a large influence on prairie dogs, such that individuals who have lots of contact with humans are less wary of our presence than individuals who don't. The same is true for some deer species. Similarly, magpies not habituated to human presence spend so much time avoiding humans that this takes time away from essential activities such as feeding. Researchers interested in feeding patterns must be sure their presence doesn't alter species-typical behavior, the very information they want to collect.

Recreational trails built by humans are also associated with changes in behavior and mortality. In Boulder, Colorado, within forest and mixed-grass ecosystems, nest predation is greater near trails, but we don't know if it's the trail itself, trail use by humans, trail use by predators, or all three factors that are responsible.

Many people adore young animals and try to get close to nests or dens without disturbing residents. However, nests visited regularly by humans can suffer higher predation than nests visited infrequently. It may be that birds accustomed to intrusions by humans who don't kill them subsequently allow other animals, including predators, to get too close.

Sometimes just being there has an influence, whether or not there's any hands-on contact. People enjoy watching animals from cars, boats, or airplanes. However, the noise and presence of vehicles can produce changes in movement patterns (elk), foraging (mountain sheep), and incubation. In swans, the noise and presence of cars result in increases in the mortality of eggs and hatchlings. Once again, these effects aren't obvious when they occur, but data show they're real.

Activities such as mountain climbing are also intrusive. Climbers can affect birds so that they fly more, perch less and consequently waste energy. In many places in Colorado, climbing is restricted during nesting season. In a study of the effect of climbers on grizzly bears in Glacier National Park, Montana, researchers discovered that climber-disturbed bears spent about 50 percent less time foraging. …