Imagine Colorado without ring-necked pheasants, rainbow trout or fox squirrels. We take these familiar animals for granted as park of our state’s wildlife, yet they are all species not originally native to Colorado. The ring-necked pheasant, for example, is a Chinese bird introduced to the U.S. in the last century as a game bird. The fox squirrel is an animal of eastern woodlands. The treeless Great Plains acted as a barrier to them, but as settlers planted trees across the middle of the country, and as river-ways became forested due to changes in water flow patterns, fox squirrels began to move west (some were intentionally released in Colorado). Rainbow trout are a West Coast species first introduced to Colorado in 1882 as a sport fish.
So what is “native wildlife”? The statutory definition includes “those species and subspecies of wildlife which have originated naturally either presently or historically in Colorado… Those which have been introduced into the wild in Colorado by the Division… (and) Those which have been classified as native wildlife by the Commission.” By law, then, ring-necked pheasants, northern pike, bullfrogs, starlings and mountain goats (which were introduced in the 1940s) join elk, chipmunks, bullsnakes and meadowlarks as native wildlife.
Despite these statutory definitions, when we talk about natives, we usually mean animals. Thus, we don’t usually include wildlife like fox squirrels, whose westward migration was made possible by human changes to the landscape.
Non-native wildlife, often referred to as exotic, are a mixed blessing. On the plus side, many introduced species have great recreational value. Colorado isn’t rich in native sport-quality fish. Those familiar trout that give anglers such delight—rainbows, lake trout, brookies, brown trout—are all non-native fish introduced specifically as sport fish. Mountain oats are an addition welcomed by both hunters and wildlife watchers. Many non-natives are better able to take advantage of and adapt to changed and disturbed habitats resulting from human expansion, giving us a way to maintain some wildlife in these altered places.
But some exotic species have brought along a new set of problems (see “Gone Awry”). They often threaten the survival of native plants and animals. Some become residential and agricultural pests. Often exotics can better exploit resources; they compete with the natives and “win”. They impact some native species through direct predation, competition for resources, changes to habitat and hybridization with natives. Predation by northern pike on round-tailed chub could be contributing to he chub’s suspected decline. At certain times of year, some fox squirrels move into foothills pine forests occupied by native Abert’s squirrels where, University of Colorado researchers suspect, they out-compete the native squirrels for resources. A University of California study indicates bullfrog tadpoles may alter pond habitat (perhaps through chemicals they secrete) in ways detrimental to native frogs. And as eastern bluejays have expanded their range into Colorado, aided by the foresting of the Great Plains, they are beginning to interbreed with our native Steller’s jays.
As we learn from these situations, our perspective is changing. Over the last 150 years, we have done what seemed desirable at the time, but our understanding of how natural systems work was and is rudimentary. We now know that bringing in anything new can have a host of ramifications. When we consider introducing new species—as domestic pets or for recreation, management or other purposes—we’re trying to first evaluate as much as possible their potential impact on existing habitat and wildlife before we “tinker” with the natural order. In keeping with that, Colorado does not allow into the state many exotic species of deer, swine, Pronghorn, sheep and goats, which might be imported for commercial hunting ranches, out of fear they might hybridize with our wildlife, out-compete them for habitat and introduce exotic diseases.
Today we must live with the creatures we’ve brought here, whether intentionally or otherwise. We can’t get rid of all the non-native species, and we don’t want to. What we must do is balance their existence with preserving out native species.
So why do we care so much about preserving native species? If a brook trout is a good sport fish that does well in Colorado waters, why worry about saving greenback cutthroat trout, just because they’re native? Valuing native species, both animal and plant, entails a shift in traditional outlooks on natural resources to include scientific, environmental and aesthetic reasons. It’s no longer acceptable or logical to ignore a species because we don’t see a use for it. Ecosystems, with all their components, evolved to work in complex ways we frequently don’t understand. Realizing how little we know, we’re learning to balance our use of natural resources with environmental considerations.
Native wildlife evolved with and are adapted to the natural environment of Colorado. As such they are very good indicators of environmental health and quality, and how much we’re changing Colorado. Preserving native species maintains a healthy ecosystem and natural diversity. “To keep every cog and wheel is the first precaution of intelligent tinkering,” wrote Aldo Leopold in Round River. Once we start to tinker, we may lose some pieces (native species), making a ripple that spreads through the system and eventually affects us.
Finally, a major reason we value native wildlife is an intangible one. Native wildlife are as part of our natural heritage; they’re a part of the beauty and richness of our state. They’re like the hometown team. Why do you support the Broncos? Why do you root for Team USA in the Olympics? You probably don’t have a personal connection to any of the athletes, yet in an emotional and spiritual way, they are a part of you. Rooting for the Miami Dolphins, or the French Olympics team, just wouldn’t be the same. By the same token, if all the elk disappeared and we replaced them with zebras, it just wouldn’t be Colorado, would it?
Next: Gone Awry
(The information contained in this issue of Colorado's Wildlife Company was accurate at the time of original publication. Situations and circumstances described, staff positions, contact information, and dates of some events may have changed in the interim. Present knowledge and understanding of biological and behavioral facts and information may also be different, now, than presented here.)