The Importance of Biodiversity
by Michael Jeffords

ARTICLE FIRST APPEARED: 1995 Summer

(Co-written by Susan Post)

TWG Editor: The following article is excerpted, with permission, from the Summer 1995 issue of an excellent magazine called Illinois Steward ($10/yr.; published quarterly; W-503 Turner Hall, 1102 S. Goodwin Ave., Urbana, IL 61801). The authors work for the Illinois Natural History Survey. Along with their compatriot, Kenneth Robertson, they recently published a book I recommend highly. It is entitled, Illinois Wilds [see sidebar, p.3]. The authors may be reached at (217) 333-6880.

What sets the Earth apart from the other planets in our solar system, perhaps from all others in our galaxy? The answer is simple: life, an amazing and bewildering variety of life that we call biodiversity. From the ocean depths to the highest mountain peaks the Earth is enveloped in a mantle of living organisms. Varying in size from bacteria to blue whales, they have colonized virtually every habitat on the planet. Even in the extreme conditions surrounding the poles exists a contingent of life.

From a strictly human perspective, this biological diversity is the most important, yet least understood, of all natural resources. Earth's diverse species provide most of the life-support materials we ultimately rely on. Each species is unique, a magical well of eons-old-genetic information 行 information that we humans cannot afford to be without. Every species that is lost reduces the options for nature 行 and for us 行 to respond to a continually changing environment.

While extinction of species is a natural process, the current rate is abnormally high. Scientists have found that the normal extinction rate on a geological time scale is one species every 1,000 years. By 1950, however, one species was being lost every 10 years. Today the rate is estimated at one every day! In this context, perhaps the least useful statement that a human can make regarding an organism is "What good is it?" Ignorance of the potential use of a species to humans is a poor excuse for the finality of extinction.

Despite its importance, biodiversity remains an enigma for most citizens. A nationwide phone survey of 1,209 randomly selected adults in April 1994 revealed that 73 percent were totally unfamiliar with the concept of "loss of biodiversity."

How Much Diversity?

In the last 30 to 40 years, the sciences of taxonomy and systematics (the naming of organisms and the study of their natural relationships) have expanded rapidly. As a result, vast information about the diversity of Earth's organisms is accumulating. Currently about 1.4 million species of plants and animals have been described and named by scientists. About 800,000 are insects, 250,000 are plants, and 41,000 are vertebrates (mammals, birds, etc.). The remaining species include invertebrates, fungi, algae, and microorganisms.

Despite these numbers, fewer than 15 percent of species have been named; estimates of Earth's species range from 50 to 30 million! We are still woefully ignorant of the organisms with whom we share the earth. Our knowledge of the life histories of species and their ecological interactions encompasses a relatively few organisms, confined mostly to those that are directly beneficial or harmful to us.

What about the biodiversity of Illinois? Most citizens would say it's a nice place to live but far from a biological wonderland. A trip across the state yields a vast panorama of corn and soybean fields, interspersed with the occasional urban or industrial complex. In 196l scientist Philip Smith of the Illinois Natural History Survey described Illinois as "a great corn desert."

But to judge Illinois from the view on an interstate highway does the state a disservice. Because of its unique geographic location, Illinois houses an unusually large variety of plants, animals, and habitats. Illinois has nearly 100 habitat types, and conservative estimates number species within the state at more than 53,000.

This is especially high for a geographic area the size of Illinois in a temperate climate. Situated at the intersection of the eastern deciduous forest, the western Great Plains, the southern coastal plain, the Ozark uplift, and the boreal (northern) forests, Illinois provides a meeting ground for organisms from very different geographic regions. These wondrous, rich, self-sustaining natural ecosystems, home to everything from lady's slipper orchids to badgers, are our natural heritage. And despite the precipitous increase in species extinctions on the Earth, most of the organisms that existed in Illinois before settlement by Europeans are still here.

Illinois Species

In the book The Current State of Biological Diversity, E. O. Wilson -- a Harvard University entomologist -- noted that we do not know the true number of species on Earth, possibly even to the nearest order of magnitude. The same is true for Illinois. In 1855, the first attempts to list the number of species in the state appeared as three species lists in Transactions of the Illinois State Agricultural Society. Today's list of Illinois species 行 54,754 plus 行 is still only an approximation. We are fairly certain of the numbers of our more visible fauna in the phylum Chordata: the reptiles, amphibians, fishes, birds, and mammals. In other phyla, however, we are less certain. Research on many of these groups is at an early stage, and new species are frequently found.

The vast majority of Illinois species remain unmonitored. Like the dead in Gray's Elegy Written in a Country Churchyard, they may pass from state to state, unnoticed and unknown.

Habitat Diversity Then and Now

In general, the more habitats, the greater the potential for species diversity. Habitat types originally found in Illinois included forests, prairies, savannas, marshes, fens, lakes and ponds, streams, and caves. Although each habitat continues to exist, most habitats are exceedingly small and often rare because of the extensive urban and agricultural development in Illinois during the past 150 years. E. O. Wilson observed that "humanity spread across the world . . . godstruck, firm in the belief that virgin land went on forever."

Inevitably, as land use changed, the number of species and the population sizes of most declined. The decline in biodiversity is not usually the direct result of human exploitation (despite numerous examples of this) but rather of the habitat destruction associated with development and expansion of human activities.

Even though Illinois has nearly 100 habitat types, these fit nicely into three categories: prairies, forests, and wetlands. In 1820 about 13.8 million acres of Illinois were forested. Today only about 4.3 million acres of trees can be found in Illinois. Most of today's forest acreage is second- or third-growth timber or pine plantations; a scant 13,500 acres of relatively undisturbed forests remain. Why is this important? Illinois forests provide habitat for more than half of the state's native plants. In addition, half of Illinois' threatened and endangered species are forest inhabitants, and three-quarters of the wildlife habitat in the state is found in forests.

Early European settlers of the land that became Illinois were concerned with surviving to make a new life on the prairies and forests. They navigated and explored, logged, farmed, and constructed. Resources appeared inexhaustible. Many of the first Europeans to see the Illinois country had crossed a vast ocean, snaked their way through a nearly impenetrable mountain range, and forged a path through 1,000 miles of dense, primeval forest. They did it with indomitable spirit and by sheer force of will. Yet when they reached the edge of the eastern deciduous forest, today approximated by the Indiana-Illinois border, they stopped in wonder at the splendor and magnitude.

Here was a landscape so different from what these newcomers had known 行 a grassland that stretched for 1,000 miles 行 that they had no words for it. In time this landscape came to be known as "prairie," derived from the French word for meadow. At first early settlers avoided living on the prairie. But they soon discovered that it made excellent cropland 行especially after John Deere invented the moldboard plow, which allowed virgin prairie soil to be relatively easily broken.

The wild prairies became cropland at an astonishing rate 行 about 3.3 percent a year. More than 300,000 people settled on the prairie between 1830 and 1840, and by 1860 nearly all the prairie had disappeared. Only 2,300 of 21.6 million acres of prairie survive, or less than 0.045%. Ironically, in early Illinois, human developments existed as tiny islands in a sea of grass. Today the plants and animals that made up the Illinois prairie are equally tiny sanctuaries in a vast sea of development.

A poll of current Illinois residents would find that most do not consider their state to be particularly wet (notwithstanding the flooding of 1993); the early settlers, however, would have had a very different impression. Illinois originally had an estimated 8 million acres of wetlands. Since Illinois became a state in 1818, more than 95 percent of these have been drained (the tile shop was one of the first businesses to open its doors in areas of new settlement); a concomitant loss in the natural biodiversity that wetlands contain was inevitable. Today, high-quality wetlands that reflect pre-settlement conditions are rare. Only about 6,000 acres remain.

In 1890, A. W. Herre commented on the demise of the Illinois landscape: "What a pity that some of it could not have been preserved, so that those born later might enjoy its beauty also." Fortunately, his lament was heeded; remnants of nearly all the habitats that originally occurred in our state can be found in nature preserves, state parks, conservation areas, and other protected sites that shelter much of the state's biological diversity.

Illinois is a leader among states in preserving natural areas, perhaps because much of its native landscape has already been lost. Dedicated environmentalists and scientists were able to convince the General Assembly to pass into law a means whereby samples of the natural environment would be protected in perpetuity. In 1963, the Illinois Nature Preserves Commission became the first state system of nature preserves to be established in the United States. In 1994, over 200 official nature preserves, encompassing more than 30,000 acres, have been dedicated.

Even though the wildness that was Illinois has long since departed, some wildness yet remains. Illinois' wilds may be as simple as a few violets growing in a lawn -- a remnant of an ancient prairie grove -- or as complex as hundreds of acres of cypress-tupelo swamp in southern Illinois. Regardless of size, wildness is important. As E. O. Wilson has said, "those with the foresight to preserve and treasure even a small part of this heritage will be remembered far longer than those who destroy the rest."

TWG Editor: I thought it unfair to present the concept of "biodiversity in your backyard" and then leave you without any resources to help you plan the addition of natives into your landscape. Of course, you can do what I do and experiment willy-nilly, but most reasonable people would seek help.

On p. 6 are individuals and firms whose consulting practices specialize in native plants. These range from those who prefer consulting on small residential jobs to those who only consult on the restoration of the ecology of large holdings. I have not listed native plant nurseries or landscape contractors unless they have "designers" who make house calls. There's such a variety of consultants here that all I can do is give you some choice; it's up to you find the right fit. If you should be on this list, please contact me. I will correct this list and run your name in the next issue of TWG. By the way, if you want to enjoy some really great conversation, phone any of these individuals.

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