Text excerpted, by permission, from The Nature of Nebraska: Ecology and Biodiversity, by Paul A. Johnsgard ’55.
There is a Place…
If you plan for one year, plant rice. If you plan for 10 years, plant trees. If you plan for 100 years, educate mankind. —Kuan-Tzu
There is a place in America where East and West merge together as smoothly as one river flows into another. That place is called the Great Plains. There is a river in America that gave sustenance to perhaps a hundred thousand migrants who trudged westward in the mid-nineteenth century along the Mormon and Oregon Trails. That river is called the Platte. There is a vast region of sandy grasslands in America that represents the largest area of dunes and the grandest and least disturbed region of tallgrass prairies in all of the Western Hemisphere. That region is called the Sandhills. There is an underground reservoir in America that at maximum may be close to 1,000 feet deep and provides the largest known potential source of unpolluted water to be found anywhere. That reservoir is called the Ogallala aquifer. There is a state in America that offers unhindered vistas of the West, contains stores of vast fossil deposits that shed light on our collective past, and boasts an enlightened citizenry that has built an enviable human history and looks confidently toward the future. That state is called Nebraska.
Nebraska has now been a state for more than 130 years, and I have lived within its borders for almost a third of that entire period. During this time I have learned to love it and its wild places even more than I have loved my native North Dakota. Yet it has taken many years to discover its beauties, which are often little known. I have increasingly realized that, even with my access as a university professor to a variety of books, journals, and other resources that are available to few others living in the state, it is sometimes difficult or nearly impossible to extract even rather simple information on a species or a habitat, to say nothing of trying to understand an entire ecosystem. Furthermore, many of these species and their habitats have literally disappeared before our eyes in my lifetime, and others are in the process of vanishing. Once they are gone, they are gone forever, and tomorrow’s Nebraskans will be the poorer for it, even if they may be unaware of their loss. It is hard to mourn something or some creature that one has never been exposed to, but it is even harder to refrain from mourning those whom we have come to know personally and will see no more. There are no longer any wild elk to announce the coming of each prairie autumn in eastern Nebraska with their melancholic bugling calls. The great flocks of Eskimo curlews that arrived each March after a long flight from the Argentine pampas have been replaced by clouds of blackbirds and grackles. The sounds of uncountable bison herds thundering over the Nebraska plains can now only be heard in our imagination, as can the wail of prairie wolves on a star-drenched night in the Sandhills. But the calls of sandhill cranes still spill forth from our skies every spring, and the rattling dances of sharp-tailed grouse on a frosty March sunrise somehow bring to mind the lost cultures and nearly forgotten traditions of the Pawnee, the Otoe, and the Dakota, who knew these birds much better than most of us can ever hope to.
In talking with young schoolchildren and even with university students, it is apparent to me that, rather than filling our newspapers and magazines with unending news of scheduled athletic events and their outcomes, we would do better to take note of when the pasque flowers bloom or when the snow geese materialize each spring and fall. Even more important, we should hope to gain some sense of what the role of the pasque flower and the snow goose might be in the greater scheme of things, whether it may be source of pollen for some obscure insect or as a source of inspiration for an equally obscure poet. We can never know the purpose of all things in nature; it is often impossible in our short lifetimes to understand our own individual roles and possible purpose for living. Probably nonhumans don’t even ask themselves these questions, so it is our human responsibility to try to fathom their secrets, and, failing that, to act to preserve these natural treasures long enough for future generations to ask these same questions if they should care to do so.
Braided Streams and Sandy Shores
Perhaps few Nebraskans would claim the Platte River as their favorite river; it is slow, mostly knee-deep or even shallower, is sometimes somewhat unpredictable in its course, and often is no more scenic than your average Nebraska irrigation ditch. This is not the Platte’s fault; for a century and more it has had its lifeblood water diverted, pumped, and polluted with fertilizers, pesticides, and animal wastes nearly all the way from its inconspicuous mountainous origins in eastern Wyoming and Colorado to its confluence in easternmost Nebraska with the Missouri. In May 1833, during his exploration of the upper Missouri Valley, Prince Maximilian of Wied reported that, even some 4 or 5 miles downstream from its confluence with the turbid Missouri River, the unsullied “clear and blue” effluent water from the Platte could still be easily distinguished from that of the much larger Missouri.
That the Platte River has survived at all in the face of almost two centuries of destructive influences is a small miracle. Had Michelangelo’s statue of David been subjected to the same treatment as has the Platte, it would have long since been consigned to the scrap pile, so the Platte needs to be viewed with a gentle and forgiving eye. It must be appreciated for what it once was, like the once-pristine Parthenon, rather than what it has now become, a ghost of river and a frequent repository for trash. It is ironic that the 200,000 or so migrants who laboriously walked the length of the Platte on their way westward left only a few simple gravestones to mark their passing; modern humans prefer to leave abandoned cars to mark theirs.
In spite of all this, the Platte Valley is still able to attract half a million sandhill cranes each March, and nearly 10 million waterfowl use it every spring, plus some 300 other bird species pass through the valley at various times of the year. Of these, at least 121 species breed in the central Platte Valley, including two nationally endangered species (least tern and piping plover). And the endangered whooping cranes reliably return each spring and fall, now in ever-increasing numbers, and sandhill cranes gather in almost uncountable flocks to rest and sleep beside the peaceful sandbars of the Platte. Through the night the cranes converse with the river, speaking in tongues that are both archaic and yet seemingly wise, and the river patiently listens. The voice of the river is even softer and possibly even older than that of the cranes; we would do well to try to hear and understand its plaintive message while it is still able to speak.
The Ecology and Chemistry of Water
Although it has been written that we are but dust and to dust we shall return, it would be far more accurate to say that we came from water (our human bodies are nearly two-thirds water) and to water we must eventually return. Water is one of the most abundant compounds on Earth and one of the most critical components for sustaining life on this planet. It is also one of the most remarkable substances. No other common inorganic material is fluid at temperatures that support life, making it possible for floating and swimming organisms to have evolved and become mobile. Although fluid, the viscosity of water allows for rowing or undulating body movements to provide for easy mobility. Additionally, few natural compounds are so resistant to temperature changes (its so-called specific he
at), which helps buffer living cells from rapid, perhaps fatal heating and cooling and also limits the rate of evaporation. Water dissolves essentially all the critical elements needed for life, including all the basic nutritional salts as well as vital gasses such as oxygen, hydrogen, and carbon dioxide. Its biochemical presence is also needed for facilitating all the basic photosynthetic and respiratory processes of living cells that involve carbon, oxygen, and hydrogen.
Although water becomes denser as it cools and approaches freezing, it actually expands as it freezes. Thus ice forms at the tops of lakes and rivers first, rather than from the bottom up. This curious fact allows aquatic organisms to survive in a fluid environment while separated from subfreezing atmospheric conditions above by a protective ice ceiling, thus enabling them to endure long winters or even more prolonged arcticlike conditions. Although water strongly resists freezing, it easily evaporates and by later condensation is able to spread life-giving moisture across the drier parts of the globe as various forms of precipitation.
Because cold water is relatively dense and sinks and warmer water correspondingly rises, oceans develop vertical cycles. As a result, warmer, low-latitude waters rise and replace sinking polar waters, producing upwellings of deep, dissolved ocean nutrients, access to which would otherwise be forever lost to plants and animals. These oceanic cycles, aided by the energy of planetary spin effects, produce enormous clockwise or counterclockwise surface-level currents such as the Gulf Stream, which may either warm or cool adjoining land masses, causing offshore or onshore winds and resulting in increased or reduced coastal precipitation. Oceanic currents therefore influence large-scale terrestrial wind as well as precipitation variables and thereby control continentwide climatic patterns, as recent cycles of La Niña and El Niño have so effectively proven in recent years.
Even in smaller ecosystems and communities such as lakes, marshes, and temporary wetlands, water strongly influences and ultimately controls local species diversity and the overall abundance of plants and animals. This control is largely brought about by the influence of available water in allowing photosynthesis to proceed and thus regulate the initial plant production and subsequent storage of organic matter such as carbohydrates. These materials are then successively funneled through food chains in a predictable and diminishing sequence of exploitation by consumer organisms such as herbivores and carnivores. The consumers in turn are ultimately exploited and transformed back again into their inorganic compounds by lowly decomposer organisms such as bacteria. In short, the water that helped to convert carbon dioxide to organic carbon molecules by green plants is again finally released as water in the process of respiration and decomposition by both plants and animals. As stated earlier, water we are and to water we shall return.
Of all the wonders of Earth, nothing is more valuable than water; without it Earth would be as lifeless as Mars. Nevertheless, nothing on our planet seems to be wasted so flagrantly or polluted so recklessly by humankind as water. Ultimately, we earthlings will have to decide if we wish to share Mars’s fate; postulated interplanetary attempts by NASA to reach and colonize it and to use its possible subsurface ice supplies for human consumption and industrial purposes would be roughly comparable to visiting Earth as it may have appeared 3 billion years ago and hoping to set up a profitable car-wash operation there. It would seem that conserving water on Earth is far simpler, much more profitable, and immensely more critical to our own survival than hoping to find and extract water on Mars.
If the sandhill crane had been called the “sacred crane,” something like the sacred ibis of Egypt, for example, it might have been accorded more respect by the general public. Instead, many Nebraskans still confuse sandhill cranes with great blue herons, a much more serious taxonomic blunder than, for another example, referring to some distant cousin as a “dumb ape.”
Sandhill cranes were not, as some imagine, named for the Nebraska Sandhills, although the species once nested in the marshes there and they still frequent these same marshes in spring and fall. For nearly all of the twentieth century the cranes used Nebraska only as a way station to and from their breeding grounds, but in the late 1990s single pairs of cranes were known to have nested in the Rainwater Basin region.
Even if the cranes have not nested here continuously, they have used the Platte Valley for untold millennia as a prime staging area. Fossil remains of a sandhill crane dating back at least 8 million years have been found, suggesting the sandhill crane’s love affair with Nebraska is a very long one indeed. From the time the Platte River becomes ice free in February until almost the middle of April, hundreds of thousands of sandhill cranes use the valley every year, by far the largest assemblage of any cranes in the world. Along dozens of the more remote stretches of river, roosts of up to 20,000 birds gather to spend the night standing in shallow waters. They select the widest stretches of river that offer nearly vegetation-free sandy islands and sandbars, which places them out of danger of land-based predators such as coyotes. Eagles may still pose a threat to sick or wounded birds, but a healthy crane is nearly an even match for an eagle, unless the crane is attacked in the sky when the eagle has the advantage of surprise.
We do not know what originally drew the cranes to the Platte, but the unique present-day combination of a wide, sandy river, adjacent wet meadows with a supply of invertebrate foods for a source of calcium, and an almost unlimited amount of waste corn in nearby fields for getting abundant carbohydrates that can be converted and stored as fat provide the magic attraction now. Millions of snow geese, Canada geese, and other geese join in on this feast, as do several million ducks, making March in Nebraska a bird-watcher’s paradise. This alone is enough to warm the heart during the long days of winter, and the sounds of cranes filling the sky when they finally do arrive is at least as thrilling as hearing a massed choir singing the triumphant chorus to Beethoven’s Ninth Symphony.
By permission of the University of Nebraska Press. © 2001 by the
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