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Showing posts from June, 2007

Rain Train

For the past two weeks, upper level low pressure has settled over west Texas and western Oklahoma, pumping a steady stream of moisture northward from the Gulf of Mexico. To the east, a dome of high pressure has kept this stream along its outer edge, steering it over eastern Texas, eastern Oklahoma and southeastern Kansas. This persitent weather pattern has produced an unending chain of thunderstorms and heavy rains across that swath, leading to widespread, historic flooding.

In the past few days, a week cold front has pushed down from the northwest, stalling out along a line from New Mexico to northern Illinois. As a result, the stream of precipitation has been directed eastward, following the border of the stalled front. Looking at the weather radar, one sees an unbroken arc of rain and thunderstorms from Houston to Wichita to St. Louis. Here in Columbia, rain has been falling for three days, recharging our creeks and wetlands. Relief from the deluge is expected in the next couple of …

Ohio's Black Hand Region

A thick bed of sandstone stretches through east-central and south-central Ohio. Deposited in shallow seas and along river deltas of the Mississippian Period, 330 million years ago, this multi-layered bedrock is named for a prehistoric pictograph found on one of its outcrops. While it was untouched by the Pleistocene glaciers, the Black Hand Sandstone was carved and molded by torrents of meltwater and by the heavy precipitation of that Epoch. Today, a landscape of rugged hills, deep gorges, rock bridges, waterfalls, recessed caves and glacial relict vegetation reflect the erosional forces and climatic conditions of that periglacial zone.

Northwest of Athens, a chain of parks and nature preserves protect a wonderland of sandtone formations. Most renowned is Hocking Hills State Park, home to Old Man's Cave, Cedar Falls and Ash Cave; the latter is the largest recessed cave in Ohio and its 90 foot cascade is the highest waterfall in the State. Just north of the State Park is Conkle…

Two Hundred Years

From the perspective of our short life spans, we often assume that the assembly and formation of our continents and oceans were events of the past, preparing the world for human habitation.
But we need only look at the events of the past 200 years to realize that the landscape of this planet is still a work in progress and that we humans are not immune to those forces.

In 1811-1812, the New Madrid earthquakes shook the heart of North America and altered the course of the Mississippi River. Three years later, the eruption of Tambora, in Indonesia, killed over 100,000 people and triggered a volcanic winter. Krakatoa erupted in the Java Straits in 1883; its massive explosion and secondary tsunami killed 40,000. The great San Francisco earthquake of 1906, famous in the U.S., killed 3000 while a 1923 earthquake in Tokyo took 140,000 lives. The greatest death toll in recent history was caused by the 1976 Tangshan earthquake, in China/Tibet, which killed 500,000 people. More fresh in our minds…

Killer Heat

Now that the first heat wave of the summer is moving through the Northeast, we will soon be hearing about heat-related deaths in our major cities. Yet, since man evolved in the tropics, we are equipped with efficient mechanisms for heat dissipation, primarily through our skin and lungs. And, except for those who venture out unprepared, we rarely hear about heat-induced deaths in desert regions, where human and animal inhabitants have learned to retreat to caves, burrows, rock shelters and other oases during the heat of the day.

Indeed, heat-related deaths are far more common in our modern cities, where the brick and concrete radiate heat throughout the day and night and where numerous frail and elderly persons live in cramped, uncooled and poorly ventilated apartments. And then there are the macho deaths, generally induced by zealous drill sergeants and football coaches, who force their recruits to exercise in the mid-day sun.

Most of us can easily prevent heat-related illness by drinki…

Dog Day Cicadas

After several weeks of hot, humid weather, the annual cicadas are beginning to emerge in central Missouri. Unlike their periodic cousins, which appear in huge numbers during late spring, this species waits for the stifling conditions of mid summer and is thus called the Dog Day Cicada. And while their periodic counterparts remain underground for 13 or 17 years, the larvae of the annual cicadas are ready to emerge within two years; populations mature each year and, in contrast to the explosive arrival of periodic broods, their emergence is spread over 8 to 10 weeks.

Upon reaching the surface, the larva climbs onto a tree, fence or building to dry out and molt to the adult form. Its adult life, lasting but a week or two, is dedicated solely to breeding; the males attract mates with their high-pitched "song" (which tends to peak in the evenings) and the females lay their eggs on the tender vegetation of shrubs and trees. Though they don't eat during their brief life span, ad…

Settling Down

While humans evolved 125,000 years ago and had spread to six of the continents by 15-20,000 years ago, we did not establish towns and cities until the end of the Pleistocene Ice Age. Prior to that time, humans were nomadic, living in small clans and moving about in the pursuit of game and other food sources. Indeed, it was the hunting of migratory mammals such as bison and reindeer that primarily led man across the globe.

At the dawn of the Holocene, 10,000 years ago, man began to establish settlements in the Fertile Crescent of the Middle East; this cultural shift soon spread throughout the Mediterranean region and across the southern rim of Asia. Though dogs had been domesticated 2000 years earlier, goats were the first animals raised for food, milk and hides; this occured in the Middle East about 10,000 years ago while pigs and sheep were domesticated in Syria 1000 years later. Cattle were brought under human control 8000 years ago, in western Asia and northern Africa, and chick…

Stranded

After several weeks of hot weather and little rainfall, the Forum Nature Area wetland, in southwest Columbia, is drying up. An expansive, shallow lake just a month ago, the central basin is now covered by grassy fields, mudflats and a few dwindling pools. On our visit this morning, killdeer and a pair of spotted sandpipers hunted across the muddy shores while a few mallards huddled in the shallows. Taking advantage of the concentrated prey, green-backed herons patrolled the waterline, patiently stalking insects and small amphibians.

But the spectacle of this morning was the large number of bullfrogs and green frogs that waded through the shrinking ponds. Normally hidden by marsh and lake waters, these hapless residents sat silently in the pools, seemingly stunned by their loss of habitat. Easy prey for snakes, mink, fox and great blue herons, stranded frogs must find a moist retreat or venture off to locate another pond. Whatever choice they make, the ongoing drought will surely …

Life on the Wing

The magnificent frigatebird, also called the hurricane bird or the Man O' War bird, spends almost all of its life in the air. Landing in mangroves only to nest, this seabird is usually seen alone or in pairs, soaring offshore or drifting in to circle above the barrier islands of the Gulf Coast or Baja; during the breeding season, they gather in colonies on remote, mangrove keys. On occasion, they are seen inland, especially after tropical storms pass through the region.

Easily recognized by its long, thin wings (held in a bent position), long, hooked bill and long, forked tail, the frigatebird has the greatest wing span per body weight of any bird, including the albatross. Indeed, its 90 inch wing span is more than twice as long as its length from bill to tail. Males are solid black except for a red-orange throat pouch which expands during the mating season; females are also black but have a white chest.

Unable to take flight from the ground, frigatebirds must land on trees or cliff…

Front Range Summer

As spring gives way to summer, the weather along Colorado's Front Range enters a predictable pattern. Daytime heating on the Piedmont causes warm air to rise along the mountain slopes and, by late morning, clouds boil up above the Continental Divide. Some of these will become thunderstorms and, as their tops enter the upper atmosphere, high level westerlies push them to the east. Dropping isolated sheets of rain along the way, they merge into monstrous thunderheads on the eastern plains of Colorado, often producing large hail and tornados.

As they move across the urban corridor, the thundershowers reward some neighborhoods with heavy downpours while leaving most high and dry. When showers are light, the thin, dry air of the Piedmont often causes the rain to evaporate before it hits the ground; called virga, such aborted showers are a common sight during the summer months. By evening, the skies are clearing along the foot of the mountains and Front Range residents are treated to dra…

Summer Solstice

Today is the summer solstice, the first day of summer and the longest day of the year in the Northern Hemisphere. The changing seasons are a result of the Earth's tilt on its axis; as our planet makes its annual trip around the sun, our Hemisphere tilts toward the sun in the months surrounding June 21 and away from the sun in the months surrounding December 21 (of course, the opposite is true for the Southern Hemisphere). On this solstice, we are at our maximum tilt toward the sun and, from now until December 21, our days will gradually shorten.

While this is the longest day of the year, our warmest months lie ahead. This is due to the continued, gradual warming of the ground, lakes and ocean waters of the Northern Hemisphere, moderation of the Arctic conditions via the perpetual daylight of summer and a "high riding" jet stream, which blocks cool Canadian air from moving southward. We can't expect much relief from the hot, hazy days of summer until this pattern b…

The Okefenokee

The broad basin that now holds the Okefenokee Swamp, in southeast Georgia, was an arm of the Atlantic Ocean at the end of the Mesozoic Era. While the sea retreated millions of years ago, the basin's landscape has undergone a series of reincarnations, changing in concert with the regional climate. The current swamp ecosystem began to develop 7000 years ago, reflecting the onset of a warm, wet climate, averaging 55 inches of precipitation each year. Over this time, thick deposits of peat, formed by the decay of aquatic and semiaquatic vegetation, settled on the sandy basin floor, setting the stage for today's mosaic of ponds, wet prairies, drier scrub zones and tree islands; the latter, which include stands of blackgum, pond cypress, red bay, red maple and pine, are home to the endangered red-cockaded woodpecker.

The Okefenokee Swamp, covering 700 square miles, is drained primarily by the Suwannee River; the St. Mary's River drains the southeast corner of the refuge. Countles…

High, Dry and Fractured

The Great Basin of western North America stretches from the crest of the Sierra Nevada to the summit of the Wasatch Plateau and from southern Nevada to central Oregon; this vast, high desert covers western Utah, most of Nevada, eastern California, south-central Oregon, the southeastern rim of Idaho and extreme southwestern Wyoming. As its name implies, the rivers and streams of the Basin do not flow to the sea; rather, they empty into shallow, saline lakes that expand and contract with the seasons. The Great Salt Lake, a remnant of Pleistocene Lake Bonneville, is, of course, the largest of these basin lakes.

Cut off from precipitation by high mountains to its east and west, the Great Basin is North America's largest desert; sage grasslands and salt flats cover the majority of its surface with pine and juniper woodlands limited to the higher terrain of its stark ranges. During the Miocene-Pliocene Uplift, which began about 15 million years ago, the crust of the Great Basin began to …

Fireflies

Adult fireflies have reappeared in the dusk sky of mid Missouri this week. Members of the beetle family, over 2000 species inhabit our planet, 10% of which live in North America. During their brief lifespan (a few weeks to a couple of months), these fireflies attract mates with their unique pattern and color of flash; while most will enjoy a limited diet of small insects and nectar, some species are canni-balistic and will use their flash to attract meals.

Female fireflies lay their eggs in loose, moist soil where they will hatch into larvae in a week or two. Unlike the adults, firefly larvae are voracious predators, feeding on worms, slugs and snails. Come autumn, the larvae burrow into the soil or retreat beneath the leaf litter to spend the winter; if not consumed by moles, shrews or birds, they will emerge in the spring and, within a few weeks, molt to the adult form.

A welcome sign of summer and a joy for many children, fireflies produce their "lightning bug" flash via th…

Fathers

In the great majority of animal species, the male parent's respon-sibilities end with fertilization; unfortunately, some human males adhere to that pattern. Mothers of "lower" animals such as fish, insects, amphibians and reptiles also have little, if any, interaction with their offspring but the maternal parent of birds and mammals takes an active role in nourishing, protecting and rearing their young. In fairness, most male birds, while monogamous for the breeding season only, do take part in nest building and feeding.

On the other hand, most mammal fathers are both polygamous and devoid of parenting skills. Some predators and most primates form family groups but these are generally short lived; only humans maintain a long term relationship with their offspring and it is only in the human species that the ongoing role of the father is critical. Throughout most of human history, the father has been the primary hunter, protector and enforcer; whether he is less skilled in…

The Great Dunes

The Great Sand Dunes of the San Luis Valley, now protected within a National Park, are a relatively new feature of Colorado's landscape. During the Pleistocene Ice Age, 2 million to 10 thousand years ago, mountain glaciers and heavy meltwater eroded the San Juan, La Garita and Sangre de Cristo ranges which flank the Valley; the Rio Grande River and its many tributaries spread a thick layer of this sandy debris across the basin. As the Pleistocene ended and the climate warmed, the San Luis Valley, cutoff from moisture by the surrounding mountains, became a high desert. Over the past 10,000 years, prevailing westerlies have carried the sand eastward and, funneled toward Medano and Mosca passes, dropped their cargo at the base of the Sangre de Cristos; this process continues today.

Rising 700 feet from the valley floor and covering 55 square miles, the Great Sand Dunes are the tallest sand dunes in North America; shimmering like a mirage and backed by the majestic Sangre de Cristo Mou…

Wild Borders

Most of us have planted trees and shrubs to beautify our property, provide shade or attract wildlife; sometimes they thrive and sometimes they don't. The best way to bring a wide variety of native plants to your yard is to establish a natural border. In these areas, protected from lawn mowers and other human distrubance, an amazing diversity of flora will develop.

On our Colorado farm, we have established a natural border that is 200 feet long and 20 feet deep. Since we bought the property, in 1990, this area has filled in with mulberry, ash, Siberian elm, crabapple and black locust trees; wild cherry, chokecherry, sumac, honeysuckle and lilac cover most of the understory while pockets of current and various wildflowers line the margin. In Missouri, our natural border is much smaller but the higher humidity and greater precipitation produces a larger variety of plants; black walnut, mimosa, red oaks, black maple, boxelder, yellow poplar, redbud and redcedar rise above elderberry, y…

Weather and Climate

The peak of the snowmelt season, a heavy mountain snowpack and an exceptionally wet spring have all combined to produce the highest flow in the South Platte River that Colorado has seen in many years while, across the Great Plains, deep winter snows and heavy spring rains have created an unusually verdant landscape. At the same time, severe drought persists in parts of the northern plains and southern California and Lake Superior is at its lowest level in decades, reflecting a regional dirth of rain and snow over the past few years. While Tropical Storm Barry brought some relief to the parched landscape of the Southeastern States, the region's annual precipitation remains well below normal.

Such regional, cyclic weather patterns are distinct from climate change. The latter is a slow, steady change in the weather of a region, continent or the planet as a whole, resulting from long term changes in ocean currents, atmospheric conditions or even the location of the continents; for …

Flying Mammals

A pair of little brown bats zig-zagged above our farm last evening, feasting on mosquitos, moths and other flying insects. Locating their prey by high-frequency sonar (echolocation), bats capture small insects directly in their mouth but use their wing membranes to snare larger victims. Contrary to popular folklore, bats are also equipped with good visual acuity.

Bats evolved early in the Cenozoic Era, just after the demise of the dinosaurs. The forelimbs of their terrestrial ancestors developed into webbed digits and thence into membranous wings while the hindlegs retracted into short, clawed appendages. Today, more than 920 species of bat inhabit our planet, representing 20% of all mammals. Large, fruit eating bats, often called "flying foxes," are found throughout the tropics, as are the infamous vampires; most bat species are relatively small insectivores.

Bats of the Temperate Zone hibernate through the winter, using caves or attics. Though most of these species bre…

Man and Religion

Ever since man spread through southern Africa and dispersed across the globe, he has had plenty to fear. Storms, wild animals and hostile tribes likely topped the list but natural events such as comets, earthquakes and volcanic eruptions also triggered fear and uncertainty. With the development of agriculture, some 10,000 years ago, he also learned to fear drought, floods and insect hordes. Of course, as the first animal capable of intellectual fear, he has long worried about injury, illness and death.

Throughout his history on Earth, man has associated various gods with the natural forces that either threaten or sustain him. He learned to thank gods that brought him rain, light, hunting success or a good harvest; he also learned to appease the gods that threatened him with storms, fire, flood or other natural disasters. Today, we enlightened humans look back on the "pagan" rituals and beliefs of these early humans with a sense of superiority; how silly and ignorant they were…

Brushpiles

One of the best ways to attract wildlife to your yard is to create a brushpile. We have several on our Littleton farm and they are often the focus of wildlife activity.

Decaying wood and its associated fungal growths attract a wide variety of small invertebrates, including worms, insects, spiders and slugs. In turn, these primary consumers are preyed on by dragonflies, mantids, toads, lizards, mice, shrews and birds; among the latter, wrens, thrashers, catbirds, towhees, sparrows and mourning doves are frequent patrons of brushpiles. Higher in the food chain, snakes, opossums and raccoons feed on many of the primary and secondary consumers but may, themselves, fall prey to hawks, owls and fox.

In a way, brushpiles are miniature wildlife areas. The life and death struggles that occur within and around their tangled architecture mirror the cycles of nature as a whole. After providing the basic structure, we need only observe and enjoy the many creatures that live and hunt in this ba…

The Verdant Plains

Driving back to our Colorado farm, it soon became apparent how much last winter's heavy snows and this spring's ongoing rains have transformed the landscape of the Great Plains. Just west of Columbia, the Missouri River was still spilling onto its floodplain, taking in heavy drainage from Nebraska, Iowa and the Dakotas. In like manner, the swollen Kansas River flowed into Lawrence, swirling among trees that normally stand above its banks.

West of Topeka, the Flint Hills were emerald green and their stream beds, often just rock-lined crevices, were now washed by gurgling creeks. Near Salina, the Solomon and Saline Rivers had come down but shallow lakes still covered depressions in the Kansas crop fields. Even the High Plains of western Kansas and eastern Colorado were verdant; the sparse trees looked especially vigorous and the vast grasslands were thick and green. Farm ponds and marshes, nearly dry in recent years, were filled to the brim and reflected the deep blue western sky…

The Toba Winter

The eruption of the Toba Volcano, 74,000 years ago, was the largest in the last 2 million years. This "supervolcanic eruption" ejected 2800 cubic km of ash into the atmosphere; by comparison, the 1980 eruption of Mt. St. Helens produced 1 cubic km of ash. Twenty foot layers of compacted Toba ash has been found in central India, 1900 miles from the volcano. Today, the remnant caldera of this violent explosion, located in northern Sumatra, is up to 60 miles in diameter; Lake Toba fills much of this basin and a new volcanic dome forms a large island near its western shore.

Climatologists believe that the Toba eruption produced a "volcanic winter" that lasted for several years, lowering worldwide temperatures by 5 degrees C or more. Furthermore, DNA studies indicate a significant reduction of the human population, perhaps to 10,000 individuals or less, that seems to coincide with this event. At the time of the Toba eruption, early man had spread out of Africa and was co…

Big Sky, Short Grass

West of the 100th Meridian, the Great Plains of North America become semiarid. The rain shadow of the Rocky Mountains, higher elevations and an increasing distance from the Gulf of Mexico combine to limit annual precipitation to 20 inches or less. Stretching from eastern Montana to West Texas and eastern New Mexico, this province is the domain of the Shortgrass Prairie; blue grama and buffalo grass dominate, with pockets of sand dropseed, three-awn, sideoats grama and western wheatgrass. Saltbush, chokecherry, winterfat and groves of cottonwood line the drainages while yucca, prairie sunflowers, prickly pear and Indian paintbrush add color to the landscape. Today, most of this province has become a mosaic of irrigated croplands and cattle ranches.

The Pawnee National Grasslands, in northeastern Colorado, is one of the better places to explore what remains of the shortgrass prairie. Stretching north of Colorado 14, between Ault and New Raymer, the Grasslands are accessed by a network of…

The Blue Bird

One of my earliest memories is of a bright blue bird in the shrubs behind our Cincinnati home. Five or six at the time, I remember wondering whether it was someone's pet bird, freed from its cage. Today, more than 50 years later, the image of that bird remains very clear in my mind and I recognize it as an indigo bunting.

Such childhood experiences, compounded over the years, awaken us to the natural diversity of this planet and set the stage for a commitment to conservation later in life. As parents and grandparents, we should do whatever we can to expose our young ones to the many fascinating creatures that share this planet. We and they will be enriched by the process and nature will be the ultimate beneficiary.

Tropical Savior

Tropical Storm Barry was a godsend for Florida, southern Georgia and the Southeast Coast, bringing 2-10 inches of rain to the area and putting a large dent in the regional drought. Hopefully, a few more of these tropical systems will bring an end to the wildfires and water shortages.

Like all Tropical Cyclones, Barry began as a Tropical Disturbance; this meteorological term refers to a cluster of thunderstorms that persists for 24 hours or more and moves with no relation to a front. In Barry's case, this distrubance developed in the western Caribbean while, later in the hurricane season, many develop as tropical waves, moving west from Africa. Once an internal rotation develops and sustained winds reach 23 miles per hour, the system becomes a Tropical Depression; Tropical Storms (which are named) have winds between 39 and 73 miles per hour while Hurricanes have sustained winds of 74 mph or higher.

The development of tropical storms requires three conditions: a water surface temperat…

Dragonflies

Part of our natural world for 300 million years, dragonflies patrolled the primordial swamps and coal forests of the Pennsylvanian Period. Today, much smaller than their prehistoric ancestors, dragonflies have diversified into more than 5000 species, almost 10% of which inhabit North America. Of course, most are found in tropical and subtropical regions but they have adapted to a wide range of habitats, including subalpine and subarctic zones.

Equipped with keen vision and superb flying skills, dragonflies feed on mosquitos and other flying insects. Their ability to hover and maneuver in all directions results from the independent motion of their two wing pairs. Dragonflies are larger and much bolder than their brightly colored, dainty cousins, the damselfies; in addition, dragonflies rest with their wings in a flat, horizontal position while damselfies fold their wings vertically.

After mating, the female dragonfly deposits her eggs on aquatic vegetation or directly in the water, o…

Hurricane Stuntmen

Today is the first day of the Atlantic Hurricane Season, which extends into mid November. These will be cherished months for travelling weathermen and exposure-concious reporters as they fan out across the Southeastern and Gulf Coasts, ready to provide eye-witness accounts of these powerful storms. Their patron saint is none other than Dan Rather, who, in the 1960s, launched his career by reporting on a Texas hurricane while lashed to a tree.

Though equipped with high-tech, long-range cameras, these intrepid reporters prefer to stand in the wind and rain, all the while admonishing the locals to evacuate the area. The lucky ones, cloaked in their ponchos and goggles, will bring the full-force of the storm into our homes. Those who choose the wrong location must be content with shots of waving flags and roadside puddles.
Unfortunately, it will probably take a serious, on-air accident or death to bring an end to this folly.