Memories & Childhood Development

On our last day in Ohio, our grandson asked to see Inside Out, an animated movie by Pixar, a division of Walt Disney Pictures.  Though my wife and I had limited knowledge of the film, we were more than pleased with our grandson's recommendation.

Focused on the development of a young girl, from birth to prepubescence, this clever production places emphasis on childhood memories, the emotions associated with them and their role in a child's emotional maturation.  Represented by a host of cartoon characters, the emotions include Joy, Sadness, Anger, Disgust and Fear.  The concept of "core memories," related to key aspects of a child's life, was a theme throughout the film.

In my opinion, three points made in the story deserve special mention.  First was the message that sadness is an unavoidable component of our childhood experience, one that places our other emotions in context and, in the end, is vital in molding our self-esteem.  Second was the point that an individual must abandon their childhood fantasies (here represented by an imaginary friend) in order to attain maturity.  Finally, when parents fail to recognize and address emotional turmoil in their children, tragic consequences may ensue.  I highly recommend this film.

Pickerelweed

Clumps of pickerelweed, an emergent perennial, are found along the shallows of Sandy Lake, in northeast Ohio.  Identified by their rich green leaves (heart to lance shaped) and purple flower spikes, these plants are native to eastern North America, from Labrador to Florida and Texas.

Favoring the shallow rim of ponds and lakes, pickerelweed may also colonize sluggish, meandering streams.  Since it spreads by both seed and rhizomes, this aquatic plant often forms extensive colonies and helps to stabilize shorelines and river banks.  It is also highly beneficial to wildlife; a variety of bees and butterflies feast on and pollinate its flowers, deer, muskrats and ducks feed on its foliage, fruits and seeds and dense clumps of pickerelweed provide cover for waterfowl and fish.  Even humans consume its leaves and seeds.

Gliding past a stand of pickerelweed in my kayak, I notice the pollinators and the numerous predatory insects (dragonflies and damselflies) that hover above the plants, snaring mosquitos, gnats and other small prey.  What I cannot see are the nurseries of numerous aquatic invertebrates that lie beneath the surface, thriving amidst the tangles of roots and stems; these tiny creatures are primary consumers, vital to the ecology of ponds, lakes and rivers.

Sandy Lake from a Kayak

Though there is a pleasant, graveled trail that loops around Sandy Lake, one cannot truly appreciate this ecosystem without getting out on the water.  Fortunately, we have access to two kayaks and I spent yesterday morning exploring the undeveloped margins of the lake.

There, water lilies spread across the shallows and marsh plants line the shores, attracting a wide variety of wildlife.  Green frogs bounded from the lily pads and painted turtles lounged on logs or fallen limbs that poke above the waterline.  Thousands of neon blue damselflies hunted in the wetlands and two snapping turtles haunted the deeper waters, one of which cruised along the side of my kayak.  Numerous songbirds fed in the lakeside trees, dominated by eastern wood pewees, black-capped chickadees and house wrens; a few great blue herons also stalked the shallows.

Heading toward the center of the lake, I watched ring-billed gulls and ospreys as they circled overhead, joined by squadrons of purple martins.  Double-crested cormorants dove for fish in the calm waters and a lone bald eagle cruised above the lake, apparently headed for a large reservoir to our north.  Back at our cottage within an hour, kayaking was a great way to combine exercise and wildlife watching, not to mention cool, fresh air and sunshine!

Martin Mania

Behind our cottage on Sandy Lake, in northeast Ohio, two purple martin structures tower above the end of a dock, each harboring a dozen nest cavities.  There are no vacancies this summer and the vocal residents put on a noisy show throughout the day.

Currently raising their second broods of the season, attentive parents are constantly leaving or returning to the nest sites, attempting to satiate their demanding chicks.  Often hunting in pairs, they circle above the lake, twisting or diving to snare an insect.  Resting between forays, some of the parents gather on the rooftops, twittering with one another (and perhaps sharing their frustration).  At one point this morning, the entire flock suddenly took to the air, strafing the top of a shade tree until a sharp-shinned hawk escaped across the lake.

While the purple martins of the Eastern U.S. generally nest in man-made boxes, those in the West utilize abandoned woodpecker cavities in trees or cacti.  As their breeding season comes to an end, our largest swallows gather in huge flocks before departing for wintering grounds in South America.

North through Appalachia

Leaving Athens, Ohio, this morning, we headed northeast through the Sunday Creek Valley, a tributary of the Hocking River.  As is typical across the unglaciated Appalachian Plateau, the road (Route 13) snakes through a maze of ridges and valleys where the natural beauty is balanced by, in my case, the unease of claustrophobia; broad views are limited to a few stretches where the two-lane road crossed treeless ridgetops.

Further north, after we crossed the Muskingum and Tuscarawa Rivers, the Plateau has a more open feel.  Here the Pleistocene Glaciers eroded the landscape, diminishing the relief between the ridges and valleys.  Inclined toward broad vistas, I find this area more appealing.

Indeed, we will spend the next week at a family retreat along Sandy Lake, one of many glacial lakes across the Glaciated Appalachian Plateau of northeastern Ohio.  There we'll enjoy a mix of activities with our oldest grandson; swimming, kayaking, hiking, birding and fishing (likely futile) are on the preliminary list.

Heading for the Hills

Invited to attend a wedding in southeastern Ohio, we left Columbia this morning and drove east on Interstate 70.  For most of our trip, we crossed the Glaciated Plain of the American Midwest, a relatively flat landscape quilted with farms and broken by wooded stream valleys, all draining southward to the Missouri, Mississippi and Ohio Rivers.

Just beyond Columbus, Ohio, we turned onto Route 33, angling southeastward. Once we reached Lancaster, we could see the westernmost hills of the Appalachian Plateau, rising above the Central Lowlands.  While this topographic transition has been obscured by glacial erosion in northeast Ohio, the western edge of the Plateau is more distinct south of Columbus and remains evident through eastern Kentucky, central Tennessee and northern Alabama.  Capped by Pennsylvanian sandstone, the Appalachian Plateau reaches its highest elevations along its eastern edge, where it towers above the Ridge and Valley Province as the Allegheny Front.

Snaking into the Plateau east of Lancaster, Route 33 soon reaches the Black Hand Sandstone region of Ohio, among the most scenic areas in the Midwest.  Having explored that natural wonderland in the past, our sights were set on Athens, the home of Ohio University and the location of tomorrow's celebration.

Summer Dusk

It is in mid summer that we most appreciate dusk, a welcome reprieve from the late afternoon heat.  Venturing outdoors, we often enjoy a soft, cool breeze as evening shadows stretch across the landscape.

Here in central Missouri, damselflies and hummingbirds make their last forays through the flower beds while, overhead, squadrons of dragonflies feast on flying insects, dodging the swifts, nighthawks and Mississippi kites that patrol the evening sky.  Brown thrashers and gray catbirds, having spent the day in the shade of woodlands, now emerge to scour the lawns and shrubs, serenaded by the mellow tunes of wrens, cardinals and robins.  As darkness expands, the incessant cicada chorus begins to wane, replaced by the scratchy notes of tree crickets.

On some evenings, American toads appear on the lawn, searching for moths and earthworms, or an opossum may saunter from the woods, ready for a night of scavenging.  We humans, not endowed with night vision, may head indoors as the curtain of daylight fades in the west or stay to watch as distant suns appear in the darkening sky.

Mid Summer Relief

After more than a week of hot, humid weather, a cold front has dropped into central Missouri.  Igniting thunderstorms early this morning, with periods of heavy rain, the front has brought welcome relief from the oppressive summer heat.  Currently stretching from central Colorado to the Upper Midwest, it may remain stationary, extending our mild, rainy weather, push further south to usher in cool, dry air or balloon back to the north, allowing hot, humid air to return from the south; the battle of high pressure domes to our north and south will determine the outcome.

Walking through campus this morning, it felt more like May than mid July.  The temperature was in the mid seventies (F) and an intermittent light drizzle and east breeze added to the cooling effect.  Heavy rains from the early morning storms had spread mud, mulch and tree debris across the campus walkways, providing a literal windfall for the resident birds and squirrels.

However long it may last, this mid summer respite is surely appreciated by humans and wildlife alike.  After all, invigorating autumn weather is still at least two months away and we'll need more of these cold fronts to draw us from our air-conditioned retreats.

The Trump Phenomenon

Donald Trump knows America.  He understands that racism and intolerance pervade our society, that many Americans fear "foreigners" and that a sizable contingent of American citizens are convinced that the Federal Government is out to steal their guns, their property and their money.

Trump also knows the American media, a segment of our society that he has courted for many years.  Most importantly, he understands that cable news programs are enamored with celebrities, especially those who relish the spotlight and provide "news" fodder by making outrageous and provocative statements.

Claiming to be a serious Presidential candidate, Trump is taking advantage of paranoid, right-wing zealots and tabloid journalists to expand his brand and feed his narcissism.  In the end, thoughtful, moderate Americans will reject Trump's self-righteous hyperbole and he will retreat to the world of flamboyant moguls and "reality" television.  In the meantime, our obsession with his self-serving rhetoric reflects an ugly and worrisome undercurrent in American society.

Legions of Legumes

Yesterday morning, before the heat of the day, I removed tree seedlings from our flower beds.  While some were oaks or maples, the great majority were redbuds and mimosas, members of the legume family.

Legume trees are highly prolific species, producing numerous seed pods while also spreading via suckers.  In addition, most species adapt well to a wide variety of soil conditions, out-competing shrubs and trees that have more specific requirements.  While we enjoy the beauty of redbuds in the spring and mimosas in summer, their seedlings spring up on every piece of open soil on our Columbia, Missouri, property.

In like manner, black and New Mexico locusts and honeylocusts, also legumes, spread across our Littleton, Colorado, farm, invading the "lawns" and pastures; without regular clipping, a forest of locusts would soon cover much of the property.  Though these trees also produce abundant seed pods, suckering is their primary means of spread in the semiarid environment of the Front Range.  See also Bean Trees and Mimosas.

Horsemint

The lavender blossoms of horsemint (also known as wild bergamot) were abundant at Forum Nature Area, in Columbia, this morning.  A common member of the mint family, this wildflower is found throughout Missouri and across most of the country; the plant, up to three feet tall, favors open, sunny fields, prairies, glades and roadsides where it often grows in sizable stands.

The attractive flowers of horsemint, which bloom from late May through August, attract a wide variety of pollinators, including bees, moths, butterflies and hummingbirds; indeed, it is commonly planted in butterfly gardens.  Humans have also been attracted to this wildflower, using it to make herbal tea that, it is claimed, offers a variety of medicinal benefits.

In addition to the horsemint, yellow and purple coneflowers, prairie blazing star, showy milkweed and Queen Ann's lace adorned the Hinkson Creek floodplain this morning.  Painted turtles lounged along the seasonal lake, bullfrogs and green frogs called from the marshy shores and young toadlets hopped across the graveled path, oblivious of the human and canine traffic.  Birds of note included indigo buntings, eastern bluebirds, common yellowthroats and yellow-billed cuckoos.

Rendezvous with Pluto

This morning, 9.5 years and 3 billion miles after launching from Earth, the New Horizons spacecraft will zip past Pluto, coming within 7800 miles of the dwarf planet (closer than any of its five moons).  Having departed Earth in January, 2006, New Horizons swung past Jupiter in February, 2007, gaining momentum and refining its course in the process.

Today, as it flashes past Pluto and its largest moon Charon, the spacecraft will be traveling at 31,000 miles per hour but will retrieve photos and scientific data never before available to human beings; this evening, that data will be transmitted to Earth, completing the primary goals of this amazing space mission.  Already, we have learned that Pluto is greater than 1470 miles in diameter, larger than previously thought, and that it harbors a polar cap of frozen methane.

After collecting data on Pluto and its largest moon, New Horizons will travel through the Kuiper Belt on its way to the edge of our solar system and beyond.  Aboard are the ashes of Clyde Tombaugh, the astronomer who discovered Pluto in 1930 (at the age of 24); of course, his partial remains will be the first human material to leave the solar system that gave birth to our species (some 4.9998 billion years after its formation).

Correction:  the flyby distance was incorrect when first posted and has been changed

Correction 2:  I clearly had a bad math day.  Time from solar system formation to human evolution has been corrected

The Residential Finch

Natives of the American West, house finches inhabit foothills, desert canyons and open woodlands, including urban parks and suburban neighborhoods.  During the 1940s, some of these birds were released on Long Island, New York, and, by the mid 1960s, had colonized the New York Metro Area.  According to Audubon's Guide to Birds of the Eastern U.S., published in 1977, house finches could be found from Maine to North Carolina.  Today, the eastern population has spread across almost all of the Eastern and Central U.S. (South Florida excluded) and have crossed the Great Plains along riparian corridors; in effect, the native Western and transplanted Eastern populations have merged and house finches have become one of the most abundant and widespread birds in the U.S.

Indeed, these medium-sized songbirds are among the most common birds observed at feeders in most regions of the country. Consuming a wide variety of seed, buds and berries, house finches shun insects in their diet and feed plant material to their nestlings.  Permanent residents where they do reside, house finches may be confused with purple finches during the winter months, when the latter migrate south from northern climes; however, the head and chest coloration of male house finches tends to be reddish-orange while the larger male purple finch sports a red-wine wash.  In addition, purple finches have a notched tail and heavier bill and females have a broad white stripe above their eyes.

The melodious song of the house finch, often delivered from the top of trees, makes them welcome in residential areas across America.  Having first encountered these songbirds in Metro Denver, when we moved there in 1982, I can now enjoy their presence in towns, cities and nature preserves throughout the country, including our property in Columbia, Missouri.

Back in the Jungle

After a month in Colorado, I have returned to the heat and humidity of central Missouri.  Fed by these jungle-like conditions, including copious rainfall, the vegetation on our Columbia property had grown, spread and lost any semblance of human control.  After all, nature abhors clean edges.

Not that I'm fastidious when it comes to landscaping.  Favoring a naturalized look (which requires much less work), I focus on cutting our modest-sized lawn and keeping vines from smothering the other plants.  Some "weeding" is necessary in the flower beds (we don't use herbicides) and storm refuse must be collected and hauled to the city's composting center.

For a while, I'll enjoy the Midwest summer with its cicada chorus, buzzing insects, colorful songbirds and vibrant greenery.  But I'll soon dream of autumn, with its cool, dry air and vocal migrants.  Or I'll just head back to Colorado, where a simple patch of shade is sufficient to escape the summer heat.

Prickly Poppies

By mid summer, clumps of prickly poppies are abundant along the Colorado Front Range, their large white flowers shimmering above ranchlands and dry riverbeds of the High Plains, along country roads and on disturbed meadows of the Piedmont and lower foothills.  Protected by spines on their foliage (hence the nickname thistle poppy) and thick, noxious sap in their stems, these open country wildflowers are generally avoided by grazing livestock and wild herbivores.

Represented by 15 species across the U.S., prickly poppies favor dry sandy soil and are most common across the Southern Plains and Desert Southwest.  Their large flowers, up to 4 inches across, possess petals that have the appearance and texture of wrinkled paper; in most species they are white while pink or purplish petals occur in some regions.  The central dome of stamens is bright yellow or reddish in color, drawing a wide variety of insect pollinators.  Seeds of the prickly poppy, which are rather large, have a high oil content and are favored by ground feeding birds, such as pheasants, quail and doves, and small mammals.

The abundance of this wildflower in dry, hot regions of the country is due, in part, to its long tap root that reaches moisture deep within the soil.  Despite its poisonous sap, various components of the prickly poppy have been used for medicinal purposes by Native Americans.  For the rest of us, their showy flowers, often adorning a dry, stark landscape, are reason enough to appreciate these plants.

U.S. Chamber promotes Smoking

We Americans, proud of our Democracy and enjoying unparalleled freedom, tend to assume that U.S. intervention across the globe is always well intentioned.  After all, we combat terrorism, help to build democracies, respond to natural disasters and assist victims of war, famine and genocide.  Then stories like the one reported in the New York Times this week surface and the image of our generous and honorable country is tarnished.

According to the Times, the U.S. Chamber of Commerce, in an effort to assist American Tobacco Companies, has contacted numerous foreign countries, encouraging them to scale back or abandon their anti-smoking campaigns.  Directed primarily at poor, developing countries, where tobacco use remains high, this pressure is clearly designed to counter efforts to inform citizens of the health consequences of smoking.  While such an effort within the U.S. would surely be grounds for lawsuits, the manipulation of scientific data and promotion of risky behavior in impoverished countries is just another tool of Big Tobacco and its Chamber enablers.  Who cares if thousands of Third World humans die an early death when profits are at stake?

Worse yet, the New York Times reports that a number of health care organizations sit on the Board of the U.S. Chamber of Commerce; one of them, CVS Health, resigned in response to this pro-tobacco campaign.  Will the others follow suit or is preventive healthcare only for Americans?

The Nature of Alzheimer's Disease

First described by Dr. Alois Alzheimer, a German psychiatrist, in 1906, Alzheimer's Disease is rapidly becoming the third most common cause of death in the United States (trailing only heart disease and cancer).  Primarily affecting individuals aged 65 and older, it is responsible for up to 80% of the cases of dementia; early-onset Alzheimer's Disease, representing 5% of those afflicted, is a familial, genetic-based form of the disease that presents in middle age.

The earliest sign of Alzheimer's disease is usually disordered short-term memory; indeed, imaging and pathologic studies reveal that the disease generally begins in the hippocampus, an area of the brain that stores and retrieves memory.  Over time, the disease spreads throughout the cerebral cortex, resulting in diminished cognitive function and leading to the inability to reason, think clearly and control emotions and behavior.  Medical research has revealed the presence of beta amyloid and tau protein buildup in the brains of patients with Alzheimer's Disease; these changes may precede clinical symptoms of the disease by a decade or more.  Whether the abnormal proteins are the cause of Alzheimer's disease or merely reflect underlying pathophysiology (e.g. vascular inflammation) has yet to be determined.  Current evidence suggests that the disease may be the product of genetic predisposition, aging and environmental factors; by age 80, 50% of persons have some degree of Alzheimer's disease.

There is no current cure for Alzheimer's Disease and treatment is limited to medications and supportive therapies that may slow the patient's mental decline; the course of the latter varies widely (2-20 years) but most often leads to death within 8 years.  As one who has cared for many individuals with Alzheimer's Disease over the years, I have witnessed the de-humanization wrought by this relentless malady and the emotional, physical and financial stress that it imposes on family members; until a cure for this devastating illness is found, I personally favor the right of patients to choose assisted suicide before the disease robs them of their humanity.

Cool Change for Denver

Over the past 36 hours, a cold front dropped across the Front Range, putting an end to several weeks of hot, sunny weather.  Behind the front, an upslope flow developed across the Northern Plains, shoving cool, moist air toward the Continental Divide and dropping steady, light rain along the Front Range urban corridor.

Yesterday's high topped out at 60 degrees F and our overnight low dropped into the mid 50s.  This morning, the upslope is beginning to break down and patches of blue dot the rising overcast; limited sunshine is forecast for this afternoon, warming surface air into the lower 70s and setting the stage for late day thunderstorms, fueled by our initial plume of monsoon moisture.

Living along the Colorado Front Range is a treat for weather junkies.  The mountain wall to the west, Palmer Divide to the south and tilted plains to the east produce ever-changing weather conditions; wind shifts, developing in response to high pressure domes, surface lows and intervening fronts, can produce dramatic temperature changes within a few hours.  Rising air, augmented by mountainous terrain, ignites thunderstorms when fueled by summer heat; when driven upslope by a passing cold front, it provides a cool, damp respite from the intense summer sun.

Evolution of Large Flightless Birds

Looking at the current distribution of ratites (large flightless birds including ostriches, rheas, emus and cassowaries) and understanding the history of Continental Drift, one is inclined to assume that a common ancestor of these birds lived on Gondwanaland (the unified Southern Continents) after the breakup of Pangea and that they diversified as the component Continents split apart.  Indeed, this has been the accepted theory of ratite evolution since the dawn of plate tectonics.

Pangea, formed by the merger of all major land masses during the Permian Period, split into Laurasia (the Northern Continents) and Gondwanaland (the Southern Continents) during the Triassic Period (some 200 million years ago -MYA).  Africa (the current home of ostriches) and South America (now inhabited by rheas), broke from Gondwanaland about 140 MYA and split from one another 100 MYA.  Madagascar (the former home of the elephant bird, an extinct ratite) rifted from Africa 160 MYA, joining India-Antarctica-Australia; India-Madagascar split from Antarctica and Australia about 90 MYA.  Finally, Australia (now inhabited by emus and cassowaries) broke from Antarctica 55 MYA and Madagascar split from India 75 MYA, drifting back toward the southeastern Africa Coast.

Fossil and recent molecular evidence suggest that ratites evolved from flight-capable species about 60 MYA, soon after the demise of the dinosaurs.  This suggests that the various ratites evolved in geographic isolation though, apparently, from a common flying ancestor (or family of ancestors); no doubt, the fossils of early ratites also lie beneath the ice of Antarctica.  If nothing else, the unfolding natural history of these birds illustrates the fact that common sense, devoid of scientific evidence, can be misleading; nevertheless, I suspect that the mystery of ratite evolution has yet to be fully solved.

Shark Attacks on Humans

The plethora of shark attacks along the Carolina Coast this summer has spawned headlines across the country and, I assume, around the globe; reading or hearing those accounts, one might think that cosmic forces have aligned to drive us from the beaches. After all, we humans look at ourselves as custodians of this planet, immune to the predator-prey relationship that lower creatures must endure.

Yet, during our 130,000 year history on Earth, we have been attacked, killed and/or eaten by a wide variety of predators, including big cats, bears, wolves, hyenas, snakes, bees and mosquitoes, to name just a few.  Once we entered marine environments, some 70,000 years ago, we became susceptible to sharks and other ocean predators as well.  Of course, in recent centuries, we have come to adore the beach, crowding there during the warmer months to lounge in the sun and surf like so many seals and walruses.

Entering the domain of sharks, we place ourselves at the mercy of natural killers that have inhabited the oceans for 350 million years.  While they may be drawn toward shore by other prey (schools of fish, sea turtles, etc.) they have no reason to ignore thrashing human beings, just another convenient source of food.  After such attacks, the media tends to report that the shark "mistook" the person for a seal or large fish; in fact, we humans, despite our superior intelligence, are just hunks of meat to a shark.  The only way to totally prevent shark attacks is to stay out of their habitat (or, perhaps, to swim in a suite of armor).

The Asteroid Belt

As the sun formed, 5 billion years ago, surrounding gas and debris gradually coalesced into the planets, four inner solid planets and four outer gaseous giants; Pluto's status as a planet is a matter of debate (see The Orphaned Planet).  Additional debris aligned within the Asteroid Belt, between the orbits of Mars and Jupiter, the Kuiper Belt (which includes Pluto), beyond the orbit of Neptune, and the Ort Comet Cloud, near the outer edge of the solar system (see The Nature of Comets).

The Asteroid Belt consists of millions of orbiting rock units, ranging in size from the dwarf planet Ceres down to pebble-sized debris; three proto-planets (Vesta, Palias and Hygiea) also orbit within the belt.  Ceres accounts for 30% of the mass of the Asteroid Belt while this dwarf planet combined with the three proto-planets harbor 50% of the total mass.  Though the Belt is relatively stable at this point in time, such was not the case during the chaotic early history of our solar system; during that period, they were slung about space, slamming into the planets and pockmarking their moons (as we observe on Mars and our cratered Moon today).  Of course, asteroids within the Belt also collided with one another, a process that continues today; such collisions, combined with gravitational effects from Jupiter, still send wayward asteroids into space, threatening Earth with disastrous impacts.

Space probe Dawn, launched by NASA in 2007, explored Vesta in 2011-2012 and is now orbiting Ceres, sending back fascinating photos of the asteroid's cratered surface.  Of most interest are bright white spots, up to 4 miles across, which may represent mineral deposits left behind by melted surface ice; the presence of water vapor has previously been documented on this dwarf planet.

Season of Discovery

Naturalists and birders look forward to the cooler months of the year when large flocks of migrant cranes and waterfowl stop to rest and feed in their region, when irruptive species move south to join (and compete with) winter residents, when rare vagrants turn up on reservoirs, at refuges or in backyards and when a wide variety of raptors are especially conspicuous in the barren trees and across the bleak farmlands.  However, for most of us, new discoveries in nature are more likely to occur during the warmer months of the year.

Surveying their property or meandering through local nature preserves, veteran and amateur naturalists observe a tremendous diversity of plants and animals; new personal discoveries most often involve wildflowers, fungi, insects and other invertebrates but might also include certain amphibians, reptiles and small songbirds (warblers, vireos, flycatchers) that theretofore had not been identified by that individual.

Such discoveries, however meager, add to our appreciation of the complexity and diversity of regional ecosystems.  Hopefully, they also fuel our commitment to preserving and protecting each and every species; indeed, all species on our planet, including humans, play vital roles in the health of our natural environment.