THE LOSS OF THE diversity of life on earth has implications for man that we appear ready to ignore. Mammals, reptiles, birds, amphibians, and fish possess what are called “ecosystem services,” functions they perform that are crucial to the well-being of nature and Homo sapiens. Their loss is our loss. Without their survival, ours is in question. It’s why some scientists believe man won’t survive a mass extinction, because of all the ecosystem services we will lose in such an event.
We’ve seen how diversity of forest animals can help protect us from disease, but this is not nature’s only gift for our survival. Other living things, like plants, insects, and microbes, play vital roles in our lives as well. One of those valuable roles is creating clean water. New York City’s drinking water, which is naturally cleansed on its 125-mile journey from the Catskills to the city, is an example. Many of the system’s best purifiers lie beneath the forest floor: in the fine roots of the trees filtering the water, and in microorganisms in the soil that break down contaminants. These natural processes in the watershed absorb as much as half of the nitrogen coming into the waterways from auto emissions, fertilizers, and manures. In the wetlands section of the water’s travels, cattails and other plants also help filter nutrients as they trap sediment and heavy metals.
New York’s system of waterways owes its existence in part to an epidemic of Asiatic cholera, which in 1832 killed nearly one in fifty of the city’s inhabitants and prompted more than half the population to leave town. New York City politicians quickly launched the construction of a major drinking water system by damming the east and west branches of the Croton River, forty miles upstate in Westchester and Putnam Counties, and then built aqueducts to channel that water to reservoirs in downtown Manhattan.
But New Yorkers were still thirsty. So the city’s Board of Water Supply looked farther out of town to the Catskill Mountains. Today, New York City’s source is the Catskill/Delaware Watershed, named after the two rivers that have delivered water to the city for most of the twentieth century. The watershed provides drinking water to nearly ten million people, and for a long time its supply has been kept clean by natural filtration. But in 1986 the US Congress amended the Safe Drinking Water Act, which was originally passed by Congress in 1974 to protect public health by regulating the nation’s public drinking water supply. The amendment pressed New York City to build a $6 billion to $8 billion filtration system. Instead the city proposed protecting this valuable watershed by buying land as a buffer and a natural filter while upgrading sewage treatment plants.
But housing development got in the way. Roads and homes started to appear in the Catskill/Delaware Watershed, and New York City politicians procrastinated on their land purchase proposal. To get things going, Robert F. Kennedy Jr., son of the late senator, then the attorney for New York’s clean water advocate, Riverkeeper, solicited a real estate agent who estimated that it would cost only $1 billion to buy every acre in the Catskill/Delaware Watershed, several billion dollars less than a filtration system. The real answer, Kennedy told one reporter, was to “stop development. That’s what you have to do, but nobody wants to say it.”
Kennedy kept pushing the city on Catskill land purchases, taking film crews into one faulty hospital treatment plant, showing how sewage and wastewater were leaking out into the New York system. The New York Post reported that the Croton reservoir had been shut down due to pollution by sewage, but a New York City spokesman countered that it had been shut down by “organic material.” The late-night television host David Letterman joked that the story “scared the organic material out of me.”
New York City reacted by putting severe restraints on development, new sewage plants, paved surfaces, and farming activities in the watershed, but local residents countered with lawsuits alleging they were being asked to shoulder the cost of New York’s drinking water. The battle ended in a compromise in which the city promised to spend $1.5 billion to buy up land and to construct and repair necessary storm drains and sewage systems. The EPA put off the New York City requirement to build a drinking water filtration system for another five years.
Today the city does everything to guarantee the safety of its water, including following urban sales of Pepto-Bismol and Imodium, both dysentery medicines, to help monitor water quality. Inspectors look for outbreaks of disease caused by single-celled parasites such as Giardia lamblia and Cryptosporidium parvum in the city’s water supply. Giardia can cause cramps and diarrhea, but just one cyst of Cryptosporidium can lead to severe illness or death in people with weakened immune systems.
Right now nature is producing the correct amounts of plants, forests, cattails, earthworms, and soil bacteria to keep these and other illnesses out of New York. But if we keep destroying species, the biological equilibrium of these natural systems won’t be there to offer its first line of defense.
How do we destroy species in a watershed? Lots of ways. Invasive pests such as the emerald ash borer, the gypsy moth, and the Asian long-horned beetle threaten Catskill trees. Pollution runoff can overwhelm wetland abilities to trap sediment and heavy metals, and if forests and wetlands go, so do the filtration efforts of the plant roots. Climate change is reducing snowfall in the Northeast, and this exposes the roots of trees to colder temperatures than they would experience under a blanket of snow, and this can lead to diminished watershed trees. And diminished trees mean diminished microbial communities beneath them.
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Protecting natural environments for the sake of their ecosystem services isn’t just a trendy New York City idea. Boston escaped an order from the EPA to filter its water by enacting a watershed program similar to New York City’s that included land purchases, wildlife control, and the regulation of development along tributaries. In Costa Rica, the government charges customers a few cents more on their monthly water bills to pay upstream farmers to preserve and restore the tropical forest. The European Union requires watershed protection of woodlands to ensure the quality and clarity of its water.
In the late 1980s, Perrier water in northeastern France began protecting the Rhine-Meuse watershed for fear that pesticides and fertilizers would compromise the quality of its famous bottled water. In 1990, the water was temporarily pulled off the shelf when it was found to contain the carcinogen benzene, a component of gasoline. Rather than relocate, Perrier spent $9 million to buy six hundred acres around its famous spring. They also entered into long-term agreements with local farmers to use more environmentally friendly practices on four thousand more acres of surrounding land.
Though there is a substantial amount of knowledge about the importance of natural systems to the human economy, the idea hasn’t entered the consciousness of public and political minds. Ecosystem services are the processes by which natural ecosystems and the species they contain sustain human life. They bring us seafood, forage, timber, biomass fuels, natural fiber, pharmaceuticals, and more.
Critical services could include the purification of water and air, mitigation of floods and droughts, breakdown of wastes, generation of soil, pollination of crops, control of agricultural pests, dispersal of seeds, protection from the sun, moderation of temperature, winds, and waves, as well as enough aesthetic beauty to lift the human spirit.
That’s a lot of important functions. There are legions of ecosystem soldiers contained in some of those goods. One square meter (1.2 square yards) of Denmark pasture, for instance, is populated with approximately 50,000 earthworms, 50,000 insects and mites, and nearly 12 million roundworms. A single gram of soil has about 30,000 protozoans, 50,000 algae, 400,000 fungi, and billions of individual bacteria. These life-forms perform complex natural cycles that are critical to human life.
Without birds and other insect predators, pesticides alone could not control agricultural pests. Without pollinators, plants would not produce food. But many of our ecosystem “soldiers” are in trouble. Nearly twenty thousand species of animals and plants are presently considered at high risk of extinction. A study in Nature concluded that if all the species that were considered threatened were lost in this century, and if the rate of extinction continued, we would be on track to lose three-quarters or more of all species within the next century. The International Union for Conservation of Nature has evaluated more than fifty-two thousand animal and plant species for their ability to survive. Their conclusion is that 25 percent of mammal species are threatened, as well as 13 percent of bird species, 41 percent of amphibian species, 28 percent of reptile species, and 28 percent of known fish species.
Yet we are dependent upon these species for our own survival. Ecosystems of multiple species interact with one another and their environments, and those interactions are essential for human life. They represent the genetic diversity of life, providing the raw ingredients for new medicines, new crops, and new livestock.
Forests store more carbon from carbon dioxide if they have a greater variety of tree species. Streams clean up more pollution if they have a greater variety of microbes. Increasing the diversity of fish means there are greater fishery yields. Increasing plant diversity means they can better fend off invasive plants. Natural enemies better control agricultural pests if they are composed of a variety of predators, parasites, and pathogens. And ecosystems with a greater biodiversity can better withstand stress such as higher temperatures.
On the other hand, less diversity means less carbon capture, more polluted streams, fewer fish, more invasive plants, more agricultural pests, and more of the species that do poorly under stress.
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There is a cultural aspect to ecosystem services as well. Madhav Gadgil of the Indian Institute of Science, Bangalore, and Kamaljit Bawa of the University of Massachusetts Boston divide the consumers of the world into two categories: there are ecosystem people who include forest dwellers, herders, fishers, and peasants who rely on local ecosystems to fulfill most of their needs; and there are biosphere people who extract ecosystem products over a larger international range for commercial purposes. Their rewards are uneven. Even when ecosystem people extract local products for biosphere people, they often do so for low wages because they don’t own the land or the trucks, trains, and airplanes to get the products to commercial markets.
Communities relying on local goods have an incentive to conserve the products so they are there tomorrow. But what happens, says Gadgil and Bawa, is that local people without a controlling interest in the ecosystems nearby aren’t as involved or committed to the long-term survival of these ecosystems. Approximately fifty million people in India live in proximity to forested areas and derive the majority of their living from forest products. But they often don’t have ownership of the lands or the goods.
According to Gadgil and Bawa, if restoration of the environment is to be paramount in economic decisions, then some of that locally controlled, locally extracted, and locally used philosophy has to rub off on the biosphere people. Just because one enjoys blueberries in the middle of winter doesn’t mean that it’s a good or healthy idea to buy produce that comes from the other side of the globe. Next time you see food that is shipped more than a hundred miles to your door, think about all the pollutants that are coming out of the back of that truck or the fuselage of that plane to get to where you are in winter. It may be benefiting some corporation, the biosphere people, but it’s not beneficial for local economies or local health. And with climate change, local health and local economy are vitally connected with international health and economies.
Training our tongue to enjoy foods that are local and in season is healthier for us all. Says Julia Kornegay, a horticulturalist at North Carolina State University, “Trying to have strawberries and raspberries 365 days a year and expecting them to taste good isn’t sensible.”
Consider also the ecosystem services we derive from diverse tropical plants through the development of medicines. Fifty percent of all medicines owe their origins to species of either plants or animals. Those include tranquilizers, diuretics, analgesics, antibiotics, and more. Aspirin owes its origination to the willow tree. The contraceptive pill originally comes from the wild yam, which grows in the Mexican forests. The bark of the yew tree in the US Pacific Northwest contains the biological compound for Taxol (paclitaxel), which attacks cancer cells that don’t respond to other drugs. Madagascar’s rosy periwinkle has fostered two different drugs that have altered the outcome of a child with newly diagnosed leukemia from one chance in ten of remission in the 1960s (before these medicines) to nineteen chances in twenty today (after their discovery).
Anticancer drugs derived from plants save about thirty thousand lives each year, with an economic savings of $370 billion in terms of lives saved, suffering reduced, and work hours maintained. Many recent anticancer drugs have been found in the tropics, but unfortunately this is also where the majority of plant species extinctions have occurred.
Norman Myers at Oxford points out that Eli Lilly, a global pharmaceutical company, exploiter of the rosy periwinkle for two anticancer drugs, has profited with over $100 million a year in sales going back to the 1960s. Madagascar, where the plant was taken, hasn’t received any of that. This gives that country little incentive to protect the remaining tropical forests even though they may contain the seeds of discovery for a host of other important pharmaceuticals. Homo sapiens evolved from an ancestor who hunted for a living, going to each new area, killing the animals, and using the plants. Though our technology has rapidly expanded, our primary instincts are back in the Stone Age.
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The forest itself is part of our treasure chest of natural resources, one that has many ecosystem services to offer, but again one that we fail to appreciate. If there are trees by the road or in our neighborhood, then all is well. But if deforestation occurs off the road, in other states, or other countries, we object less forcefully. Out of sight, out of trees.
A prime example of man’s selective values can be found in the forests of Central America. I met Dalia Amor Conde, an assistant professor at the Max-Planck Odense Center, in Odense, Denmark, at Flores, a city in the northern department (province) of Petén, Guatemala. The city is located on an island in Lake Petén Itzá, just outside Tikal National Park, famous for its Mayan ruins and its wildlife. Conde was born in Mexico and got her PhD at Duke University, where she began studying jaguar movements in the tropical forest of Central America to determine their habitat and how roads and other infrastructure planned for the region might affect them.
Her goal is to save enough contiguous land to allow jaguars to migrate between isolated populations, keeping the gene pool of the animal mixed and vital. In the process, this encourages the preservation and vitality of a host of plants and animals that reside in the same ecosystem. It is known as the umbrella effect. By saving this charismatic species, Conde hopes to also save the multitude of animals, plants, and birds that reside under the jaguar’s umbrella.
On a misty tropical morning, she took me to a local zoo in the middle of Lake Petén Itzá. The zoo had a spotted jaguar whose head and muscular body looked quite regal. We both squatted down to get an eye-level look at the animal, though the jaguar ignored our presence while it paced around its enclosure. This cat is the third-largest feline in the world after the tiger and the lion, and the largest in the western hemisphere. Conde had been on a number of expeditions in the tropical forest whose purpose was to capture jaguars and then release them into the wild with radio collars so biologists could track their movements.
She described to me one hunt in the rain forest surrounding the Mayan ruins of Calakmul in the Yucatán, where birds filled the air with their calls and howler monkeys roared from the treetops. She’d accompanied a caravan of vehicles filled with four biologists, two trackers, five dogs, and a veterinarian to check bait stations along a dirt road through Calakmul National Park. The bait consisted of large chunks of sterilized goat meat spiked with enough drugs to slow the animals down. They were placed every mile at seven spots along a dirt road.
The tracker was Tony Rivera, a former jaguar hunter and now director of EcoSafaris. He got out of his car and announced that the big cat had taken the bait, and the frenzy of dogs in the back of the truck told him the animal was near. Though the group had been up since 3 a.m., everyone suddenly came alive, piled out of the cars, and readied for the hunt.
Rivera let the dogs go, and they took off into the jungle—the biologists doing their best to keep up. As the sound of the dogs’ barking changed, Rivera quickened his pace, approaching a tree in which the jaguar had taken refuge. The dogs were pulled back. Rivera raised his rifle, took aim, and fired a tranquilizer dart into the animal’s side. Soon the drug took effect, and the biologists were assessing the cat’s health and attaching a radio collar to its neck to follow the animal’s movements.
Conde found the process transformative. “The first time I looked into the eyes of a jaguar changed my life forever,” said Conde.
Conde works with the Mexican NGO Jaguar Conservancy and the National Autonomous University of Mexico to save the Mesoamerican forest, which runs from Panama to Mexico, the largest remnant of rain forest outside of the Amazon in the western hemisphere. And they are doing this by preserving the jaguar, an animal with a lot of cachet in Latin America.
She was trying to pinpoint specific areas of forest with high populations of jaguars, to make sure they were connected to areas where populations were low. On the boat ride back from the island zoo, Conde said, “With so little of the forest left, the connectivity between the patches is critical. We have isolated populations of jaguars in a sea of human land use.”
The habitat of the jaguar, which once ranged from the southern boundaries of the US all the way to Brazil, has shrunk by 80 percent in the last one hundred years. Now the jaguar is alive, though threatened, in the Maya forest, a tract within the Mesomerican forest of about four thousand square miles of tropical rain forest that extends over the adjoining borders of Mexico, Belize, and Guatemala, where most of Conde’s work is focused. The Maya forest comprises a number of national parks and protected zones. In order to save the jaguar, one had to save the forest.
Conde’s work was part of a bigger plan to build the Mesoamerican Biological Corridor, which would allow jaguars and other animals to migrate all the way from Panama to southern Mexico. The project was supported by the Central American nations and the investment of $400 million by the Inter-American Development Bank. The problem was the Inter-American Development Bank was also simultaneously investing $4 billion in the construction of more than 332 dams and 4,000 square miles of roads that could, ironically, very well negate the efforts behind the corridor.
Conde was attracted to the jaguar not only for its nobility but because it was a top predator. If you save the jaguar, you also save all the other species that are beneath it on the food web, which are a part of its ecosystem. Plus you save the tropical forest, which is important not only to local species but to North American migratory birds as well. At least 333 species of birds exist in this region, and the Nature Conservancy estimates that 40 percent of the migratory birds from North America stop in the forests and marshlands of this area during their travels. Natural ecosystems tend to be interrelated.
Jaguars are known to take down a number of medium-size animals including white-tailed deer, smaller local red brocket deer, collared peccary (wild pig), Baird’s tapir, agouti (a large rodent), armadillo, and coatimundi (a relative of the raccoon). Jaguars are ambush predators, hunting along paths in the forest, mostly in the night, overcoming their prey with powerful teeth and claws. But in doing this the jaguar is helping the populations of these animals, culling the sick and the weak, a natural process that makes these populations stronger. The predator plays an important evolutionary role in keeping wildlife populations fit and healthy.
Jaguars mostly stay away from people. But they do take an occasional cow, goat, or chicken, possibly putting them at odds with local ranchers and farmers. Conde and other biologists tried to get the governments of Mexico, Belize, and Guatemala to create jaguar insurance whereby they would pay biologists to remove problem jaguars and take them to areas where they would do less harm.
Unfortunately, Conde’s studies have been limited due to the costs of jaguar collars ($4,000 to $7,000 each), but the data she has retrieved has given her a vital look into the type of habitat jaguars need. Though the animals would travel through secondary forests and developed land, her collared jaguars spend most of their time in primary or pristine forest. Conde said this showed the jaguar needs undisturbed areas.
Deforestation in Mexico, Belize, and Guatemala is having devastating results. On a cloudy day during the rainy season in Petén, the frontier region of northern Guatemala, I accompanied Conde and Lucrecia Masaya, the research and conservation director at Defensores de la Naturaleza, in Guatemala City, into Laguna del Tigre National Park. According to Masaya, her group was interested in a number of environmental causes and “the healthy populations of jaguars are one way to tell if the things we are doing are working or not,” she said.
The dirt road we traveled on was only two years old, yet slash-and-burn agriculture had already destroyed wide swaths of tropical forest along its path. The group took a boat up the Río San Pedro to the Macaw Biological Station. At dusk, we climbed a tower on a nearby knoll, gazed at the surrounding rain forest, watched tropical birds fly by, and listened to the monkeys in nearby trees. The following morning, I accompanied Conde as she showed Masaya a map of the new roads that the government of Guatemala has planned to attract tourism from the Yucatán to the Mayan ruins in Guatemala. The plans called for thirty-nine-foot-wide (twelve-meter) paved roads. Conde referred to the deforestation the group saw on the road leading into the park: “And that was along a dirt road. Can you imagine the devastation that will come from paved roads?”
In the past fifty years, Guatemala has lost two-thirds of its original forested area and the biodiversity that it held. According to the United Nations’ figures, since 1990 about 133,000 acres (54,000 hectares) of Guatemala’s forests have been lost each year.
The importance of that forest, and how its fate was interconnected with man’s, was on display when Hurricane Mitch hit Central America in 1998. The storm formed over the Atlantic and moved toward the central Caribbean Sea in late October. As the storm drifted over warm water, it quickly intensified to a category 5 hurricane with 180-mile-per-hour (290-kilometer-per-hour) winds, then stalled just off the north coast of Honduras, below Guatemala and Belize. The hurricane slowly weakened as it inched southward toward the shore, then westward over Central America. Eventually the heavy rain (36 inches, or 91 centimeters) in Choluteca, Honduras, caused flooding and landslides, killing more than 19,000 people and devastating the entire infrastructure of Honduras and parts of Nicaragua, Belize, El Salvador, and Guatemala. Whole villages and their inhabitants were swept away in torrents of floodwaters and deep mud.
Landslides were particularly virulent on hillsides cleared of vegetation for agriculture. Without the forest to anchor the soils, the rapid runoff from the rains formed rivers of mud. In areas where land had not been cleared, fewer landslides occurred. Even plots of land farmed with crops like coffee and cocoa under the shade of canopy trees did much better than cleared land. Natural and diverse landscapes fared far better than manicured ones.
Mangroves are great buffers against storm damage—more effective than the best concrete dikes, because they capture sediments and build mounds with their roots that keep up with the rise of the sea level. But, since 1950, Guatemala has lost about 65,500 acres (26,500 hectares) of mangrove forests, representing 70 percent of its historic area, according to the Nature Conservancy.
Mangroves can stabilize coastal lands and provide a strong buffer to coastal storms, even hurricanes. Nature has the ability to evolve with change in general, something man does not always appreciate.
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For many, Las Vegas, Nevada, with its abundance of neon lights, swimming pools, and wildly decorated hotels might be one place where the concerns of nature could take a backseat to man, but this is not the case. I arrived in Las Vegas after a long day of driving through the desert. I’d come here to see if this neon city ran independently of nature or if its fate was much more intertwined. I checked into my hotel on the main strip and headed out onto Las Vegas Boulevard. It was 11 p.m. on a Thursday, but the city was still very much alive.
The hotels that lined the boulevard looked like amusement park rides. The New York-New York Hotel & Casino was a three-story replica of the New York City skyline and the Statue of Liberty. The Paris Las Vegas had a slightly leaning Eiffel Tower in front of it. The Bellagio looked like Venice, with more than 1,200 dancing fountains that moved to music on a lake of more than 8.5 acres of water.
Charles R. Marshall, an ecologist whom I visited at the University of California, Berkeley, several months before, said, “It’s so spectacular, out of control, and extreme. It’s one of my favorite places, though that usually horrifies most people I know.” Marshall, who grew up in Australia before coming to the US, was married in Las Vegas. His father was, too.
Gambling is king here. My mother once rolled eleven consecutive wins at the craps table at Caesars Palace, and the crowds gathered around the table four or five people deep. They don’t get that excited about nature.
Though many visitors see only the man-made side of Las Vegas, it does have a natural history. In the late 1800s, Las Vegas was just a stage stop on the Santa Fe Trail. It had two freshwater springs. Las Vegas is Spanish for “the Meadows.” In 1900, the population had grown to around thirty, which didn’t even make the census.
But in 1904 the town was picked as the ideal layover spot for crew change and service on the Union Pacific train that ran from Salt Lake City to Los Angeles, and the town started growing. The state of Nevada long embraced permissiveness, and Las Vegas ran with that idea. It allowed gambling, prostitution, quickie marriages, and relatively quick divorces.
Four days before Christmas in 1928, President Calvin Coolidge signed a bill authorizing $175 million for the construction of the Boulder Dam (later rechristened the Hoover Dam) outside of Las Vegas, and the town went wild. Nevada lawmakers made their state the only one in the nation to allow legal, wide-open casino-style gambling. Then they lowered the divorce residency requirement from six months to six weeks and that got Hollywood’s attention.
Bugsy Siegel, head of an underworld coalition known as the Syndicate, came to Las Vegas in the 1940s. He was immediately enamored of the whole “Sin City” scenario, built himself the Flamingo hotel, and started palling around with Hollywood stars, including his rumored “old friend” George Raft. But Siegel ran into trouble with the Syndicate, and in June 1947 got a bullet in the eye as a reward.
On January 27, 1951, the Atomic Energy Commission tested the first of a series of atom bombs outside Las Vegas. Soldiers were purposely exposed to the tests to gauge the effects of radiation on human beings. Vegas didn’t seem to mind, though the first test left a trail of broken glass across the city. Eventually these tests were moved underground. Over the years Las Vegas has decorated all of its casinos with neon lights—perhaps to make up for the loss of nuclear illumination.
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The following morning, I drove a couple of miles off the strip to the University of Nevada, Las Vegas (UNLV), and met with Stan Smith, an ecologist. He showed me some of the desert landscaping that had made the campus famous right outside his office door. The school advertises itself as an arboretum that includes the entire 335-acre campus. Smith had been studying how plants adapt to stress. He’d also looked at how climate change would affect the structure and function of desert landscapes and ecosystems.
An amiable man with wavy silver hair and lots of anecdotes, Smith was raised in Las Cruces, New Mexico, but spent time in Reno, Nevada, and Phoenix, Arizona, before coming to Las Vegas. He was quite familiar with the Southwest desert, although he claimed most Las Vegans were more familiar with the gambling. “You see slot machines all over—at the airport, at the end of the line at the grocers. People in Arizona and California utilize their desert for recreation. But when I was last on jury duty, the other members were comparing coupons from different casinos to see which ones gave the best rewards. Though there are true outdoor enthusiasts here, most people just aren’t that interested,” says Smith.
Las Vegas casinos keep their curtains closed so you don’t look outside. They don’t have clocks on the walls, and the lighting is such that it is difficult to tell if it’s day or night. Hotels like Caesars have elaborately decorated moving sidewalks to get you inside the casino, but once you are there it is really hard to find the exit sign. And when you manage to escape, it’s usually into a parking lot or curbside area that is a lot less friendly than that moving sidewalk you came in on.
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The outdoors may not impress the majority of its Las Vegas citizens and its fortune-seeking visitors, but nature is the real treasure here. Though the desert shrubs cover only about 20 percent of the desert floor, they are the crucial habitat of lizards, snakes, mice, and birds. Birds and bats are important seed dispersers, eating desert fruits during the wet season and spreading their seeds through droppings. These flowers are essential to the health of migrating birds and raptors. The mountains around Las Vegas contain bobcats, coyotes, mountain lions, desert tortoises, and bighorn sheep. Near Lake Meade on the Colorado River just outside Las Vegas, I stood one hundred yards away from a watering hole at midday and saw twenty bighorn sheep, several with large curling horns, as they came to take a drink.
Though it goes unnoticed by most, among the most important natural elements here are the crusts that cover much of the desert in the Southwest. Biological soil crusts form in open desert areas from a highly specialized community of cyanobacteria, mosses, and lichens. Crusts generally cover all soil spaces not occupied by plants, which can be up to 70 percent of open spaces.
Biological and mineral crusts help keep soil stable, reports Jayne Belnap, a US Geological Survey research biologist in Moab, Utah. A well-developed biological crust is nearly immune to wind erosion. “It’s tough as nails against all wind forces,” she says. “Tests in wind tunnels of undisturbed crusts in the national parks show that biological crusts can withstand winds up to one hundred miles per hour.”
But once these crusts are broken, they become dust sources and can fuel powerful dust storms. That dust can travel quite a distance. Biologists have tracked dust storms over Africa spreading all the way to the Amazon in South America. Dust storms over China have been tracked all the way to the US and out over the Atlantic.
If models of Southwestern responses to climate change are correct, Southwest US deserts should get warmer and drier. With less moisture, crusts may not form, and sandstorms could become much more common. Cyanobacteria, mosses, and lichens are critical to the formation of crusts, and crusts are as important to the residents as gambling, though they don’t get much appreciation for their valuable services.
As important as the crusts are, Las Vegas owes its life to the water that is brought to the city by the Colorado River. As with the New York City watershed, the water from the Colorado River originates upriver in less developed forest. The Colorado begins its journey from the snowpack in the central Rocky Mountains and travels south 1,450 miles (2,330 kilometers), draining an expansive yet arid area that encompasses parts of seven US and two Mexican states.
The Colorado River is the principal river of the Southwestern United States and northwestern Mexico. Prior to European settlement, the river entered Mexico, where it formed a large delta before emptying into the Gulf of California off Mexican shores. But for much of the past half century, intensive water consumption upriver has stolen the moisture of the last hundred miles of the river, and it no longer makes it to the Gulf except in years of heavy runoff. Although it is the seventh-longest river in the US, its water volume is quite low. And to make matters worse, for the last couple of decades the population growth along this already strained river has been the greatest in the country.
The immediate outlook is dim, and the long-range picture dimmer. Between 85 and 90 percent of the Colorado River’s discharge originates in snowmelt, mostly from the Rocky Mountains of Colorado and Wyoming. Nevada and other Western states like California and Arizona are already struggling with the problem of diminishing snowpack in their own states, and rely on the Colorado River for much-needed water. Climate change will decrease the volume of precipitation in the Southwest while decreasing the snowpack in the Rockies. Water will be released earlier, which means winter and spring may have sufficient moisture but summer and fall will be dry.
The critical part of this equation for Las Vegas and the Colorado River is increasing use by other desert cities, including Phoenix and Los Angeles. One of the main reasons for building the Hoover Dam in the first place was to bring Colorado River water to Los Angeles and the rest of Southern California, places that never seem to get enough.
Emma Rosi-Marshall, an aquatic ecologist at the Cary Institute of Ecosystem Studies, works with native fish in the Colorado River. The two major dams, the Hoover Dam near Las Vegas and the Glen Canyon Dam below Lake Powell in Utah, have had major effects on wildlife and fish in the Colorado River, altering their natural ecosystems, drowning their habitat, and changing the temperatures of the waters in which they evolved.
Completed in 1963, the Glen Canyon Dam in northern Arizona is one of the last large dams built in America. To provide pressure for power generation, the Glen Canyon Dam draws water from the cold depths of Lake Powell, making the water flowing out of the dam much colder than it is naturally for most of the year. This change in the temperature has had enormous consequences for aquatic species. Worms, snails, and many native aquatic insects have disappeared. These were all-important food sources for native fish. The result is the decline of half the native fishes in the Grand Canyon ecosystem.
Rosi-Marshall works with the charismatic and oddly shaped humpback chub, one of the Colorado River’s native fish, a federally endangered species and an important member of the native aquatic environment. Prior to damming, the chub benefited from snowmelt from the Colorado Rockies during spring thaw that would naturally flood the banks of the Colorado River and shape the surrounding wetlands and beaches. With pressure from environmental groups, state water agencies now release water at different times of the year to try to imitate natural runoff. But the benefits of this strategy remain under investigation. It may be that the Glen Canyon and Hoover Dams have altered the river’s ecosystem beyond the point where regulating the flow of water through the dams is going to achieve anything like the natural flow of water that existed before them.
The biggest problem for the future of the Colorado River and its surrounding environments is that the river is rapidly losing water, an issue with repercussions for practically every animal and every plant that relies on it, including man. The volume of water in Lake Meade is down to about 40 percent. Las Vegas currently has two major pipes drawing water out of the lake, but the city needs more. Below Lake Meade, the river is drying up. One of the biggest water users is agriculture in Southern California, and UNLV ecologist Smith wonders just how important and productive those farms are. But if you get rid of local agriculture, then you have to go farther away for your food, inevitably putting more CO2 in the atmosphere from food transport, and that could result in decreased snowpack in the Rocky Mountains and diminished rains in the Southwest desert, causing water levels to fall even lower. As at the craps tables at the nearby casinos, in the end you just can’t win.
The Las Vegas Valley, which includes the city, has a population of close to two million, about two-thirds of the people in the entire state. Engineers are proposing to tap underground waters of upstate ranchlands with 145 huge wells spread out over 20 percent of Nevada and connected by one thousand miles of pipe. Such a situation occurred about one hundred years ago when Los Angeles went looking for water in the Owens Valley about three hundred miles upstate on the eastern side of the Sierra Nevada mountains. Los Angeles bought up water rights from Owens Valley ranchers who were misled into thinking they were getting some help with building their reservoirs, but Los Angeles built an aqueduct and sent all the water south.
The Owens Valley slowly surrendered its moisture and the farmers and ranchers moved elsewhere. Water diversions for Los Angeles residents left Owens Lake bone-dry by 1920. Then the dust started blowing. By the 1990s, the Owens Lake playa was the largest producer in North America of PM10 atmospheric dust—particulate matter small enough to enter human lungs. The courts forced Los Angeles to put some water back into the lake, though ecologists continue the fight for more changes in water and land use there. According to Greg Okin, a professor of geography at the University of California, Los Angeles, “Climate models predict that the Southwest should get warmer and drier, and that by 2050 soil moisture could be lower than the US Dust Bowl Era.”
The Dust Bowl occurred in the Great Plains of Midwestern America in the 1930s. An unusually wet period had encouraged people to settle there, and the existing rains convinced many to begin plowing the grasslands deeply. This destroyed the grasses, which normally trapped soil and moisture during times of drought and high winds. Thus when drought came in the 1930s, there was little grass to hold the topsoil. In 1930 an extended and severe drought caused crops to fail, leaving the plowed fields exposed to wind erosion, which carried the fine soils east.
The “black blizzards,” as the dust storms were called, began blowing, with disastrous consequences. In May 1934 two dust storms removed massive amounts of topsoil from Great Plains farms and carried it all the way to Chicago, dumping 12 million pounds of dust on that city. Two days later the storm reached the East Coast, dumping huge amounts of dust on Boston, New York City, and Washington, DC, reducing visibility to three feet (one meter) in some places. It has been called the worst drought in US recorded history.
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Las Vegas is a human phenomenon, an incredibly large futuristic infrastructure that was built almost entirely in the last hundred years. In 1900 there were about thirty settlers in the valley. Today it has two million. If it took only a hundred years to get to where it is now, how many more years—one hundred? two hundred? three hundred?—will it take to get to the point where there is not enough water for the city to survive, the desert crusts vanish, the dust starts blowing, and the tourists go home?
To get a glimpse of that dusty, thirsty future, all one needs to do is head down the Colorado River to where it ends about fifty miles south of the US border. The water that lies in its bed there is but a shallow, narrow swamp of salt and pesticide-laced runoff from crop irrigation.
Aldo Leopold, an American ecologist, forester, environmentalist, and author of A Sand County Almanac (1949), once described the Colorado River Delta as a “milk and honey wilderness where egrets gathered like a snowstorm, jaguars roamed, and wild melons grew.” Today, the Cucapá Indians eke out a living in an estuary that is filled with weeds, trash, and occasional swamps of unhealthy water.
Or perhaps the real future of Las Vegas might lie on the banks of the Salton Sea in Southern California, about 120 miles north. This area was born when the Colorado River temporarily diverted into the Salton Sea in 1905. For a time, runoff from farms kept the lake level constant if not polluted. Though the largest lake in California, the Salton Sea is also the lowest, and its water is saltier than the Pacific Ocean.
The Salton Sea enjoyed some success as a resort area in the 1950s as resort communities at Salton City, Salton Sea Beach, and Desert Shores on the western shore and Desert Beach, North Shore, and Bombay Beach on the eastern shore got started and looked promising for a while. But very little development followed due to the area’s isolation and lack of local employment opportunities. With no outflow, the lake kept getting more polluted. In the 1970s, most of the buildings constructed along the shoreline were abandoned. The episode “Holiday Hell” from the television series Life After People used the Salton Sea as an example of how a resort town like Palm Springs or Las Vegas could decay if there were no humans left to maintain it.
The birds that migrate to the south side of the lake in winter still draw bird watchers, but that is primarily because all the marshlands in the Imperial Valley, where the Salton Sea lies, are taken up by agriculture. There’s no place else for the birds to go.
The east side of the sea around the former yacht club is mostly old abandoned trailers and assorted ruins that photographers like to visit—to celebrate what once was, or because some find art in old rusted ruins.
Las Vegas could get there, too. If the water in the soil gets below Dust Bowl levels, the crusts would break down and the sands might pick up and fly with the wind. If the water runs out and the city goes dry, it wouldn’t take long for the golf courses, the fountains, and the swimming pools to lose their appeal. And if the desert gets hotter and dryer, the great migration and construction boom of the last fifty years could take its final bow.
Some future artist might revel in the rusted infrastructure of the famous Sin City, go looking for relics of slot machines in the nearby dump, or collect neon artifacts for some museum. Or he or she might go rummaging through old books or magazines to discover the tale of how Sin City finally succumbed to drought, dust storms, and sky-high electric bills, and the day the last neon light flickered out.