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.
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.
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.
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 ge
t 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.
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 Indi
ans 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.
The Next Species: The Future of Evolution in the Aftermath of Man Page 15