South America, The Wondrous Workings of Planet Earth

The driest desert and the largest rainforest in the world can both be found on the same continent: South America. This landmass is defined by its backbone, the Andes, which is the longest mountain range in the world!

The glaciers high in the Andes provide water to the mighty Amazon basin and its hundreds of connecting rivers. The Amazon basin supports tropical agriculture like cacao and coffee and is a major source of the world’s lumber. The Andes also shield the western deserts of South America from rainfall. The arid heat of those deserts has exposed minerals, especially copper, that are mined to this day as one of Chile’s largest exports. Southeast of the mountains are the fertile grasslands of the Argentine Pampas, where agriculture produces wheat, soy, and cattle.

The natural bounty of the Andes made it one of the six cradle civilizations where the environment and natural resources allowed ancient nomadic humans to settle down, farm, and create cities for the first time. The earliest civilization in the Americas, called the Norte Chico, was located in what is now Peru. Norte Chico’s first city was built over 5,500 years ago, a few hundred years before the first pharaoh was crowned in ancient Egypt. People began to cultivate crops like squash, beans, and cotton—beginning humans’ transformation of the South American wilderness. Today, South America is home to many cultures as diverse as its natural landscapes. Resources, minerals, and food produced in South America are exported and enjoyed all over the world. But with this comes a danger of overusing the land. Right now, the world’s largest rainforest is shrinking. With our knowledge of ecology, we can use both new and traditional techniques to take from the land while preserving its vital ecosystems.

The Amazon is the world’s largest rainforest, and it is the densest and richest place for life on Earth. Covering two million square miles across eight different countries (60 percent of which is in Brazil), the massive jungle has been nicknamed “the green ocean.” The Amazon is home to 10 percent of all the known species in the world. Glowing insects, exotic dancing birds, flesh-eating fish, tiny pygmy sloths—you name it, you will find it in the Amazon.

The Amazon’s millions of different plants and animals must compete for resources. Plants fight to break through the shady jungle canopy for sunlight; some plants have evolved to grow not in soil, but instead on top of trees as tall as skyscrapers. Competition for food sometimes results in specialized evolution, where a new species emerges with a super-specific niche. The sword-billed hummingbird’s beak is longer than its entire body, so it can feed from only certain types of long tubular flowers that are impossible for other hummingbirds’ bills to reach (which means no sharing).

Life here is fueled by the Amazon River, one of the longest rivers on Earth. Fresh water also comes from above. During the six-month rainy season, over 200 billion metric tons of rain floods an area of the forest floor larger than the entire United Kingdom. During this season, fish and even dolphins swim through the jungle. This water sustains the massive numbers of trees that are crucial to creating oxygen and regulating the whole planet’s climate. The Amazon absorbs over 2.4 billion metric tons of carbon each year. Rainforests produce about 20 percent of the world’s oxygen. This is why the Amazon rainforest is nicknamed “the Lungs of the Planet.”

BIGGEST BENEFITS

The huge density of plants in the Amazon influences global carbon and water cycles, creating oxygen and regulating the weather patterns and climate for the entire world. Thirty million people (including 350 indigenous tribes and ethnic groups) living in the jungle and the surrounding cities depend on the jungle for food and jobs.

There is so much food in the Amazon that animals can eat enough to grow to huge sizes, like the capybara, the world’s largest rodent.

During the rainy season, freshwater Amazonian manatees will leave the rivers and graze in the flooded forest.

The forest canopy is so thick with leaves that only a small amount of light breaks through, leaving the forest floor in nearly perpetual darkness.

The Amazon is home to one of the rare freshwater dolphins called the pink Amazon River dolphin.

Jaguars regularly hunt crocodiles and many think the original Tupi name for Jaguar (îagûara) directly translates to “he that kills with one leap.”

GREATEST THREAT

New, poorly planned infrastructure, including the construction of massive new dams, break up the river systems that are crucial to life in the rainforest. Unsustainable and illegal logging also puts the jungle at risk. Fires are burned in the forest to remove trees and make space for cattle, releasing millions of tons of carbon into the atmosphere annually, which contributes to global warming. Indigenous communities like the Asháninka are working with conservationists to protect the rivers and the jungle. The Amazon rainforest is crucial to the entire planet’s health, and it is critical to combat deforestation.

Ecosystem of the Atacama Desert

The last time it rained in parts of the Atacama Desert was before humans began to record history in writing—that is how dry it is. The only places on Earth with less rainfall are the very tips of the North and South Poles. Located on the Pacific coast west of the Andes, this desert is unusally high above sea level and is shielded from rain by the Andes mountains, giving it a unique climate and landscape. The Atacama Desert is filled with bright red canyons, stark white salt flats, and the most beautifully clear sky in the entire world. Although life struggles to survive in this harsh climate, a small number of plants and animals have adapted to call this “alien” landscape home.

The Atacama’s closeness to the ocean causes fog zones known as “fog oases” or lomas, where the steep coastal cliffs and hills can catch moisture from the clouds that roll off of the Pacific Ocean. This small amount of water is the most moisture that parts of the Atacama will ever see. Yet it’s enough to sustain some scrub plants and many types of birds like the Peruvian song sparrow and Pacific blue-black grassquit, and small mammals, like viscachas (a rabbit-like rodent) and foxes. As it gets even drier, only a scarce cactus, vulture, mouse, or scorpion can be found. South of the Chilean city Antofagasta, the terrain becomes a sea of red rocks, looking more like Mars than Earth. In some parts of the Atacama, farthest away from the fog, the climate is so dry even bacteria struggle to live. The heat that makes life so hard also creates clear, cloudless skies and a crystal-clear view of the Milky Way that can be seen with the naked eye at night. Some say this night sky is one of the desert’s greatest natural resources.

BIGGEST BENEFITS

The Atacama Desert’s uniquely high elevation, clear skies, and lack of light pollution make it perfect for researching stars. This desert is home to the largest international astronomy project on Earth: a group of radio telescopes called The Atacama Large Millimeter/submillimeter Array. The telescopes’ delicate long-wavelength readings give scientists detailed images of faraway stars and a better understanding of our universe.

Even though it has not rained for centuries in the Atacama, its ancient lakes are still evaporating, creating huge salt lakes and salt flats. The largest salt flat in Chile is found in the Atacama Desert.

Large flocks of flamingos eat algae that grows in the shallow water in the Atacama’ salt flats. (A flock of flamingos is called a “flamboyance”!)

NASA tested the Mars Rovers in the Mars-like landscape of the Atacama.

The Valle del Arcoíris (Rainbow Valley) is named for its naturally occurring brightly colored rocks; the Valle de la Luna (Valley of the Moon) has stone and sand formations like those on the moon.

Home to many large active volcanoes, including the famous Licancabur.

GREATEST THREAT

As towns and cities grow near the desert so does the amount of artificial light in the night sky. This light pollution can confuse and disrupt nocturnal animals. It’s important that new construction is done in a way that is sensitive to the ecosystem’s needs. By installing special types of lights and enforcing light pollution regulations, we can preserve the desert’s most amazing natural resource: the clearest view of the night sky to be found on Earth.

Ecosystem of the Pampas

The gauchos ride across a seemingly endless expanse of grass. For over 200 years, these South American cowboys have managed sheep, cattle, and horses in the Pampas, using the same techniques and traditions. The rolling hills of the Pampas are dotted with shrubs and trees and watered by lagoons and rivers. All that grass flourishes in the humid climate and heavy rainstorms called pamperos.

The native grasses and plants, like flechillar, have supported native wildlife like the guanaco (a wild llama) and the pampas deer, long before cattle were brought to the region. In the mid-1800s the Spanish colonized South America and brought along the domesticated horses and cows that now dominate the countryside. Much like grasslands all over the world, the ecosystems and landscape of the Pampas have been transformed by ranching and farming.

Although the Pampas seems huge, covering parts of Argentina, Uruguay, and Brazil, it is not an inexhaustible resource. Overuse of the land for farming and unsustainable grazing practices have made the Pampas ecosystem one of the most endangered in the world. When grassland doesn’t have enough time to bounce back after animal grazing, soil erodes more quickly, making it harder for plants to grow. The gaucho has always been a symbol of the Pampas, but as the grassland’s ecosystem becomes more endangered, so does the gaucho way of life. Right now scientists, gauchos, and private landowners are working together to create and implement new grazing and farming techniques that minimize environmental impact. Through proper management, the land can continue to be used for many generations.

BIGGEST BENEFITS

The grasslands of the Pampas are a valuable part of Argentina’s economy and a center of agriculture in South America. Rich soil and abundant grasses make it great for growing crops and grazing herd animals like cattle. As farming and ranching expand it is important to keep native grasslands partially intact, because they naturally help prevent desertification and floods.

The Pampas is home to the greater rhea, an emu-like bird that runs in a zigzag when chased.

The guanaco’s thick, luxuriant eyelashes help protect their eyes from dust.

Buenos Aires, Argentina’s most populous city, is located in the Pampas.

Baggy pants worn by the gauchos are called bombachas.

GREATEST THREAT

The unnecessary draining of vital grassy wetlands, overgrazing of farm animals, and the destruction of native grassland to make room for new unsustainable farms threaten the Pampas ecosystem. All of these activities increase soil erosion, making new grass harder to grow. To feed our ever-expanding human population, we need to find the balance between large-scale farming and sustainable techniques that keep the grasslands intact.

Ecosystem of The Tropical Andes

The Earth’s surface is always moving. Over long periods of time, tectonic plates under the continents and oceans shift and collide. This is how the supercontinent Pangea started to break apart over 200 million years ago into the continents we have today. It is also how our greatest mountain ranges, like the Andes, were created. This 4,300-mile-long range, which stretches along the entire western side of the continent, is home to many of the tallest peaks in the Western Hemisphere. The three main climates of the Andes are dry, wet, and tropical. The tropical Andes are a huge biodiversity hotspot that follows the path of the mountains for 3,300 miles, from Venezuela to Bolivia.

The temperature in the tropical Andes gets colder as you climb into the mountains, causing climate fluctuations. These microclimates allow for many different types of niches and habitats for large amounts of diverse animals and plants. At 15,700 feet, the tropical Andes are covered in grasslands and snow. At lower elevations, starting at 11,500 feet, is the largest cloud forest in the world, its plants shrouded in fog. Lower still, at 4,900 feet, it begins to be warm enough for tropical rainforest wildlife to prowl the forest.

Climate is not the only factor that makes the this forest so diverse. Unlike a normal forest, the tropical Andes’ forests are spread out across the mountains. Like on islands surrounded by water, certain wildlife species are unable to leave certain peaks. Many unique species of animals and plants can be found on only one mountain in the entire range.

BIGGEST BENEFITS

Fifteen percent of the world’s known plant species can be found in the Tropical Andes. In just 2.5 acres of the tropical Andes are over 300 different flower species. The abundance of plants in this forest help to create oxygen and absorb 5.4 billion tons of carbon each year. That is equivalent to the yearly carbon emissions created by one billion cars.

The spectacled bear found in the Andes got its name because its markings look like glasses. Its sounds—like screeching and soft purring—are very rare among bears.

The Andes used to be the home of the Inca Empire, the largest civilization in the pre-Columbian Americas.

Potatoes and tobacco both originated in the Andes and are now grown all over the world.

The yellow-eared parrot is endangered, but with help of conservationists, the population has been increased to over 1,500 individuals.

The tropical Andes have the greatest animal and plant diversity of all the world’s designated biodiversity hotspots.

GREATEST THREAT

As the human population grows, so does the demand for fuel, wood, and food. As a result, the tropical Andes face timber exploitation and illegal hunting. This contributes to deforestation and puts animal species at risk. Unsustainable large-scale production of cacao and coffee in the region damages the soil and forces local communities to clear even more forestland to farm food they can actually eat. The region’s poverty must be addressed to prevent illegal poaching and deforestation. When people have food security, they are better able to protect wildlife.