North America

North America extends from freezing and icy Greenland to warm and lush Panama. This continent has been called “the New World,” and its history and legacy have shaped the path of human history.

The first people to live in North America were Asiatic people, over 10,000–20,000 years ago. Many archeologists have found evidence that a large nomadic tribe traveled on foot over an ancient (now nonexistent) bridge of land that connected Siberia to North America. Over thousands of years and many generations, a population of people spread from the tip of the Arctic Circle all the way down to South America, creating many different nations, cultures, and tribes along the way. Only a few of these once-numerous indigenous communities still exist today. In the 1500s there was a wave of exploration from the European continent, led by Portugal and Spain. In fact, the name “America” came from the Italian explorer Amerigo Vespucci, who was part of the first wave European exploration. This new “discovery” for Europe was followed by the conquest and colonization of North America and violent subjugation of its indigenous people. With these human invaders also came new species of bacteria, animals, and plants, which transformed and in many cases destroyed certain ecosystems. The negative effects of colonization are still felt today by the surviving indigenous communities.

The New World offered opportunities to colonizing Europeans away from the strict class system of the “Old World.” With them came not only invasive species but also drastic changes in the types of agriculture production of the land. From the 1700s to today, waves of immigrants have traveled to North America in search of opportunity, bringing plants and animals from their old homes with them. Although the introduction of new wildlife can cause great harm and unbalance an ecosystem, sometimes introducing a new species can provide solutions to big problems. For example, horses and wheat were brought to the Americas from Europe and Asia. These animals and plants were used for transportation and agricultural purposes and became an integral part of the landscapes, cultures, and economies of various North American regions. North America continues to be a home for new immigrants from all over the world and has become a beautiful melting pot of cultures.

Ecosystem of the Redwood Forest

In the world’s tallest forest, trees the size of skyscrapers are bathed in dense fog near the ocean. In the redwood forest, the coastal redwood tree can grow over 300 feet high and live over 2,000 years. They are relatives of the same trees that lived during the Jurassic period, 160 million years ago. As American author John Steinbeck wrote, “[Redwoods] are not like any trees we know; they are ambassadors from another time.”

Redwoods are one of the most resilient species on Earth, able to withstand both floods and fires. Redwood trunks contain so much water that they can survive being burned. This comes in handy, because moderate fires actually help other types of trees—such as firs, spruces, and western hemlocks—compete and flourish. In the redwood forest, small fires help maintain biodiversity and prevent larger catastrophic fires from igniting later.

Although redwood trees are very resilient, they can only survive in a very specific cool and wet environment. Coastal redwoods grow along a narrow strip of land on the Pacific Coast of North America, where the ocean creates precipitation and fog. Plentiful rain leads to flooding that strips nutrients from the soil. On the forest floor, insects and decomposers like fungi and mosses revitalize the soil by breaking down burned trees and dead plants and animals. Through decomposition, this ecosystem is hard at work creating new topsoil, and the results are beautiful. Careful fire management, support, and protection from the U.S. national park system allow visitors to continue to enjoy these ancient forests.

BIGGEST BENEFITS

Dense forests worldwide absorb carbon from the atmosphere and create oxygen. But redwood forests absorb carbon at a heroic rate. Large coastal redwood trees grow quickly and store up to three times more carbon in their trunks than most other types of trees. With an increase in carbon dioxide pollution from cars and factories, it is more important than ever to preserve redwood trees.

One redwood tree grows at a rate of over five cubic feet a year (equal to 3.2 million pencils).

Redwood trees have basal burls, knotty growths filled with seeds. When the main trunk of a tree is damaged, these dormant seeds begin to sprout a new tree.

In the late 1800s and early 1900s, a few coast redwoods and giant sequoias (an inland species) had tunnels cut into them so that tourists could drive through them! Some of these “tunnel trees” are still around, but cutting through a redwood always results in its eventual death.

You can see seals, sea lions, dolphins, and whales off the coast of the redwood forest.

Native Hawaiians used fallen redwood logs that drifted from the coast of California to make 100-foot-long canoes.

GREATEST THREAT

Although most of the redwood forest is protected, the forest is still threatened by bad lumber practices and encroaching cities. Edge ecosystems act as watersheds and shield the forest from extreme flooding. When trees are removed and surrounding ecosystems are disturbed it can hurt the whole forest. Ecologists are working to restore impacted parts of Redwood forests while not interfering with natural disturbances like small wildfires that are good for it.

Ecosystem of the Northern Great Plains

“There is so great a charm in absolute solitude, in the wild, lonely freedom of the Great Plains, that often I would make some excuse and go off entirely by myself.” This is how U.S. President Theodore Roosevelt described the Great Plains of the central United States. His appreciation of and respect for the natural world led to the establishment of the U.S. National Park System. The Great Plains may seem like just a quiet expanse of flat grassland, but it is actually a wilderness teeming with life. Snakes, gophers, and insects battle it out in the underbrush while birds soar above. These native grasses are the basis of an ecosystem that has some of the most nutrient-rich soil in the world. These plains used to support massive herds of bison and elk, with an abundance of wildlife that rivaled that of the African savanna (see this page), but much has changed over the last 200 years.

As human populations grew larger in the 1800s, so did their use of the fertile Great Plains for farming, herding, and hunting. With any rich resource often comes the overuse and destruction of that resource. Bad farming practices combined with drought led to the devastating Dust Bowl of the 1930s. When this decade-long drought ended, drastic intervention was needed for the soil to bounce back. Much of the Great Plains is still used for farming today. The natural life cycles of native grasslands create rich soil and the grasses’ long roots lock in moisture to prevent droughts. When farmers preserve native grasslands, they can use these natural benefits to help prevent another Dust Bowl from happening again.

BIGGEST BENEFITS

The long roots of the Great Plains’ native grasses can absorb up to eight inches of rainfall! This prevents floods during rainy seasons. Water stored in these roots keeps the soil moist during the dry seasons. The life cycles of grassland wildlife create naturally nutrient-rich soil that is perfect for supporting farming and livestock. When farmers keep native grasslands as a part of the agriculture fields, they use less water and chemical fertilizers on their crops.

The pronghorn of the Great Plains is the fastest animal in North America and can run at speeds of up to 55 miles an hour.

Has one of the largest wind farms in the world.

In the 1890s, the 60 million bison that lived on the plains were nearly driven to extinction by over-hunting. Luckily, from about a thousand remaining bison, conservationists were able to bring them back, and today half a million bison still roam the plains.

The Greater Sage-Grouse is known for its dramatic courtship displays. A large population of sage grouse indicates that the entire ecosystem is intact and healthy.

Nine million acres of the North American plains are managed by Native American tribes, many of whom are helping to restore the land through their own ecological initiatives.

GREATEST THREAT

Despite President Roosevelt’s wish to preserve nature, the Great Plains is one of the least-protected ecosystems on Earth. More and more of the plains are being used for unsustainable large-scale monocrop farms (which grow just one type of plant) that destroys biodiversity. Poorly planned building on the plains threatens wildlife migration routes and habitats. Sustainable farmers, ranchers, conservationists, and Native American tribes are doing what they can to preserve the ecosystems on their land by expanding protected areas and restoring what little native grassland is left.

Ecosystem of the Mangrove

It is not hard to get lost in the swamps of a mangrove forest—visitors often have to canoe through a tight maze of tangled mangrove tree roots and branches. These roots and branches may seem like a big mess, but they are what make this ecosystem so successful and important.

Mangroves are found in tropical regions worldwide. The Florida mangrove forest is an edge ecosystem (an ecotone) in between the salty Atlantic Ocean and the shallow freshwater “river of grass” known as the Everglades. Mangroves are types of shrubs and trees that grow in brackish coastal water and are uniquely able to filter out salt to create their own fresh water. Mangroves provide habitat for numerous animals, and their dense root systems act as a physical barrier that protects Florida’s coastal land from erosion and storms.

If all that wasn’t enough to earn mangroves MVP status, their leaves are also the basis for the entire ecosystem’s food web, making them a keystone species. Bacteria and baby crustaceans break down their floating leaves in the water, attracting large animals, birds, and (of course) large predators. White pelicans and egrets perch in the mangrove branches, while alligators and crocodiles float below, staying perfectly still until their next meal swims by. This ecosystem truly shows how one kind of plant can transform an entire coastline!

BIGGEST BENEFITS

Mangrove forests protect the coastal land from erosion and storms, and are important homes for marine and intertidal species, including endangered species like the Florida manatee, the American crocodile, and the Key deer. The mangrove forest acts as nursery to many marine animals before they are mature enough to swim into the ocean—the roots protect developing eggs and young fish and crustaceans from prey. This makes them a vital resource for commercial fisheries in the Gulf of Mexico.

Mangrove leaves taste salty because they “sweat out” some of the salt that the trees absorb from the water.

Southern Florida is the only place on Earth where both crocodiles and alligators live in the same area.

Iguanas are not native to Florida but can be found hanging out all over the mangrove swamp.

Mangroves have special breathing tubes called lenticels on their roots; these let them breathe underwater during high tide. Although plants “exhale” oxygen, they also need to consume some for cellular respiration.

GREATEST THREAT

Nearly half of the mangrove forests worldwide have been destroyed since the 1950s for firewood or have been cleared for construction. Mangroves are now a protected species in Florida, but are under continued threat in Mexico, South America, and Asia. The loss of these forests decreases the population of important aquatic animals that are part of larger ocean food web. International preservation groups are working to protect what is left of these important ecosystems.

Ecosystem of the Mojave Desert

The Mojave Desert in the southwestern United States has been described as otherworldly—dotted with strangely shaped red rocks and spiky Dr. Seussian Joshua trees, which don’t grow anywhere else in the world. The Mojave was once the site of many ancient lakes and riverbeds, which have since dried up. Long ago these rivers and lakes carved what is now the deepest valleys in North America, right next to snowcapped mountains. They also left behind hidden underground water reservoirs and rich minerals that can be found throughout the desert.

During the rainy season, the Mojave is home to a limited variety of plant life, with cacti, shrubs, and colorful flowers flourishing. But in the summer, you can see why European settlers called it “the land that God had forsaken.” This desert is home to the hottest, driest place on Earth: California’s Death Valley. There, temperatures regularly reach 120°/49°F (hot enough to melt the sneakers right off your feet!) and it boasts the world record temperature of 134°F/57°C!

How can anything survive in such heat? Life depends on water, and desert plants and animals have adapted to survive on the occasional winter rainstorms and by finding underground aquifers. A few animals, like the kangaroo rat, do not drink water at all and get all their hydration from the leaves and seeds they eat. Meanwhile, other animals avoid the hot sun by leaving dens and burrows only at night, like a coyote or a jackrabbit. Although desert life can be hard, the Mojave Desert’s unique elevations and hidden water sources makes it home to some of the most beautiful wildlife and landscapes in the world.

BIGGEST BENEFITS

The Mojave Desert’s generally sunny, cloudless weather and high elevation has made it home to one of the world’s largest solar energy farms. Its ancient lake beds are a rich source of minerals like salt, copper, silver, and gold that have been mined throughout history. The lakes also left an underground water supply that is one of the water sources for the surrounding communities and cities.

Badwater Basin in Death Valley is the lowest point in North America, at 282 feet below sea level. Extreme differences in elevation in the Mojave create dramatic contrast, with snowcapped mountains surrounding the basin.

The mountains that surround the Mojave block almost all rain from reaching the desert. Scientists call this a “rain shadow desert.”

In the ecotone of the Mojave Desert and the Great Basin is the world’s rarest fish. The Devils Hole pupfish is found only in Devils Hole, an aquifer so deep that earthquakes on the other side of the world cause the water to ripple.

The desert tortoise stores water in its bladder during the rainy season and uses it to survive the dry parts of the year. (Like a camel, but slower!)

So-called “sailing stones” are found in parts of the Mojave. They leave trails across the flat surface of dry lake beds, seeming to have moved on their own. When conditions are right, thin ice sheets break apart and are blown by the wind, pushing the rocks across the clay lake beds.

GREATEST THREAT

When an area has valuable natural resource, even if that resource is as limited as water in the desert, there is the threat of people overusing it. Surrounding cities have been draining the aquifers of the Mojave, depriving wildlife that depends on that water and causing the desert floor to slowly sink. More and more of the desert is also being used as garbage landfill space. To help preserve the desert, we need to be more mindful of how we use water in our cities and think about what we throw away in our daily lives.