After returning to the mainland, we headed east to a region of the country locals call “El Oriente.” Beyond the most easterly ridge of the Andes, there is a sharp drop-off, and as one winds through gravel roads that hug the sides of sheer cliffs, the sparse vegetation of the mountains give way to some of the lushest and densest jungle on the planet, the Amazon Basin. Of all the species of plants and animals on Earth, over half live in tropical rainforests. A tropical rainforest is an ecosystem identified by having 4 to 8 meters of rain each year and no winter or summer. The Amazon Rainforest is the largest intact rainforest on Earth.
We are venturing into the forest along the Rio Bobonaza and Rio Napo, two rivers that later join to become the Amazon. Both human and natural life has a very distinct feeling here. In the words of one of our hosts, you have to try not to grow plants in the Amazon. The climate, with its sun and moisture, is perfect for plants; just by throwing out some pineapple you can grow a pineapple tree! When walking along the forest floor, there is nothing but green in every direction, ground cover beneath, transitioning to bushes, then vines, then the towering trees.
This dense plant life creates mini ecosystems, or environments, throughout the forest. For instance, the Ceiba, or Kapok, tree grows to the top of the canopy, and over its life provides homes for countless species of life form, from the baby vultures we saw nested in its gargantuan root systems to the birds and insects in its leafy canopy, to the mammals that use its wide branches as forest highways. Even within this micro-ecosystem, there are smaller ones! Bromeliads are small flowering plants that grow in the branches of trees, absorbing all the water they need from the moist air and rain running down branches. They gather this water together in pools at their core, and these pools are prime nesting spots for both insects and the frogs that feed on them! The way that a species fits in as a particular part of an ecosystem is called that species’ niche.
The images below were taken at various different levels of the rainforest in Jatun Sacha Ecological Reserve as we climbed higher. What differences can you spot? What animals might do well in these different niches? Print the worksheet below these photos to learn more!
These niches create a complex puzzle of animal and plant species that have evolved to fit together in fascinating and sometimes surprising ways. For example, some species of ants and trees have evolved together in such a way that benefits both the ants and the trees, a relationship called mutualism. Take the tree Duroia hirsuta, which provides ants with the honeydew on which they feed. In return, these ants fend off herbivores which might eat the tree, and the ants also clear the area of other competing plants. The resulting stands of trees are called “devil’s gardens” or “supay chakras” in Kichwa.
All this lush plant and insect life means plenty of food to go around for an incredible variety of species! I was lucky enough to visit one of the reserves of Fundacion Jatun Sacha on the Rio Napo. Jatun Sacha, meaning Big Forest in Kichwa, is the only private organization to have reserves in each of the unique biomes of Ecuador. These reservations are reserved for use by scientists and researchers and provide a powerful perspective on how the different environments function and fit together. The Jatun Sacha Reserve in the Amazon was the first of these, founded in 1982 and encompassing over 200 hectares of the jungle that has never been cut down, which biologists refer to as primary forest. In primary forests, we are able to see the widest diversity of animals and plants behaving the way they would in an uninterrupted environment.
This is an important resource for many scientists, such as the entomologists (scientists who study insects) and arachnologists (scientists who study spiders) I encountered there. They were studying everything from the architecture of spiders’ webs to parasites that prey on spiders. A parasite is an animal that lives in or on another animal, called a host, at the host’s expense. The wasps being studied in Jatun Sacha actually lay their eggs inside of spiders, and after hatching, the larvae eat their way out! It may not be cute or pretty in the way that we imagine many tropical species, but this unique adaptation shows just how creative life can be in the rainforest!
Another seemingly fantastical creature that lives in the Jatun Sacha Reserve is the Hoatzin, which has puzzled scientists for ages. Its distinctive blue face and crested crown are unmistakable, and this combined with the size and shape of the bird (over two feet head to tail) led ornithologists (scientists that study birds) to link Hoatzin to pheasants, peacocks, or cockatoos. However, genetic evidence now shows that they are in a group all their own, having their own genus, family, and order! Scientists today hypothesize that they are closest related to birds of prey, such as owls, hawks, and falcons, but the Hoatzin is one of the few birds to be completely vegetarian! Their diet of almost entirely leaves requires a different stomach from most birds, and so they have developed a digestive system similar to that of a cow, earning them the nickname of cowbird. They store their food in a fold of skin in their throat known as a crop, where bacteria ferments the food, much as it does in cows, before swallowing the food down to their actual stomach. This fermentation gives them a distinct odor that has also earned them the nickname of skunk bird. The enlarged crop for fermentation also has grown so large that it displaces the flight muscles, making adult hoatzin unable to fly, despite their large wings. However, as babies, they can fly and swim, making them one of the few animals I can think of that is more strong and mobile when it is young than fully grown. Baby Hoatzins also have another unique trait; they are born with claws on their wings! The fossil record shows scientists that birds are evolved from dinosaurs, and clawed hands eventually became feathered wings, but the Hoatzin shows both traits and might give us a clue as to what early birds might have looked like. The Hoatzin is quite common throughout South America, but an animal with such peculiar traits can only exist in such an environment. The steep competition for food in the jungle has forced the Hoatzin to have a unique diet, and without an endless supply of leaves as well as branches to clamor back and forth on, this animal would likely starve or fall prey to a large predator. This is just one way that the climate of the Amazon basin gives organisms a unique challenge and blessing, leading to such mind-blowing biodiversity.
It’s hard to imagine, but this climate is pretty nice for humans, too. I expected to find the jungle hot, muggy, and buggy, but it actually felt less hot, less humid, and with seemingly fewer mosquitoes than Memphis! While I’m not sure about the reasoning behind the mosquitoes, the temperate weather is due to a combination of factors. The first is the lack of seasons at the equator; since it remains at relatively the same distance from the sun all year round, it has neither winter nor summer! In Ecuador, the temperature is also kept down by the altitude. Since the Andes are so high above sea level, the temperature is cooler (see journal 3). A third factor that keeps it a nice temperature is the ice cold currents that run up the coast. This flow of water, called the Humboldt Current after Alexander von Humboldt, brings cold water from around Antarctica up the Pacific coast of the Americas all the way to California!
It’s no surprise, with the pleasant temperature and fertile soil, that people have long been living in this region. Though this was one of the final areas on Earth for humans to arrive, it is also one of the final places where people are living in a hunter-gatherer lifestyle. Several of the groups in the Amazon Basin have managed to remain isolated from globalized forces, even going to the point of shooting massive arrows at passing planes or shrinking the heads of foreigners who attempt to enter their land. While I did not attempt to go this far into the jungle, we stayed in several communities that are still quite remote and follow more traditional lifeways, like Canelos. After getting somewhat lost on unpaved roads, we found a spot to park, unloaded our backpacks and trekked across the river and onwards on foot. Past where roads can be cut, heavy loads of goods must be moved either on foot or in traditional dugout canoes made from a single tree. These canoes are better for wide, shallow rivers than boats made of multiple pieces of wood or metal because they can scrape the river bottom without coming apart and are made from readily available resources. In Canelos, we were able to take a walk through the rainforest with a member of the indigenous community, Luis, who pointed out to us just how much one can find a use for in the rainforest. In the next journal, I will discuss how indigenous peoples (and people in the US) are dependent on the abundant resources of the tropical rainforest.
Practice this week’s vocabulary terms with these printable vocab cards: