Deforestation of the Amazon gets a large amount of attention and scientists are worried about that, but they are also worried about something just as important. The freshwater ecosystems in the Amazon basin need protection, too.
The Amazon is the world's largest remaining rain forest. It is home to one of the greatest varieties of plants and animals on Earth. It covers 2.1 million square miles of land. The Amazon is shared by Brazil, Peru, Colombia and six other countries. The whole area covers 40 percent of South America, which is one of the world's seven continents.
Freshwater ecosystems are bodies of water where plants and animals interact with their environment. Scientists say they are critical to the health of the Amazon basin. The basin is the largest network of rivers, streams and lakes in the world. It covers over 2.6 million square miles and funnels water into the 4,000-mile-long Amazon River.
The plants and animals that make their homes in the Amazon are facing a number of threats. In the magazine Global Change Biology, scientists recently wrote that finding better ways to protect the water systems is especially important. They say the people who live there need protection, along with the plants and animals.
Leandro Castello is a professor at Virginia Tech University. He helped write the article. He used to work on fish conservation in the Amazon. Castello says he was disappointed in how much more attention was paid to the rain forest's trees than its water systems.
Freshwater ecosystems in the Amazon provide many crucial services to the plants, animals and people who live there. The ecosystems move water through the rain forest, cycle soil and regulate microclimates, spots where the climate is different from the other areas nearby. The water systems are also home to a variety of plants and animals, including thousands of fish species. In addition, people who live in the Amazon need the ecosystems for food and water. In spite of their importance, the freshwater ecosystems are in trouble.
One cause of the troubles is a change in hydrology or the way water moves around. Castello says that kind of change is one of the worst things for a freshwater ecosystem.
"If you change the amount of water in either a lake or river or stream, you will change a lot of processes," Castello says.
Dams change hydrology by interrupting natural water flow and collecting water in reservoirs. When that happens, fish and other animals cannot move through the water and nutrients in the water cannot move downstream. Studies show that damming is not only a threat to people who make their living by fishing, but also a threat to people who eat the fish.
There are many dams in the Amazon basin already, and more are planned. In the magazine, scientists say that if all the new dams are built, only three rivers will be left untouched.
Mining Pollution, Deforestation Danger
Mining can also change water systems. Gold mining often removes sand and mud from the bottom of rivers and streams. The process can alter river beds and introduce pollutants such as heavy metals into the water.
In addition to dams and mining, deforestation is one of the most serious threats to freshwater ecosystems. Trees perform an important step of the water cycle, Castello says. Trees take water from the soil and let it evaporate through their leaves. When there are fewer trees to do this, water trickles back into the rivers, bringing soil with it.
Deforestation can also reduce rainfall and make droughts worse. In addition, plants and trees are important for the soil structure on land. Removing them can cause soil to wash into the water and even reshape rivers and streams.
Climate change, the heating up of the Earth's climate, may add another problem. As temperatures in the Amazon basin go up, droughts and severe storms may become more frequent and intense. Drier conditions may also lower water levels in rivers, and some streams might disappear completely.
Castello says that the key to better conservation is for lawmakers to develop a plan that includes both land and freshwater ecosystems. He also says that satellites could be useful for monitoring freshwater ecosystems in the Amazon. Satellites already help governments track illegal deforestation.
Scientists also say that although much of the Amazon is protected, many freshwater areas are not. Some freshwater ecosystems are even in protected areas, but they're still affected by dams outside their boundaries. There are also exceptions in the rules to allow activities such as mining.
Marcia Macedo is a scientist with the Woods Hole Research Center in Massachusetts. She also helped write the article. She says policymakers should consider how effects from development projects like dams do not stay in one place.
"You have the impacts moving downstream in the river, across official boundaries, across state and country lines," Macedo says.
Claudio Maretti works for a conservation organization in Brazil.
"The most important thing is to build the information across borders," Maretti says. If countries have the same rules and policies, they can do a better job of protecting species and ecosystems, he believes.
1. Which section of the article highlights specific ways trees and water systems work together?
(A) "World's Largest Water Network At Risk"
(B) "Damage From Too Many Dams"
(C) "Mining Pollution, Deforestation Danger"
(D) "Hotter Climate, Fewer Streams"
2. What is the author’s MAIN purpose for including quotes from Macedo and Maretti in addition to Castello?
(A) to demonstrate how damaging dams are to river systems in the Amazon
(B) to give credibility to Castello's argument and emphasize the importance of working across borders