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Fisherman in Burma. (Photo by R. Glsco)
IMPORTANCE OF RAINFOREST RIVERS TO PEOPLE
Tropical rivers have always played an essential role in the ecology
of the rainforest, but they have also been important in the lives of forest and non-forest peoples. Before the arrival of the Europeans,
sprawling civilizations and smaller societies formed along major waterways which served as a means of transport
and communication, a route for trade, and a source of fish and fresh water. However, because of their location along
major rivers, such settlements were the first to disappear, either directly affected by warfare or indirectly affected
by the onslaught of European diseases.
Today, large tropical rivers remain important forms of infrastructure providing a cheap, reliable, and easy means
for transportation and communication. Major rivers ports like Iquitos, Peru, and Manaus, Brazil, are trade centers
where forest products are exchanged for outside goods. Often, the only access to such ports, isolated by the surrounding
forest, is by water or air. For example, there are no roads leading into to Iquitos and all construction materials,
automobiles, and other essentials must be shipped into the city by river or air.
Amazonian River Boat, Brazil 1999
Besides providing a means for commerce and communication, tropical rivers are a key source of protein, in the form
of fish, for the population. However in some areas, fishermen report smaller catches as regional overfishing takes
its toll. The river also provides services for city dwellers by fertilizing the surrounding soils every flood season
and by taking away the tons of human waste and pollutants that city dwellers dump into the river.
Tropical fish provide an important source of income for many city dwellers, especially in the Amazon, which is home
to some 3,000 species of fish. Many of the fish seen in temperate-zone aquarium shops are imported from Brazil and
Peru.
LAKES
Peruvian Amazon river
Aerial view of a meandering river in the rainforest of Peru. If you look closely, two oxbow lakes are visible towards the center of the image. One is considerably "darker" than the other, but both are isolated from the main channel of the river.
The vast majority of natural lakes in lowland rainforests are oxbow lakes. An oxbow lake is a crescent-shaped lake formed when a river changes course. In lowland rainforests like the parts of the Amazon where soft alluvial soils dominate, meandering rivers gradually shift due to erosion and sediment deposition. Oxbow lakes typically form when loops in the river become so extreme that the main channel erodes a new straighter route, leaving the river bend apart from the river. As time passes, the oxbow lake becomes increasingly distant from the main channel. Water conditions change as the water stagnates.
The characteristics of an oxbow lake generally depend on its age. Younger oxbow lakes may be "flushed" by river currents, especially during the flood season. These lakes tend to be slightly more turbid (less transparent) and less acidic than older lakes more distant from the river channel.
Oxbow lakes are key habitats for many species of fish and aquatic animals. A number of popular tropical aquarium fish species live exclusively in oxbow lakes, which also serve as the primary habitat for giant river otters in South America.
Free-standing lakes in the rainforest also exist, though they are not as abundant as tropical rivers. Like oxbow lakes,
the tend to become more acidic with time as vegetation decays.
Ecological benefits of REDD boosted by inclusion of private landowners, potentially harmed by plantations
(11/17/2009) Reducing Emissions from Deforestation and Degradation [REDD] programs that include landowners will conserve more habitat and ensure greater ecosystem services function than programs that focus solely on protected areas, report researchers from the Woods Hole Research Center (WHRC), the Instituto de Pesquisa Ambiental da Amazônia (IPAM), and the Universidade Federal de Minas Gerais (UFMG).
Forgotten species: Madagascar's water-loving mammal, the aquatic tenrec
(11/12/2009) There are many adjectives one could attach to the aquatic tenrec: rare, mysterious, elusive, one-of-a-kind, even adorable, though one tries to stray from such value-laden titles since it excludes so many other non-adorable inhabitants of the animal kingdom. This small and, yes, cute insectivore, also known as the web-footed tenrec, lives in Eastern Madagascar where at night it spends the majority of its time swimming and diving in fast-moving streams for insects and tadpoles. It sleeps during the day in small streamside burrows. To date that is about the extent of our knowledge of this species.
Will Brazil's blackout drive a new push for more rainforest dams?
(11/12/2009) The power outage that affected nearly a third of Brazil's population Tuesday could be used by development interests to justify a renewed push for hydroelectric dams in the Amazon rainforest.
Amazonian natives say they will defend tribal lands from Hunt Oil with "their lives"
(10/25/2009) Indigenous natives in the Amazon are headed to the town of Salvacion in Peru with a plan to forcibly remove the Texas-based Hunt Oil company from their land as early as today. Peruvian police forces, numbering in the hundreds, are said to be waiting in the town. The crisis has risen over an area known as Lot 76, or the Amarakaeri Communal Reserve. The 400,000 hectare reserve was created in 2002 to protect the flora and fauna of the area, as well as to safeguard watersheds of particular importance to indigenous groups in the region.
