Tapajós-Xingu moist forests


The Tapajós-Xingu moist forests is an ecoregion in the eastern Amazon basin. It is part of the Amazon biome.
The ecoregion extends southwest from the Amazon River between its large Tapajós and Xingu tributaries.

Location

The Tapajós-Xingu moist forests lie between the Tapajós river to the west and the Xingu rivers to the east, tributaries of the Amazon River to the north. They have an area of.
The rivers act as barriers to the movement of plants, animals and insects to and from adjacent regions.
In the south the rugged Serra do Cachimbo divides the ecoregion from other moist forest areas.
There are urban centers at Santarém at the mouth of the Tapajós, Aveiro on the lower Tapajós and Altamira on the Iriri River.
The ecoregion is crossed by the Trans-Amazonian Highway and the BR-163 highway from Santarém to Cuiabá.
To the northwest the ecoregion adjoins the Madeira-Tapajós moist forests on the other side of the Tapajós River.
To the north it adjoins the Gurupa várzea along the Amazon River.
The Uatuma-Trombetas moist forests are on the opposite bank of the Amazon.
To the east are the Xingu-Tocantins-Araguaia moist forests.
To the south and southwest the ecoregion blends into the Mato Grosso seasonal forests ecoregion.

Physical

Elevations range from above sea level along the Amazon to in the south.
The ecoregion mostly lies on the undulating terrain of the ancient Brazilian Shield.
Soils are often rich in nutrients, but poor soils are found in the higher areas.
The main rivers are blackwater, with little or no suspended sediment.
The largest is the Iriri, a tributary of the Xingu.
Others are the Jamanxim, Curuá, Crepori, Curuá Una, and Jaraucu.

Climate

The Köppen climate classification is "Am": equatorial, monsoonal.
Temperatures are fairly uniform throughout the year, slightly cooler in July and slightly warmer in April.
They range from to, with a mean of just under.
Annual rainfall is.
Monthly rainfall ranges from in July to in February, with rain falling on about 240 days of each year.

Ecology

The ecoregion is in the Neotropical realm and the tropical and subtropical moist broadleaf forests biome.

Flora

The regions with rich soil have diverse flora and fauna with many endemic species.
Mostly the forests are evergreen tropical rainforest on terra firme, not subject to flooding.
There is lowland forest along the Amazon River.
Further south the forest is submontane, open canopy forest with patches of dense forest.
Where the blackwater rivers flood they create igapó forests.
An unusual form of forest with many large lianas at all levels is found on the higher land in the south and southeast of the ecoregion.
Typically these forests are found on richer soils, and have a canopy under, lower than the canopy of the humid terra firme forest.
Lianas belong to the families Bignoniaceae, Fabaceae, Hippocrateaceae, Menispermaceae, Sapindaceae and Malpighiaceae.
Large trees in the liana forests include Apuleia molaris, Bagassa guianensis, Caryocar villosum, Hymenaea parvifolia, Tetragastris altissima, Astronium graveolens, Astronium lecointei, Apuleia leiocarpa, Sapium marmieri, Acacia polyphylla, Elizabetha species, Brazil nut and mahogany.
Endemic trees and lianas include Cenostigma tocantinum, Ziziphus itacaiunensis and Bauhinia bombaciflora.
Common trees in eastern Pará that are not found to the west of the Tapajós include Zollernia paraensi, cupuaçu and Cordia goeldiana.
The predominant white-sand igapó forest along the clearwater Tapajós holds species of the family Myrtaceae and trees such as Triplaris surinamensis, Piranhea trifoliata, Copaifera martii, Alchornea castaneifolia and Handroanthus heptaphyllus.

Fauna

161 species of mammals have been recorded.
The white-nosed saki occurs only to the east of the Tapajós.
Other mammals are the red-bellied titi, Azara's night monkey, white-cheeked spider monkey, white-lipped peccary, collared peccary, cougar, jaguar, South American tapir, and brocket deer.
The rivers are home to spectacled caiman, black caiman, yellow-spotted river turtle, Amazonian manatee, Amazon river dolphin and tucuxi.
Endangered mammals include the white-cheeked spider monkey, white-nosed saki and giant otter.
556 species of birds have been recorded.
These include osprey, harpy eagle, channel-billed toucan, little chachalaca, nine tinamou species, seven macaw species including hyacinth macaw, many parakeets, parrots and the hoatzin.
Endangered birds include the green-thighed parrot and red-necked aracari.

Status

The World Wildlife Fund classes the ecoregion as "Vulnerable".
The Tapajós-Xingu, Xingu-Tocantins-Araguaia and Tocantins-Pindara moist forest ecoregions on the eastern edge of the Amazon basin have all been badly affected by human settlement and deforestation.
Roads have opened the region to rapid and uncontrolled growth of colonies, logging, ranching and major projects that have destroyed large areas of forest and degraded the land.
The remaining forests are threatened by large and uncontrolled man-made fires.
Miners seeking gold and other mineral pollute the rivers with chemicals.
During the period from 2004 to 2011 the ecoregion experienced an annual rate of habitat loss of 0.38%.
Global warming will force tropical species to migrate uphill to find areas with suitable temperature and rainfall.
Low, flat, deforested ecoregions such as the Tapajós-Xingu moist forests are extremely vulnerable.
The Amazônia National Park protects both sides of the Tapajós near Itaituba, with an area of, but it is underfunded.
The Tapajós National Forest does little to protect the forests near Aveiro.