The Chiquitano dry forests is a
tropical dry broadleaf forest ecoregion
An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...
in
Bolivia
Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...
and
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
. The ecoregion is named for the
Chiquitano people who live in the region.
[
]
Setting
The Chiquitano dry forests cover an area of . The ecoregion lies east of the Andes
The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...
in the lowlands of eastern Bolivia and the Brazilian states of Mato Grosso
Mato Grosso ( – ) is one of the states of Brazil, the List of Brazilian states by area, third largest by area, located in the Central-West Region, Brazil, Central-West region. The state has 1.66% of the Brazilian population and is responsible ...
and Rondônia
Rondônia () is one of the 26 states of Brazil, located in the northern subdivision of the country (central-western part). It is bordered by Acre (state), Acre in the west,
Amazonas, Brazil, Amazonas in the north, Mato Grosso in the east, and Bo ...
.
The World Wildlife Fund
The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the ...
includes the Chiquitano dry forests in the Amazon biome.
The ecoregion adjoins the Dry Chaco ecoregion to the south and the Pantanal
The Pantanal () is a natural region encompassing the world's largest tropical wetland area, and the world's largest Flooded grasslands and savannas, flooded grasslands. It is located mostly within the Brazilian state of Mato Grosso do Sul, but i ...
ecoregion to the southeast.
To the northeast it blends into the Cerrado
The Cerrado () is a vast ecoregion of Tropics, tropical savanna in central Brazil, being present in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Maranhão, Piauí, Bahia, Minas Gerais, São Paulo (state), São Paulo, Paraná ...
ecoregion.
To the northwest it adjoins the Madeira–Tapajós moist forests
The Madeira–Tapajós moist forests (NT0135) is an ecoregion in the Amazon basin. It is part of the Amazon biome.
The ecoregion extends southwest from the Amazon River between its large Madeira River, Madeira and Tapajós tributaries, and crosses ...
and Southwest Amazon moist forests
The Southwest Amazon moist forests (NT0166) is an ecoregion located in the Upper Amazon basin.
The forest is characterized by a relatively flat landscape with alluvial plains dissected by undulating hills or high terraces. The biota of the sou ...
ecoregions.
Climate
The climate of the Chiquitano dry forests is tropical
The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...
, with a strong dry season during the southern hemisphere winter. Average precipitation ranges between 1,000mm in the south and 2,000mm in the northwest, varying with orography.
Flora
There are several common plant communities, or associations, which vary in structure and characteristic species. The forests of the region are adapted to the strong seasonal variation in rainfall, including wet-season flooding and dry-season fires. Many trees are deciduous, losing their leaves during the winter dry season, Deciduousness is more common in the semi-arid south.[Killeen, Timothy & Chavez, Ezequial & Peña-Claros, M. & Toledo, Marisol & Arroyo, Luzmila & Caballero, Judith & Correa, Lisete & Guillén, René & Quevedo Sopepi, Roberto & Saldias, Mario & Soria, Liliana & Uslar, Ynés & Vargas, Israel & Steininger, Marc. (2006). The Chiquitano Dry Forest, the Transition between Humid and Dry Forest in Eastern Lowland Bolivia. ''Neotropical Savannas and Seasonally Dry Forests: Plant Diversity, Biogeography and Conservation''. 213-233. 10.1201/9781420004496.ch9.]
The soto/ association includes the trees soto ('' Schinopsis brasiliensis''), curupaú ('' Anadenanthera macrocarpa''), momoqui ('' Caesalpinia pluviosa''), morado ('' Machaerium scleroxylon''), roble ('' Amburana cearensis''), and cedro ('' Cedrela fissilis''). This association is found on well-drained soils. Trees form a canopy averaging 20 meters in height with emergent trees up to 30 meters. The canopy is 80% closed, and there is an understory of shrubs and herbs.[ Emergent soto trees are some of the largest in the forest, reaching up to 35 meters in height and living up to 500 years.
In the cuchi/ association, either curupaú ('' Anadenanthera macrocarpa'') or cuchi ('' Astronium urundeuva'') predominates. It grows on well-drained but nutrient-poor soils, including rocky mountain slopes and sandy lowland soils. The canopy varies from 10 to 15 meters in height and is 65% closed, with emergent trees up to 25 meters high.][
The cuta/ajo-ajo association is predominantly cuta ('' Phyllostylon rhamnoides'') and ajo-ajo ('' Gallesia integrifolia''). This association is found on seasonally-flooded soils near streams.
The tajibo/ association is of Tajibo ('' Tabebuia heptaphylla'') and ('' Machaerium hirtum''). It forms patches of forest on low rises (half a meter to a meter) surrounded by open savanna.][
The ecoregion also has areas of grassy savanna similar to the ]Cerrado
The Cerrado () is a vast ecoregion of Tropics, tropical savanna in central Brazil, being present in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Maranhão, Piauí, Bahia, Minas Gerais, São Paulo (state), São Paulo, Paraná ...
savannas further east.
Fauna
The ecoregion has 42 species of mammals, including marsh deer (''Blastocerus dichotomus''), white-lipped peccary (''Tayassu pecari''), giant armadillo
The giant armadillo (''Priodontes maximus''), colloquially ''tatu-canastra'', ''tatou'', ''ocarro'' or ''tatú carreta'', is the largest living species of armadillo (although their extinct relatives, the Glyptodontidae, glyptodonts, were much l ...
(''Priodontes maximus''), jaguar
The jaguar (''Panthera onca'') is a large felidae, cat species and the only extant taxon, living member of the genus ''Panthera'' that is native to the Americas. With a body length of up to and a weight of up to , it is the biggest cat spe ...
(''Panthera onca''), maned wolf
The maned wolf (''Chrysocyon brachyurus'') is a large canine of South America. It is found in Argentina, Brazil, Bolivia, Peru, and Paraguay, and is almost extinct in Uruguay. Its markings resemble those of a red fox, but it is neither a fox nor ...
(''Chrysocyon brachyurus''), giant otter
The giant otter or giant river otter (''Pteronura brasiliensis'') is a South American carnivorous mammal. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, reaching up to . Atypical of mustel ...
(''Pteronura brasiliensis''), and the rodent Goodfellow's tuco-tuco (''Ctenomys goodfellowi'').[
Native birds include the black-and-tawny seedeater (''Sporophila nigrorufa''). Native reptiles include the broad-snouted caiman (''Caiman latirostris'').][
]
Conservation and protected areas
During the period from 2004 to 2011 the ecoregion experienced an annual rate of habitat loss of 0.62%.
In response to indigenous demands for control over their home territories, the Bolivian government issued a decree in 1990 designating indigenous territories in the lowlands, and acknowledging the rights of indigenous peoples to collectively govern those territories. A 1993 agrarian reform law acknowledged indigenous communities' collective land ownership and formalized Native Community Lands
Native Community Lands (, acronym: TCO; also translated as Communal Lands of Origin), according to Bolivian law, are territories held by Indigenous peoples in Bolivia, indigenous people through Collective ownership, collective title. The creation ...
(called ''Tierras Comunitarias de Origen'' , or TCOs) as the vehicle for ownership, and the 1995 constitutional reform further guaranteed the rights of indigenous peoples to Native Community Lands. Portions of the dry forests are within TCOs. A 1996 reform of Bolivia's forestry law required forest management plans and forest inventories, established harvest limits, and guaranteed the rights of indigenous communities to manage timber harvesting on forest lands within TCOs, and to engage in customary forms of forest product harvesting without central government approval.
From August to November 2019, fires burned 1.4 million hectares of the dry forests, an estimated 12% of the Chiquitano forest area before the fires. Earlier in 2019 the Bolivian government issued a decree supporting clearance of forest lands in the Chiquitano and Amazon regions for cattle and soya production. Civil society organizations concluded the fires were mostly deliberately set by people seeking to clear land, and linked the increase in fires to the change in government policy. Those organizations and indigenous leaders petitioned the government to repeal the pro-clearance policies, better protect the forests, and uphold indigenous land rights.[Wordley, Claire F.R. "It’s not just Brazil’s Amazon rainforest that’s ablaze – Bolivian fires are threatening people and wildlife." ''The Conversatation'', 23 August 2019. Accessed 15 July 2020]
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A 2017 assessment found that 55,861 km², or 24%, of the ecoregion is in protected areas.[ Protected areas include Noel Kempff Mercado National Park and Ríos Blanco y Negro Wildlife Reserve in Bolivia.
]
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Ecoregions of Bolivia
Ecoregions of Brazil
Forests of Bolivia
Forests of Brazil
Amazon biome
Neotropical dry broadleaf forests