The ões–JapuráSolimões-Japurá moist forests (NT0163) is an ecoregion in northwest Brazil and eastern Peru and Colombia in the Amazon biome. It has a hot climate with high rainfall throughout the year, and holds one of the most diverse collections of fauna and flora in the world. The ecoregion is relatively intact.
Location
The Solimões-Japurá moist forests has an area of divided between Colombia, Brazil and Peru. The northern boundary of the western portion in Colombia is defined by the Caqueta River. The Caqueta separates the ecoregion from the Caquetá moist forests to the north. The Caqueta becomes the Japurá River when it crosses the border with Brazil, and the Japurá (or the Purus várzea along the Japurá) defines the northern boundary in Brazil to the point where the Japurá meets the Solimões River. The Japurá-Solimões-Negro moist forests lies to the north of the Japurá.
The Purus várzea and then the Iquitos várzea along the Solimões define the southern boundary in Brazil and Peru. The Purus várzea forms the south east border, and elements of the Purus várzea are found along rivers throughout the Solimões-Japurá ecoregion. The Iquitos várzea forms the southwest border, separating the Solimões-Japurá ecoregion from the Southwest Amazon moist forests further south.. The Solimões-Japurá moist forests adjoins the Napo moist forests to the west. The Napo River separates the Solimões-Japurá moist forest from the Napo moist forests.
Physical
The ecoregion covers upland alluvial plains formed in the Tertiary period. The terrain includes floodplains, rolling hills, steep banks and plateaus. Elevations are typically from , but in Colombia the sandstone plateaus rise to . The Putumayo River, which defines the border between Peru and Colombia, runs through the region, which is also drained by the Caquetá, Napo and Solimões. There is a variety of soil types, but most are oxisols and ultisols poor in nutrients and high in aluminum and iron.
Ecology
The Solimões-Japurá moist forests ecoregion is in the Neotropical realm and the tropical and subtropical moist broadleaf forests biome. The climate and complex physical environment make the ecoregion one of the most biologically diverse in the world.
Climate
The climate is hot and humid, with high rainfall. The Köppen climate classification is "Af": equatorial, fully humid. Temperatures vary little throughout the year, with mean temperatures from , minimum temperatures from and maximum temperatures from . There is heavy precipitation throughout the year, ranging from an average of in August to in April. Rain falls almost every day of the year. Total annual precipitation is around .
Flora
15 types of vegetation have been defined in just one part of the ecoregion in Colombia. Most of the vegetation is tall, dense evergreen tropical rainforest, rich in plant species. It includes well-drained terra firme upland forest, well-drained floodplain forest, poorly drained floodplain forest and swamp forest. The whitewater rivers carry organic and mineral sediments washed down from the Andes, which they deposit during the annual floods, so the soils in the floodplains are richer in nutrients than in the terra firme areas. The floodplain forests belong to the Purus várzea ecoregion. The Peruvian part of the ecoregion contains areas of nutrient-poor white sand similar to the Brazilian campinarana ecoregion. The vegetation is sclerophyllous low scrub or open-canopy low forest with distinctive flora and fauna and high levels of endemism. The sandstone plateaus in Colombia have shrub and savanna vegetation related to the Guiana region.
The dense forests on the uplands have a canopy of up to with emergent trees up to . The forests often have a dense understory of lianas, palms, epiphytes, mosses and ferns. Flora are typical of the Amazon biome. The most common families of trees are Annonaceae, Lecythidaceae, Myristicaceae, Fabaceae and Sapotaceae. Emergent trees include Ceiba pentandra, Terminalia amazonia, Cedrelinga cateniformis, Carapa guianensis and Hevea guianensis. Commercially valuable timber trees include Virola surinamensis, Cedrela odorata and Carapa guianensis.