The park's terrain is representative of the Negro-Solimões interfluvial plateau.
It has two main areas: the Trombetas/Negro plateau and the lower western Amazon plateau.
The higher area has hills with flat tops at 150 to 200 metres (490 to 660 ft) cut by valleys, while the lower area has altitudes of about 100 metres (330 ft).
There are large areas of seasonally flooded land with poor drainage, and some permanent lakes.[4]
Average annual rainfall is over 2,500 millimetres (98 in), and the wettest months occur in March and September, when maximum short wave solar radiation is being received and so maximum convectional rainfall occurs.
Temperatures range from 22 to 32 °C (72 to 90 °F) with an average of 26 °C (79 °F).[4]
Vegetation types are dense rainforest (77%), open rainforest (14%), transition from rainforest to campinarana (7%) and campinarana (2%).
Botanists have catalogued about 400 plant species, several of which are restricted to certain environments such as the uplands and the flooded areas.
263 species of fish have been recorded, some new to science.[1]
Conservation
The park is classed as IUCN protected area category II (national park).
The objective is to preserve an Amazonian black water ecosystem for environmental education, interaction with local communities, sustainable tourism and the research.
The park is designed as a mega-reserve and world heritage site for present and future generations.[4]
Protected species in the park include the margay (Leopardus wiedii), jaguar (Panthera onca), giant otter (Pteronura brasiliensis) and Amazonian manatee (Trichechus inunguis).[3]
Another reason why the Jaú park is conserved is that of the group of people that call themselves the "okampha" (Oh//camp//ah). The Okampa originated in the park long before it had even been discovered, having been living there for almost two centuries. They are a very secluded people who never show themselves to tourists or even other native groups that live there. Very few people have had the opportunity to actually see an okamphian.