The Sucunduri Dome acts as a geological spine running between two of the Amazon's major river systems. The Juruena River forms the park's eastern boundary, separating it from the Juruena National Park across the border in Mato Grosso. From the south, the Bararati River -- a left tributary of the Juruena -- flows north through the park's interior. The Sucunduri River itself rises within the park and flows northward, eventually joining the Acari River to form the Canuma. Rocky outcrops along these waterways produce rapids and falls that make navigation difficult but create habitats of extraordinary biological richness. At the Monte Cristo rapids on the Sucunduri, the concentration of animal and bird life draws researchers from across Brazil. The Augusto Salto on the Juruena, with its dramatic cascades, holds what park managers describe as high tourist potential -- though reaching it requires commitment.

Sucunduri sits in one of the Amazon's most ecologically complex zones: a contact area where dense rainforest transitions into the drier cerrado biome. The result is a botanical inventory that reads like a greatest-hits list of South American flora. Open rainforest covers fifty-two percent of the park, dense rainforest another thirty-two percent, and the remaining sixteen percent consists of savanna-rainforest contact zones and savanna-seasonal forest transitions. Tree species include mahogany, cedar, copaiba, andiroba, Brazil nut, and rosewood -- the last of which is critically threatened by its own economic value. Surveys of the western portion of the Apui Mosaic have documented 850 tree species, 46 mammals, more than 300 birds, 27 reptiles, 30 amphibians, and nearly 100 species of fish. The region harbors more than thirteen endemic primate species, and researchers continue to discover aquatic species previously unknown to science.

In 2006, an illegal mining settlement occupied the Monte Cristo rapids -- the same site prized for its wildlife. By 2014, a far larger threat loomed. The federal government proposed two hydroelectric dams, the Sao Simao Alto and Salto Augusto Baixo, with a combined forecast capacity of 4,940 megawatts. The reservoirs would have flooded more than 40,000 hectares, inundating portions of the Juruena National Park, the Igarapes do Juruena State Park, the Escondido and Apiaka do Pontal indigenous territories in Mato Grosso, and parts of Sucunduri itself. WWF-Brasil led the opposition campaign, and in September 2014, the federal government withdrew its proposal. The victory was hard-won but not without cost: in March 2015, an agreement was reached to compensate for the irreversible environmental damage already caused by the Teles Pires hydroelectric project, with R$500,000 directed to the park.

Sucunduri State Park does not stand alone. Created by decree 24.810 on January 21, 2005, it forms a critical piece of the Apui Mosaic, a patchwork of conservation units totaling 2,467,243 hectares. The mosaic includes the Guariba State Park, the Bararati and Aripuana sustainable development reserves, the Guariba Extractive Reserve, and four state forests. Together, these areas constitute part of the 90,000-square-kilometer Southern Amazon Conservation Corridor, a region where the agricultural frontier -- driven by soy and cattle -- pushes relentlessly into the forest. Administered by Ipaam, the Instituto de Protecao Ambiental do Amazonas, Sucunduri was established to preserve ecosystems of ecological relevance and scenic beauty while supporting scientific research and ecotourism. The Amazon Region Protected Areas Program provides additional backing. But the park's value lies as much in its connections as in its boundaries: without the surrounding mosaic, this island of ancient stone and living forest would be far more vulnerable to the pressures bearing down on it from every direction.