Guajará-Mirim State Park straddles two landscapes. Sixty percent of it is savanna — open grassland studded with stunted trees and pierced by rocky outcrops. Another twelve percent is the contact zone where that savanna yields to dense Amazon rainforest, a gradient visible from the air as a darkening of green. The park spans the Guaporé plateau and the southern Amazon depression, with soils ranging from red-yellow podzols to quartz sands and lithic rubble. An estimated 500 species of birds inhabit the park, including species threatened by hunting elsewhere in their range. Between 40 and 50 amphibian species have been documented, comparable to other Amazon sites. The Jaci Paraná River basin collects the park's waters, feeding tributaries that wind through forest and grassland before joining the larger Madeira system.

Sometime before 2004, an illegal 14-kilometer road was bulldozed from the BR-421 federal highway straight through the park, splitting it east to west and severing the Guaporé-Mamoré ecological corridor. The road was built right beside the park headquarters, where state environmental officials from SEDAM were stationed. According to reports, it was funded by loggers with connections to senior state politicians. A federal injunction in August 2004 demanded that agencies prevent further environmental degradation in the park, but the road was already a fact on the ground. The 2002 boundary revision had already excluded 4,906 hectares from the park's northern tip to accommodate the BR-421, which ranchers and loggers had opened illegally years earlier. In compensation, 14,325 hectares were added in the southeast — a swap that looked balanced on paper but rewarded the very destruction it was meant to prevent.

In February 2014, the Igarapé das Araras — a tributary of the Madeira River — flooded and submerged the BR-425 highway, cutting off the cities of Guajará-Mirim and Nova Mamoré from the rest of the state. President Dilma Rousseff visited Rondônia and backed the opening of the road through the park as an emergency measure. By April 2014, the federal court authorized it. The road connecting Buritis and Campo Novo to Nova Mamoré and Guajará-Mirim sliced the northern ten percent of the park away from the rest. Control points were established at both entrances, and vehicle traffic between 6:00 p.m. and 6:00 a.m. was prohibited to protect animals crossing at night. What had been an ecological corridor was now bisected by headlights and diesel exhaust — legally, this time.

The road made things worse, fast. Kanindé environmentalist Ivaneide Bandeira warned that the opening had increased pressure on the park and was being used to transport stolen cars. In May 2015, state deputy Lazinho da Fetagro took the assembly floor to denounce ongoing invasions. The intruders were not landless families seeking subsistence, he said — tracks had already been cut into the forest, and logging was clearly about to begin. The surrounding municipalities of Campo Novo de Rondônia and Buritis press against the park's boundaries with ranching and agriculture. To the southwest, the Rio Ouro Preto Extractive Reserve and to the east the Pacaás Novos National Park provide some continuity of protected land, but the park itself remains a pressure point, squeezed between legal protections that exist on paper and economic forces that operate on the ground.

In August 2014, the Associação de Defesa Etnoambiental Kanindé was tasked with developing a management plan. The approach was collaborative: environmentalists, park management, and local residents would define the process together before Kanindé launched a full survey of the park's fauna, flora, physical characteristics, and socioeconomic factors. By January 2016, SEDAM and Kanindé were reviewing the protection plan that had been in place since the park's creation in 1990 — a plan that, in the intervening quarter century, had proven insufficient against the combined force of logging, ranching, flooding, and political expedience. Two research bases on the Formoso River remain staffed, and the Amazon Region Protected Areas Program continues to provide support. Whether that support can hold the line is the question the park lives with daily.