Parks under attack: Brazil's Iguaçu National Park illustrates a global threat to biodiversity.

National parks are under attack in many parts of the world, including Brazil, which the Convention on Biodiversity ranks as the world’s most biodiverse country. Brazil has been experiencing an unprecedented environmental crisis, and the political situation in the country favors approval of environmentally damaging measures by both the legislative and executive branches of government. A new and largely unreported setback is a proposal in the National Congress for a road cutting the Iguacu National Park in two. Here, we identify environmental threats from the proposed road and pressures on the park from the surrounding human population. The proposed laws violate Brazil’s constitution and would cause immeasurable damage to the park’s biodiversity and associated ecosystem services. The road would reduce the cost of transport between two municipalities (counties), but not the cost of transporting soybeans, their main agricultural product. However, the local population would be better served by strengthening its ties to the park and promoting economic alternatives such as tourism, agroforestry, and organic agriculture. The Caminho do Colono road illustrates the danger posed by downgrading the status of protected areas in order to allow environmentally damaging activities. This trend is occurring in many countries and is especially evident in Brazil.