The BR-163 Highway (Fig. 1) was originally built by the Brazilian Army in 1973 and 1974. It has remained passable since, although poor road conditions in the unpaved portion (the 646-km portion in the state of Pará from the border with Mato Grosso to Trairão) impede use of the road as a significant export route. Reconstructing the highway has been a (so-far unimplemented) part of an evolving series of plans for massive expansion of infrastructure: Brasil em Ação (Brazil in Action) for 1996–1999, Avança Brasil (Forward Brazil) for 2000–2003, and the Pluriannual Plan for 2004–2007 (Laurance et al. 2001; Fearnside 2002). Soybean plantations in the northern part of the state of Mato Grosso have been rapidly expanding, partly in anticipation of the BR-163 being reconstructed and paved (Fearnside 2001). The governor of Mato Grosso since 2003 is Brazil's largest soybean entrepreneur and a major force in inducing the federal government to pave the road. With the construction of the BR-163, northern Mato Grosso would be linked to the ports of Miritituba and Santarém (Fig. 1), halving the current distance for transportation, as currently soybeans from northern Mato Grosso are exported through the port of Paranaguá in the state of Paraná. A future plan would take the soybeans by rail from Cuiabá to Santos. Cost savings for soybean export of US$ 11.6 per tonne relative to the rail route through Santos (Alencar et al. 2005) provide an economic argument for the BR-163 project. Soybean production in northern Mato Grosso was 3.61 million tonnes in 2004 (Alencar et al. 2005), worth approximately US$ 813 million. Nevertheless, even with substantial monetary benefits for the BR-163, the various forms of impact from the project must be quantified and compared to the benefits before a decision is made (Fearnside 2005).