Cropland expansion changes deforestation dynamics in the southern Brazilian Amazon

TLDR

Intensive mechanized agriculture in the Brazilian Amazon expanded by over 3.6 million ha between 2001 and 2004. The study aims to quantify whether cropland expansion in the Amazon stems from intensifying use of already cleared cattle pasture or from new deforestation, given its implications for future deforestation dynamics and ecosystem services. The authors integrated deforestation maps, field surveys, and satellite‑based vegetation phenology data to track the post‑clearing fate of large clearings (>25 ha) in Mato Grosso, distinguishing cropland, pasture, or regrowth. During 2001‑2004, more than 540,000 ha of forest were directly converted to cropland—peaking at 23 % of 2003 deforestation—while cropland clearings were twice the size of pasture clearings, planted within the first year, and strongly correlated with soybean prices (R² = 0.72), suggesting that rising crop prices could drive deforestation back to 2003‑2004 levels; although pasture remains dominant, the increasing scale and speed of cropland conversion establish a new paradigm of forest loss and contradict the notion that intensification does not cause new deforestation.

Abstract

Intensive mechanized agriculture in the Brazilian Amazon grew by >3.6 million hectares (ha) during 2001-2004. Whether this cropland expansion resulted from intensified use of land previously cleared for cattle ranching or new deforestation has not been quantified and has major implications for future deforestation dynamics, carbon fluxes, forest fragmentation, and other ecosystem services. We combine deforestation maps, field surveys, and satellite-based information on vegetation phenology to characterize the fate of large (>25-ha) clearings as cropland, cattle pasture, or regrowing forest in the years after initial clearing in Mato Grosso, the Brazilian state with the highest deforestation rate and soybean production since 2001. Statewide, direct conversion of forest to cropland totaled >540,000 ha during 2001-2004, peaking at 23% of 2003 annual deforestation. Cropland deforestation averaged twice the size of clearings for pasture (mean sizes, 333 and 143 ha, respectively), and conversion occurred rapidly; >90% of clearings for cropland were planted in the first year after deforestation. Area deforested for cropland and mean annual soybean price in the year of forest clearing were directly correlated (R(2) = 0.72), suggesting that deforestation rates could return to higher levels seen in 2003-2004 with a rebound of crop prices in international markets. Pasture remains the dominant land use after forest clearing in Mato Grosso, but the growing importance of larger and faster conversion of forest to cropland defines a new paradigm of forest loss in Amazonia and refutes the claim that agricultural intensification does not lead to new deforestation.