Attributing deforestation-driven biodiversity decline in the Gran Chaco to agricultural commodity supply chains

• Pasture expansion had a greater biodiversity impact than cropland expansion. • Biodiversity decline from consumption depended on location and quantity of volumes. • Domestic consumption risked driving greater biodiversity decline. • Differing results based on facet of biodiversity considered. Agricultural expansion is one of the principal drivers of biodiversity loss globally. Attributing biodiversity loss to domestically consumed versus internationally traded agricultural production is vital to make supply chains more transparent and sustainable. However, such an attribution is challenging due to the complexity of agricultural supply chains and the lack of tools and data. Here, we attributed biodiversity decline in the Gran Chaco, specifically the Argentinian and Paraguayan Chaco, to both soy and beef agricultural commodities and the domestic and foreign demand for these. We integrated three sources of multitemporal data at a subnational scale (data on mammal diversity, land use change and commodity trade) to first differentiate pasture- versus cropland-driven biodiversity decline and second, to assess the share of the decline associated with domestically consumed and internationally traded Argentinian and Paraguayan soy and Paraguayan beef. In doing so, we provided four novel insights. First, pasture expansion had a greater relative biodiversity impact than cropland expansion. Second, the biodiversity decline associated with domestic and international consumption depended on both the quantity of imports and the precise location of production and sourcing. Third, domestic consumption of commodities in Argentina and Paraguay was associated with a much greater risk of driving decline in biodiversity than agricultural exports from these nations. Fourth, considering only one facet of biodiversity risks underestimating the decline in biodiversity linked to agricultural expansion and commodity supply chains. By connecting agriculturally driven biodiversity decline in the Gran Chaco to commodity supply chains, we highlight the importance of increasing the transparency of supply chains to make them more sustainable. Doing so will be critical to prevent further biodiversity loss in not only the Gran Chaco but also the other dry forests of the world.