Forest fragments and natural vegetation patches within crop fields contribute to higher oilseed rape yields in Brazil

Abstract

Ecosystem services are fundamental to the maintenance of biodiversity, food security, livestock and biofuel production. Here, we analyze the impact of the distance between forest fragments and oilseed crops (Brassica napus) on the crops' yield (kg/ha) and economic value (US$). For crop yield, the total loss field−1 was calculated as the difference between the most lucrative parcel and the least lucrative parcel. Hypothetical models were developed to estimate the potential changes in crop incomes due to progressive replacement of the lowest income crop area(s) by natural vegetation. Our findings demonstrate a significant decrease in the mean number of seeds per silique and in seed production as the distance from forest fragment progressively increases. The productivity loss throughout this gradient may reach up to 2760 kg/ha (i.e. US$804.08). Our models indicate that parcels further than 325 m from forest fragments were poorly pollinated. Our models also demonstrated that farmers could boost their yields if more natural areas (as small as 5%) were included inside crop fields, even though this reduces their arable area. In conclusion, adding small natural patches within crop fields will most likely lead to a higher seed production and successive increases in the economic value of canola crops.