Consequences of agroindustrial sugarcane production to freshwater biodiversity

SchiesariSugarcane is a highly productive bioenergy crop that is extensively grown in Brazil. The agricultural industrialization of the sugarcane, like any other crop, could potentially be harmful to the environment depending on how land-use changes and how the land will be managed. To understand the consequences of sugarcane production to stationary freshwater systems (lentic), Luis Schiesari and Decio T. Corrêa assessed the physical, chemical and biological properties of lentic sites in the sugarcane-rich area of southeast Brazil. Half of all sugarcane grown in Brazil is grown here.

Schiesari and Corrêa surveyed lentic water bodies that are distributed across a wide range of land use intensity-- from sugarcane plantations, to pastures, to the Atlantic forest, and to tropical savannas. According to the authors, these locations include land conversions that are typically associated with the expansion of sugarcane: the conversion of native habitats to pasture, the conversion of native habitats to sugarcane, and the conversion of pasture to sugarcane. Of primary interest was the biodiversity of algae, tadpoles, invertebrates (dragonflies, bugs, and beetles) and fish within lentic systems. The biodiversity of these organisms give insight to the overall health of the ecosystem.

Schiesari and Corrêa found that intensification in land use from native habitats to pastures to sugarcane plantations led to an increase in the pollution of freshwater by terrestrial materials (siltation), decreased regional (across the entire study area) biodiversity, and increased freshwater productivity from nutrient enrichment. However, tadpole and predator frequency and density was not affected nor was biodiversity reduced at local scales. Conversion of pastures to sugarcane fields, suggested as a strategy to increase biofuel production while reducing competition for land with food production and biodiversity conservation, does not appear to have strong consequences to lentic freshwater systems, provided that wetlands and surrounding buffer strips are preserved. There is currently very little research regarding the impact of sugarcane on biodiversity and as the crop continues to expand, this study will provide guidance for both researchers and policy makers.

Schiesari, L. and Corrêa, D. T. (2015), Consequences of agroindustrial sugarcane production to freshwater biodiversity. GCB Bioenergy. doi: 10.1111/gcbb.12279