Restoring Biodiversity to Improve Food Security

By Matt Styslinger

The new report, Toward Sustainable Agricultural Systems in the 21st Century, published by The National Research Council’s (NRC) Committee on Twenty-first Century Systems Agriculture evaluates “alternative” agricultural approaches that could improve the sustainability of small-scale agricultural systems in less developed countries.

Biodiversity in farming systems is increasingly recognized as essential for sustainable agriculture and food security. (Photo credit: Bernard Pollack)

Biodiversity in farming systems is increasingly recognized as essential for sustainable agriculture and food security. The NRC report highlights several innovations that improve biodiversity on farms by integrating them with the larger local ecosystem, and utilizing ecosystem services that improve yields and cut costs.

The inclusion of non-crop vegetation on farmland provides valuable ecosystem services. Filter strips, hedgerows, woodlots, and other areas of native plants help to reduce soil erosion, buffer wetlands from direct pesticide and nutrient runoff, and increase plant and animal diversity. Filter strips host wintering bird populations and butterfly species, hedgerows provide habitats for beetles and spiders, and grassy strips in the margins of fields increase the biodiversity of soil microfauna within fields and across farms. This diversity can help to naturally control some crop pests. Birds, beetles and spiders consume large quantities of pest insects like aphids and lygus bugs. For example, including sweet alyssum in the margins of lettuce fields helps to attract natural predators of aphids, a lettuce crop pest.

Restored or constructed wetlands can be used to remove a variety of water quality contaminants, like erosion sediments and nitrogen and phosphorous from fertilizer and manure runoff. They can also help mitigate pesticide contaminants. In Ireland, a constructed wetland used to treat dirty water from a dairy farm was shown to have 94 percent removal efficiency for suspended solids, 99 percent for ammonia-nitrogen and 92 percent for molybdate reactive phosphorous. A restored wetland in Pennsylvania was shown to remove 65 percent of the nitrate load.

Although, according to the NRC report, there is ample evidence that enhancing and integrating biodiversity in agriculture contributes to the resilience of farming systems, biodiversity in many parts of the world has been degraded due to commodity policies that support monocultural production and a heavy reliance on agrochemicals. By recognizing that farming systems exist within an ecosystem, farmers can manage ecosystems to support crop production, reducing the need for expensive, unnatural inputs and restoring lost biodiversity.

To read more on the National Resource Council’s report, see: Instead of One Size Fits All, Many Innovations for Improving Small-Scale Agriculture.

Matt Styslinger is a research intern with the Nourishing the Planet project.

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