By Nathan Chan, TerViva Germplasm Development Associate
We often think of the environmental impacts of agriculture being limited to things like pesticides and nutrient runoff polluting waterways (see my colleague’s post for more on this), and methane emissions from livestock contributing to climate change, but one of agriculture’s biggest impacts has been its role as a leading cause in declines in wildlife and natural habitat. That may not resonate with those of us in Europe and the United States, where we’ve had a fairly mature agricultural industry for the past 100+ years (I challenge you to imagine what the West may have looked like before humans), but deforestation to create lands suitable for agriculture in South America and Southeast Asia is directly responsible for the loss of hundreds of thousands of hectares of habitat for thousands of species. This is not a sustainable approach moving forward as we aim to feed 9 billion people worldwide while working to maintain our remaining biodiversity.
A popular framework for finding a sustainable solution gives us two strategies: “land sharing” and “land sparing”. In land sharing, lower intensity agriculture is practiced in favor of less productive methods that promote more suitable conditions for wildlife resulting in less food produced per acre. In land sparing, farmers practice high intensity agriculture to boost yields, enabling them to forego expansion and leave natural areas “wild”. There are tradeoffs with both approaches — organic “land sharing” farms have on average 30% higher species richness and 50% higher abundance than conventional “land sparing” farms, but produce 20-25% less yield per acre.
In an article examining the tradeoffs of food production and wildlife published by The Breakthrough Institute, Linus Blomqvist puts forward the idea that higher yields, especially in the row crops that use the most land globally, will always result in lower on-farm biodiversity because there are “simple biophysical components of yield growth that there is not much of a way around.” The highly specific management practices farmers must use to get maximum yields from a specific crop preclude the establishment of other plants, which form the basis of a habitat that can sustain wildlife. As evidence, Blomqvist cites declines in farmland bird populations in Europe and America being driven by the loss of habitat and nesting sites in high-intensity agriculture settings – not due to direct mortality from pesticides.
Even in the most organic, ecologically friendly, “land sharing” farm one can imagine, any decision to increase yields would result in higher-intensity practices that would in turn decrease the farm’s ability to support wildlife. If higher yields per acre on an organic farm decrease on-farm habitat quality, than the only way to increase yield while maintaining habitat quality is to use more land. In the West, more land probably means acquiring farmland or uncultivated land from a neighbor. However, in South America, Asia, or Africa expanding croplands often takes place at the expense of natural habitats like forests. Any gains in on-farm biodiversity may be offset entirely by the loss of natural habitats.
As we try to feed a human population of 9 billion-plus people, agricultural land will expand and will undoubtedly come at the expense of wildlife and natural habitats. The question we face is how to minimize that impact. Land sharing and land sparing underscore the idea that there is a tradeoff between food production and biodiversity: increasing one will invariably decrease the other. Fortunately, there are ways in which we can try to mitigate that trade off. Embracing GM technologies like Bt enables crops to produce their own insecticide (that is safe for human consumption) and reduce the need for spraying pesticides allowing non-target species to thrive. Incorporating staples of organic or agroecological farming like crop rotations and cover crops make it difficult for a single pest species to persist from year to year further reducing pesticide loads.
There is no correct answer to the land sharing vs. land sparing debate. Both ideas have their merits and embracing one or the other is better than nothing. The growth of the global human population will continue and it will be at the expense of the natural world, but through the discussion and implementation of ideas like land sparing and land sharing, and the incorporation of new crop technologies and agronomic practices we can hopefully reduce that negative impact.
Author’s Note: The idea behind this blogpost came largely from the previously mentioned article published by The Breakthrough Institute, Food Production and Wildlife on Farmland. I encourage you to read it if you are interested in this topic.