How to guarantee global food security whilst reducing the environmental impact of agriculture is one of the most urgent questions humanity faces. We were very pleased, therefore, that this topic was discussed in the very first issue of Nature Ecol & Evo. However, whilst we agree with Professor Bennett that the lens of the debate should be widened1, we disagree that it should be framed exclusively around human well-being and argue that it would be more productive to build on, rather than abandon, existing analytical frameworks.
Focusing solely on human well-being prioritises species that provide ecosystem services – usually common species close to people2. Most species, however, are rare and sensitive to human disturbance. This is why field studies of several thousand species – from birds in Kazakh steppe, Latin American grasslands, and equatorial African forests, to South American dung beetles and trees across three continents3,4 – show that land-sparing approaches that promote the protection or restoration of natural habitats would, if implemented, benefit a range of taxa in a wide variety of landscapes. Despite concerns surrounding the generalisability of these case-studies, the results are remarkably consistent. Focusing only on human well-being risks abandoning these species in the face of ever-increasing threats.
Managing multifunctional landscapes requires difficult decisions about the trade-offs and prioritization of services. In some cases, multiple services will benefit from the same land use. However, in many cases what benefits one metric will negatively impact another. Attempting to maximise any aspect of biodiversity, human well-being or food production without considering consequences for the others will therefore lead to sub-optimal solutions. Instead, we need quantitative frameworks that allow us to weigh-up the pros and cons of different land-use decisions for multiple landscape functions5. The land-sparing/sharing framework explicitly does this, and has already been extended beyond biodiversity and food production to address forestry and urban planning6,7, ecosystem services3,7–9, lifestyle interventions such as dietary change and food waste reductions8, and mixed (rather than binary) land-use scenarios10.
We believe that quantitative frameworks such as the land-sparing/sharing framework have greatly expanded our understanding of how to balance human and environmental needs. In some cases the interests of both will align, but, as many studies have demonstrated, there are also unavoidable trade-offs. If we want wildlife to persist alongside food production, flood protection, climate mitigation, and other services, we should use all tools at our disposal to evaluate these trade-offs, rather than hope that a focus on human well-being will benefit all life on earth.
We'd welcome comments on our thoughts, as well as on Prof. Bennett's original piece and, if you're interested in this kind of thing, there is also a discussion on the Food Climate Research Network.
David R. Williams, Tom Finch, Erasmus K. H. J. zu Ermgassen
1. Bennett, E. M. Changing the agriculture and environment conversation. Nat. Ecol. Evol. 1, 0018 (2017).
2. Kleijn, D. et al. Delivery of crop pollination services is an insufficient argument for wild pollinator conservation. Nat. Commun. 6, 7414 (2015).
3. Gilroy, J. J. et al. Optimizing carbon storage and biodiversity protection in tropical agricultural landscapes. Glob. Change Biol. 20, 2162–2172 (2014).
4. Balmford, A., Green, R. & Phalan, B. Land for Food & Land for Nature? Daedalus 144, 57–75 (2015).
5. Charpentier, A. Insights from life history theory for an explicit treatment of trade-offs in conservation biology. Conserv. Biol. J. Soc. Conserv. Biol. 29, 738–747 (2015).
6. Edwards, D. P., Gilroy, J. J. & Woodcock, P. Land-sharing versus land-sparing logging: reconciling timber extraction with biodiversity conservation. Glob. Change Biol. 20, 183–191 (2014).
7. Stott, I., Soga, M., Inger, R. & Gaston, K. J. Land sparing is crucial for urban ecosystem services. Front. Ecol. Environ. 13, 387–393 (2015).
8. Cohn, A. S. et al. Cattle ranching intensification in Brazil can reduce global greenhouse gas emissions by sparing land from deforestation. Proc. Natl. Acad. Sci. U. S. A. 111, 7236–7241 (2014).
9. Lamb, A. et al. The potential for land sparing to offset greenhouse gas emissions from agriculture. Nat. Clim. Change 6, 488–492 (2016).
10. Butsic, V. & Kuemmerle, T. Using optimization methods to align food production and biodiversity conservation beyond land sharing and land sparing. Ecol. Appl. 25, 589–595 (2015).