One of the most hotly debated subjects in environmental science is how to optimize land-use to secure production of food and other goods while protecting biodiversity at the same time. As land conversion has slowed down, land-use intensification is becoming the predominant strategy to boost agricultural production. Previous syntheses have shown that the conversion of uncultivated land to agriculture leads to a 10-40% loss of biodiversity. Yet, there is surprisingly little known about the simultaneous effects land use intensification has on biodiversity and yield. We here try closing this knowledge gap by conducting a meta-analysis that synthesizes field studies that assessed changes in yield and biodiversity on the same patches of land, while providing information on the original land-use and the nature and level of its intensification. The meta-analysis synthesizes actual measurements of biodiversity and yield, rather than on extrapolated or modeled values, and includes 449 cases from 115 published studies across the globe.
A major message of this study is that so-called “win-win” strategies in which increased land use boosts yield but has no or even positive effects on biodiversity, are highly improbable. In contrast, averaged across all studies, intensification causes increases in yield (+20.3) and losses in biodiversity (-8.9%), which are both largest (-22.9%; +84.9%) if moderately used patches are subject to a small intensification increase. When a relatively natural patch is subject to increasing levels of modification, yield generally goes up while biodiversity goes down. Intensely modified patches show that those that are most natural to start with will give the biggest increase in yield and the biggest biodiversity loss. Our results underline that, while we must consider the value of managed land for biodiversity preservation more, seeking for an ultimate bargain poses the risk to lose remaining natural areas to land conversion.